Those most affected by heat extremes are the socially isolated elderly and poor. Populations living at the margins of malaria and dengue habitat, without effective primary health care, will be the most affected if these diseases expand their geographic range.
NC Human Impact Unit
Humans and Nature: An Overview
“The environmental crisis is an outward manifestation of a
crisis of mind and spirit. There could be no greater
misconception of its meaning than to believe it is concerned
only with endangered wildlife, human-made ugliness, and
pollution. These are part of it, but more importantly, the
crisis is concerned with the kind of creatures we are and
what we must become in order to survive.”
~ Lynton K. Caldwell
If you really got a hold
of anything in the
Universe, you find out
that it’s hitched to
John Muir, Founder,
Diagram makes it clear that environmental science is
multidisciplinary and interdisciplinary.
That is, “it takes all kinds” of observations and inputs to “do”
The Human Impact Problem?
Several themes—recurring and inter-connected
Human population x demand for resources = root
(Problem for each other as individuals, communities,
nations; for the rest of the ecosphere.)
The impact of environment on human health
Assignment – Cats of Borneo
A simple exercise to get you thinking about the
interconnectedness of man, environment and how one
decision can cause a domino effect in the scheme of
Complete “Cats of Borneo” activity
You will receive an envelope with 13 statements
which are numbered.
Your job as a group is to order them by event
Based on a true story
Change in the Biosphere
= change in the environment
Changes in the Lithosphere
•Leads to local and global
•Competition for resources
•Destruction of habitats and
upheaval of human populous
Changes in the Atmosphere
Normal or enhanced?
Loss of ozone due to
Increase of natural
gases (Sulfur and
CO2) due to volcanic
Changes in the hydrosphere
*remember, water flows downhill—The 1st Law of Ecology
What characteristics of Earth make life possible?
Air (nitrogen, oxygen,
carbon dioxide and
Sun – driving force
behind all life
All the parts of Earth that
support and contain life.
Reaches from the floor of
the ocean to the tops of
Approximately 20 km
(12.4 mi) thick.
If the earth were an apple, the
ecosphere would be no thicker
than the apple’s skin!
Study of the interaction between
organisms and their environment,
composed of abiotic (NON-Living) and
biotic (living) factors
Food Web – a network of food chains
representing the feeding relationships
among the organisms in an ecosystem
concentration of a
pollutant in organisms at
higher trophic levels in a
Ex. In 1972 the US
banned the use of DDT.
By 1991 bald eagle
population rebounded 4X.
Diversity and Stability
A deciduous forest is an example of a
stable ecosystem that has a food web with
A small disturbance has a small effect on
a deciduous forest. Conversely, a tundra
has few links in the web, therefore a small
disturbance can have a larger impact.
Energy in the Ecosystem
The ultimate and only significant source
of energy in most ecosystems is that
radiated by the sun.
This energy is the driving force of
photosynthesis. Of the total sunlight
received on the earth, only 20-25% is
available for photosynthesis because
only the longer wavelengths are used in
Key players in ECOLOGY:
Producers, Consumers and Decomposers
All biomes (and ecosystems within
biomes) contain three different kinds of
Organisms that make
their own food from
EX. - Plants
1) Cannot produce their own food
(animals, humans- any living thing
that does not have chlorophyll)
2) Must eat other organisms (plants
and/or animals) to get their energy
EX: animals, fungi, protists and
Bacteria and fungi that consume the bodies of
dead organisms and other organic wastes.
Decomposers complete the cycle of matter in
call the different
feeding levels of
organisms in a
From the root
meaning to feed
the higher one
consecutive layer or
level contains fewer
organisms than the
level below it.
The total amount of
organic matter present
in a trophic level.
Potentially food for the
next trophic level.
As organisms do work,
they use energy, and
must continue to take
in additional fuel to
continue doing work
Cycles of Matter
Chemical composition of human body
Water Cycle – All the water on Earth which is
continually cycled from hydrosphere to atmosphere and
Plants use CO2 and
sunlight to make
sugars and starches
Organisms require nitrogen in order to
make amino acids, the building blocks of
80% of Earth's atmosphere is made up of
nitrogen in its gas phase.
Plants take up the nitrates and convert
them to proteins that then travel up the
food chain through herbivores and
carnivores. When organisms excrete
waste, the nitrogen is released back into
The extinction of a population due to direct
competition with another species for a resource.
If two species try to share the same niche in the
same habitat, they will compete for resources.
If one is better than the other, one will have to
move to another area or extinction may occur.
Exponential Growth –
population growth in
which the rate of
growth in each
generation is a
multiple of the
City Lights from Space
Geospatial demographers, such as Deborah Balk, use satellite images of the Earth at
night to estimate population densities.
Human Population on the 50th Earth Day
The following is from an insert to a solicitation
letter from the group Zero Population Growth.
In the seconds it takes you to read this sentence, 24 people will be added to
the Earth’s population.
Before you’ve finished this letter, that number will reach 1,000. Within an
hour ... 11,000. By day’s end ... 260,000.
Before you go to bed two nights from now, the net growth in human numbers
will be enough to fill a city the size of San Francisco.
It took four million years for humanity to reach the 2 billion mark. Only 30
years to add a third billion. And now we’re increasing by 95 million every
No wonder they call it the human race.
The number of individuals of a species
that can be supported by an ecosystem.
As population grows, it takes more from its
Resources such as food and living space
As resources become scarce, individuals
begin to compete.
Change is a fact of life!
Living things have evolved in response to
As an environment changes, the
community changes with it.
In many cases, different communities
follow one another in a definite pattern.
Evolution and Adaptation
over time and
changes in the
the evolution of
Health depends on
Good health depends
on accessibility to
Bad health results
from inaccessibility to
or exposure to a
Both exist in the
Therefore, quality of
health depends on
Community Action and the
What are the environmental problems that
we face as communities, as states, as a
country, and as part of the global
How many environmental problems are
you aware of?
Human Population and
What impact does an ever increasing
population have on global health issues?
What characteristics of life allow it to influence the
environment on the global scale?
Life spreads exponentially
The environmental problems we face –
population growth, wasteful use of
resources, destruction and degradation of
wildlife habitats, extinction of plants and
animals, poverty, and pollution – are
interconnected and are growing
More People = More Competition
According to the United
Nations, world population
reached 7 billion on
October 31, 2011
According to the most
recent estimates, world
population is expected to
reach 8 billion people in
the spring of 2024.
What matters is that we
are competing for
Which leads to global environmental
Risk, Toxicology and Human Health
Climate, Global Warming and Ozone
Water resources and water quality
Solid and hazardous waste disposal
TRUE or NOT???
Regardless of whether you believe that
man is enhancing global warming or we
are just in a “normal” warming period – the
ensuing environmental changes will have
an impact on both animals and humans!
60 Minutes Video on evidence in Antartica
What impact will climate change (global
warming) have on the human species?
Loss of fresh water
Increase in disease
6 of Change!
Climate Change and Food
Climate Change and Food Security: Out of
Now that scientists agree? What do
to feed the world in 2050: actions
in a changing climate
Human Human Health
What impact will global warming have on
our human health?
Think about disease and the spread of
disease – can you make a connection
between climate change and the spread
Kinds of health impacts resulting
from climate change:
Direct- result from
Social factors affecting health
Level of economic development of the
Pre-existing health status
Availability of health care
Human Population Dynamics
What have we learned about the impact of
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