Download to read offline
![The term greenhouse gas refers to gases that are transparent to visible light
emitted from the sun, but opaque (absorptive) to the “infrared” radiation emitted by
the earth. This follows from fundamental physical principles described by the
Boltzmann law, after Ludwig Boltzmann, a 19th-century Austrian physicist. All
mass radiates energy, depending on temperature. The hotter a body (could be your
body, the earth, or the sun), the more energy it radiates: and the peak energy occurs
at different wavelengths. The peak radiation of the sun (surface temperature = 6,000
Kelvin2
[K] or 10,000 °F: very hot either way) radiates a lot of the light we call
visible. It is no accident our eyes evolved to be able to ‘see’ in the visible where the
maximum solar emission is. Objects with cooler temperatures such as the tem-
perature of the earth at about 300 Kelvin (80 °F) radiate in the infrared (longer
wavelengths with much lower energy). These objects include our bodies, the earth
itself, the ocean surface or clouds.
Greenhouse gases, like the glass in a greenhouse, allow in visible light from the
sun, but absorb (and re-emit back down) the infrared energy from the earth.3
The
higher the concentration of these gases in the atmosphere, the greater the warming
effect. The most important greenhouse gas is water vapor. Water vapor also has
some other important effects in the climate system. The second most important gas
is carbon dioxide.
The basic picture of the flows of energy in the atmosphere is illustrated in
Fig. 2.2. The arrows represent approximate sizes of the energy flows4
in the energy
budget. Solar energy comes in; the atmosphere, clouds and the earth absorb some
and reflect some. The technical term for the ratio of reflected over total energy is
albedo. White/light surfaces reflect a lot and have a high albedo: snow, ice, bright
sand. Black/dark surfaces absorb a lot and have a low albedo: dark green trees, the
ocean, asphalt. This is why a black car is hotter than a white car or asphalt is hotter
than concrete in the sun. The energy absorbed warms the object (clouds, atmo-
sphere, surface of the earth/ice/ocean) and it ‘re-emits’, but now at longer wave-
lengths and lower energy since the temperature of the surface is much lower than
the sun. For common temperatures at the earth’s surface (0–100 °F, –20 to 40 °C),
this emission occurs in the infrared. Infrared radiation is absorbed in the atmosphere
by greenhouse gases and clouds, and some returns to the earth. The earth warms the
atmosphere above it in two ways. The direct conduction of heat from a warm
2
The Kelvin temperature scale has the same increment as the Celsius scale but starts at absolute
zero, while Celsius starts at the freezing point of water and can be negative. The Fahrenheit scale
has a smaller increment and the freezing point of water is 32 °F. So 1 °K = 1 °C = 9/5 °F. Scientists
use °K, the United States uses °F and most other countries use °C. We will typically provide °F
and °C.
3
Strictly speaking, the analogy is not correct: The glass in a greenhouse also prevents air from
escaping, and simply being transparent in the visible and restricting air motion is sufficient to keep
a greenhouse warm. The actual “greenhouse” effect for glass is a small part of it.
4
For a more detailed treatment of the energy budget, see Trenberth, K. E., Fasullo, J. T., & Kiehl,
J. (2009) “Earth’s Global Energy Budget.” Bulletin of the American Meteorological Society, 90(3):
311–323.
2.1 Components of the Earth System 15](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-34-320.jpg)
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laws of the country where you are located before using this
eBook.
Title: Conscience & Fanaticism: An Essay on Moral Values
Author: George Henry Lane Fox Pitt-Rivers
Release date: October 19, 2018 [eBook #58136]
Language: English
Credits: E-text prepared by Turgut Dincer, Martin Pettit, and the
Online Distributed Proofreading Team
(http://www.pgdp.net) from page images generously
made available by Internet Archive
(https://archive.org)
*** START OF THE PROJECT GUTENBERG EBOOK CONSCIENCE &
FANATICISM: AN ESSAY ON MORAL VALUES ***](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-60-320.jpg)
![PREFACE
In presenting this little volume to the public I am fully conscious of
my presumption in introducing my personal views in a region where
many hundreds of better qualified writers have devoted their best
efforts. Since, however, no apology can justify a profitless task, if
such it be, or add to its utility, if indeed it possesses any, I will not
attempt to make one.
If I have contributed in ever so slight a degree towards an
understanding of the mental state or attitude we call fanaticism, for
the purpose of guarding against the catastrophes it begets, I shall
have achieved my purpose. It is unfortunately inevitable that a
discussion which involves current opinions and beliefs must
necessarily encounter strong prejudices and opposition, but it is less
on this account that this little work is likely to fail than for the reason
to which Hume attributed the failure which attended the publication
of his "Treatise of Human Nature," which he described as his guilt
"of a very usual indiscretion, in going to the press too early." A
circumstance which prevented that "unfortunate literary attempt
from reaching such distinction as even to excite a murmur among
the zealots."[1]
Needless to say, I have relied for my interpretation of human notions
and ideas, and the conduct which results from them, very largely
upon the works of past and contemporary writers; and my
indebtedness to those with whom I differ no less than those with
whom I agree is but very inadequately acknowledged in my
references to the works of some of them.
The earlier portions of the essay are devoted chiefly to an
examination of moral ideas, the latter portions more exclusively to
the facts of nature and of mind from which they derive their](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-63-320.jpg)
![meaning. Throughout I have attempted to keep the argument as
free as possible from the thin air of philosophical and scholastic
dialectic, and as far as possible in terms of common usage and
thought. With this end in view, and for the sake of brevity, the
authors to whose works I have referred most frequently have been
selected either because they are better known or because their
opinions are more widely held than in the case of others. But in any
case no claim to exhaustive or even adequate treatment can be
made for so slight a review of so vast a subject.
The first problem which I have attempted to deal with is one which
confronts all moralists. It consists in the difficulty of deriving ethical
notions from notions which are not ethical, or of deducing the moral
law from the facts of experience and of nature. The attempt to
escape from this difficulty often takes the form of adopting a theory
by which the whole world is divided into two unrelated worlds, a
world of values and a physical world of mechanical sequences. In
order to bring these two independent and self-consistent systems
within the same reality and to weld them together, God is
postulated. God is necessary, it is argued, to prove the objectivity of
morality. That is to say, that since moral values are eternally valid,
independently of man's capacity to be conscious of them, they can
only have existence in the one eternal mind.[2]
The purpose of this essay is to offer a different solution. As this
question of the status of moral values is of great importance to the
moral argument, a preliminary examination of the ground may be
helpful.
The predication of value to an object which elicits moral approbation
is not, as most Theistic writers stubbornly maintain, an implicit
acknowledgment of the objectivity of the goodness predicated, it is
merely the act of appreciating the subject or valuer's attitude in
relation to the object (the relationship may be purely hypothetical),
but it may, and usually does, invite a similar attitude on the part of
any number of subjects.[3] The relation of subject to object—this
also applies to all relations—may belong to objective reality, but not](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-64-320.jpg)
![the moral worth we ascribe to the object as a result of that
relationship. This distinction is important and involves, necessarily, a
discrimination (not always made) between the treatment of
knowledge and of value. Hume, by denying the objective character
of the relations and connexions of nature equally with moral
judgment, in his interpretation of individual experience, treated
moral judgment and knowledge of natural science in an identical
manner. In the following discussion truth, to which I have denied
relativity, is accorded a position altogether distinct from value.
Appreciation of truth and interest in knowing is treated as a value,
but not truth itself to which subjectivity is denied. The method I
have adopted of treating this fundamental point may perhaps be
made clearer by a simple illustration. Let us take any particular
moral judgment, for example, "A [a conscious individual] is good."
The assertion implies that A is the habitual doer of desirable actions,
or is benevolently disposed towards the valuer, Society at large, or
God, according to the valuer's idea of goodness. In any case A's
conduct or his attitude must have evoked approbation by reason of
its effect (emotional or material) upon the valuer or those with
whom he is in sympathy. The valuer might attempt to refute this
definition by maintaining that A's habitual conduct does him the
greatest injury, but that his predication of good in respect of A is the
assertion of an objective fact. In spite of such an objection, I would
reply that the moral judgment may indeed be intended to imply
certain definite objective qualities or properties because the valuer
considers these desirable, and chooses arbitrarily to define "good" as
containing those definite properties, or because in the community to
which he addresses himself they are customarily so defined. The
veracity, however, of the moral judgment, considered as a statement
of fact, can only be tested after an agreement has been reached as
to the content of the symbol "good." It has then been given a
meaning which alone it does not possess. The validity of moral
judgment, when it is not merely the expression of individual attitude,
will therefore always depend upon the criterion of conduct previously
adopted. In this way it is held that a moral judgment differs from a](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-65-320.jpg)
![And now, as we stand on the threshold of a new era—a new world
in search of its soul—what better precept can we have than the
simple words of the great thinker who, three hundred years ago,
also stood on the threshold of a new world of thought?
"Il suffit de bien juger pour bien faire, et de juger le mieux
qu'on puisse, pour faire aussi tout son mieux, c'est-à-dire, pour
acquérir toutes les vertus, et ensemble tous les autres biens,
qu'on puisse acquérir; et lorsqu'on est certain que cela est, on
ne saurait manquer d'être content."—Descartes, "Discours de la
Méthode."
G. P. R.
Hinton St. Mary, Dorset
January 1, 1919
FOOTNOTES:
[1] Hume's "Autobiography."
[2] This is the position of the Idealistic schools and is adopted in
Professor Sorley's recently published Gifford Lectures, "Moral Values
and the Idea of God."
[3] This relationship may be expressed in psychological terms. Dr.
McDougall expresses it thus: "Objects have value for us in proportion
as they excite our conative tendencies; our consciousness of their
value, positive or negative, is our consciousness of the strength of
the conation they awake in us."—"Body and Mind," p. 329.](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-68-320.jpg)
![I
INTRODUCTION
In all ages conscience has been the theme of priest, politician,
philanthropist and obstructionist. So often used and so seldom
analysed, beyond a bare assertion of its function, it is curious to
reflect on the strange medley of uses to which this word is put.
Conscience is at once the standard and the refuge of orthodox and
fanatic, patriot and anarchist—according as they are described by
admirer or detractor—but, let us believe with Lecky,[4] least often of
the genuine hypocrite.
Never was a nation so beset with "conscientious" men and women
as England is to-day; some helping, some hindering, some having
little effect on the national welfare. Some flaunt the badge
obtrusively, they label themselves "conscientious objectors to
military service," "conscientious objectors to vaccination,"
"conscientious teetotallers"; in some cases anti-vivisectionists,[5]
social reformers and (formerly) suffragettes proclaim their exertions
endured for "conscience' sake"; so, for the most part, do
missionaries and religious functionaries, and, in fact, all and any who
engage in propaganda or obstruction, "because," they say,
"something higher than reason prompts our motives—'conscience'."
[6] Others refer to conscience shyly as of something too sacred to
be spoken of publicly, and again others only in moments of intense
earnestness—or alcoholic remorse.
A conscience, in fact, is an invaluable asset; where it does not gain
approbation, it at least gains some measure of respect.
Most people, then, admit the existence and the reality of what we
popularly call "conscience," and although fewer people are agreed as](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-72-320.jpg)
![to its origin and nature, it is, nevertheless, accorded a high place of
importance and almost universal recognition as an arbiter in the
affairs of men.
So undisputed is this claim to inviolability of conscience in twentieth-
century England that the State, in framing her laws, modifies their
application by the interspersion of caveats in the form of "conscience
clauses."
The principle on which the conscience proviso is allowed to negative
the universal applicability of the State's demand for service or
compliance with her rules appears, however, to be somewhat
arbitrary and uncertain, and can hardly be said to be devised solely
in deference to any possible religious sanction, since, although a
man's conscience is allowed to exempt him from vaccinating his
children, the plea of religious sanction, in the case of a man
professing the polygamous doctrine of Brigham Young,[7] would not
exempt him from amenability to the law concerning bigamy; or,
again, the conscience of a Quaker or of a Christadelphian[8] is
recognized as a stronger qualification for exemption from combatant
service than the equally recalcitrant consciences of, e.g. an Atheist
or a Member of the Church of England. Yet the standardization of
"privileged" denominational consciences is strongly disavowed! In
spite, however, of a certain illogical inconsistency in practice, it is
virtually conceded as a right that a man should justify any conduct
by the plea of "conscience," even, in many cases, when it militates
directly against the good of the State.
Even more than the State and public opinion does the Protestant
Church insist upon the authority and inviolability of "conscience."
Driven, step by step, from the time of the Reformation, by the
encroachments of science and the progress of Rationalism, from her
defence of the infallibility of Doctrine and Scripture, the Protestant
Church has sought to render her position impregnable by increased
insistence upon the inviolability and sanctity of revelation and
conscience. Lecky, speaking of the trend of "Protestant Rationalism,"
says: "Its central conception is the elevation of conscience into a](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-73-320.jpg)
![position of supreme authority as the religious organ, a verifying
faculty discriminating between truth and error."[9]
The most recent stalwarts of the Church of England are equally
insistent upon this point, thus the Rev. G. L. Richardson writes: "We
shall appeal to and invigorate the conscience in proportion as we
rely upon the Holy Spirit as the one source of spiritual power.... 'The
fellowship of the Holy Ghost' and His grace through the Church is
the master word of the twentieth century."[10] This passage well
illustrates the supreme importance, with regard to her position,
which the Church attaches to the appeal to conscience at the
present day. In another passage the same author says, "the
authority of conscience is ... paramount for the individual." Dr. J. N.
Figgis in his "Churches in the Modern State" says that any doctrine
which would "destroy the springs of spiritual life in the individual
conscience would be disastrous to civic as well as to religious life."
Having raised the individual conscience to a pinnacle of ethical
omniscience, the ecclesiastic next proceeds to bring it into line with,
or rather into synchronous subordination to, the aggregate "Church
Conscience." "The Church is a Divine society, her members will feel
an obligation to be loyal to her discipline.... The conscience of her
members will respond with approval or shame when they keep, or
neglect to keep, her standards." From this the resulting "code and
sentiment" is the "Church Conscience."[11]
Mr. G. K. Chesterton throws further light on this interrelationship.
"The 'Church Conscience' is rather to be conceived as a fortress to
which the individual may return for shelter and strength when the
attacks of temptation threaten to overwhelm him. At such times it is
well to feel that we are not dependent on the 'inner light' of
conscience alone, but that we can throw ourselves on a social force
mightier than our own, and behold with astonishment and
enthusiasm a Divine company and a Divine Captain."[12]
Whilst Church and State are in agreement regarding its importance
and sanctity, the same unanimity is not exhibited in dealing with the](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-74-320.jpg)
![origin and character of conscience. Equally divided in this respect are
the philosophers and psychologists.
Priests are fond of telling us that conscience is "the voice of God
within us." To some men it appears strange that the voice of the
same God should frequently induce men to oppose each other with
such particular bitterness. This objection is sometimes met by the
explanation that although it is the voice of God speaking through the
medium of our souls, we fail to recognize or interpret rightly its
significance. This explanation, again, is not altogether satisfactory,
since, if that were the case, the voice of God must be so uncertain a
guide it were better not to rely on it.
When we look back through the pages of History and consider the
actions of men and the motives to which they ascribe them, and see
what an orgy of blood, of persecutions, of burnings, of torturings, of
blind passions and religious frenzy, of diabolical imaginings and
monstrous eschatology has been conceived at the instigation of
conscience and religion, and prescribed in the name of God, we are
inclined to inquire more deeply into the meaning and credentials of
this watchword of all ages.
FOOTNOTES:
[4] "Hypocrites, who from interested motives profess opinions which
they do not really believe, are probably rarer than is usually
supposed."—"Rise and Influence of Rationalism in Europe."
[5] A few years ago the Animal Defence and Anti-Vivisection Society
distributed pamphlets from their headquarters in Piccadilly,
beginning "Do not ask of your doctor his opinion on this matter, ask
your conscience," etc.
[6] This distinction is commonly made between conscience and the
intellectual faculty of reason; thus, when a man says, "My
conscience tells me," he usually means, "No reason will deter me."](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-75-320.jpg)
![[7] Mormon leader and preacher, died in 1877, leaving seventeen
wives.
[8] The establishment of bona fide membership of either of the
above-mentioned religious societies (inter alia) by a "conscientious
objector" was recognized by Military Service Tribunals (acting under
official instructions) as sufficient cause for a verdict of exemption.
[9] "Rationalism in Europe," 1913 edition, p. 167.
[10] "Conscience, its Origin and Authority" (1915).
[11] "Conscience, its Origin and Authority," p. 150.
[12] "Orthodoxy," p. 137, quoted by G. L. Richardson.](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-76-320.jpg)
![II
THE VALIDITY OF MORAL JUDGMENTS
Any investigation of the phenomenon of moral conduct, and of its
interpretation, brings us face to face with two sets of conflicting
theories. These may, for convenience, be roughly divided into the
two principal schools of thought which have been termed
respectively the "Moral Sense" or "Intuitive" schools and the
"Rationalistic schools of ethics." Certain writers in their search for
the springs of moral conduct have attempted to place the issue
between Naturalism or Determinism (by no means synonymous or
necessarily connected) on the one side, and Theism on the
other[13]; and, in their eagerness to discredit the former to the
advantage of the latter, imagine they demolish Determinism (at any
rate in the ethical sphere) by "pushing it to its logical conclusion"
and by showing that it "has connected completely and indissolubly,
as far as observation can carry us, mind with matter; it has
established a functional relation to exist between every fact of
thinking, willing or feeling, on the one side, and some molecular
change in the body on the other side, and man, with all his ways
and works, is simply a part of nature, and can, by no device of
thought, be detached from or set above it."[14]
What, after all, is involved in the acceptance of such a conclusion?
What is there to fear? To concede this, it is thought, would mean to
relegate man to the position of a mere "automaton," freed from
"accountability to God, responsibility to man, and the fears of
conscience."
So far from ridding man of responsibility, the clear recognition by
him of the true nature of his environment and antecedents, the laws
by which they influence him, and his inherent capacity of resistance
—in other words, the two processes observable in the world, action](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-77-320.jpg)
![contrary to, and action along, the line of least resistance[15]—does,
on the contrary, greatly increase his responsibility of action and his
power to know himself.
Is not mind and matter subject to the same law? Do they not react
to the same God? What matter, then, if we adopt the formula of
Pampsychism and assert that "all individual things are animated
albeit in divers degrees"? or endorse the conclusion of Professor
James Ward, who "finds no ground for separating organic life from
psychical life"? and continues: "All life is experience. We cannot
therefore assume that experience has no part in the building up of
the organism, and only begins when viable organism is already
there."[16]
The belief that there can be no life without mind does not
necessarily imply that there can be no mind without body. As John
Stuart Mill pointed out, Determinism does not imply Materialism, a
man may be a spiritual being but yet subject to the law of causation.
Neither does it deny the dynamic character of will, but allows that
not only our conduct but our character is in part amenable to our
will. The causality involved in human actions would, however, enable
any one who knew perfectly our character and our circumstances to
predict our actions.
Such considerations, however, although contributory, do not, of
themselves, decide the question with which we are here concerned,
namely, What is the real meaning and what the authority of
"conscience," or of that mental act which takes place in our minds
when we call certain conduct "right" and certain conduct "wrong"?
Apart from the question of the ultimate sanction of moral conduct,
there have always been two explanations of the mental act variously
known as "ethical judgment," "moral faculty," "moral sense" or
conscience. On the one side there have been those who considered
that moral judgment was an emotion, an intuition, or instinctive
recognition of right or wrong, which implied no rational or
intellectual process beyond that which is involved in registering or](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-78-320.jpg)
![perceiving the fact. And on the other side there have been those
who treat moral approbation as essentially an act of judgment—the
result of the reasoning and intellectual function of the mind.
The earliest exponents of a morality that in no way depended upon
the work of Reason were the ancient Epicureans and Cyrenaics;
since for them good was pleasure and evil was pain, the sources and
tests of all ethical truth were necessarily, in consequence, the
feelings and emotions.
In the eighteenth century there arose a school, associated with the
names of the third Lord Shaftesbury and Francis Hutcheson, the
Scotch philosopher, which became known as the "moral sense"
school, widely different from the old hedonistic philosophers, since
they were the first to assert the existence of a distinctively ethical,
as opposed to a merely pleasurable, feeling.
The philosophers of the "moral sense" school attempted to prove
that there existed a distinct moral "faculty" which differed from all
other perceptions or ideas, in that it was a separate medium by
which men could recognize ethical truth, which was rather a matter
of the heart than of the head.
As a result of the attacks of the various rationalist schools this idea
of a "moral faculty" has been for the most part abandoned by those
who approach ethics from the Religious or Theistic standpoint, for
they are far more concerned to establish the "Divine authority" and
sacrosanct character of conscience than influenced by psychological
or metaphysical distinctions. For the most part such writers are
content to assume that "conscience" is the knowledge of one's own
soul with regard to questions of right and wrong, but insist on that
element of Divine Guidance which alone, they think, can give it the
necessary authority and sanctity.
The Rev. G. H. Richardson[17] defines conscience as "the whole
personality acting ethically; or, more precisely, conscience is the](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-79-320.jpg)
![reaction, pleasurable or painful, of the whole personality in response
to a human or Divine standard."
It is neither wholly emotional nor wholly rational, but "is sensitive to
motives of which the pure reason would take no account; it is more
akin to instinct than intelligence." Yet "without reason, conscience
would be blind impulse, though it might feel the consciousness of
obligation."[18]
Clearly, then, conscience can derive little validity from intelligence;
the concession to the Rationalists does not amount to much; it might
almost get on without reason altogether. It is the Divine authority of
conscience which, for the Theistic writer, is the factor of prime
importance.
"As we are bound to trust reason in the intellectual sphere, so we
are bound to trust conscience in the moral sphere. To deny the
authority of the one or the other is to distrust the Power in whom
physical and moral law have their source. The authority of
conscience is thus paramount for the individual; it will be better for
me to do what is objectively wrong, but what I conscientiously
believe to be right, than do what is in fact right, but what my
conscience disapproves."[19]
Here the writer appears to abandon his Rationalistic friends
altogether; the fanatic is given free rein, his ravings are sacred.
Dr. H. Rashdall, who by many is considered representative of
rationalistic ethics, insists on the "objectivity of moral judgment.
Feelings or emotions possess no objectivity; and 'without objectivity,'
in the words of Eduard von Hartmann, 'ethic has no meaning'."[20]
The all-important task for the Theistic writer is to establish the factor
of Divine impulse. "Therefore we say that conscience is a
fundamental form of man's personal consciousness of eternity; that
ineffaceable certainty that the relation of Duty, with Responsibility
and Judgment, is not a relation which stands and falls with our
relations to the world and to men, but in its essence is a relation to](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-80-320.jpg)
![the holy and Almighty God.... Additional force seems to be given to
this way of regarding the Authority of conscience if we consider that
its activity is set in motion by an impulse from the Divine
Personality."[21]
Bishop Butler refers to conscience as the "voice of God," and as
"supreme among human faculties"; and this is endorsed by
Richardson, who finds that Theism is essential to any doctrine of
conscience, because the alternative is "destructive of its authority."
Let us now summarize the Theistic conscience, variously described in
different passages, in the author's own words: "Its activity is set in
motion by an impulse from the Divine Personality, and does not
originate in the individual nor the world," yet it "reacts to public
opinion," is "often unreasonable and inconsistent," is "subject to
evolutionary growth" and is "not infallible," is "capable of infinite
variety of interpretation" and "reacts to a human standard," which,
however, "trails some clouds of glory from its Divine original"; and in
conclusion, "If we regard conscience not as a phosphorescent gleam
playing upon the surface of consciousness, but as a vital impulse,
partly rational, partly instinctive, welling up from the depths of
Personality, we shall not run the risk of denying its authority."[22] It
would be well, however, not to underestimate the risk, although it
undoubtedly caters for a great variety of tastes.
Allied to the Emotional school for the purpose of proving conscience
are those Rationalists, of whom we have taken Dr. Rashdall as an
example, who have for an object the establishment of the
"objective" validity of moral judgment. The real contention becomes
clearer; the chief point at issue is the question of authority.
We see, then, that there are two points to be decided: (1) the
ultimate validity, with which is connected the question of the Divine
Authority, of moral judgments; and (2) the mode of recognition, with
which is connected the cause or propellent which induces moral
action.](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-81-320.jpg)
![Rashdall summarily dismisses the dual character of the problem in a
phrase. "The question at issue between Rationalists and
Emotionalists is not what impels me to do a virtuous act, but how I
know it to be virtuous."[23] The connexion between motive and
judgment is too closely related to be thus calmly ignored. It is
agreed that the motive does not affect the intrinsic character or
"rightness" of an action, but at the same time it most certainly does
affect a man's estimation of his action; and this, in order to arrive at
the value of moral judgments, is most obviously relevant.
For Dr. Rashdall the distinction between how I know my action to be
right or virtuous, and how it is virtuous, does not exist. Both imply
recognition or statement of indisputable fact; for him there can be
no ultimate doubt as to the character of moral "good," which can in
no way be a matter of opinion, for good is sui generis: it is good and
nothing else; happiness may be good, honesty may be good, but
good is good for no other reason than because such an abstraction
is supposed to exist as a transcendental fact. "Therefore good can
be recognized just as any axiomatic truth can be recognized; as, for
instance, the fact that 2 + 2 = 4, or two straight lines cannot
enclose a space." How is it then that people even of the highest
intelligence do not invariably agree about what is good or morally
right?
There are no two opinions about whether 2 + 2 does, or does not,
equal 4, yet there is no such general agreement about what is right.
If asked why a thing is right or good most people would reply either
by giving a reason to show that it is desirable or else by quoting the
authority of some one else's ipse dixit (in which case it is inferred
that the authority quoted had some reason for supposing it
desirable). The reason that 2 + 2 = 4 is, on the other hand, that
there can be no possible alternative. Yet is it true to say that there
can be no possible alternative to what the consensus of opinion in
any one country considers morally right? Some things that are
considered immoral in England are considered moral in Japan, and
vice versa.](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-82-320.jpg)
![Dr. Rashdall, however, conceives of but two alternatives in estimating
moral values, the first of which he dismisses, because on this view
"our moral judgments could possess no objective validity." He says:
"... I examined the question whether our moral judgments are in
ultimate analysis merely statements asserting the existence of a
particular kind of feeling in particular minds, or whether they are
intellectual judgments of universal validity—judgments, of course, of
a very peculiar and distinctive kind, but just as much intellectual and
universal judgments about the nature of Reality as the judgments 2
+ 2 = 4, or 'this is a good inference and that is a bad one'."[24]
It is difficult to know whether this arbitrary elimination of the
subjective element from ethical judgments, and the attempt to
translate moral values into terms of mathematical formulæ, is
intended to denote the infusion of a mystic factor into the "exact
sciences," or an attempt to reduce metaphysics and morality to rule
of thumb! The following thesis, however, which will be elaborated in
the course of this discussion, is based on a synchronous realization
of rational principles and psychological processes.
Thus, what an individual conceives to be morally right and good,
when he is conscious of having acted so according to his own
standard, may be either:
(1) Wholly irrational, illogical, anti-social and undesirable (from every
point of view except his own), even though arrived at solely by an
intellectual and reasoning process; or
(2) An entirely instinctive, blindly impulsive or emotional action,
afterwards endorsed by the intellect (i.e. subsequently rationalized);
or
(3) The result of thoughtful deliberation, carefully and logically
designed to bring about certain preconceived "moral" ends such as
social happiness, justice, fulfilment of duty; all of which are artificial
and conventional standards, and good only because they are](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-83-320.jpg)
![Force, because it is the continuity of Existence, or after the manner
of Leibnitz: "Substance, the ultimate reality, can only be conceived
as force." Any moral law which may be said to be fundamental in
itself and independent of circumstances will be in relation to force.
But such "laws" will also be independent of the moral imperatives
and written codes, for they are independent of volition—of the will to
obey them. Can a man be possessed of love, greatness, nobility,
courage, honour, at a word of command? Therefore if it can be truly
said that "love is the greatest thing in the world," it is because it is
the most powerful force. Hate is disruptive, disintegrating and
annihilating; love is integrating and strengthening.
But there is yet one "good," one fundamental imperative which
needs no proof, and that is Truth—ultimate truth, because it is the
statement of what Is; without which logic, or, indeed, intelligible
language, would be impossible. But truth is not opinion, or assertion,
or hope, or faith, or in the words of Huxley "those idols built up of
books and traditions and fine-spun ecclesiastical cobwebs." Truth
and all its derivatives—honesty, integrity, truthfulness and sincerity—
have an intrinsic value of their own, for their negation implies the
negation of the principles of Existence.
But men require more than this, they require a "moral code" or
standard to give coherence to their relationships; this code, then, is
that which is desired, or imposed, and this want is most efficiently
supplied by the principle of "Utility."
FOOTNOTES:
[13] See "Conscience, its Origin and Authority," p. 25.
[14] W. H. Mallock, quoted by Richardson.
[15] Professor James Ward uses the terms "anabolic" and "catabolic"
processes in this connexion, also in a sense analogous to the
distinction between doing and suffering.](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-85-320.jpg)
![[16] J. Ward, "Heredity and Memory," 1913.
[17] "Conscience, its Origin and Authority," p. 69.
[18] Ibid., pp. 67 and 68.
[19] "Conscience, its Origin and Authority," p. 96.
[20] Hastings Rashdall: "Is Conscience an Emotion?"
[21] "Conscience, its Origin and Authority," p. 99.
[22] "Conscience, its Origin and Authority," pp. 99, 95, 96, 70, 72
and 73.
[23] "Is Conscience an Emotion?" p. 113.
[24] "Is Conscience an Emotion?" p. 52.](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-86-320.jpg)
![Not only is this position not admitted by Utilitarians, but John Stuart
Mill long ago pointed out that such a hypothesis "is to mistake the
very meaning of a standard of morals, and to confound the rule of
action with the motive of it. It is the business of Ethics to tell us
what are our duties, or by what test we may know them; but no
system of ethics requires that the sole motive of all we do shall be a
feeling of duty.... The great majority of good actions are intended,
not for the benefit of the world, but for that of individuals, of which
the good of the world is made up; and the thoughts of the most
virtuous man need not on these occasions travel beyond the
particular persons concerned, except so far as is necessary to assure
himself that in benefiting them he is not violating the rights—that is,
the legitimate and authorized expectations—of any one else."[25]
This is sufficient refutation of such objections to Utilitarianism as the
one brought forward by Richardson, and clearly founded on a
misconception.
Mill, in what is still the best defence of this system, continues:
"Utilitarians ... are ... of opinion that in the long run the best proof of
a good character is good actions; and resolutely refuse to consider
any mental disposition as good, of which the predominant tendency
is to produce bad conduct."[26]
"The creed which accepts as the foundation of morals, Utility, or the
Greatest Happiness Principle, holds that actions are right in
proportion as they tend to promote happiness, wrong as they tend
to produce the reverse of happiness."[27]
The Theistic writer says "the essence of morality is sacrifice."[28]
The utilitarian morality does recognize in human beings the power of
sacrificing their own greatest good for the good of others. It only
refuses to admit that sacrifice is itself a good. A sacrifice that does
not increase, or tend to increase, the sum total of happiness, it
considers as wasted.](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-88-320.jpg)
![As regards "conscience": the Utilitarian, when he attempts an
analysis, realizes that "in that complex phenomenon as it actually
exists, the simple fact is in general all encrusted over with collateral
associations derived from sympathy, from love, and still more from
fear; from all forms of religious feeling; from recollections of
childhood and of all our past life; from self-esteem, desire of the
esteem of others, and occasionally even self-abasement."[29]
For the priest "ethics cannot be built securely upon anything less
than religious sanctions, and it is for the sake of conscience that
ethics have a practical value."[30]
Can an honest and unbiased thinker doubt that the first is the truer
statement?
Let us now return to a further statement of the position of
Utilitarianism as dealt with by J. S. Mill. From Professor Sidgwick and
those Utilitarians who attempt to claim for the atheistic moralist a
conscience of mathematical accuracy we are unlikely to derive much
assistance.
"According to the Greatest Happiness Principle, the ultimate end,
with reference to, and for the sake of which, all other things are
desirable (whether we are considering our own good or that of other
people), is an existence exempt as far as possible from pain and as
rich as possible in enjoyments, both in point of quantity and quality;
the test of quality, and the rule for measuring it against quantity,
being the preference felt by those who, in their opportunities of
experience, to which must be added their habits of self-
consciousness and self-observation, are best furnished with the
means of comparison."[31]
This, according to Utilitarians, is also the standard of morality.
In conformance with this principle of moral obligation, we choose
the greater before the lesser good. Between General Morality and
the obligation of Duty, with which he associates justice, Mill draws
what appears to be a somewhat unnecessarily hard line of](https://image.slidesharecdn.com/29520928-250525003241-98226a38/85/Demystifying-Climate-Models-Andrew-Gettelman-Richard-B-Rood-89-320.jpg)
Demystifying Climate Models Andrew Gettelman Richard B Rood
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- 5. Earth Systems Dataand Models Andrew Gettelman Richard B. Rood Demystifying Climate Models A Users Guide to Earth System Models
- 6. Earth Systems Dataand Models Volume 2 Series editors Bernd Blasius, Carl von Ossietzky University Oldenburg, Oldenburg, Germany William Lahoz, NILU—Norwegian Institute for Air Research, Kjeller, Norway Dimitri P. Solomatine, UNESCO—IHE Institute for Water Education, Delft, The Netherlands
- 7. Aims and Scope Thebook series Earth Systems Data and Models publishes state-of-the-art research and technologies aimed at understanding processes and interactions in the earth system. A special emphasis is given to theory, methods, and tools used in earth, planetary and environmental sciences for: modeling, observation and analysis; data generation, assimilation and visualization; forecasting and simulation; and optimization. Topics in the series include but are not limited to: numerical, data- driven and agent-based modeling of the earth system; uncertainty analysis of models; geodynamic simulations, climate change, weather forecasting, hydroinformatics, and complex ecological models; model evaluation for decision-making processes and other earth science applications; and remote sensing and GIS technology. The series publishes monographs, edited volumes and selected conference proceedings addressing an interdisciplinary audience, which not only includes geologists, hydrologists, meteorologists, chemists, biologists and ecologists but also physicists, engineers and applied mathematicians, as well as policy makers who use model outputs as the basis of decision-making processes. More information about this series at http://www.springer.com/series/10525
- 8. Andrew Gettelman •Richard B. Rood Demystifying Climate Models A Users Guide to Earth System Models
- 9. Andrew Gettelman National Centerfor Atmospheric Research Boulder USA Richard B. Rood Climate and Space Sciences and Engineering University of Michigan Ann Arbor USA ISSN 2364-5830 ISSN 2364-5849 (electronic) Earth Systems Data and Models ISBN 978-3-662-48957-4 ISBN 978-3-662-48959-8 (eBook) DOI 10.1007/978-3-662-48959-8 Library of Congress Control Number: 2015958748 © The Editor(s) (if applicable) and The Author(s) 2016. This book is published open access. Open Access This book is distributed under the terms of the Creative Commons Attribution- Noncommercial 2.5 License (http://creativecommons.org/licenses/by-nc/2.5/) which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The images or other third party material in this chapter are included in the work’s Creative Commons license, unless indicated otherwise in the credit line; if such material is not included in the work’s Creative Commons license and the respective action is not permitted by statutory regulation, users will need to obtain permission from the license holder to duplicate, adapt or reproduce the material. This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publi- cation does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, express or implied, with respect to the material contained herein or for any errors or omissions that may have been made. Printed on acid-free paper This Springer imprint is published by SpringerNature The registered company is Springer-Verlag GmbH Berlin Heidelberg
- 10. Acknowledgments Amy Marks providedvery careful and thorough edit, as well as numerous helpful suggestions. Cheryl Craig, Teresa Foster, Andrew Dolan, and Galia Guentchev contributed their time to reading through drafts and providing a needed reality check. Prof. Reto Knutti helped this book take shape while Andrew Gettelman was on sabbatical at ETH in Zurich. David Lawrence shared critical insights and PowerPoint figures on terrestrial systems. Thanks also to Markus Jochum for straightening us out on explaining how the ocean works. Jan Sedlacek, ETH-Zürich, helped with figures in Chap. 11 (especially Fig. 11.6). Mike Moran and David Edwards of the National Center for Atmospheric Research provided financial support. Lawrence Buja and the National Center for Atmospheric Research hosted Richard Rood’s visitor status. The National Center for Atmospheric Research is funded by the U.S. National Science Foundation. We thank the staff and students of the University of Michigan’s Climate Center for reviews of the manuscript: Samantha Basile, William Baule, Matt Bishop, Laura Briley, Daniel Brown, Kimberly Channell, Omar Gates, and Elizabeth Gibbons. Richard Rood thanks the students in his classes on climate change problem-solving at the University of Michigan and acknowledges in particular the project work of: James Arnott, Christopher Curtis, Kevin Kacan, Kazuki Ito, Benjamin Lowden, Sabrina Shuman, Kelsey Stadnikia, Anthony Torres, Zifan Yang. Richard Rood acknowledges the support of the University of Michigan and the Graham Sustainability Institute, and grants from the National Oceanographic and Atmospheric Administration (Great Lakes Sciences and Assessments Center (GLISA)—NOAA Climate Program Office NA10OAR4310213) and the Department of the Interior, National Park Service (Cooperative Agreement P14AC00898). Francesca Gettelman exhibited nearly unlimited patience with some late nights. v
- 11. Contents Part I BasicPrinciples and the Problem of Climate Forecasts 1 Key Concepts in Climate Modeling . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1 What Is Climate? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2 What Is a Model? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 1.3 Uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 1.3.1 Model Uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . 10 1.3.2 Scenario Uncertainty. . . . . . . . . . . . . . . . . . . . . . . . . 10 1.3.3 Initial Condition Uncertainty . . . . . . . . . . . . . . . . . . . 11 1.3.4 Total Uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1.4 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 2 Components of the Climate System . . . . . . . . . . . . . . . . . . . . . . . . 13 2.1 Components of the Earth System . . . . . . . . . . . . . . . . . . . . . . 13 2.1.1 The Atmosphere. . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.1.2 The Ocean and Sea Ice . . . . . . . . . . . . . . . . . . . . . . . 17 2.1.3 Terrestrial Systems . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2.2 Timescales and Interactions . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2.3 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 3 Climate Change and Global Warming . . . . . . . . . . . . . . . . . . . . . 23 3.1 Coupling of the Pieces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 3.2 Forcing the Climate System. . . . . . . . . . . . . . . . . . . . . . . . . . 26 3.3 Climate History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3.4 Understanding Where the Energy Goes. . . . . . . . . . . . . . . . . . 30 3.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 4 Essence of a Climate Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 4.1 Scientific Principles in Climate Models . . . . . . . . . . . . . . . . . . 38 4.2 Basic Formulation and Constraints . . . . . . . . . . . . . . . . . . . . . 41 4.2.1 Finite Pieces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 4.2.2 Processes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 vii
- 12. 4.2.3 Marching Forwardin Time . . . . . . . . . . . . . . . . . . . . 49 4.2.4 Examples of Finite Element Models . . . . . . . . . . . . . . 50 4.3 Coupled Models. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 4.4 A Brief History of Climate Models. . . . . . . . . . . . . . . . . . . . . 52 4.5 Computational Aspects of Climate Modeling . . . . . . . . . . . . . . 53 4.5.1 The Computer Program. . . . . . . . . . . . . . . . . . . . . . . 53 4.5.2 Running a Model . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 4.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Part II Model Mechanics 5 Simulating the Atmosphere. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 5.1 Role of the Atmosphere in Climate . . . . . . . . . . . . . . . . . . . . 62 5.2 Types of Atmospheric Models . . . . . . . . . . . . . . . . . . . . . . . . 66 5.3 General Circulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 5.4 Parts of an Atmosphere Model. . . . . . . . . . . . . . . . . . . . . . . . 71 5.4.1 Clouds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 5.4.2 Radiative Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 5.4.3 Chemistry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 5.5 Weather Models Versus Climate Models. . . . . . . . . . . . . . . . . 78 5.6 Challenges for Atmospheric Models . . . . . . . . . . . . . . . . . . . . 79 5.6.1 Uncertain and Unknown Processes . . . . . . . . . . . . . . . 79 5.6.2 Scales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 5.6.3 Feedbacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 5.6.4 Cloud Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 5.7 Applications: Impacts of Tropical Cyclones . . . . . . . . . . . . . . . 83 5.8 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85 6 Simulating the Ocean and Sea Ice. . . . . . . . . . . . . . . . . . . . . . . . . 87 6.1 Understanding the Ocean . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 6.1.1 Structure of the Ocean . . . . . . . . . . . . . . . . . . . . . . . 88 6.1.2 Forcing of the Ocean . . . . . . . . . . . . . . . . . . . . . . . . 89 6.2 “Limited” Ocean Models. . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 6.3 Ocean General Circulation Models . . . . . . . . . . . . . . . . . . . . . 92 6.3.1 Topography and Grids . . . . . . . . . . . . . . . . . . . . . . . 92 6.3.2 Deep Ocean. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 6.3.3 Eddies in the Ocean . . . . . . . . . . . . . . . . . . . . . . . . . 96 6.3.4 Surface Ocean . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 6.3.5 Structure of an Ocean Model . . . . . . . . . . . . . . . . . . . 100 6.3.6 Ocean Versus Atmosphere Models . . . . . . . . . . . . . . . 101 6.4 Sea-Ice Modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 6.5 The Ocean Carbon Cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 6.6 Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 6.6.1 Challenges in Ocean Modeling. . . . . . . . . . . . . . . . . . 105 6.6.2 Challenges in Sea Ice Modeling . . . . . . . . . . . . . . . . . 105 viii Contents
- 13. 6.7 Applications: Sea-LevelRise, Norfolk, Virginia . . . . . . . . . . . . 106 6.8 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 7 Simulating Terrestrial Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 7.1 Role of the Land Surface in Climate. . . . . . . . . . . . . . . . . . . . 109 7.1.1 Precipitation and the Water Cycle. . . . . . . . . . . . . . . . 110 7.1.2 Vegetation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 7.1.3 Ice and Snow. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 7.1.4 Human Impacts . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112 7.2 Building a Land Surface Simulation . . . . . . . . . . . . . . . . . . . . 113 7.2.1 Evolution of a Terrestrial System Model . . . . . . . . . . . 113 7.2.2 Biogeophysics: Surface Fluxes and Heat . . . . . . . . . . . 115 7.2.3 Biogeophysics: Hydrology. . . . . . . . . . . . . . . . . . . . . 116 7.2.4 Ecosystem Dynamics (Vegetation and Land Cover/Use Change) . . . . . . . . . . . . . . . . . . 118 7.2.5 Summary: Structure of a Land Model . . . . . . . . . . . . . 120 7.3 Biogeochemistry: Carbon and Other Nutrient Cycles . . . . . . . . 121 7.4 Land-Atmosphere Interactions . . . . . . . . . . . . . . . . . . . . . . . . 125 7.5 Land Ice . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126 7.6 Humans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129 7.7 Integrated Assessment Models . . . . . . . . . . . . . . . . . . . . . . . . 131 7.8 Challenges in Terrestrial System Modeling . . . . . . . . . . . . . . . 132 7.8.1 Ice Sheet Modeling. . . . . . . . . . . . . . . . . . . . . . . . . . 132 7.8.2 Surface Albedo Feedback . . . . . . . . . . . . . . . . . . . . . 133 7.8.3 Carbon Feedback . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 7.9 Applications: Wolf and Moose Ecosystem, Isle Royale National Park. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134 7.10 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136 8 Bringing the System Together: Coupling and Complexity . . . . . . . 139 8.1 Types of Coupled Models . . . . . . . . . . . . . . . . . . . . . . . . . . . 139 8.1.1 Regional Models . . . . . . . . . . . . . . . . . . . . . . . . . . . 140 8.1.2 Statistical Models and Downscaling . . . . . . . . . . . . . . 141 8.1.3 Integrated Assessment Models . . . . . . . . . . . . . . . . . . 143 8.2 Coupling Models Together: Common Threads . . . . . . . . . . . . . 144 8.3 Key Interactions in Climate Models . . . . . . . . . . . . . . . . . . . . 147 8.3.1 Intermixing of the Feedback Loops. . . . . . . . . . . . . . . 147 8.3.2 Water Feedbacks . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 8.3.3 Albedo Feedbacks . . . . . . . . . . . . . . . . . . . . . . . . . . 149 8.3.4 Ocean Feedbacks . . . . . . . . . . . . . . . . . . . . . . . . . . . 150 8.3.5 Sea-Level Change . . . . . . . . . . . . . . . . . . . . . . . . . . 150 8.4 Coupled Modes of Climate Variability . . . . . . . . . . . . . . . . . . 151 8.4.1 Tropical Cyclones . . . . . . . . . . . . . . . . . . . . . . . . . . 151 8.4.2 Monsoons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 Contents ix
- 14. 8.4.3 El Niño.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152 8.4.4 Precipitation and the Land Surface . . . . . . . . . . . . . . . 153 8.4.5 Carbon Cycle and Climate. . . . . . . . . . . . . . . . . . . . . 153 8.5 Challenges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154 8.6 Applications: Integrated Assessment of Water Resources. . . . . . 155 8.7 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157 Part III Using Models 9 Model Evaluation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161 9.1 Evaluation Versus Validation. . . . . . . . . . . . . . . . . . . . . . . . . 161 9.1.1 Evaluation and Missing Information . . . . . . . . . . . . . . 162 9.1.2 Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164 9.1.3 Model Improvement . . . . . . . . . . . . . . . . . . . . . . . . . 168 9.2 Climate Model Evaluation. . . . . . . . . . . . . . . . . . . . . . . . . . . 169 9.2.1 Types of Comparisons . . . . . . . . . . . . . . . . . . . . . . . 169 9.2.2 Model Simulations . . . . . . . . . . . . . . . . . . . . . . . . . . 170 9.2.3 Using Model Evaluation to Guide Further Observations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172 9.3 Predicting the Future: Forecasts Versus Projections. . . . . . . . . . 173 9.3.1 Forecasts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 9.3.2 Projections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173 9.4 Applications of Climate Model Evaluation: Ozone Assessment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 9.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 10 Predictability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177 10.1 Knowledge and Key Uncertainties . . . . . . . . . . . . . . . . . . . . . 178 10.1.1 Physics of the System. . . . . . . . . . . . . . . . . . . . . . . . 178 10.1.2 Variability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180 10.1.3 Sensitivity to Changes. . . . . . . . . . . . . . . . . . . . . . . . 180 10.2 Types of Uncertainty and Timescales . . . . . . . . . . . . . . . . . . . 181 10.2.1 Predicting the Near Term: Initial Condition Uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182 10.2.2 Predicting the Next 30–50 Years: Scenario Uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183 10.2.3 Predicting the Long Term: Model Uncertainty Versus Scenario Uncertainty . . . . . . . . . . . . . . . . . . . 189 10.3 Ensembles: Multiple Models and Simulations . . . . . . . . . . . . . 191 10.4 Applications: Developing and Using Scenarios. . . . . . . . . . . . . 195 10.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 196 x Contents
- 15. 11 Results ofCurrent Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199 11.1 Organization of Climate Model Results. . . . . . . . . . . . . . . . . . 199 11.2 Prediction and Uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . 200 11.2.1 Goals of Prediction. . . . . . . . . . . . . . . . . . . . . . . . . . 201 11.2.2 Uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202 11.2.3 Why Models? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203 11.3 What Is the Confidence in Predictions?. . . . . . . . . . . . . . . . . . 204 11.3.1 Confident Predictions . . . . . . . . . . . . . . . . . . . . . . . . 205 11.3.2 Uncertain Predictions: Where to Be Cautious. . . . . . . . 210 11.3.3 Bad Predictions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212 11.3.4 How Do We Predict Extreme Events?. . . . . . . . . . . . . 214 11.4 Climate Impacts and Extremes . . . . . . . . . . . . . . . . . . . . . . . . 215 11.4.1 Tropical Cyclones . . . . . . . . . . . . . . . . . . . . . . . . . . 216 11.4.2 Stream Flow and Extreme Events. . . . . . . . . . . . . . . . 216 11.4.3 Electricity Demand and Extreme Events . . . . . . . . . . . 217 11.5 Application: Climate Model Impacts in Colorado . . . . . . . . . . . 217 11.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219 12 Usability of Climate Model Projections by Practitioners. . . . . . . . . 221 12.1 Knowledge Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 222 12.2 Interpretation and Translation. . . . . . . . . . . . . . . . . . . . . . . . . 224 12.2.1 Barriers to the Use of Climate Model Projections . . . . . 225 12.2.2 Downscaled Datasets . . . . . . . . . . . . . . . . . . . . . . . . 226 12.2.3 Climate Assessments . . . . . . . . . . . . . . . . . . . . . . . . 227 12.2.4 Expert Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228 12.3 Uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 228 12.3.1 Ensembles. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 231 12.3.2 Uncertainty in Assessment Reports . . . . . . . . . . . . . . . 231 12.4 Framing Uncertainty. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 232 12.5 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235 13 Summary and Final Thoughts . . . . . . . . . . . . . . . . . . . . . . . . . . . 237 13.1 What Is Climate? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237 13.2 Key Features of a Climate Model. . . . . . . . . . . . . . . . . . . . . . 238 13.3 Components of the Climate System . . . . . . . . . . . . . . . . . . . . 239 13.3.1 The Atmosphere. . . . . . . . . . . . . . . . . . . . . . . . . . . . 240 13.3.2 The Ocean. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 241 13.3.3 Terrestrial Systems . . . . . . . . . . . . . . . . . . . . . . . . . . 242 13.3.4 Coupled Components . . . . . . . . . . . . . . . . . . . . . . . . 243 13.4 Evaluation and Uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . 244 13.4.1 Evaluation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 244 13.4.2 Uncertainty . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 245 13.5 What We Know (and Do not Know) . . . . . . . . . . . . . . . . . . . 246 Contents xi
- 16. 13.6 The Futureof Climate Modeling . . . . . . . . . . . . . . . . . . . . . . 248 13.6.1 Increasing Resolution . . . . . . . . . . . . . . . . . . . . . . . . 248 13.6.2 New and Improved Processes. . . . . . . . . . . . . . . . . . . 249 13.6.3 Challenges. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 250 13.7 Final Thoughts. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 251 Climate Modeling Text Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 255 Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 271 xii Contents
- 17. About the Authors AndrewGettelman is a Scientist in the Climate and Global Dynamics and Atmospheric Chemistry and Modeling Laboratories at the National Center for Atmospheric Research (NCAR). He is actively involved in developing atmosphere and chemistry components for global climate models at NCAR. Dr. Gettelman specializes in understanding and simulating cloud processes and their impact on climate, especially ice clouds. He has numerous publications on cloud physics representations in global models, as well as research on climate forcing and feed- backs. He has participated in several international assessments of climate models, particularly for assessing atmospheric chemistry. Gettelman holds a doctorate in Atmospheric Science from the University of Washington, Seattle. He is a recent recipient of the American Geophysical Union Ascent Award, and is a Thompson-Reuters Highly Cited Researcher. Richard B. Rood is a Professor in the Department of Climate and Space Sciences and Engineering (CLaSP) at the University of Michigan. He is also appointed in the School of Natural Resources and Environment. Prior to joining the University of Michigan, he worked in modeling and high performance computing at the National Aeronautics and Space Administration (NASA). His recent research is focused on the usability of climate knowledge and data in management planning and practice. He has started classes in climate-change problem solving, climate change uncer- tainty in decision making, climate-change informatics (with Paul Edwards). In addition to publications on numerical models, his recent publications include software engineering, informatics, political science, social science, forestry and public health. Rood’s professional degree is in Meteorology from Florida State University. He recently served on the National Academy of Sciences Committee on A National Strategy for Advancing Climate Modeling. He writes expert blogs on climate change science and problem solving for the Weather Underground Richard Rood is a Fellow of American Meteorological Society and a winner of the World Meteorological Organization’s Norbert Gerbier Award. xiii
- 18. Introduction Human-caused climate changeis perhaps the defining environmental issue of the early twenty-first century. We observe the earth’s climate in the present, but observations of future climate are not available yet. So in order to predict the future, we rely on simulation models to predict future climate. This book is designed to be a guide to climate simulation and prediction for the non-specialist and an entry point for understanding uncertainties in climate models. The goal is not to be simply a popular guide to climate modeling and prediction, but to help those using climate models to understand the results. This book provides background on the earth’s climate system and how it might change, a detailed qualitative analysis of how climate models are constructed, and a discussion of model results and the uncertainty inherent in those results. Throughout the text, terms in bold will be referenced in the glossary. References are provided as foot- notes in each chapter. Who uses climate models? Climate model users are practitioners in many fields who desire to incorporate information about climate and climate change into planning and management decisions. Users may be scientists and engineers in fields such as ecosystems or water resources. These scientists are familiar with models and the roles of models in natural science. In other cases, the practitioners are engineers, urban planners, epidemiologists, or architects. Though not necessarily familiar with models of natural science, experts in these fields use quantitative information for decision-making. These experts are potential users of climate models. We hope in the end that by understanding climate models and their uncertainties, the reader will understand how climate models are constructed to represent the earth’s climate system. The book is intended to help the reader become a more competent interpreter or translator of climate model output. Climate is best thought of as the distribution of weather states, or the probability of finding a particular weather state (usually described by temperature and pre- cipitation) at any place and time. Climate science seeks to be able to describe this distribution. In contrast, the goal of predicting the weather is to figure out exactly which weather state will occur for a specific place and time (e.g., what the high temperature and total precipitation will be on Tuesday for a given city). Even in xv
- 19. modern societies, weare still more dependent on the weather than we like to admit. Think of a winter storm snarling traffic and closing schools. Windstorms and hailstorms can cause significant damage. Or think of the impact of severe tropical cyclones (also called hurricanes or typhoons, depending on their location), per- sonified and immortalized with names like Sandy, Andrew, or Katrina. Persistence (or absence) of weather events is also important. Too little rain (leading to drought and its resulting effects on agriculture and even contributing to wildfires) and too much rain (leading to flooding) are both damaging. Although we are tempted to speak of a single “climate,” there are many climates. Every place has its own. We build our societies to be comfortable during the expected weather events (the climate) in each place. Naturally, different climates mean different expected weather events, and our societies adapt. Buildings in Minneapolis are built to standards different from buildings in Miami or San Francisco. City planning is also different in different climates. Minneapolis has connected buildings so that people do not need to walk outside in winter, for example. Singapore has connected buildings so that people do not need to walk outside in heat and humidity. Not just the built environment, but the fabric of society may be different with local climates. In warmer climates, social life takes place outdoors, for example, or the flow of a day includes a rest period (siesta in Spanish) during the hottest period of the day. We construct our lives for possible and sometimes rare weather events: putting on snow tires for winter even though snow may not be around for over half a winter. We build into our lives the ability to deal with variations in the weather. A closet contains coats, gloves, hats, rain jackets, umbrellas, sun hats, and sun- glasses: We are ready for a range and for a distribution of possible weather states. Some events are rare: Snow occasionally has fallen in Los Angeles, for example. But it is usually the rare or extreme weather events that are damaging. These outliers of the distribution are typically damaging because they are unexpected and therefore we do not adequately prepare for them. Or rather, the expectation (probability) is so rare that it is not cost-effective for society to prepare for them. This applies to the individual as well: if you live in Miami your closet contains more warm weather gear, and less cold weather gear. It is unlikely you would be able to dress for temperatures well below freezing. The impacts of extreme weather are dependent on the climate of a place as well. For example, a few inches (cen- timeters) of snow is typical for Denver, Minneapolis, or Oslo, but it will shut down Rome or Atlanta. One inch (25 millimeters) of annual rainfall is typical for Cairo, but a disaster in most other places. Where the most damaging weather events occur are at the extremes of the cli- mate distribution. One problem is that we often do not know the distribution very well. Every time we hit a record (e.g., a high temperature, rainfall in 24 hours, days without rain), we expand the range of observed events a little, and we learn more about what might happen in a particular place. Because extreme events are rare, we do not really know the true chance of their occurrence. Think about your knowledge of the climate where you live or in a place you have visited several times. At first, you might not have a good grasp of what the seasons are like. After a few years, xvi Introduction
- 20. you think youknow how the seasons evolve. But there are always events that will surprise you. The record events are those that surprise everyone. What is the probability of a hurricane flooding Houston as New Orleans was flooded by Katrina? It has not happened since the city of Houston has been there, so we may not know. The extremes of the distribution of possible weather states are not well known. This creates even more of a problem when these extremes change. Changing the distribution of weather is what we mean by climate change. The cause of those changes might be natural or they might be human caused (anthropogenic). So how do we predict the future of weather and the distribution of weather that represents climate in a location? To understand and predict the future, we need a way to represent the system. In other words, we need a model. This book is about how we attempt to use models to represent the complex climate system and predict the future. Our goal is to explain and provide a better understanding of the models we use to describe the past, present, and future of the earth system. These are commonly known as climate models. Scientists often refer to these models formally as earth system models, but we use the term climate model. The purpose of this book is to demystify the models we use to simulate present and future climate. We explain how the models are constructed, why they are uncertain, and what level of confidence we should place in those models. Uncertainty is not a weakness. Understanding uncertainty is a strength, and a key part of using any model, including climate models. One key message is that the level of confidence depends on the questions we ask. What are we certain about in the future and why? What are we less certain of and why? For policy-makers, this is a critical issue. Understanding how climate models work and how we get there is an important step in making intelligent decisions using (or not using) these climate models. Climate models are being used not just to understand the earth system but also to provide input for policy decisions to address human-caused climate change. The direction of our environment and economy is dependent on policy options chosen based on results of these models. The chapters in Part I serve as a basic primer on climate and climate change. We hope to give readers an appreciation for the complexity and even beauty of the complex earth system so that they can better understand how we simulate it. In Part II, we discuss the mechanics of models of the earth system: How they are built and what they are trying to represent. Models are built to simulate each region of the climate system (e.g., atmosphere, ocean, and land), critical processes within each region, as well as critical interactions between regions and processes. Finally, in Part III, we focus on uncertainties and probabilities in prediction, with a focus on understanding what is known, what is unknown, and the degree of certainty. We also discuss how climate models are evaluated. In the concluding chapter, we discuss what we know, what we may learn in the future, and why we should (or should not) use models. Introduction xvii
- 21. Part I Basic Principlesand the Problem of Climate Forecasts
- 22. Chapter 1 Key Conceptsin Climate Modeling In order to describe climate modeling and the climate system, it is necessary to have a common conception of exactly what we are trying to simulate, and what a model actually is. What is climate? What is a model? How do we measure the uncertainty in a model? This chapter introduces some key terms and concepts. We start with some basic definitions of climate and weather. Everyone will come to this book with a preconceived definition of what climate and weather are, but separating these concepts is important for understanding how modeling of climate and weather are similar and why they are different. It also makes sense to discuss what a model is. Even if we do not realize it, we use models all the time. So we describe a few different conceptual types of models and put climate models in context. Finally we introduce the concept of uncertainty. As we discuss later in the book, models may have errors and still be useful, but this requires understanding the errors (the uncertainties) and understanding where they come from. Most of these concepts are common to many types of modeling, and we provide examples throughout the text. 1.1 What Is Climate? Climate is perhaps easiest to explain as the distribution of possible weather states. On any given day and in any given place, the history of weather events can be compiled into a distribution with probabilities of what the weather might be (see Fig. 1.1). This figure is called a probability distribution function, representing a probability distribution.1 The horizontal axis represents a value (e.g., tempera- ture), and the vertical axis represents the probability (or frequency of occurrence) of that event’s (i.e., a given temperature) occurring or having occurred. If based on observations, then the frequency can be the number of times a given temperature occurs. The higher the line, the more probable the event. The most frequent 1 There is quite a bit of statistics in climate, by definition. For a technical background, a good reference is Devore, J. L. (2011). Probability and Statistics for Engineering and the Sciences, 8th ed. Duxbury, MA: Duxbury Press. Any specific aspect of statistics (e.g., standard deviation, probability distribution function) can be looked up on Wikipedia (www.wikipedia.com). © The Author(s) 2016 A. Gettelman and R.B. Rood, Demystifying Climate Models, Earth Systems Data and Models 2, DOI 10.1007/978-3-662-48959-8_1 3
- 23. occurrence is thehighest probability (the mode). The total area under the line is the probability. If the total area is given a value of 1, then the area under each part of the curve is the fractional chance that an event exceeding some threshold will occur. In Fig. 1.1, the area to the right of point T1 is the probability that the temperature will be greater than T1, which might be about 20 % of the curve. The mean, or expected value, is the weighted average of the points. It need not be the point with the highest frequency. The mean value is the point at which half the probability (50 %) is on one side of the mean, and half on the other. The median is the value at which half the points are on one side and half on the other. Here is an important and obvious question: How can we predict the climate (for next season, next year, or 50 years from now) if we cannot predict the weather (in 5 or 10 days)? The answer is, we use probability: The climate is the distribution of probable weather. The weather is a particular location in that distribution, and it is conditional on the current state of the system. The chance of a hurricane hitting Miami next week depends mostly on whether one has formed or is forming, and if one has formed, whether it is heading in the direction of Miami. As another example, the chance of having a rainy day in Seattle in January is high. But, given a particular day in January, with a weather state that might be pushing storms well to the north or south, the probability of rain the next day might be very low. In 50 Januaries, though, the probability of rain would be high. So climate is the distri- bution of weather (sometimes unknown). Weather is a given state in that distri- bution (often uncertain). In a probability distribution of climate, the probabilities and the curve change over time: In the middle latitudes, the chance of snow is higher in winter than in summer. The curves will look different from place to place: Some climates have narrow distributions (see Fig. 1.2a), which means the weather is often very close to the average. Think about Hawaii, where the average of the daily highs and lows do not change much over the course of the year or Alaska, where the daily highs and lows may be the same as in Hawaii in summer, but not in winter. For Alaska the annual distribution of temperature is a very broad distribution (more like Fig. 1.2b). Frequency of Occurrence Value (e.g., temperature) Hot Cold Mean T1 Fig. 1.1 A probability distribution function with the value on the horizontal axis, and the frequency of occurrence on the vertical axis 4 1 Key Concepts in Climate Modeling
- 24. Of course, evenin Hawaii, extreme events occur. For a distribution like precipi- tation, which is bounded at one end by zero (no precipitation) the distribution might be “skewed” (Fig. 1.2c) with a low frequency of high events marking the ‘extreme’. As events are more extreme (think about hurricanes like Katrina or Sandy), there are fewer such events in the historical record. There may even be possible extreme events that have not occurred. So our description of climate is incomplete or uncertain. This is particularly true for rare (low-probability) events. These events are also the events that cause the most damage. One aspect of shifting distributions is that extremes can change a lot more than the mean value (see Fig. 1.3). The mean is the value at which the area is equal on each side of the distribution. The mean is the same as the median if the distribution is symmetric. Simply moving the distribution to the right or left causes the area (meaning, the probability) beyond some fixed threshold to increase (or decrease). If the curve represents temperature, then shifting it to warmer temperatures (Fig. 1.3a) decreases the chance of cold events and really increases the chance of warm events. But note that some cold events still occur. Also, you can change the distribution without changing the mean by making the distribution wider (or broader). The mathematical term for the width of a distribution is variance, a statistical term for variability. This situation is illustrated in Fig. 1.3b. The mean is unchanged in Narrow (a) (b) (c) Wide Uneven (Skewed) Fig. 1.2 Different probability distribution functions: a narrow, b wide and c skewed distributions 1.1 What Is Climate? 5
- 25. Fig. 1.3b, butthe chance of exceeding a given threshold for warm or cold tem- peratures changes. In other words, the climate (particularly a climate extreme) changes dramatically, even if the mean stays the same. The change need not be symmetric: Hot may change more than cold (or vice versa). Figure 1.3c is not a symmetric distribution. The key is to see climate as the distribution, not as a fixed number (often the mean). This brings us to the fundamental difference between weather and climate forecasting. In weather forecasting,2 we need to know the current state of the system and have a model for projecting it forward. Often the model can be simple. One “model” we all use is called persistence: What is the weather now? It may be like that tomorrow. In many places (e.g., Hawaii), such a model is not bad, but sometimes it is horribly wrong (e.g., when a hurricane hits Hawaii). So we try to use more sophisticated models, now typically numerical ones. These models go by the name numerical weather prediction (NWP) models, and they are used to “forecast” the evolution of the earth system from its current state. Increase in mean Lots more ‘hot’ (some off scale: records) (a) (b) (c) Less cold Increase in variance More hot and cold: both off scale Same mean Increase in mean and variance Lots more hot, off scale Less cold Fig. 1.3 Shifting probability distribution functions are illustrated in different ways going from the blue to red distribution. The thick lines are the distribution, the thin dashed lines are the mean of the distributions and the dotted lines are fixed points to illustrate probability. Shown is a increase in mean, b increase in variance (width), c increase in mean and variance 2 For an overview of the history of weather forecasting, see Edwards, P. N. (2013). A Vast Machine: Computer Models, Climate Data, and the Politics of Global Warming. Cambridge, MA: MIT Press. 6 1 Key Concepts in Climate Modeling
- 26. Climate forecasting usesessentially the same type of model. But the goal of climate forecasting is to characterize the distribution. This may mean running the model for a long time to describe the distribution of all possible weather states correctly. If you start up a weather model from two different states (two different days), you hope to get a different answer each time. But for climate, you want to get the same distribution (the same climate), regardless of when the model started. We return to these examples again later. 1.2 What Is a Model? A model, in essence, is a representation of a system. A model can be physical (building blocks) or abstract (an image on paper like a plan, or in your head). Abstract models can also be mathematical (monetary or physical totals in a spreadsheet). Ordinary physics that describes how cars go (or, more importantly, how they stop suddenly) is a model for how the physical world behaves. Numbers themselves are abstract models. A financial statement is a model of the money and resource flows of a household, corporation or country. Models are all around us, and we use them to abstract, make tractable and understand our human and natural environment. As a concrete example, think about different “models” of a building. There can be many types of models of a building. A physical model of the building would usually be at a smaller scale that you can hold in your hand. There are several different abstract models of a building, and they are used for different purposes. Architects and engineers produce building plans: two-dimensional representations of the building, used to construct and document the building. Some of these are highly detailed drawings of specific parts of the building, such as the exterior, or the electrical and plumbing systems. The engineer may have built not just a physical model of the building, but perhaps even a more detailed structural model designed to understand how the building will react to wind or ground motion (earthquakes). Increasingly, these models are “virtual”: The structure is simulated on a computer. We are familiar with all these sorts of model, but there are other more abstract models that deal with flows and budgets of materials or money. The owner and builder also probably have a spreadsheet model of the costs of construction of the building. This financial model is not certain, because it is really an estimate (or forecast, see below) of all the different costs of construction. And, finally, the owner likely has another model of the financial operation of the building: the money borrowed to finance the building, any income from a commercial building, and the costs of maintenance and operations of the building. The operating plan is really a projection into the future: It depends on a lot of uncertainties, like the cost of electricity or the value of the income from a building. The projection depends on these inputs, which the spreadsheet does not try to predict. The prediction is con- ditional on the inputs. 1.1 What Is Climate? 7
- 27. Models All AroundUs Models are everywhere in our world. Many models are familiar and physical, such as a small-scale model of a building or a bridge, or a mockup of a satellite or an airplane. Some models we use every day are made up of numbers. Many people use a model with numbers to manage income and expenses, savings and debts; that is, a budget. When the model of a bridge is placed in a computer-assisted design program, or a financial budget is put into a spreadsheet on a personal computer, then one has a “numerical” model. These models have a set of mathematical equations that behave with a specific set of rules, principles or laws. Climate models are numerical models that calculate budgets of mass, momentum (velocity) and energy based on the physical laws of conservation. For example, energy is conserved (neither created or destroyed) and can, therefore, be counted. The physical laws on which climate models are based are discussed in more detail in Chap. 4. Weather and climate are dynamical systems; that is, they evolve over time. We rely on models of dynamical systems for many aspects of modern life. Here we illustrate a few examples of models that affect our everyday lives. Climate models are closely related to weather forecast models; both simulate how fluids (air or water) move and interact, and how they exchange heat. An obvious example of a model that affects daily life is the weather forecast model, which is used in planning by individuals, governments, corporations and finance. The exact same physical principles of fluid flow are used to simulate a process in a chemical plant that takes different substances as liquids or gasses, reacts them together under controlled temperature and pressure, and produces new substances. Water and sewage treatment plants share similar principles and models. Internal combustion engines used for cars, trucks, ships and power plants are developed using models to understand how fuel enters the engine and produces heat, and that heat produces motion. Airplanes are also developed using modeling of the airflow around an aircraft. In this case, computational modeling has largely replaced design using wind tunnels. All of these models involve fluid flow and share physical princi- ples with climate models. The details of the problem, for example, flow in pipes as contrasted to flow in the free atmosphere, define the specific requirements for the model construction. So do you trust a model? Intuitively, we trust models all the time. You are using the results of a model every time you start your car, flush your toilet, turn on a light switch or get in an airplane. You count on models when you drive over a bridge. When NASA sends a satellite or rover to another planet, the path and behavior of the space vehicle relies on a model of simple physics describing complex systems. Models do not just describe physical objects. Models of infectious diseases played an important role in management of the 2014 outbreak of Ebola. One function of models is to provide plausible representations of events to come, 8 1 Key Concepts in Climate Modeling
- 28. and then toplace people into those plausible futures. It is a way to anticipate and manage complexity. Though most times these models do not give an exact story of the future, the planning and decision making that comes from these modeling exercises improves our ability to anticipate the unexpected and to manage risk. Think of modeling as a virtual, computational world in which to exercise the practice of trial and error, and therefore, a method for reducing the “error” in trial and error. Reducing these errors saves lives and property. Models reduce the chance of errors: Airplanes do not regularly fall out of the sky, bridges do not normally collapse and chemical plants do not typically leak. Ultimately, trust of models is anchored in evaluation of models compared to observations and experiences. Weather models are evaluated every day with billions of observations as well as billions of individuals’ experiences. Trust is often highly personal. By many objective measures, weather models have remarkable accuracy, for example, letting a city know more than five days in advance that a major tropical cyclone is likely to make landfall near that city. Of course, if the tropical cyclone makes landfall just 60 miles (100 km) away from the city, many people might conclude the models cannot be trusted. Objectively, however, a model that simulated the tropical cyclone and represented its evolution with an error of 60 miles (100 km) on a globe that spans many thousands of miles can, also, be construed as being quite accu- rate. This represents the fact that models provide plausible futures that inform decision making. Like weather models, climate models are evaluated with billions of observations and investigations of past events. The results of models have been scrutinized by thousands of scientists and practitioners. With virtual certainty, we know the Earth will warm, sea level will rise, ice will melt and weather will change. They provide plausible futures, not prescribed futures. There are uncertainties, and there will always be uncertainties. However, our growing experiences and vigilant efforts to evaluate and improve will help us to understand, manage and, sometimes, reduce uncertainty. As the models improve, trust and usability increase. There remains some uncertainty in most physical models, but that can be accounted for, and we discuss uncertainty, and its value in modeling, at length. Our world is completely dependent on physical models, and their success is seen around us in the fact that much of the world “works” nearly all of the time. Models are certain enough to use in dangerous contexts that are both mundane and ubiquitous. We answer the question of whether we should trust models and make changes in our lives based on their results every time we get in an elevator or an airplane. There is no issue of should we trust models; we have been doing it for centuries since the first bridge was constructed, the first train left a station or the first time a building was built more than one story high. 1.2 What Is a Model? 9
- 29. 1.3 Uncertainty Forecasting involvesprojecting what we know, using a model, onto what we do not know. The result is a prediction or forecast. Forecasts may be wrong, of course, and the chance of them being wrong is known as uncertainty. Uncertainty can come from several different sources, but this is particularly the case when we think about climate and weather. One way to better characterize uncertainty is to divide it into categories based on model, scenario and initial conditions.3 1.3.1 Model Uncertainty Obviously, a model can be wrong or have structural errors (model uncertainty). For example, if one were modeling how many tires a delivery company would need for their trucks in a year and assumed that the tires last 10,000 miles, when they actually only last 7,000 miles, the forecast of tire use is probably wrong. If you assumed each truck would drive 20,000 miles per year and tires last 10,000 miles, the trucks would need two sets of tires. However, what if the trucks drove only 14,000 miles per year and each set of tires lasted only 7,000 miles, (still needing just two sets of tires)? Then the forecast might be right, but the tire forecast would be right for the wrong reason: in this case, a cancellation of errors. 1.3.2 Scenario Uncertainty The preceding example also illustrates another potential uncertainty faced in climate modeling: scenario uncertainty. The scenario4 is the uncertainty in the future model inputs. In the tire forecast, the scenario assumed 20,000 miles per truck each year. But the scenario was wrong. If the tire forecast model was correct (or “per- fect”) and tires lasted 10,000 miles, but the mileage was incorrect (14,000 vs. 20,000 assumed), then the forecast will still be incorrect, even if the model is perfect. If the actual mileage continued to deviate from the assumption (14,000 miles), then the forecast over time will continue to be incorrect. If one is concerned with the total purchase of tires and total cost, then the situation becomes even more uncertain. Other factors (e.g., growth of the company, change in type of tires) may make forecasting the scenario, or inputs to the model, even more uncertain, even if the model as it stands is perfect. As the timescale of the model looks farther into the 3 This definition of uncertainty has been developed by Hawkins, E., & Sutton, R. (2009). “The Potential to Narrow Uncertainty in Regional Climate Prediction.” Bulletin of the American Meteorological Society, 90(8): 1095–1107. 4 For a discussion of climate scenarios, see Chap. 10. 10 1 Key Concepts in Climate Modeling
- 30. future, more andmore different “variables” become uncertain (e.g., new types of tire, new trucks, the cost of tires). These variables that cannot be predicted, but have to be assumed, are often called parameters. Scenario uncertainty logically domi- nates uncertainty farther into the future (see Chap. 10 for more detail). 1.3.3 Initial Condition Uncertainty Finally, there is uncertainty in the initial state of the system used in the model, or initial condition uncertainty. In our tire forecast, to be specific about how many tires we will need in the current or next year, we also need to know what the current state of tires is on all the trucks. Changes in the current state of tires will have big effects on the near-term forecast: If all trucks have 6,000 or 8,000 miles on their tires, there will be more purchases of tires in a given year than if they are all brand new. Initial condition uncertainty is a similar problem in weather forecasting. As we will discuss, some aspects of the climate system, particularly related to the oceans, for example, have very long timescales and “memory,” so that knowing the state of the oceans affects climate over several decades. However, over long timescales (longer than the timescale of a process), these uncertainties fade. If you want to know how many tires will be needed over 5 or 10 years, the uncertainty about the current state of tires (which affects only the first set of replacements) on the total number of tires needed is small. 1.3.4 Total Uncertainty In climate prediction, we must address all three types of uncertainties—model uncertainty, scenario uncertainty and initial condition uncertainty—to estimate the total uncertainty in a forecast. They operate on different time periods: Initial con- dition uncertainty matters most for the short term (i.e., weather scales, or even seasonal to annual, in some cases), and scenario uncertainty matters most in the longer term (decades to centuries). Model uncertainty operates at all timescales and can be “masked” or hidden by other uncertainties. The complicated nature of these uncertainties makes prediction both harder and easier. It certainly makes it easier to understand and characterize the uncertainty in a forecast. One of our goals is to set down ideas and a framework for understanding how climate predictions can be used. Judging the quality of a prediction is based on understanding what the uncertainty is and where it comes from. Some comes from the model and some comes from how the experiment is set up (the initial conditions and the scenario). 1.3 Uncertainty 11
- 31. 1.4 Summary Climate canbest be thought of as a distribution of all possible weather states. What matters to us is the shape of the distribution. Weather is where we are on the distribution at any point in time. The extreme values in the distribution, that usually have low probability, are hard to predict, but that is where most of the impacts lie. Weather and climate models are similar, except weather models are designed to predict the exact location on a distribution, while climate models describe the distribution itself. We use models all the time to predict the future. Some models are physical objects, some are numerical models. Climate models are one type of a numerical model: As we shall see, they can often be thought of as giant spreadsheets that keep track of the physical properties of the earth system, the same way a budget keeps track of money. Uncertainty in climate models has several components. They are related to the model itself, to the initial conditions for the model (the starting point) and to the inputs that affect the model over time in a “scenario.” All three must be addressed for a model to be useful. Uncertainty is not to be feared. Uncertainty is not a failure of models. Uncertainty can be understood and used to assess confidence in predictions. Key Points • Climate is the distribution of possible weather states at any place and time. • Extremes of climate are where the impacts are. • We use models all the time to predict the future, some models are even numerical. • Weather and climate models are similar but have different goals. • Uncertainty has several different parts (model, scenario, initial conditions). Open Access This chapter is distributed under the terms of the Creative Commons Attribution- Noncommercial 2.5 License (http://creativecommons.org/licenses/by-nc/2.5/) which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The images or other third party material in this chapter are included in the work’s Creative Commons license, unless indicated otherwise in the credit line; if such material is not included in the work’s Creative Commons license and the respective action is not permitted by statutory regulation, users will need to obtain permission from the license holder to duplicate, adapt or reproduce the material. 12 1 Key Concepts in Climate Modeling
- 32. Chapter 2 Components ofthe Climate System We experience climate generally at the surface of the earth. This is the intersection of a number of different and distinct parts of the climate system. Understanding the different components of the climate system is critical for being able to simulate the system. As we will discuss, the climate system is typically simulated as a set of building blocks, from each individual process (i.e., the condensation of water to form clouds) collected into a model of one part or component of the system (i.e., the atmosphere), and then coupled to other components of the system (i.e., ocean, land, ice). Understanding and then representing in a model the different interactions between processes and then between components is critical for being able to build a representation of the system: a climate model. In this chapter we describe the basic parts of the earth system that comprise the climate system, some of the key scientific principles and critical processes neces- sary to simulate each of these components. This forms the background to a dis- cussion of how climate might change (see Chap. 3) and a more detailed discussion of each component and how it is simulated (Sect. 2.2, Chaps. 5–8). We discuss the key components of the earth system, as well as some of the critical interactions (discussed in more detail in Chap. 8). 2.1 Components of the Earth System Figure 2.1 represents a schematic of many of the important components of the earth system that govern and regulate climate. Broadly, there are three different regions of the planet: the atmosphere, the oceans and the land (or terrestrial) surface. In addition to these general regions, we also speak of a cryosphere, the snow and ice covered regions of the planet. This fourth “sphere” spans the ocean (as sea ice) and the terrestrial surface (as glaciers, snow and ice sheets). We address the cryosphere in discussions of the ocean and terrestrial surface. While modeling the surface of the earth is commonly thought of as just modeling the land surface, it also includes the cryosphere (ice and snow) that sits on land. The term terrestrial is used to encompass all these spheres, though the common term land is also used. © The Author(s) 2016 A. Gettelman and R.B. Rood, Demystifying Climate Models, Earth Systems Data and Models 2, DOI 10.1007/978-3-662-48959-8_2 13
- 33. These are thetraditional physical components of the earth’s climate system. We also introduce two more “spheres.” An important fifth component of the system is the biosphere: the living organisms on the planet, again, which span the terrestrial surface (plants, organisms in the soil, and animals) as well as the ocean (fish and plants in the ocean). We discuss the biosphere as part of both the ocean and terrestrial surface. Finally, although humans are technically part of the biosphere, our large “footprint” and impact on the global environment and the climate system is large enough that we can define a separate sphere for human activity and impacts called the anthroposphere (see Chap. 3). 2.1.1 The Atmosphere The atmosphere is usually the first part of the climate system we naturally think of. It is literally the air we breathe: mostly inert nitrogen (78 %) with oxygen (16 %) and then other trace gases (argon, water vapor, carbon dioxide). The oxygen is a by-product of the respiration (“breathing”) of plants and other organisms: It is evidence of life on earth. The oxygen in the atmosphere did not exist before the emergence of living organisms.1 Oxygen is emitted by plants as an outcome of photosynthesis that removes carbon from carbon dioxide. Oxygen reacts with materials (rock and ore) at the earth’s surface (oxidation) and disappears from the atmosphere. One of the most common reactants is iron (iron oxide = rust), which is responsible for the red color of many rocks. Unless organisms continue to produce oxygen, it will disappear from the atmosphere. It would take a long time however: hundreds of thousands to millions of years. But it is the trace species—water vapor, carbon dioxide and methane—known as the greenhouse gases, that are most important in understanding the climate system and how climate might change. Ocean Ice (cryosphere) Sun Biosphere Atmosphere Anthroposphere Terrestrial (land) Fig. 2.1 The Earth system. The climate system contains different spheres (components): atmosphere, ocean, terrestrial, cryosphere, biosphere and anthroposphere 1 Kasting, J. F., & Siefert, J. L. (2002). “Life and the Evolution of Earth’s Atmosphere.” Science, 296(5570): 1066–1068. 14 2 Components of the Climate System
- 34. The term greenhousegas refers to gases that are transparent to visible light emitted from the sun, but opaque (absorptive) to the “infrared” radiation emitted by the earth. This follows from fundamental physical principles described by the Boltzmann law, after Ludwig Boltzmann, a 19th-century Austrian physicist. All mass radiates energy, depending on temperature. The hotter a body (could be your body, the earth, or the sun), the more energy it radiates: and the peak energy occurs at different wavelengths. The peak radiation of the sun (surface temperature = 6,000 Kelvin2 [K] or 10,000 °F: very hot either way) radiates a lot of the light we call visible. It is no accident our eyes evolved to be able to ‘see’ in the visible where the maximum solar emission is. Objects with cooler temperatures such as the tem- perature of the earth at about 300 Kelvin (80 °F) radiate in the infrared (longer wavelengths with much lower energy). These objects include our bodies, the earth itself, the ocean surface or clouds. Greenhouse gases, like the glass in a greenhouse, allow in visible light from the sun, but absorb (and re-emit back down) the infrared energy from the earth.3 The higher the concentration of these gases in the atmosphere, the greater the warming effect. The most important greenhouse gas is water vapor. Water vapor also has some other important effects in the climate system. The second most important gas is carbon dioxide. The basic picture of the flows of energy in the atmosphere is illustrated in Fig. 2.2. The arrows represent approximate sizes of the energy flows4 in the energy budget. Solar energy comes in; the atmosphere, clouds and the earth absorb some and reflect some. The technical term for the ratio of reflected over total energy is albedo. White/light surfaces reflect a lot and have a high albedo: snow, ice, bright sand. Black/dark surfaces absorb a lot and have a low albedo: dark green trees, the ocean, asphalt. This is why a black car is hotter than a white car or asphalt is hotter than concrete in the sun. The energy absorbed warms the object (clouds, atmo- sphere, surface of the earth/ice/ocean) and it ‘re-emits’, but now at longer wave- lengths and lower energy since the temperature of the surface is much lower than the sun. For common temperatures at the earth’s surface (0–100 °F, –20 to 40 °C), this emission occurs in the infrared. Infrared radiation is absorbed in the atmosphere by greenhouse gases and clouds, and some returns to the earth. The earth warms the atmosphere above it in two ways. The direct conduction of heat from a warm 2 The Kelvin temperature scale has the same increment as the Celsius scale but starts at absolute zero, while Celsius starts at the freezing point of water and can be negative. The Fahrenheit scale has a smaller increment and the freezing point of water is 32 °F. So 1 °K = 1 °C = 9/5 °F. Scientists use °K, the United States uses °F and most other countries use °C. We will typically provide °F and °C. 3 Strictly speaking, the analogy is not correct: The glass in a greenhouse also prevents air from escaping, and simply being transparent in the visible and restricting air motion is sufficient to keep a greenhouse warm. The actual “greenhouse” effect for glass is a small part of it. 4 For a more detailed treatment of the energy budget, see Trenberth, K. E., Fasullo, J. T., & Kiehl, J. (2009) “Earth’s Global Energy Budget.” Bulletin of the American Meteorological Society, 90(3): 311–323. 2.1 Components of the Earth System 15
- 35. surface occurs bysensible heat. The energy hitting the surface, particularly the ocean surface, also can evaporate water vapor. Since this water vapor contains the energy used to evaporate it, it also is a way of transmitting ‘heat’ (energy), without changing the temperature. The energy in water vapor is called “latent heat”. This is the cycle of radiative energy in the earth system, flowing through the atmosphere. The ultimate source of the energy is the sun. One of the biggest complications is water, in all its forms: from the oceans, to water vapor in the atmosphere, to clouds. Put a cloud over a dark surface (ocean or forest), and you change the energy in the system. The energy changes by reflecting solar energy from the top of the cloud back to space (cooling). Then energy also changes by absorbing infrared energy radiated from below in the cloud and sending some of it back down to the surface (warming). The movement of water through the atmosphere, the surface and the ocean is called the hydrologic cycle (Fig. 2.3), which is also important for moving energy in the atmosphere. Solar energy hitting the ocean causes evaporation of vapor into the atmosphere, and plants also move water from liquid phase in the soil through their leaves, back into the atmosphere in a process called transpiration. This water carries the energy necessary for evaporation in the form of latent heat. The energy is used to make water molecules in liquid move fast enough to separate from each other into a gas. They conserve this heat of evaporation as the water vapor moves through the atmosphere. This heat of evaporation is released when water vapor undergoes condensation into cloud drops (or ice crystals). This can happen a long way from the Incoming Solar Reflected Solar Surface Absorption Surface Reflection Sensible Heat Latent Heat Outgoing Terrestrial Emission to Surface GHG’s Fig. 2.2 Energy budget. Solar energy, or shortwave radiation (yellow) comes in from the sun. Energy is then either reflected by the surface or clouds or absorbed by the atmosphere or surface (mostly). The surface exchange includes sensible heat (red striped) and latent heat (blue) associated with water evaporation and condensation. Terrestrial (infrared, longwave) radiation (purple) emitted from the earth’s surface is absorbed by the atmosphere and clouds. Some escapes to space (outgoing terrestrial) and some is re-emitted back to the surface by clouds and greenhouse gases (GHGs) 16 2 Components of the Climate System
- 36. liquid source (oceans),and clouds eventually form enough drops that they get heavy and fall (precipitate). The water thus completes a cycle, landing back on the surface. Water then enters other components of the earth system, such as glaciers, snow, soil or rivers. Soil moisture can go through plants to get back into the atmosphere by transpiration. Or it can saturate the soil, become runoff and eventually get back into the ocean, where the cycle repeats. The key is that water changes the energy budget because it forms clouds, because it is a greenhouse gas and because it moves heat around. Water evaporated in the tropics moves as water vapor with the winds to higher latitudes (see Chap. 5), where it condenses as clouds and deposits heat there. Water is magical stuff in the earth system. The cycle of water is linked to the energy budget (through latent heat), and it links the atmosphere to other pieces of the system. 2.1.2 The Ocean and Sea Ice We have discussed the ocean briefly as a source of water. The world’s oceans (or combining them into a single “ocean”) are a critical part of the climate system.5 The ocean is a tremendous reservoir of heat and holds a lot more mass than the atmo- sphere. Water is denser than air, and the mass of the top 30 feet (10 m) of ocean is equal to the mass of the atmosphere above it (90 % of the atmosphere is in the first 55,000 feet or about 17 km). The ocean is critical as a very large store of heat that can move around and come back into contact with the surface after long periods of time. Runoff River Discharge Evaporation Precipitation Condensation Transpiration Soil Moisture Fig. 2.3 The Hydrologic cycle. Water evaporates from the ocean and is carried in the atmosphere as vapor. It condenses into clouds, and precipitates to the surface, where it can become soil moisture, glaciers, or runoff as surface water into lakes and back to the ocean. Plants move soil water back to the atmosphere through transpiration 5 For a good basic overview of the ocean and climate, see Vallis, G. K. (2012). Climate and the Oceans. Princeton, NJ: Princeton University Press. 2.1 Components of the Earth System 17
- 37. The ocean hascurrents that are both shallow (near the surface, the first few hundred feet of depth) and deep (the rest of the ocean). Unlike the atmosphere, the ocean has “edges”: Land sticks up in places, dividing the seven seas into, well, seven seas (actually five ocean basins). The ocean surface currents are forced by the rotation of the earth and winds. These currents are constrained by the topography in ocean basins and generate circulation patterns of surface currents. In addition to the near surface ocean, there is a complex vertical structure to the ocean. The ocean is divided into a near surface region that is generally warmer and less salty (fresher) than the deeper ocean below it. Colder and saltier water is denser, so it tends to sink. The process often is self-reinforcing and is seen in lakes as well: The surface warms, gets less dense and mixes less with the deeper water, thus warming more over time (this is called stratification). Density is a critical part of the structure of the ocean because of changes in density due to heat and salinity, which do not change very quickly in the ocean. Density helps control the deep ocean circulation. The deep ocean has one large circulation globally, driven by the sinking of surface water that gets saltier and colder (denser) until it sinks from the surface to the deep ocean. This thermohaline circulation (thermo = heat, ha- line = salt) has sinking motion in small areas of the North Atlantic and the Southern Ocean near Antarctica, where water is cooling as it moves poleward, and where salt is expelled from formation of sea ice, increasing salinity. Both processes make the surface water denser than the water beneath it, causing it to sink. The ocean also contains parts of two other spheres. The ocean has a biosphere, consisting of plants and animals living in the ocean and nutrients that flow through the ocean. Most of the biosphere in the ocean is composed of small organisms, mostly small floating plants (phytoplankton, algae) and animals that form the basis of the marine food chain. The ocean is an important part of the flows of carbon through the earth system as well. The ocean also holds (or supports) part of the cryosphere as sea ice.6 Sea ice forms in winter in high latitudes in the Arctic Ocean and in the Southern Ocean. The sea ice moves around and can grow and melt. The ice may last several years and is a year-round feature in most of the Arctic today. 2.1.3 Terrestrial Systems Most of the land surface is not covered by ice, however. Most of it is covered by plants: the terrestrial biosphere. There are also lakes and rivers that channel precipitation and return it to the ocean. The atmosphere and ocean cause changes over time in the composition of the land by erosion and processing of rock material. Water, wind, and waves break up rock. The rock reacts with the atmosphere (ox- idation) and with water: Sometimes minerals in rocks dissolve in water. The land 6 For a primer on sea ice, see Marshall, S. J. (2011). The Cryosphere. Princeton, NJ: Princeton University Press. 18 2 Components of the Climate System
- 38. evolves by movingslowly as it floats over the crust. For purposes of climate, the land is often considered static, but we know it changes over long timescales. Volcanoes and earthquakes are evidence of this motion. The terrestrial surface is intimately connected with the plants and the biosphere that lives on it: Dead plant (and a bit of dead animal) material makes up a significant part of the soil. Plants regulate the water in the soil through uptake into plant structures and release water into the atmosphere. Plants also can be darker or lighter than the surface soil, thus absorbing (and reflecting) a different amount of energy than in their absence. Plants react to their environment (rainfall), but plants and the biosphere also create their environment. Plants cycle water vapor back into the atmosphere from the soil by moving water from the soil into the plant, where it is lost in the process of photosynthesis back to the atmosphere. Plants also change the reflectance of the surface, altering the energy absorbed in the system, and the temperature of the surface. The biosphere cycles nutrients used by plants from the soil into plant material and back again, sometimes also into the ocean. Central to the biosphere are nutrients, and the elements that make up the structure of organic molecules: oxygen (O) and hydrogen (H) and carbon (C). But some of the terrestrial surface, particularly at high latitudes, is frozen. This, of course, brings us to a discussion of ice and snow at high latitudes and altitudes: the cryosphere. Snow may be present seasonally on land at high latitudes or high altitudes. If snow lasts over the summer, and continues to pile up, it compacts into ice and forms glaciers. If glaciers get big enough, they merge into ice sheets, ranging in size from small ice sheets filling a few valleys in New Zealand or Alaska, to ice sheets covering entire land masses (Greenland) or continents (Antarctica). The Greenland and Antarctic ice sheets are up to 10,000 feet thick; 99 % of the fresh water on earth is in ice sheets. Greenland holds enough frozen water to raise the sea level 20 feet (6 m). Antarctica holds enough frozen water to raise the sea level 200 feet (60 m).7 Finally, while physically humans are part of the biosphere, our impact on the planet is large enough that they are often treated as a separate sphere, the anthro- posphere. Human emissions as a by-product of our societies now play a significant role in the climate system. Humans alter the structure of ecosystems on continent wide scales (deforestation, and subsequent afforestation). By-products of our soci- eties add to the greenhouse gas loading of the atmosphere, and change atmospheric chemical processes near the surface (creating extra ozone, which is bad for humans, plants and animals). In the upper atmosphere some of these compounds destroy ozone in the stratosphere necessary to block ultraviolet radiation from reaching the surface. These human actions are often modeled using economic models, or models of entire societies and their emissions. These models are sometimes now treated as part of the climate system because the outputs from societies can alter the climate system. 7 Values are from the National Snow and Ice Data Center (NSIDC). http://nsidc.org/cryosphere/ quickfacts/icesheets.html. 2.1 Components of the Earth System 19
- 39. 2.2 Timescales andInteractions There is a huge variety of timescales to these cycles: from seconds to millions of years. Evaporation and precipitation formation take seconds to minutes to days to cycle water through the atmosphere, but water that falls onto ice sheets may remain there for hundreds of thousands of years. The energy budget changes throughout the course of the day as the sun moves across the sky and throughout the course of a year as the sun varies its position at any place. Many of the cycles are regulated by the motion of the earth relative to the sun. Plant growth and decay cycles follow the annual cycle. On even longer timescales of thousands to tens of thousands of years, the earth wobbles a bit on its tilted axis (and the tilt changes) and in its orbit. The wobbles alter the seasonal intensity of sunlight at any given location and also alter the distance between the earth and the sun. The result is a slow change in the amount of sunlight hitting the top of the atmosphere. These orbital cycles make it warmer or colder at higher latitudes, enhancing or retarding the presence of snow and ice on the ground, ultimately leading to ice ages.8 The motion of the plates, the slow tectonic shifts that alter the terrestrial surface and expose new land over millions of years, will change the ocean basins, as well as changing the supply of raw carbon from rocks into the system, or the amount of volcanism that puts new rock onto the surface (and gases from the earth into the atmosphere). The interplay of cycles such as flows of water and carbon alters many aspects of the climate system. Changing the amount of carbon dioxide in the atmosphere changes the greenhouse effect and the temperature. The temperature change alters water vapor concentrations, potentially further altering the temperature. The cou- pled nature of the earth’s climate system gives rise to a constantly evolving series of interacting processes between the different components. The interplay of forces and pieces is a slowly evolving system with very different interactions and timescales. The climate system is a dynamical system, meaning it can be altered in many ways, and the climate will evolve or change over time. How it will change (or not change) is of critical importance to ourselves and society, and why we try to build models to understand it. Some of the most critical interactions and flows in the climate system concern carbon, as carbon dioxide (CO2), and water (H2O). Both CO2 and H2O are critical for life and the biosphere. They are the building blocks of organic molecules, but CO2 and H2O are also part of the atmosphere, and make up the largest greenhouse gases, along with methane (CH4). This is another example of the connections and interactions in the climate system. These connections are one of the reasons why climate change is hard to understand: Carbon dioxide is bad? Not always: Plants need it for their “breathing” (respiration). Carbon dioxide is used in photosynthesis, and for that more CO2 makes photosynthesis more efficient. Water and carbon flow through the climate system and link the different components. 8 Hays, J. D., Imbrie, J., & Shackleton, N. J. (1976). “Variations in the Earth’s Orbit: Pacemaker of the Ice Ages.” Science, 194(4270): 1121–1132. 20 2 Components of the Climate System
- 40. The cycle ofcarbon is illustrated in Fig. 2.4. Carbon dioxide in the atmosphere is a greenhouse gas that affects the energy budget, but it may also get taken up by plants (fixation) and form part of their structure (leaves, stems, roots). When the plant material dies, carbon enters the soil. Carbon may be broken down by microbes and get back into the atmosphere (respiration) as a carbon-containing gas (e.g., CH4, also a greenhouse gas). It may be dissolved into water and carried into the ocean by rivers, where it also may get taken up into plant or animal tissue (oceanic biota), or remain in the water column. Oceanic biomass “rains” down to the deep ocean when parts of the oceanic biosphere die, and this carbon forms sediments on the bottom of the sea. Some of the carbon dissolves in the water column, where it comes into balance (equilibrium) with the atmosphere. The sediments under the ocean eventually get compacted by sediments above, and shifted around over millions of years by tectonic plate motions, where they come back onto land, and rock is exposed to the atmosphere, where it is broken up by wind and water (weathering), and the carbon can be dissolved again in water, and react to release the carbon back into the air. This completes a cycle that might take millions of years. The cycle moves carbon in the earth’s climate system and through the biosphere. The carbon cycle contains carbon that makes up our living tissues: literally our blood. As noted in Fig. 2.3, water flows throughout the climate system in the hydrologic cycle. Water evaporates from the ocean into the atmosphere, forming clouds and affecting atmospheric and surface energy transport. It may fall on the land as rain (or snow). Snow affects the energy budget by reflecting more sunlight to space. When snow melts, the water can go into rivers or the soil, where it can be taken up by plants, and then released to the atmosphere as a side effect of pores in leaves opening up to allow carbon from the atmosphere in for photosynthesis. The water may then form a cloud and precipitate, perhaps back into the ocean. The precipi- tated water is fresh water, lowering the salt content and density of the surface ocean, and affecting the ocean circulation. Vegetation & Soil 2,400 Deep Ocean 37,000 Sediment 150 Fossil Fuels 3,700 Surface Ocean 900 Atmosphere 765 Biota 3 Weathering Fixation Respiration Rivers Amount of Carbon in Each Reservoir in 109 Tons Fossil Fuel Emissions Fig. 2.4 The Carbon Cycle. The largest climate system reservoirs include the deep ocean, soil and vegetation, the surface ocean and the atmosphere. The approximate size of exchanges (fluxes) between boxes is given by the width of the arrows; red arrows indicate perturbations by humans 2.2 Timescales and Interactions 21
- 41. 2.3 Summary The earth’sclimate system is driven by the sun. The atmosphere mediates the flow of energy between the sun and the earth, through the action of clouds and greenhouse gases. There are several different components of the earth’s climate system, usually divided into “spheres”: atmosphere, terrestrial surface, ocean, cryosphere, biosphere and even anthroposphere (the sphere of human effects). In addition to energy, several critical substancesflowthrough the earth system. Two of the mostimportant and unique are water and carbon. They are important for climate, and they are important for life: Almost all living things contain and use carbon in different forms for our bodies and as part of the cycle of energy (either photosynthesis in plants or respiration in animals). Both carbon and water have important cycles in the earth’s climate system. In the atmosphere they are greenhouse gases. Water is important for life and also as a mechanism for moving heat from where it evaporates (taking up the heat to evaporate water) and releasing it on condensation. Carbon is stored in soils and rocks, and dissolved as a gas in the ocean. We will learn more about the carbon cycle in Chap. 7. One of the reasons the climate system is complex, and compre- hensive models are necessary, is because these greenhouse gases (carbon dioxide and water vapor) are critical for understanding the energy budget, but they also flow through the whole climate system. Thus many interactions between parts of the climate system are critical for describing how climate works and how it evolves. The cycles work on many different timescales. The motion of the earth is a good example: It causes day and night, it causes the seasons, and variations in the earth’s orbit over thousands of years alter the conditions at the earth’s surface. The slow drift of continents and variations in weathering can alter the climate on even longer timescales. These pieces, and time- scales, are critical for understanding how climate may change, the subject of Chap. 3. Key Points • The energy in the climate system comes from the sun. • Greenhouse gases alter the flow of energy in the atmosphere. • Water vapor, carbon dioxide and methane are critical greenhouse gases. • Carbon and water flow through the components of the earth system. • The climate system has cycles that evolve on many timescales from seconds to millions of years. Open Access This chapter is distributed under the terms of the Creative Commons Attribution- Noncommercial 2.5 License (http://creativecommons.org/licenses/by-nc/2.5/) which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The images or other third party material in this chapter are included in the work’s Creative Commons license, unless indicated otherwise in the credit line; if such material is not included in the work’s Creative Commons license and the respective action is not permitted by statutory regulation, users will need to obtain permission from the license holder to duplicate, adapt or reproduce the material. 22 2 Components of the Climate System
- 42. Chapter 3 Climate Changeand Global Warming We have discussed the pieces of the climate system and how they interact through some of the key cycles between parts of the climate system. These cycles include the hydrologic (water) and carbon cycles. In this chapter we describe why climate changes, with a brief examination of how it changes. Details of potential specific climate changes are discussed in Sect. 3.3. The energy budget of the planet is critical for understanding how the climate system may change over time, because on long timescales, climate is governed largely by the total amount of energy in the system and where it goes. Changes to the energy budget, both natural and caused by humans, will cause climate change. Because climate is a set of different distributions of weather states in different places, climate change is the altering of some or all of these distributions (e.g., temperature or rainfall at a particular place). Global warming implies a specific metric (global average temperature) and a specific direction (warming or a positive trend). Global warming is a subset of climate change. In this chapter we start with some basic concepts. We start by showing how changes in climate can happen internally in the climate system as a result of coupling of different processes, and we introduce the concept of a feedback (see box) that alters the response of the climate system in reaction to a change to energy that forces the system. We then talk about how the climate system responds to being “pushed”: generally with a change in the external heat added or removed. Greenhouse gases trap more heat in the system; hence, they provide this push, or “forcing.” We can see how this has happened over the distant (geologic) past and what is currently happening based on the recent (observed) past. Finally, we investigate how the system responds to changes in the energy flow and where it might put the heat: how the changes to the heat input and output may result in climate changes. These are all basic background points for understanding the underlying premise of climate change and, hence, the goals of a climate model to predict climate changes. © The Author(s) 2016 A. Gettelman and R.B. Rood, Demystifying Climate Models, Earth Systems Data and Models 2, DOI 10.1007/978-3-662-48959-8_3 23
- 43. 3.1 Coupling ofthe Pieces The different components and processes in the climate system are “coupled” together like a complex and three-dimensional jigsaw puzzle. In this context, coupling refers to the two-way interaction between different parts of the climate system. Take, for example, processes regulating water in the hydrologic cycle. Water evaporates from the ocean, leaving salt and changing density, moving through the atmosphere and depositing heat when it condenses and then precipitates onto the terrestrial surface. All these steps couple water and energy together. The complex coupling of the earth system means that it is constantly evolving on many timescales from a day up to millions of years. The daily timescale is driven by earth’s rotation. The annual cycle is the earth’s orbit around the sun. There may be small fluctuations in the sun over an 11-year solar cycle, or over different solar cycles. The earth’s orbit and wobble on its axis takes thousands of years, and over millions of years the continents also rearrange themselves, affecting the components of the system such as the ocean circulation and ice sheets. And of course there are other events that are not cycles: from volcanic eruptions that put gases into the atmosphere and rearrange the surface of the earth, to meteor impacts such as the impact that likely caused the mass extinction when the dinosaurs died out. These events are external climate forcing: They exert an external push on the climate system, usually in terms of a change in energy in the system. When we speak of natural forcing of the system, it is the changes on these different timescales and how the components of the earth system interact that govern the evolution of climate. Focus for a moment on the interactions of the various parts of the earth’s climate system. Energy comes in through the sun, modulated by the atmosphere, by clouds, and by hitting the surface of the earth. The energy flows through the system (into the land, snow, oceans, and biosphere), and these components respond. The response (change in energy flow) usually has impacts on other parts of the climate system. This we call a feedback. (see box). Feedbacks Broadly, a feedback occurs when the input is modified by the output of a process. If you have taken a microphone too close to a speaker, you have experienced a positive feedback: Sound goes into the microphone, is amplified by the speaker, comes back into the microphone again, is amplified again, and SCREECH! That’s a positive feedback loop. In terms of climate science, a feedback is an internal reaction or response of the climate system to external changes (forcing) that results in more changes to the system (en- hanced or reduced forcing). A positive feedback amplifies a signal. That can mean that changes get larger in either direction. With climate, that means a positive feedback amplifies a change regardless of direction. Think of the example of a snow-covered surface. Being white, it reflects away most of the sunlight. If it 24 3 Climate Change and Global Warming
- 44. warms up andmelts, the darker surface beneath absorbs more energy and warms more. This is a positive feedback. It tends to reinforce a small change: Warming melts snow, which melts more snow and causes more warming. But, if there is a cooling that creates more snow, this causes more cooling and more snow. So a positive feedback pushes the system away from its original state: It is destabilizing. This is critical to understand. A positive feedback enhances changes in the direction they start: It enhances warming, but it also enhances cooling. One analogy is the effect of gravity at the top of a hill. If you push a ball forward from the top of a hill, it rolls forward down the hill; if you push a ball backward from the top, it rolls backward down the hill. This is an “unstable” situation, and gravity will accelerate any motion downward: it acts in the same way as the motion. There are also feedbacks that act to resist changes. This is called a negative feedback. A negative feedback tends to push the system back to its original state: a stabilizing force. Note that the connotation is the opposite of typical usage in the context of climate change: negative feedbacks stabilize the cli- mate system (which is usually a good thing), whereas positive feedbacks destabilize it. An example of a negative feedback is the “temperature” feed- back: A warmer planet radiates more energy to space, which will reduce the tendency of the surface to warm. To continue the analogy with rolling objects, if you are at the bottom of a valley and push a ball forward (uphill), it rolls backward (down) to where it started. If you push a ball backward (also uphill), it rolls forward to where it started. In this situation of a “valley,” gravity acts as a negative feedback or stabilizing force: It acts against the motion. We discuss these feedbacks when we discuss the atmosphere in Chap. 5. Feedbacks are also important in understanding the climate system.1 Feedbacks govern the sensitivity of climate to changes (also called climate sensitivity). If we change CO2 (or more specifically the overall radiative forcing from CO2 and other gases), how much energy will remain in the earth system? Feedbacks “amplify” (or dampen) radiative forcing, resulting in more or less forcing of the system. If CO2 increases the energy in the system (and the temperature), this might melt more snow and the darker surface increases the energy in the system by decreasing the albedo (more absorption). This is a positive feedback, which increases the sensitivity of the climate system to changes in the energy budget, the amount of energy in the earth system. Changes to the energy budget are of fundamental importance because the overall “level” of energy in the system governs the expected average temperature at the surface. An overall energy change implies, “shifts” in the distribution function of climate (refer back to Fig. 1.3), and the sensitivity tells us the degree of shift for a 1 See Stocker T. S., et al. (2001). “Physical Climate Processes and Feedbacks.” In Houghton, J. T., Ding, Y., Griggs, D. J., et al. (eds). Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change. Cambridge, UK: Cambridge University Press. 3.1 Coupling of the Pieces 25
- 45. given amount offorcing from CO2 and other gases. So it becomes a useful metric (measure) of where the system might be heading. We cover feedbacks in more detail when discussing the specific components of the climate system and how we model them in Sect. 3.2. As described in the box, there are both positive feedbacks (like the ice-albedo feedback) and negative feedbacks (like the temperature feedback) in the climate system. Put a lot of complex feedbacks together, and the climate system starts to sound less like the single screech of an electronic microphone and more like the complex tones of a symphony, perhaps one without a conductor. Many of these tones or combinations of tones have feedback loops, like the example of the sea ice–albedo feedback described here. We discuss this feedback more in Chap. 5, after we introduce additional concepts about how the atmosphere works. To understand the climate system and how it will evolve over time, it is critical to understand these complex interactions. Most climate science is dedicated to understanding the components of the system, their coupling, and how they work now and have worked in the past, so that we can understand how they might work in the future. The imperative to understand the climate system stems solely from how society is affected by variations in high-frequency extreme weather events and lower frequency climate extremes and how they may change over time in response to different forcings within the system. Or even with no forcing of the system. The importance of understanding weather and climate is independent of any human influence. Even if we did not have reason to think the climate was changing due to human activities, it would still be important and critical to understand and simulate the climate system to predict the natural variability and potential changes in the system so that we can adjust. This is also called adaptation to climate changes, as in adapting our society to a new climate. 3.2 Forcing the Climate System The anthroposphere, the range of human activity, now exerts a strong effect on the climate system. The change in greenhouse gases caused by human activity changes the energy flow in the climate system and creates a forcing on the system. Humans, though largely terrestrial creatures (except for our boats, surfboards, and air travel) are a significant part of the climate system. It is not from the carbon in our bodies. We are small fish, really, compared to all the fish, or rather plankton, in the sea. Our impact comes instead from the carbon from dead plant and animal material that we use as energy. Fossil fuels (coal, oil, and gas) are buried sediments of carbon that we pull out of the ground and break apart by oxidizing them at high temperatures. We break carbon bonds in C–H (and C–H–O) compounds, adding oxygen from the air, and get energy, heat, and the chemical by-products: gaseous CO2 and water (H2O). There is nitrogen, too, but we consider that later. Over the last 200 years, accelerating energy use and industrialization has led to the build-up of CO2 in the atmosphere. We have observed this in a number of ways. 26 3 Climate Change and Global Warming
- 46. The most directis through measurements of the concentration of CO2 in the atmosphere since the 1950s. Every month for 60 years or so, a sample of air is taken and analyzed. Since CO2 is well mixed in the atmosphere, it represents a broad region (the Northern Hemisphere). Now there are many samples at different stations and multiple instruments, but the answer is the same. The curve in Fig. 3.1 shows two things. One is the upward march of CO2 concentration over time. The other is the annual cycle of the earth’s biosphere: There is an annual cycle in atmospheric CO2 concentration that occurs because plants in the Northern Hemisphere grow in the spring and turn CO2 into plant material (leaves, for example), drawing down the concentration. In the autumn, leaves fall and decompose, and much of the carbon returns to the atmosphere. But upward the concentration goes. The curve in the figure is iconic enough to be named the Keeling Curve after the American scientist, Charles Keeling, who first started the measurements in 1958 and made the plot.2 The units are in parts per million, which means one molecule of CO2 for every one million molecules of air. Some observers like to compare this annual cycle of respiration of the whole biosphere (the sum of life on the planet) to the “breathing” of the planet: equating the earth to a single living being. This is an element of the Gaia hypothesis put CO2 Concentration at Mauna Loa 1950 1960 1970 1980 1990 2000 2010 2020 Date (Years) 300 320 340 360 380 400 CO 2 Concentration (ppm) Fig. 3.1 Atmospheric CO2 concentration from Mauna Loa, Hawaii, in parts per million (ppm) as a function of time 2 For a history of the Keeling curve mixed in with the science of climate (and then some policy), see Howe, J. P. (2014). Behind the Curve: Science and the Politics of Global Warming. Seattle, WA: University of Washington Press. 3.2 Forcing the Climate System 27
- 47. forward by JamesLovelock and Lynn Margulis in the 1970s.3 It makes an inter- esting and powerful analogy that, like a living thing, the earth and its biosphere (the living sphere) interact to make the whole planet itself seem to act like an organism. It is also wonderful to note that the biosphere is so entwined with our planet’s climate system that its “breathing” changes the atmosphere. This is another way that life changes the composition of the atmosphere (the oxygen itself is there because of life as well). And it shows the importance of life to the cycle of CO2 in air. Now let’s talk about the increase over time (the trend), the second important part of Fig. 3.1. There is a steady increase of CO2 in the atmosphere. This is the result of human emissions of greenhouse gases. It follows fairly closely with the total amount of fossil fuel combustion (burning) estimated over the last few hundred years, starting with the industrial revolution. We have many lines of evidence that indicate the upward march of CO2 con- centrations is due to human activity. One way is through a direct measurement of the type of carbon present in the atmosphere as CO2. Different types of the same element are called isotopes,4 with different numbers of neutrons in their atomic nucleus (see box on carbon isotopes). This means they have slightly different mass. And the relative amounts of the different isotopes of carbon atoms in the atmo- sphere are looking more like the carbon isotopes in fossil fuels. Plant tissue has a slightly different balance of carbon isotopes (see box), and the atmosphere is becoming more abundant in this isotope. This indicates the combustion of dead plant material from fossil fuels. If the fossil fuels were not causing the increase, we would not see changes to the carbon isotopes. Carbon Isotopes The standard form (isotope) of carbon has 6 protons and 6 neutrons (12 C). In chemical nomenclature, a preceding superscript number on the element (C) indicates the total number of protons and neutrons. The form resulting from cosmic rays hitting CO2 in the atmosphere has 6 protons and 8 neutrons (14 C). 14 C is used to carbon date archaeological finds. The atmosphere is starting to have less of a stable form of carbon that has 6 protons and 7 neutrons (13 C). 13 C occurs differently in the atmosphere than in plant tissues, and the proportion of 13 C in the atmosphere is of the right proportion as dead (and fossilized) plant material in fossil fuels. 3 The original paper on the Gaia hypothesis is Lovelock, J. E., & Margulis, L. (1974). “Atmospheric Homeostasis by and for the Biosphere: The Gaia Hypothesis.” Tellus Series A (Stockholm: International Meteorological Institute), 26(1–2): 2–10. There are some good later books by James Lovelock, including, Lovelock, J. (1988). The Ages of Gaia: A Biography of Our Living Earth. New York: Norton; and Lovelock, J. (2009). The Vanishing Face of Gaia. New York: Basic Books. 4 For a background on isotopes in the environment, see Michener, R., & Lajtha, K. (2008). Stable Isotopes in Ecology and Environmental Science. New York: Wiley. 28 3 Climate Change and Global Warming
- 48. 3.3 Climate History Inaddition to direct observations of the atmosphere for the past 50 years, there exist “fossilized” pockets of the atmosphere: samples of air trapped in ice sheets. Direct measurements of air trapped in ice go back all the way to the formation of the glaciers in Antarctica: nearly 800,000 years of CO2 measurements. The time is measured first by accumulation of layers of ice, then by dating trace elements that decay in the ice or air bubbles, or counting layers. Figure 3.2 illustrates this record from the Vostok station ice core in Antarctica. Two curves are shown. The first is CO2 concentrations from bubbles in the ice. Notice how it goes up and down. The times when CO2 is low correspond to ice ages. At 10,000 years ago, the CO2 concentration rises and the last ice age ends. Why the cycles? They correspond roughly to some of the changes in the earth’s orbit. When conditions favor colder Northern Hemisphere land temperatures, snow sticks around in the summer and ice sheets grow on northern continents. These conditions occur with shifts in the earth’s orbit: changes to the tilt of the earth’s axis so that a larger tilt gives more severe winters in the Northern Hemisphere, or a shift in orbit so that the earth is farther from the sun during the Northern Hemisphere winter. These cycles are called Milankovitch cycles,5 after Milutin Milanković, a Serbian geophysicist of the early 20th century. These cycles provide a way of understanding past (and future) variations in the earth’s orbit and estimates of the change in solar input (insolation) that results. The change in insolation is a natural forcing. The ice core record also contains some interesting signatures in the ice itself.6 The oxygen in the ice (H2O) also has isotopes. The forms with more neutrons are “heavier” (18 O versus 16 O). The heavier form of water tends to remain in liquid phases when water evaporates at the ocean surface, and the relative amounts of heavy and light oxygen in ice thus give a rough measure of the ocean temperature when the ice was deposited. It is not a pure “thermometer” but a relative one, and we can guess at the scale. So oxygen isotopes are used to determine an approximate thermometer and the temperature scale on the right side of Fig. 3.2 is derived from these isotopes (there were no thermometers half a million years ago). The oxygen isotope record is a proxy record of temperature. The story told in the ice is remarkable: The temperature seems to vary in lock step (highly correlated) with the CO2. When there is more CO2 (trapping more heat), the temperature is warmer. When there is less CO2 (less heat trapping), the temperature is colder. We have not said whether the carbon causes the temperature to change or the temperature changes the carbon. 5 For more details on paleo-climate, see Hays, J. D., Imbrie, J., & Shackleton, N. J. (1976). “Variations in the Earth’s Orbit: Pacemaker of the Ice Ages,” Science, 194(4270): 1121–1132. 6 For background and details of ice core science, a good review is Alley, R. B. (2000). “Ice-Core Evidence of Abrupt Climate Changes.” Proceedings of the National Academy of Sciences, 97(4): 1331–1334. doi:10.1073/pnas.97.4.1331. 3.3 Climate History 29
- 49. One of themajor complexities of the climate system and climate change is that the “problem” or “pollutant” we are discussing (CO2) is not something “foreign” to the system. It is a part of the system, a critical part that is naturally all around us. We drink CO2 (incarbonateddrinksandbeer,forexample), weexhaleit,andarebodiesaremade up of carbon. Carbon is absorbed by plants with photosynthesis and used to build their tissues. This creates the natural annual cycle in Fig. 3.1 of carbon in air. So CO2 is not bad; it is a natural part of the system. The breathing is natural, but the increase is not. Thus we have direct records of CO2 in the atmosphere and evidence that recent changes are caused by humans. This is a strong forcing on the system. We also have evidence through proxy records that temperature has been correlated with CO2. So we know that in the past the earth’s climate has changed with CO2. To link the change in energy (forcing) with the changes in temperature, we need to understand where the energy goes in the climate system. Climate models are one tool for that, but we can discuss the energy flow in more detail. 3.4 Understanding Where the Energy Goes As discussed in Chap. 2. The earth radiates away energy to space. Greenhouse gases trap some of this energy that would be radiated away. Higher levels of greenhouse gases mean a small fraction of the energy that used to escape stays in Vostok Ice Core Data 0 100 200 300 400 500 Time (1000s Years Before Present) 180 200 220 240 260 280 300 CO 2 Concentration (ppm) -10 -8 -6 -4 -2 0 2 4 Temperature Anomaly (K) CO2 Temperature Fig. 3.2 Vostok ice core data. Proxy temperature (from oxygen isotope ratios) in red (right scale) and CO2 concentration of air bubbles in black (left scale). Data from NOAA paleoclimatology program. Petit, J. R., et al. Vostok Ice Core Data for 420,000 Years. IGBP PAGES/World Data Center for Paleoclimatology Data Contribution Series #2001-076. NOAA/NGDC Paleoclimatology Program, Boulder, CO 30 3 Climate Change and Global Warming
- 50. the system. Understandingwhere the energy goes is critical for understanding how the climate might change over time. The energy has to go somewhere. It can start by evaporating water, for example, but this energy will be released as heat when the water condenses. The energy might heat ocean water, and this water might sink away from the surface of the earth (though it is harder for warmer water to sink). It might be radiated back to space somehow. Or it might go to heat up part of the earth system eventually. The challenge is to use what we know about the system to figure out where the energy goes. All of these possibilities imply some change in “cli- mate” somewhere, even if there is no mean temperature change. The increase in CO2 in the atmosphere adds more heat to the system. But we are changing the system by only a small amount. Notice that the vertical axis on Fig. 3.1 does not start at zero. Why should that matter? The complexity with understanding climate change is that we are adding a tiny bit of energy to this wonderfully complex system. What is going to happen? Perhaps the best analogy for adding CO2 to the climate system is an analogy with our bodies. CO2 is like a steroid,7 a natural substance in our bodies that helps our muscles function. Add a bit more, though, and it throws the system out of balance. Steroids enhance muscle performance in the short term (they may also cause long-term damage), enhancing athletic performances. It only takes a small amount of additional steroid to significantly affect athletic performance. The analogy can be taken one step further. How do you know that any single athletic performance was enhanced by an added steroid? A particular basket in basketball, a hit in baseball, a goal in European football (soccer for those in the United States) depends on a lot, not just the steroids in an athlete’s body. And the natural steroids vary as well. So it is hard to say that a single home run in baseball, a single goal, or a single time for a distance runner or cyclist, for example, is due to altered per- formance. But now look at the distribution of that event over time (number of home runs in a season, average time in a race) and the distribution may have changed (more home runs over a season, for example). So it goes with adding carbon to the system and shifting the distribution of climate events (hurricanes are the tropical thunderstorm equivalent of a home run or a goal). This is how we statistically try to ferret out climate change from all the statistical “noise” of weather events. Returning to the concept of climate as a distribution introduced in Chap. 1, climate change is the change in that distribution. This is illustrated graphically in Fig. 3.3 (a reprint of Fig. 1.3). We often discuss climate as either the average (or mean, where the area is equal on either side) or the mode (the most frequent occurrence in the distribution).8 But as we said earlier, no one ever gets killed by the global average temperature. Nor is anyone killed by mean temperature or 7 The analogy between CO2 and a steroid is usually credited to Jeff Masters and Anthony Broccoli. There is a good video description at https://www2.ucar.edu/atmosnews/attribution/steroids- baseball-climate-change. 8 Don’t be scared by the statistics. See Devore, J. L. (2011). Probability and Statistics for Engineering and the Sciences, 8th ed. Duxbury, MA: Duxbury Press, or the terms can be looked up specifically in Wikipedia. 3.4 Understanding Where the Energy Goes 31
- 51. precipitation at agiven place and time. The extremes (often called the “tails” for their long, skinny graphical appearance) are really the important part. And because they are rare (not very probable; on the graph, a low extent in the vertical), they are hard to predict statistically. Here’s a simple example: We often talk about a 50-year flood. This means the flood’s “return time” is estimated at 50 years. Or the prob- ability of having such an event in any year is 1/50, or 2 %. If we try to estimate this from a 25- or 50-year record, we may be in error. What if it was a dry period, and in 25 years no floods of a given level were seen? We might conclude that the specific level of flooding can never be higher than what occurred in the last 25 years in a given place. This clearly may not be accurate with a short record. Thus the infre- quent tails of the distribution are highly uncertain. This makes climate change more difficult to estimate. Let’s shift the distribution now and assume the climate changes. We can do this first by leaving the shape the same (Fig. 3.3a). Notice what happens to the extremes. At the warm end, the area under the curve beyond some threshold becomes much larger. The area is related to the probability of an event: the fraction of the area is a percent chance of Increase in mean Lots more ‘hot’ (some off scale: records) Less cold Increase in variance More hot and cold: both off scale Same mean Increase in mean and variance Lots more hot, off scale Less cold (a) (b) (c) Fig. 3.3 Shifting probability distribution functions are illustrated in different ways going from the blue to red distribution. The thick lines are the distribution, the thin dashed lines are the mean of the distributions and the dotted lines are fixed points to illustrate probability. Shown is a increase in mean, b increase in variance (width), c increase in mean and variance 32 3 Climate Change and Global Warming
- 52. occurrence. And atthe cold end, the probability (area) goes way down (gets smaller), even though the mean of the distribution does not change that much. Here is another example (Fig. 3.3b). Suppose we change the climate by increasing the variability: making the curve wider. The “mean” stays the same, but now the extremes have higher probability in both directions. Here is an example of climate change, without changing the mean (temperature, for example). Think again about living in such a place. Suddenly there is more hot and cold weather, even if the average is the same. In other words, there’s a different climate (e.g., more air conditioners or more snow shovels). Finally, consider a change to both the mean and the distribution (Fig. 3.3c) at the same time. Now one extreme becomes much more probable at the expense of another. What are the implications? Where does the heat go? When CO2 is added, the extra heat is absorbed in the atmosphere initially. Recall that it is the heat radiated away from the earth. It’s like another thin blanket is added to the thick blankets of greenhouse gases in the atmosphere. The added blanket absorbs a little more heat, which is radiated down to the oceans and land. So there is more energy available at the land surface. There is also more energy available to the ocean surface. Oceans can warm, but not all the heat added to the ocean will warm the surface temperature. First, some of the heat in the surface ocean may end up in the deep ocean away from the surface. The oceans have a complex circulation, as we will discover in Chap. 6. Some of the water in the ocean is rapidly carried down into the deep ocean in certain regions. If the water contains more heat, this heat will be put deep into the ocean and will not warm the surface. Second, some energy increases evaporation at the ocean’s surface and the warmer atmosphere can hold more water. The increased water in the atmosphere can move more heat around. This may not directly heat the surface locally, but it will move heat in the system. The impacts of these CO2 changes thus induce several important feedbacks (see box on feedbacks, earlier in this chapter). The first feedback is from additional water vapor that results from warming temperatures. Since water vapor is also a greenhouse gas, adding a little bit of an extra CO2 blanket to the atmosphere heats the atmosphere by trapping more heat. This allows more water vapor in the atmosphere, which also traps more heat (positive water vapor feedback). Second, warming due to CO2 and water vapor may cause changes to the albedo (whiteness) of the planet. This can happen in two ways. Warming can melt snow and ice, or it can change clouds. Melting of snow and ice results in a darker ocean or land surface than when frozen, so more heat is absorbed (a positive snow-albedo feedback). Changes to clouds alter how energy is absorbed or reflected. Clouds are the largest uncertainty in this picture. Clouds broadly cool the planet (they are white and mostly low), but the changes to clouds may warm (if low clouds decrease and the planet is darker) or cool (if the clouds get more extensive). The resulting changes in the surface temperature and the distribution of heat may change wind patterns. The energy of the water is deposited in different places and changes clouds. The heat going into ice and snow can cause melting when it gets to the melting point. Melting may significantly change the surface albedo. For both 3.4 Understanding Where the Energy Goes 33
- 53. clouds and ice/snow,the contrast in color (white ice and clouds versus darker land or ocean) is also important: It causes more energy absorption. There are several important feedbacks with the terrestrial surface as well. Since plants are made of carbon, they remove it from the atmosphere. Generally, plants get more efficient at growing with more CO2, just like animals (including humans) do better with more oxygen. If plants have enough water and nutrients to grow, they should increase their growth with more CO2 in the atmosphere, removing CO2 into their tissues. This is a negative feedback: More CO2 enhances its removal by plants. These feedbacks are treated more fully in Chap. 7. The main point is that increasing CO2, even a little, throws the earth’s climate system out of balance. We have some idea of how it will adjust: There is more heat trapped in this system. This sets off a particular set of feedbacks. Some of the feedbacks are well understood. Some feedbacks are not well understood. Some feedbacks are positive; some are negative. We do not fully know exactly where all the extra energy will show up: as wind, as heat, or as rain. We expect the distri- bution of climate to evolve over the planet. 3.5 Summary This chapter has sketched out the essence of climate change. The climate system as a whole responds to a forcing in complex ways. The complexity arises because the different parts of the climate system are coupled together. There are many feedbacks in the system. We have a good idea of the past and present forcing that is pushing on the climate system. For the recent past, we have strong evidence that this forcing is from a buildup of CO2 in the atmosphere over the past 150 years. From the composition of the atmosphere (isotopes), we know this is a result of human activities: We are changing the very composition of the atmosphere. Section III of this book will treat in detail the uncertainties in climate prediction, but we can make some broad statements. When discussing future climate change, we usually mean anthropogenic (human-caused) climate change, where the change is in response to a forcing from humans. We also can discuss natural climate change. But the human-caused climate change is because of more CO2, trapping more energy in the system. Globally, the distribution of global average tempera- tures is expected to shift toward warmer conditions; hence, we sometimes refer to anthropogenic climate change as “global warming.” The change in the regional and local distribution of climate variables (temperature and precipitation) might be expected to increase warm extremes at the expense of cold extremes. But the distribution shape may shift over time in ways we do not yet understand. Since different places have different climates with different distributions, they may change in different ways. This might mean big differences in extreme events (the tail of the distributions in Fig. 3.3): tropical cyclones, extended droughts. We have theories about how the different feedbacks in the climate system work based on observations from past and present climates. We discuss these feedbacks 34 3 Climate Change and Global Warming
- 54. in the contextof models in the next chapters. To confirm our understanding, we also try to use models of the system to estimate what has happened in the past and what will happen in the future. We can do this by applying forcing to models and observing how they respond. Thus climate models are used to translate the basic constraints on climate from forcing and feedbacks into specific predictions about regional or local climate changes. Key Points • Understanding how parts of the climate system are coupled with feedbacks is critical. • Greenhouse gases (CO2) have been increasing over the past 60 years (based on measurements of air samples) and for the past 150 or so (based on ice cores). • The composition of the atmosphere tells us that the increased CO2 comes from fossil fuels. • Increasing greenhouse gases trap more energy in the system. The energy has to go somewhere. Open Access This chapter is distributed under the terms of the Creative Commons Attribution- Noncommercial 2.5 License (http://creativecommons.org/licenses/by-nc/2.5/) which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. The images or other third party material in this chapter are included in the work’s Creative Commons license, unless indicated otherwise in the credit line; if such material is not included in the work’s Creative Commons license and the respective action is not permitted by statutory regulation, users will need to obtain permission from the license holder to duplicate, adapt or reproduce the material. 3.5 Summary 35
- 55. Random documents withunrelated content Scribd suggests to you:
- 59. The Project GutenbergeBook of Conscience & Fanaticism: An Essay on Moral Values
- 60. This ebook isfor the use of anyone anywhere in the United States and most other parts of the world at no cost and with almost no restrictions whatsoever. You may copy it, give it away or re-use it under the terms of the Project Gutenberg License included with this ebook or online at www.gutenberg.org. If you are not located in the United States, you will have to check the laws of the country where you are located before using this eBook. Title: Conscience & Fanaticism: An Essay on Moral Values Author: George Henry Lane Fox Pitt-Rivers Release date: October 19, 2018 [eBook #58136] Language: English Credits: E-text prepared by Turgut Dincer, Martin Pettit, and the Online Distributed Proofreading Team (http://www.pgdp.net) from page images generously made available by Internet Archive (https://archive.org) *** START OF THE PROJECT GUTENBERG EBOOK CONSCIENCE & FANATICISM: AN ESSAY ON MORAL VALUES ***
- 61. E-text prepared byTurgut Dincer, Martin Pettit, and the Online Distributed Proofreading Team (http://www.pgdp.net) from page images generously made available by Internet Archive (https://archive.org) Note: Images of the original pages are available through Internet Archive. See https://archive.org/details/consciencefanati00pittuoft CONSCIENCE & FANATICISM
- 62. CONSCIENCE & FANATICISM AN ESSAYON MORAL VALUES BY GEORGE PITT-RIVERS "Æquam memento servare mentem" LONDON: WILLIAM HEINEMANN London: William Heinemann, 1919
- 63. PREFACE In presenting thislittle volume to the public I am fully conscious of my presumption in introducing my personal views in a region where many hundreds of better qualified writers have devoted their best efforts. Since, however, no apology can justify a profitless task, if such it be, or add to its utility, if indeed it possesses any, I will not attempt to make one. If I have contributed in ever so slight a degree towards an understanding of the mental state or attitude we call fanaticism, for the purpose of guarding against the catastrophes it begets, I shall have achieved my purpose. It is unfortunately inevitable that a discussion which involves current opinions and beliefs must necessarily encounter strong prejudices and opposition, but it is less on this account that this little work is likely to fail than for the reason to which Hume attributed the failure which attended the publication of his "Treatise of Human Nature," which he described as his guilt "of a very usual indiscretion, in going to the press too early." A circumstance which prevented that "unfortunate literary attempt from reaching such distinction as even to excite a murmur among the zealots."[1] Needless to say, I have relied for my interpretation of human notions and ideas, and the conduct which results from them, very largely upon the works of past and contemporary writers; and my indebtedness to those with whom I differ no less than those with whom I agree is but very inadequately acknowledged in my references to the works of some of them. The earlier portions of the essay are devoted chiefly to an examination of moral ideas, the latter portions more exclusively to the facts of nature and of mind from which they derive their
- 64. meaning. Throughout Ihave attempted to keep the argument as free as possible from the thin air of philosophical and scholastic dialectic, and as far as possible in terms of common usage and thought. With this end in view, and for the sake of brevity, the authors to whose works I have referred most frequently have been selected either because they are better known or because their opinions are more widely held than in the case of others. But in any case no claim to exhaustive or even adequate treatment can be made for so slight a review of so vast a subject. The first problem which I have attempted to deal with is one which confronts all moralists. It consists in the difficulty of deriving ethical notions from notions which are not ethical, or of deducing the moral law from the facts of experience and of nature. The attempt to escape from this difficulty often takes the form of adopting a theory by which the whole world is divided into two unrelated worlds, a world of values and a physical world of mechanical sequences. In order to bring these two independent and self-consistent systems within the same reality and to weld them together, God is postulated. God is necessary, it is argued, to prove the objectivity of morality. That is to say, that since moral values are eternally valid, independently of man's capacity to be conscious of them, they can only have existence in the one eternal mind.[2] The purpose of this essay is to offer a different solution. As this question of the status of moral values is of great importance to the moral argument, a preliminary examination of the ground may be helpful. The predication of value to an object which elicits moral approbation is not, as most Theistic writers stubbornly maintain, an implicit acknowledgment of the objectivity of the goodness predicated, it is merely the act of appreciating the subject or valuer's attitude in relation to the object (the relationship may be purely hypothetical), but it may, and usually does, invite a similar attitude on the part of any number of subjects.[3] The relation of subject to object—this also applies to all relations—may belong to objective reality, but not
- 65. the moral worthwe ascribe to the object as a result of that relationship. This distinction is important and involves, necessarily, a discrimination (not always made) between the treatment of knowledge and of value. Hume, by denying the objective character of the relations and connexions of nature equally with moral judgment, in his interpretation of individual experience, treated moral judgment and knowledge of natural science in an identical manner. In the following discussion truth, to which I have denied relativity, is accorded a position altogether distinct from value. Appreciation of truth and interest in knowing is treated as a value, but not truth itself to which subjectivity is denied. The method I have adopted of treating this fundamental point may perhaps be made clearer by a simple illustration. Let us take any particular moral judgment, for example, "A [a conscious individual] is good." The assertion implies that A is the habitual doer of desirable actions, or is benevolently disposed towards the valuer, Society at large, or God, according to the valuer's idea of goodness. In any case A's conduct or his attitude must have evoked approbation by reason of its effect (emotional or material) upon the valuer or those with whom he is in sympathy. The valuer might attempt to refute this definition by maintaining that A's habitual conduct does him the greatest injury, but that his predication of good in respect of A is the assertion of an objective fact. In spite of such an objection, I would reply that the moral judgment may indeed be intended to imply certain definite objective qualities or properties because the valuer considers these desirable, and chooses arbitrarily to define "good" as containing those definite properties, or because in the community to which he addresses himself they are customarily so defined. The veracity, however, of the moral judgment, considered as a statement of fact, can only be tested after an agreement has been reached as to the content of the symbol "good." It has then been given a meaning which alone it does not possess. The validity of moral judgment, when it is not merely the expression of individual attitude, will therefore always depend upon the criterion of conduct previously adopted. In this way it is held that a moral judgment differs from a
- 66. statement of fact,which is valid irrespective of the existence of any mind capable of apprehending that fact. In the last two chapters, where an examination of psychological processes has been necessary, I have experienced no slight difficulty in finding appropriate terms by which to distinguish certain conceptions which are in some respects new. An inapt terminology and the misuse of terms is so grave a fault, and so habitually results in errors, obscurity, and confusion, that it may not be superfluous to call attention to the terms that are more liable to misinterpretation and in many ways least satisfactory. For this purpose it will be necessary to give the briefest possible account of the use to which they are put, while their more precise definition will be left to the chapters in which they occur. The psychic life and the mental activity of human beings is conditioned by three factors. The first, heredity, denotes the accumulation of experiences and consequent structural modifications acquired by the race during the process of its adjustment to its environment; the manifestation of the result of this experience in behaviour is called instinct. The second is the result of the habits and acquirements of the individual from the moment of conception to the end of his existence: this, together with the first, produces what we call character. The third, those external influences operating upon the individual, we refer to as environment. If we would reflect upon the mental life of humanity we must consider the individual mind in relation to the world of mankind. In considering the individual mind I have adopted the terms objective mind and subjective mind to denote two aspects of mind. The words "objective" and "subjective" in conjunction with mind are used in a special sense which has to be defined. The world of men has been considered as the psychic environment of the individual mind, and I have introduced a term to denote the power of aggregations of human thoughts and impulses. It has been viewed as an aspect of the universal process underlying the conative disposition and will-to- power of all living beings, and on account of the mode of its
- 67. operation it hasbeen termed "cosmic suggestion." The term is not intended to imply that the psychic forces of the human mind can be "given off" and have separate existence, like the "odylic fluid" of the early Mesmerists. The power is that of collective minds; suggestion an effect of its activity, not a derived essence. It must be understood that these three terms are provisional, and will be discarded if, in the course of time, better ones suggest themselves. Finally, I would crave the indulgence of my readers to say a few words about the philosophy of egoism. There is a view of egoism— the principle of self-interest—as distinguished from altruism, which is seen in opposition to asceticism and mysticism, a view which prompted Lecky when he wrote: "Taking human nature with all its defects, the influence of an enlightened self-interest first of all upon the actions and afterwards upon the character of mankind, is shown to be sufficient to construct the whole edifice of civilization; and if that principle were withdrawn, all would crumble in the dust.... When, therefore, the ascetic, proclaiming the utter depravity of mankind, seeks to extirpate his most natural passions, to crush the expansion of his faculties, to destroy the versatility of his tastes, and to arrest the flow and impulse of his nature, he is striking at the very force and energy of civilization." How infinitely preferable is the spirit of enlightened egoism to the blind altruism of the fanatic! The egoism that enhances rather than dims the love of others. It is only through the realization of community of interests and aims that like thought will result in like conduct. It is a recognition of this principle of systematic integration of interests and their concomitant obligations, starting from egoism, in the sense of a realization of the relation of self to environment, and then through successive stages of widening appreciation of the full contents of environment to the identification of the self with the community, which alone leads to State or National morality, and will lead, ultimately it may be hoped, to the morality of a community of all nations—that is, a world morality. It is for this reason that we say that the end and aim of a true ethical system is to find the interests of mankind in the interests of the individual.
- 68. And now, aswe stand on the threshold of a new era—a new world in search of its soul—what better precept can we have than the simple words of the great thinker who, three hundred years ago, also stood on the threshold of a new world of thought? "Il suffit de bien juger pour bien faire, et de juger le mieux qu'on puisse, pour faire aussi tout son mieux, c'est-à-dire, pour acquérir toutes les vertus, et ensemble tous les autres biens, qu'on puisse acquérir; et lorsqu'on est certain que cela est, on ne saurait manquer d'être content."—Descartes, "Discours de la Méthode." G. P. R. Hinton St. Mary, Dorset January 1, 1919 FOOTNOTES: [1] Hume's "Autobiography." [2] This is the position of the Idealistic schools and is adopted in Professor Sorley's recently published Gifford Lectures, "Moral Values and the Idea of God." [3] This relationship may be expressed in psychological terms. Dr. McDougall expresses it thus: "Objects have value for us in proportion as they excite our conative tendencies; our consciousness of their value, positive or negative, is our consciousness of the strength of the conation they awake in us."—"Body and Mind," p. 329.
- 69. CONTENTS CHAP. PAGE I. INTRODUCTION1 The importance ascribed to the word "conscience" by public opinion: by the State: by the Church: need for examination of its credentials II. THE VALIDITY OF MORAL JUDGMENTS 7 Theism and Determinism: the Intuitive schools: the Rationalistic schools: recognition of Good: the facts stated: the Utilitarian standard demanded III. THE MEANING OF MORAL OBLIGATION 20 The argument against Utilitarianism: Mill's defence of Utilitarianism: a variation of Mill's position: the principle of proximity: the meaning of Truth: duty: an illustration from history: Robert E. Lee IV. RELIGION AND MORALITY 32 Probing the essentials: the need for a moral code: its artificial character: the deeper morality: Morality and Religion: religious and political fanaticism: moral values and psychic force: Monism and Duality: a reconciliation of systems: conservation of the soul: education and the formation of opinion. V. THE LAWS OF SUGGESTION AND "SUBJECTIVE MIND" 44 The power of ideas: origin of the World War: psychodynamics and the law of suggestion: Haeckel on emotion: Dr. Samuel Johnson on the progress of an agitator: consciousness: Hudson's hypothesis: the two aspects of mind: Theology on the origin of Good and Evil: self-knowledge: Socrates and Joan of Arc: the phenomena of madness: men of genius: evolution and organic memory:
- 70. telepathy: the powerof suggestion: psychotherapeutics: faith-healers: Christian Science: memory: Coleridge's case: William James: Bernard Shaw on Art. VI. VALUER AND VALUATION 73 Factors determining valuation and arrangement of the discussion. (1) INSTINCT AND HEREDITY 73 Prof. Ward on heredity: Haeckel on instincts: McDougall on instincts: imitation and morality: demagogues and fanatics: geniuses and politicians: maternal impressions: heredity versus environment: conscience as an emotional and instinctive organ, and conscience as a thinking and intellectual organ: the force of cosmic suggestion on morality: remorse. (2) THE FACTOR OF EMOTION 86 Emotion defined: its manifestations: its control: Ward on emotion: James on emotion: the æsthetic emotions: Racine and the element of mystery in Art: William Hazlitt on the worship of names: emotional sensibility: æsthetic appreciation. (3) JUDGMENT OF ENDS 96 The intellectual and critical processes: realization of ends: recognition of Good: the norm of valuation. (4) COSMIC SUGGESTION 99 Public opinion: emotional suggestions: individual suggestibility: gregarious attraction: ecstatic oratory: Rasputin: Mark Antony: propaganda: the Press: Mr. Hilaire Belloc's views: the influence of literature: the worship of symbols: Bergson's definition of metaphysics: the necessary task of religion: progress or decline: the highest form of morality.
- 71.
- 72. I INTRODUCTION In all agesconscience has been the theme of priest, politician, philanthropist and obstructionist. So often used and so seldom analysed, beyond a bare assertion of its function, it is curious to reflect on the strange medley of uses to which this word is put. Conscience is at once the standard and the refuge of orthodox and fanatic, patriot and anarchist—according as they are described by admirer or detractor—but, let us believe with Lecky,[4] least often of the genuine hypocrite. Never was a nation so beset with "conscientious" men and women as England is to-day; some helping, some hindering, some having little effect on the national welfare. Some flaunt the badge obtrusively, they label themselves "conscientious objectors to military service," "conscientious objectors to vaccination," "conscientious teetotallers"; in some cases anti-vivisectionists,[5] social reformers and (formerly) suffragettes proclaim their exertions endured for "conscience' sake"; so, for the most part, do missionaries and religious functionaries, and, in fact, all and any who engage in propaganda or obstruction, "because," they say, "something higher than reason prompts our motives—'conscience'." [6] Others refer to conscience shyly as of something too sacred to be spoken of publicly, and again others only in moments of intense earnestness—or alcoholic remorse. A conscience, in fact, is an invaluable asset; where it does not gain approbation, it at least gains some measure of respect. Most people, then, admit the existence and the reality of what we popularly call "conscience," and although fewer people are agreed as
- 73. to its originand nature, it is, nevertheless, accorded a high place of importance and almost universal recognition as an arbiter in the affairs of men. So undisputed is this claim to inviolability of conscience in twentieth- century England that the State, in framing her laws, modifies their application by the interspersion of caveats in the form of "conscience clauses." The principle on which the conscience proviso is allowed to negative the universal applicability of the State's demand for service or compliance with her rules appears, however, to be somewhat arbitrary and uncertain, and can hardly be said to be devised solely in deference to any possible religious sanction, since, although a man's conscience is allowed to exempt him from vaccinating his children, the plea of religious sanction, in the case of a man professing the polygamous doctrine of Brigham Young,[7] would not exempt him from amenability to the law concerning bigamy; or, again, the conscience of a Quaker or of a Christadelphian[8] is recognized as a stronger qualification for exemption from combatant service than the equally recalcitrant consciences of, e.g. an Atheist or a Member of the Church of England. Yet the standardization of "privileged" denominational consciences is strongly disavowed! In spite, however, of a certain illogical inconsistency in practice, it is virtually conceded as a right that a man should justify any conduct by the plea of "conscience," even, in many cases, when it militates directly against the good of the State. Even more than the State and public opinion does the Protestant Church insist upon the authority and inviolability of "conscience." Driven, step by step, from the time of the Reformation, by the encroachments of science and the progress of Rationalism, from her defence of the infallibility of Doctrine and Scripture, the Protestant Church has sought to render her position impregnable by increased insistence upon the inviolability and sanctity of revelation and conscience. Lecky, speaking of the trend of "Protestant Rationalism," says: "Its central conception is the elevation of conscience into a
- 74. position of supremeauthority as the religious organ, a verifying faculty discriminating between truth and error."[9] The most recent stalwarts of the Church of England are equally insistent upon this point, thus the Rev. G. L. Richardson writes: "We shall appeal to and invigorate the conscience in proportion as we rely upon the Holy Spirit as the one source of spiritual power.... 'The fellowship of the Holy Ghost' and His grace through the Church is the master word of the twentieth century."[10] This passage well illustrates the supreme importance, with regard to her position, which the Church attaches to the appeal to conscience at the present day. In another passage the same author says, "the authority of conscience is ... paramount for the individual." Dr. J. N. Figgis in his "Churches in the Modern State" says that any doctrine which would "destroy the springs of spiritual life in the individual conscience would be disastrous to civic as well as to religious life." Having raised the individual conscience to a pinnacle of ethical omniscience, the ecclesiastic next proceeds to bring it into line with, or rather into synchronous subordination to, the aggregate "Church Conscience." "The Church is a Divine society, her members will feel an obligation to be loyal to her discipline.... The conscience of her members will respond with approval or shame when they keep, or neglect to keep, her standards." From this the resulting "code and sentiment" is the "Church Conscience."[11] Mr. G. K. Chesterton throws further light on this interrelationship. "The 'Church Conscience' is rather to be conceived as a fortress to which the individual may return for shelter and strength when the attacks of temptation threaten to overwhelm him. At such times it is well to feel that we are not dependent on the 'inner light' of conscience alone, but that we can throw ourselves on a social force mightier than our own, and behold with astonishment and enthusiasm a Divine company and a Divine Captain."[12] Whilst Church and State are in agreement regarding its importance and sanctity, the same unanimity is not exhibited in dealing with the
- 75. origin and characterof conscience. Equally divided in this respect are the philosophers and psychologists. Priests are fond of telling us that conscience is "the voice of God within us." To some men it appears strange that the voice of the same God should frequently induce men to oppose each other with such particular bitterness. This objection is sometimes met by the explanation that although it is the voice of God speaking through the medium of our souls, we fail to recognize or interpret rightly its significance. This explanation, again, is not altogether satisfactory, since, if that were the case, the voice of God must be so uncertain a guide it were better not to rely on it. When we look back through the pages of History and consider the actions of men and the motives to which they ascribe them, and see what an orgy of blood, of persecutions, of burnings, of torturings, of blind passions and religious frenzy, of diabolical imaginings and monstrous eschatology has been conceived at the instigation of conscience and religion, and prescribed in the name of God, we are inclined to inquire more deeply into the meaning and credentials of this watchword of all ages. FOOTNOTES: [4] "Hypocrites, who from interested motives profess opinions which they do not really believe, are probably rarer than is usually supposed."—"Rise and Influence of Rationalism in Europe." [5] A few years ago the Animal Defence and Anti-Vivisection Society distributed pamphlets from their headquarters in Piccadilly, beginning "Do not ask of your doctor his opinion on this matter, ask your conscience," etc. [6] This distinction is commonly made between conscience and the intellectual faculty of reason; thus, when a man says, "My conscience tells me," he usually means, "No reason will deter me."
- 76. [7] Mormon leaderand preacher, died in 1877, leaving seventeen wives. [8] The establishment of bona fide membership of either of the above-mentioned religious societies (inter alia) by a "conscientious objector" was recognized by Military Service Tribunals (acting under official instructions) as sufficient cause for a verdict of exemption. [9] "Rationalism in Europe," 1913 edition, p. 167. [10] "Conscience, its Origin and Authority" (1915). [11] "Conscience, its Origin and Authority," p. 150. [12] "Orthodoxy," p. 137, quoted by G. L. Richardson.
- 77. II THE VALIDITY OFMORAL JUDGMENTS Any investigation of the phenomenon of moral conduct, and of its interpretation, brings us face to face with two sets of conflicting theories. These may, for convenience, be roughly divided into the two principal schools of thought which have been termed respectively the "Moral Sense" or "Intuitive" schools and the "Rationalistic schools of ethics." Certain writers in their search for the springs of moral conduct have attempted to place the issue between Naturalism or Determinism (by no means synonymous or necessarily connected) on the one side, and Theism on the other[13]; and, in their eagerness to discredit the former to the advantage of the latter, imagine they demolish Determinism (at any rate in the ethical sphere) by "pushing it to its logical conclusion" and by showing that it "has connected completely and indissolubly, as far as observation can carry us, mind with matter; it has established a functional relation to exist between every fact of thinking, willing or feeling, on the one side, and some molecular change in the body on the other side, and man, with all his ways and works, is simply a part of nature, and can, by no device of thought, be detached from or set above it."[14] What, after all, is involved in the acceptance of such a conclusion? What is there to fear? To concede this, it is thought, would mean to relegate man to the position of a mere "automaton," freed from "accountability to God, responsibility to man, and the fears of conscience." So far from ridding man of responsibility, the clear recognition by him of the true nature of his environment and antecedents, the laws by which they influence him, and his inherent capacity of resistance —in other words, the two processes observable in the world, action
- 78. contrary to, andaction along, the line of least resistance[15]—does, on the contrary, greatly increase his responsibility of action and his power to know himself. Is not mind and matter subject to the same law? Do they not react to the same God? What matter, then, if we adopt the formula of Pampsychism and assert that "all individual things are animated albeit in divers degrees"? or endorse the conclusion of Professor James Ward, who "finds no ground for separating organic life from psychical life"? and continues: "All life is experience. We cannot therefore assume that experience has no part in the building up of the organism, and only begins when viable organism is already there."[16] The belief that there can be no life without mind does not necessarily imply that there can be no mind without body. As John Stuart Mill pointed out, Determinism does not imply Materialism, a man may be a spiritual being but yet subject to the law of causation. Neither does it deny the dynamic character of will, but allows that not only our conduct but our character is in part amenable to our will. The causality involved in human actions would, however, enable any one who knew perfectly our character and our circumstances to predict our actions. Such considerations, however, although contributory, do not, of themselves, decide the question with which we are here concerned, namely, What is the real meaning and what the authority of "conscience," or of that mental act which takes place in our minds when we call certain conduct "right" and certain conduct "wrong"? Apart from the question of the ultimate sanction of moral conduct, there have always been two explanations of the mental act variously known as "ethical judgment," "moral faculty," "moral sense" or conscience. On the one side there have been those who considered that moral judgment was an emotion, an intuition, or instinctive recognition of right or wrong, which implied no rational or intellectual process beyond that which is involved in registering or
- 79. perceiving the fact.And on the other side there have been those who treat moral approbation as essentially an act of judgment—the result of the reasoning and intellectual function of the mind. The earliest exponents of a morality that in no way depended upon the work of Reason were the ancient Epicureans and Cyrenaics; since for them good was pleasure and evil was pain, the sources and tests of all ethical truth were necessarily, in consequence, the feelings and emotions. In the eighteenth century there arose a school, associated with the names of the third Lord Shaftesbury and Francis Hutcheson, the Scotch philosopher, which became known as the "moral sense" school, widely different from the old hedonistic philosophers, since they were the first to assert the existence of a distinctively ethical, as opposed to a merely pleasurable, feeling. The philosophers of the "moral sense" school attempted to prove that there existed a distinct moral "faculty" which differed from all other perceptions or ideas, in that it was a separate medium by which men could recognize ethical truth, which was rather a matter of the heart than of the head. As a result of the attacks of the various rationalist schools this idea of a "moral faculty" has been for the most part abandoned by those who approach ethics from the Religious or Theistic standpoint, for they are far more concerned to establish the "Divine authority" and sacrosanct character of conscience than influenced by psychological or metaphysical distinctions. For the most part such writers are content to assume that "conscience" is the knowledge of one's own soul with regard to questions of right and wrong, but insist on that element of Divine Guidance which alone, they think, can give it the necessary authority and sanctity. The Rev. G. H. Richardson[17] defines conscience as "the whole personality acting ethically; or, more precisely, conscience is the
- 80. reaction, pleasurable orpainful, of the whole personality in response to a human or Divine standard." It is neither wholly emotional nor wholly rational, but "is sensitive to motives of which the pure reason would take no account; it is more akin to instinct than intelligence." Yet "without reason, conscience would be blind impulse, though it might feel the consciousness of obligation."[18] Clearly, then, conscience can derive little validity from intelligence; the concession to the Rationalists does not amount to much; it might almost get on without reason altogether. It is the Divine authority of conscience which, for the Theistic writer, is the factor of prime importance. "As we are bound to trust reason in the intellectual sphere, so we are bound to trust conscience in the moral sphere. To deny the authority of the one or the other is to distrust the Power in whom physical and moral law have their source. The authority of conscience is thus paramount for the individual; it will be better for me to do what is objectively wrong, but what I conscientiously believe to be right, than do what is in fact right, but what my conscience disapproves."[19] Here the writer appears to abandon his Rationalistic friends altogether; the fanatic is given free rein, his ravings are sacred. Dr. H. Rashdall, who by many is considered representative of rationalistic ethics, insists on the "objectivity of moral judgment. Feelings or emotions possess no objectivity; and 'without objectivity,' in the words of Eduard von Hartmann, 'ethic has no meaning'."[20] The all-important task for the Theistic writer is to establish the factor of Divine impulse. "Therefore we say that conscience is a fundamental form of man's personal consciousness of eternity; that ineffaceable certainty that the relation of Duty, with Responsibility and Judgment, is not a relation which stands and falls with our relations to the world and to men, but in its essence is a relation to
- 81. the holy andAlmighty God.... Additional force seems to be given to this way of regarding the Authority of conscience if we consider that its activity is set in motion by an impulse from the Divine Personality."[21] Bishop Butler refers to conscience as the "voice of God," and as "supreme among human faculties"; and this is endorsed by Richardson, who finds that Theism is essential to any doctrine of conscience, because the alternative is "destructive of its authority." Let us now summarize the Theistic conscience, variously described in different passages, in the author's own words: "Its activity is set in motion by an impulse from the Divine Personality, and does not originate in the individual nor the world," yet it "reacts to public opinion," is "often unreasonable and inconsistent," is "subject to evolutionary growth" and is "not infallible," is "capable of infinite variety of interpretation" and "reacts to a human standard," which, however, "trails some clouds of glory from its Divine original"; and in conclusion, "If we regard conscience not as a phosphorescent gleam playing upon the surface of consciousness, but as a vital impulse, partly rational, partly instinctive, welling up from the depths of Personality, we shall not run the risk of denying its authority."[22] It would be well, however, not to underestimate the risk, although it undoubtedly caters for a great variety of tastes. Allied to the Emotional school for the purpose of proving conscience are those Rationalists, of whom we have taken Dr. Rashdall as an example, who have for an object the establishment of the "objective" validity of moral judgment. The real contention becomes clearer; the chief point at issue is the question of authority. We see, then, that there are two points to be decided: (1) the ultimate validity, with which is connected the question of the Divine Authority, of moral judgments; and (2) the mode of recognition, with which is connected the cause or propellent which induces moral action.
- 82. Rashdall summarily dismissesthe dual character of the problem in a phrase. "The question at issue between Rationalists and Emotionalists is not what impels me to do a virtuous act, but how I know it to be virtuous."[23] The connexion between motive and judgment is too closely related to be thus calmly ignored. It is agreed that the motive does not affect the intrinsic character or "rightness" of an action, but at the same time it most certainly does affect a man's estimation of his action; and this, in order to arrive at the value of moral judgments, is most obviously relevant. For Dr. Rashdall the distinction between how I know my action to be right or virtuous, and how it is virtuous, does not exist. Both imply recognition or statement of indisputable fact; for him there can be no ultimate doubt as to the character of moral "good," which can in no way be a matter of opinion, for good is sui generis: it is good and nothing else; happiness may be good, honesty may be good, but good is good for no other reason than because such an abstraction is supposed to exist as a transcendental fact. "Therefore good can be recognized just as any axiomatic truth can be recognized; as, for instance, the fact that 2 + 2 = 4, or two straight lines cannot enclose a space." How is it then that people even of the highest intelligence do not invariably agree about what is good or morally right? There are no two opinions about whether 2 + 2 does, or does not, equal 4, yet there is no such general agreement about what is right. If asked why a thing is right or good most people would reply either by giving a reason to show that it is desirable or else by quoting the authority of some one else's ipse dixit (in which case it is inferred that the authority quoted had some reason for supposing it desirable). The reason that 2 + 2 = 4 is, on the other hand, that there can be no possible alternative. Yet is it true to say that there can be no possible alternative to what the consensus of opinion in any one country considers morally right? Some things that are considered immoral in England are considered moral in Japan, and vice versa.
- 83. Dr. Rashdall, however,conceives of but two alternatives in estimating moral values, the first of which he dismisses, because on this view "our moral judgments could possess no objective validity." He says: "... I examined the question whether our moral judgments are in ultimate analysis merely statements asserting the existence of a particular kind of feeling in particular minds, or whether they are intellectual judgments of universal validity—judgments, of course, of a very peculiar and distinctive kind, but just as much intellectual and universal judgments about the nature of Reality as the judgments 2 + 2 = 4, or 'this is a good inference and that is a bad one'."[24] It is difficult to know whether this arbitrary elimination of the subjective element from ethical judgments, and the attempt to translate moral values into terms of mathematical formulæ, is intended to denote the infusion of a mystic factor into the "exact sciences," or an attempt to reduce metaphysics and morality to rule of thumb! The following thesis, however, which will be elaborated in the course of this discussion, is based on a synchronous realization of rational principles and psychological processes. Thus, what an individual conceives to be morally right and good, when he is conscious of having acted so according to his own standard, may be either: (1) Wholly irrational, illogical, anti-social and undesirable (from every point of view except his own), even though arrived at solely by an intellectual and reasoning process; or (2) An entirely instinctive, blindly impulsive or emotional action, afterwards endorsed by the intellect (i.e. subsequently rationalized); or (3) The result of thoughtful deliberation, carefully and logically designed to bring about certain preconceived "moral" ends such as social happiness, justice, fulfilment of duty; all of which are artificial and conventional standards, and good only because they are
- 84. desirable, not becausethey are universally valid—irrespective of time, locality and circumstances; or (4) Any combination of these three. The foregoing applies as much to the aggregate moral consciousness of a community in different stages of civilization, or in varying states of emotional abnormality, as to the individual conscience. It can also be shown that the "communal conscience" reacts upon the "individual conscience" in inverse ratio to the latter's emotional or intellectual capacity for resistance; and that the "communal conscience" (identified at a later stage of this inquiry with "Cosmic Suggestion") is the integral product of the numerical and dynamic strength of the convictions of the members of the community, and operates upon the "individual conscience," either consciously or subconsciously, in the same way that "Suggestion," according to the law discovered by Liébeault and employed by the Nancy School, operates in hypnotic phenomena. It will then (if this view can be established) be shown that the factors of conscience are: (1) emotional, (2) intellectual, (3) internal (including hereditary and organic elements), and (4) external (environment—material and psychic); and that its validity, in ultimate analysis, can but rest on codes, which may be not only Conventional and Artificial, but also Rational or Intellectual, Social and Utilitarian; and in any case variable, in the same way that the soundest and most logical policies must, to a certain extent, be variable, or capable of adjustment as circumstances change; the only elements which should be constant and invariable in any policy (which is not a misnomer) being logic and truth. So it is with rules of conduct. As regards the purely internal sanction of our actions and thoughts, that is to say, our relationship with Ultimate Reality, which is God or the Law of Existence, there is only one conception of the latter which seems to comprehend the infinite with the finite, and that is
- 85. Force, because itis the continuity of Existence, or after the manner of Leibnitz: "Substance, the ultimate reality, can only be conceived as force." Any moral law which may be said to be fundamental in itself and independent of circumstances will be in relation to force. But such "laws" will also be independent of the moral imperatives and written codes, for they are independent of volition—of the will to obey them. Can a man be possessed of love, greatness, nobility, courage, honour, at a word of command? Therefore if it can be truly said that "love is the greatest thing in the world," it is because it is the most powerful force. Hate is disruptive, disintegrating and annihilating; love is integrating and strengthening. But there is yet one "good," one fundamental imperative which needs no proof, and that is Truth—ultimate truth, because it is the statement of what Is; without which logic, or, indeed, intelligible language, would be impossible. But truth is not opinion, or assertion, or hope, or faith, or in the words of Huxley "those idols built up of books and traditions and fine-spun ecclesiastical cobwebs." Truth and all its derivatives—honesty, integrity, truthfulness and sincerity— have an intrinsic value of their own, for their negation implies the negation of the principles of Existence. But men require more than this, they require a "moral code" or standard to give coherence to their relationships; this code, then, is that which is desired, or imposed, and this want is most efficiently supplied by the principle of "Utility." FOOTNOTES: [13] See "Conscience, its Origin and Authority," p. 25. [14] W. H. Mallock, quoted by Richardson. [15] Professor James Ward uses the terms "anabolic" and "catabolic" processes in this connexion, also in a sense analogous to the distinction between doing and suffering.
- 86. [16] J. Ward,"Heredity and Memory," 1913. [17] "Conscience, its Origin and Authority," p. 69. [18] Ibid., pp. 67 and 68. [19] "Conscience, its Origin and Authority," p. 96. [20] Hastings Rashdall: "Is Conscience an Emotion?" [21] "Conscience, its Origin and Authority," p. 99. [22] "Conscience, its Origin and Authority," pp. 99, 95, 96, 70, 72 and 73. [23] "Is Conscience an Emotion?" p. 113. [24] "Is Conscience an Emotion?" p. 52.
- 87. III THE MEANING OFMORAL OBLIGATION The author of "Conscience, its Origin and Authority," attempts, after the manner of priests, to demolish the Utilitarian principle of morality by stating that the Utilitarian must, to be logical, justify any means if the end is desirable. As though the Utilitarian and not the Theist was for ever trying to show that the intrinsic character or value of an action depended upon the motive (which must be distinguished from the intention; a man who saved another from drowning in order to put him to death afterwards would be influenced by an intention to murder, but the motives were: first, desire to rescue, and, for the subsequent action, desire to kill). Mr. Richardson writes: "The Good and the Right possess their authority to the Utilitarian because they tend to the greatest possible happiness of the greatest number of sentient beings." Now suppose a case which I do not think actually happened, but which may easily be conceived as happening. Suppose that Cecil Rhodes deliberately caused the South African War, as many people believed at the time. This would be characterized (and was, in fact, characterized) as an immoral act of unscrupulous aggression. But he might defend his action thus: "Granted that so many thousands of soldiers and citizens will be slain, and the land cleared of its inhabitants. In a few years the land so cleared will produce increased harvests of gold and grain. More food will mean an increase of human productiveness and an increase of population; thriving townships and farmsteads will support a people more numerous and richer in the comforts which make life desirable than could have existed without my action. Therefore on the Utilitarian hypothesis my action was right and good, and deserved, not reprobation, but approval."
- 88. Not only isthis position not admitted by Utilitarians, but John Stuart Mill long ago pointed out that such a hypothesis "is to mistake the very meaning of a standard of morals, and to confound the rule of action with the motive of it. It is the business of Ethics to tell us what are our duties, or by what test we may know them; but no system of ethics requires that the sole motive of all we do shall be a feeling of duty.... The great majority of good actions are intended, not for the benefit of the world, but for that of individuals, of which the good of the world is made up; and the thoughts of the most virtuous man need not on these occasions travel beyond the particular persons concerned, except so far as is necessary to assure himself that in benefiting them he is not violating the rights—that is, the legitimate and authorized expectations—of any one else."[25] This is sufficient refutation of such objections to Utilitarianism as the one brought forward by Richardson, and clearly founded on a misconception. Mill, in what is still the best defence of this system, continues: "Utilitarians ... are ... of opinion that in the long run the best proof of a good character is good actions; and resolutely refuse to consider any mental disposition as good, of which the predominant tendency is to produce bad conduct."[26] "The creed which accepts as the foundation of morals, Utility, or the Greatest Happiness Principle, holds that actions are right in proportion as they tend to promote happiness, wrong as they tend to produce the reverse of happiness."[27] The Theistic writer says "the essence of morality is sacrifice."[28] The utilitarian morality does recognize in human beings the power of sacrificing their own greatest good for the good of others. It only refuses to admit that sacrifice is itself a good. A sacrifice that does not increase, or tend to increase, the sum total of happiness, it considers as wasted.
- 89. As regards "conscience":the Utilitarian, when he attempts an analysis, realizes that "in that complex phenomenon as it actually exists, the simple fact is in general all encrusted over with collateral associations derived from sympathy, from love, and still more from fear; from all forms of religious feeling; from recollections of childhood and of all our past life; from self-esteem, desire of the esteem of others, and occasionally even self-abasement."[29] For the priest "ethics cannot be built securely upon anything less than religious sanctions, and it is for the sake of conscience that ethics have a practical value."[30] Can an honest and unbiased thinker doubt that the first is the truer statement? Let us now return to a further statement of the position of Utilitarianism as dealt with by J. S. Mill. From Professor Sidgwick and those Utilitarians who attempt to claim for the atheistic moralist a conscience of mathematical accuracy we are unlikely to derive much assistance. "According to the Greatest Happiness Principle, the ultimate end, with reference to, and for the sake of which, all other things are desirable (whether we are considering our own good or that of other people), is an existence exempt as far as possible from pain and as rich as possible in enjoyments, both in point of quantity and quality; the test of quality, and the rule for measuring it against quantity, being the preference felt by those who, in their opportunities of experience, to which must be added their habits of self- consciousness and self-observation, are best furnished with the means of comparison."[31] This, according to Utilitarians, is also the standard of morality. In conformance with this principle of moral obligation, we choose the greater before the lesser good. Between General Morality and the obligation of Duty, with which he associates justice, Mill draws what appears to be a somewhat unnecessarily hard line of
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