2. CCoonntteennttss
1. Major climate controls
2. The climate of the British Isles
3. The climate of one tropical region: Tropical
monsoon climate
4. Urban climates
5. Global climate change
3. Major CClliimmaattee CCoonnttrroollss::
TThhee ssttrruuccttuurree ooff tthhee aattmmoosspphheerree
Atmosphere (air) a layer of transparent gases
surrounding the earth held in place by gravitational
pull.
Mesosphere
Extends to 85km above the earths surface. The
layers in which most meteors will burn up.
Stratosphere
The ozone layer (O³) is mainly concentrated at
15 – 35km in the stratosphere. The stratosphere
extends to 51km above the earths surface.
Troposphere
Ranges from the Earth’s surface to 7km at the
poles to 17km at the equator. An unstable layer
containing the majority of the earths climate and
weather. 99% of the total mass of the
atmosphere is found in this layer; 50% of it is
below 5.6 km, and contains 99% of water vapour.
Thermosphere
Extends to over
640km from the
earth’s surface.
The
International
Space station
orbits at around
350km.
Mesospause
Stratopause
Tropopause
An isothermal
layer: constant
temperatures.
4. TThhee ssttrruuccttuurree ooff tthhee aattmmoosspphheerree::
TTeemmppeerraattuurree
• Lapse Rate the decrease of temperature with height.
• Troposphere the temperature
decreases by 6.4°C every 1000m. At
the tropopause temperatures drop
to - 60°C.
• Stratosphere a temperature
inversion occurs: temperatures
steadily increase reaching almost
0°C due to the ozone layer absorbing
ultra-violet radiation.
• Mesosphere the temperature
decreases to almost -100°C as
radiation can not be absorbed.
• Thermosphere an inversion as
temperature rises due to solar
radiation being absorbed by the
presence of atomic oxygen.
5. TThhee ssttrruuccttuurree ooff tthhee aattmmoosspphheerree::
CCoommppoossiittiioonn
N² Nitrogen important for plant growth
O² Oxygen product of photosynthesis
Ar Argon
CO² Carbon dioxide used for
photosynthesis
Ne Neon
He Helium
CH4 Methane
Kr Krypton
H² Hydrogen
7. TThhee aattmmoosspphheerriicc hheeaatt bbuuddggeett
Solar energy affects:
• Temperature
• Climate
• Atmospheric motion
• Precipitation
• Ocean currents
The incoming solar radiation is short-wave;
insolation. As the Earth heats up it radiates its
own heat in the form of long-waves (infra-red);
terrestrial.
The albedo is the percentage of radiation that is
reflected. This depends on the type of surface.
8. • There are several
aspects that control
the amount of
incoming solar
radiation:
– Sunspot activity
– Elliptical Earth’s orbit
– Day and night
– Latitude
9. Average net radiation (w/m²)
125
100
50
25
0
25
50
100
125
Radiation balance at Earth’s surface
Net radiation gain
80 60 40 20 0 20 40 60 80
degrees from equator
How is the positive heat balance (net gain in heat radiation from the sun)
within the Tropics transferred?
1. Air Horizontally
movements, including winds, jet stream, cyclones, depressions. These
account for 80% of heat transferred. Ocean currents transfer the remaining 20%.
2. Vertically
Conduction, convection and radiation.
positive
balance
negative
balance
TThhee aattmmoosspphheerriicc hheeaatt bbuuddggeett
Radiation balance in atmosphere
10. GGeenneerraall aattmmoosspphheerriicc cciirrccuullaattiioonn
Energy deficit
Energy surplus
Energy deficit
Heat is re-distributed by
ocean currents and wind
Winds blow from areas of high pressure to areas of low pressure.
If the Earth did not rotate a single convection cell would operate
in both hemispheres.
11. GGeenneerraall aattmmoosspphheerriicc cciirrccuullaattiioonn
As air moves from high to low pressure in
the northern hemisphere, it is deflected to
the right by the Coriolis force. In the
southern hemisphere, air moving from high
to low pressure is deflected to the left by
the Coriolis force.
All points on the earth’s surface have the
same rotational velocity (they go round
once per day).
An object travelling away from the
equator (e.g. wind) will eventually be
heading east faster than the ground
below it and will seem to be moved east
by some mysterious "force". This
movement is eastwards in the northern
hemisphere and westwards in the
southern hemisphere.
The diagram illustrates how it
affects winds in both hemispheres.
High pressure
Low pressure
due to the
earth’s rotation
UK
Equator low
high
high
low
low
60
60
12. Air that does not
travel to next cell
returns to Equator
as trade winds
Hadley
cell
Warm air from the tropics
meets cold air from the pole
at the POLAR FRONT
Ferrel
cell
causing depressions
Warm air
rises
Polar
cell
North Pole 30o
Equator
High pressure
Divergence zone
Low pressure
Convergence zone
60o
Low pressure
Convergence zone
High pressure
Divergence zone
North-east trade winds
Heat from the Sun
most intense at
the Equator
ITCZ
Heavy
convection
rainfall
Air cools
and sinks
Air gets
deflected
northwards
Warm air
rises and
becomes
unstable
Easterlies (winds) South-westerlies (winds)
Cold air
sinks
Dry and
stable
Dry and
stable
AAttmmoosspphheerriicc cciirrccuullaattiioonn:: tthhee ttrriicceelllluullaarr mmooddeell
Trade winds pick
up latent heat
The Hadley cell is the largest due to the intense heating of
the Earth’s surface at the Equator.
14. TThhee IInntteerrttrrooppiiccaall ccoonnvveerrggeennccee zzoonnee ((IITTCCZZ))
• The ITCZ is the region that circles the Earth, near the Equator, where the
trade winds of the Northern and Southern Hemispheres come together.
• The intense sun and warm water at the Equator heats the air in the ITCZ,
raising its humidity and causing it to rise.
• As the air rises it cools, releasing the accumulated moisture in an almost
constant series of storms.
• Variation in the location of the ITCZ drastically affects rainfall in many
equatorial nations, resulting in the wet and dry seasons of the tropics
rather than the cold and warm seasons of higher latitudes.
• A shift in the ITCZ can have serious ramifications delaying the rainy
season resulting in drought, for example the drought in the Sahel during
the 1980s.
Cumulo-nimbus clouds along
the ITCZ
15. The location ITCZ changes seasonally; south in January and
north in July. This causes monsoons.
16. PPllaanneettaarryy ssuurrffaaccee wwiinnddss
• Winds are the movement of air in the
atmosphere.
• Wind speed is affected by a number of factors
that operate on a variety of scales. These
include:
• the pressure gradient,
• Rossby waves.
• jet streams.
• and local weather conditions such as sea
breezes and urban winds.
• Wind speed depends on how large the
difference is because the greater the difference,
the faster the wind moves between the two
points as it attempts to equalise the pressure.
• Local weather conditions can also influence wind
speed as the formation of tropical storms and
hurricanes can drastically affect the velocity of
the wind.
Jet stream
17. RRoossssbbyy WWaavveess
These are bands of strong winds blowing around the globe in the upper atmosphere (about
10km to 15km above the surface). They drive surface weather systems like depressions. A
slight change in their path is what caused the very wet summer in 2007.
18. Jet streams are bands of even faster winds (300km/hr) within the Rossby
waves at about 10km above the surface. Commercial airlines often make use
of them to reduce fuel consumption.
There are two jet streams:
• The Polar Jet above the
Polar Front (the
boundary between polar
and mid-latitude cells).
• The Subtropical Jet
(between Ferrel and
Hadley cells) which
exists as a mechanism to
transport moisture and
energy from the tropics
polewards.
JJeett ssttrreeaammss
19. OOcceeaann CCuurrrreennttss
Atmospheric processes are closely linked to the oceans because they store massive
amounts of heat energy (and water) which has a major influence on weather and
climate. They are involved in the horizontal transfer of heat with warm currents carrying
water towards the poles and cold currents towards the Equator. This has the effect of
raising or cooling the surrounding sea and air temperature which affects coastal
climate.
20. Why does temperature decrease wwiitthh aallttiittuuddee??
Temperature drops by 6.5°C
every 1000 metres.
21. The cclliimmaattee ooff tthhee BBrriittiisshh IIsslleess
The British Isles has a Cool Temperate Western Maritime Climate.
It has:
• Clearly defined
seasons
• Warm summers;
12°C to 20°C
• Mild winters
• Low temperature
ranges
24. CClliimmaattiicc ccoonnddiittiioonnss:: tteemmppeerraattuurree
60°
55°
50°
Due to the influence of
latitude the south of the
British Isles has warmer
summers and milder
winters than the north.
Due to continentality the
east of the British Isles has
warmer summers and
colder winters than the
west.
Summer: 14 °C
Summer: 14 °C Winter: 3 °C
Winter: 6 °C
Summer: 16 °C
Winter: 7 °C
Summer: 18 °C
Winter: 4 °C Prevailing wind
25. CClliimmaattiicc ccoonnddiittiioonnss:: wwiinnddss
Anabatic flow (day) Katabatic flow (night)
Surface is heated by
insolation.
Warm air
becomes
unstable. Clouds
are formed
Warm air rises up
the gradient.
Descending
cool air leaves
the centre of
the valley clear
At night the air cools and as it
become denser it sinks down the
valley sides into the valley.
Fog may form in
winter
26. Air masses aaffffeeccttiinngg tthhee BBrriittiisshh IIsslleess
An air mass is a large body of air in which temperature and humidity are almost
uniform horizontally but change vertically within. They are classified by their
surface temperature and humidity.
The temperature,
humidity and
stability of an air
mass alters as
they are
influenced by the
surface over
which they travel.
28. Air masses aaffffeeccttiinngg tthhee BBrriittiisshh IIsslleess
Polar Maritime Air
Mass
Source region: Canada
and Arctic Ocean.
Tropical Maritime Air Mass
Source Region: the Azores
Polar continental Air Mass
Source Region: Siberia & East
Europe.
Tropical continental Air Mass
Source Region: North Africa
Arctic Maritime Air Mass
Source Region: Arctic Ocean.
Frontal depressions occur
when Pm and Tm meet
See Teacher’s notes for more information
29. OOrriiggiinn aanndd nnaattuurree ooff ddeepprreessssiioonnss
Depressions occur along the polar front where Tm and Pm air masses meet.
They are low pressure weather systems; how low the pressure falls is determined by the
rate at which air rises from the surface. Average pressure is 1013mb.
The speed at which a depression travels is determined by the speed of the jet stream
in the troposphere. The life cycle of a depression is normally 3-5 days.
33. Origin and nnaattuurree ooff aann aannttiiccyycclloonnee
Source of anticyclones: Dry air in the upper layers of the atmosphere.
Dew point
As cool dry air descends
its temperature increases
at the dry adiabatic lapse
rate DLRA. High pressure
is created at surface.
Weather is drier and more
stable at the surface. The
pressure gradient is gentle
resulting in light clockwise
winds.
34. OOrriiggiinn aanndd nnaattuurree ooff aann aannttiiccyycclloonnee
In the UK anticyclones are associated with extended warm, dry conditions in
the summer and cold, frosty and sometimes foggy conditions in the winter.
An anticyclone may be 2500 km in diameter, although many are smaller.
clockwise
The satellite image shows the
cloudless skies associated with high
pressure systems. They may remain
for a number of weeks causing heat
waves across many parts of Europe
during the summer.
The synoptic chart for a mid-latitude
anticyclone
36. Associated wweeaatthheerr ccoonnddiittiioonnss ooff
aannttiiccyycclloonneess iinn wwiinntteerr aanndd ssuummmmeerr
Anticyclonic weather in the UK
Winter conditions (Polar source Summer conditions (tropical source)
Conditions Impacts Conditions Impacts
Cold day time conditions
Usually below freezing
Ice. Increase in accidents
particularly elderly
Increased power use
Hot daytime conditions
over 23o
Increase in heart
attacks/heat stroke
Increase in sales of
lettuce/ice cream/soft dinks
Hose pipe bans/drought
Very cold at night with frosts Roads need gritting Warm at night Sleeping difficulties
Clear skies Temperatures remain low Generally clear skies Sunburn/sunstroke
Stable conditions may
produce fog
Car accidents
Disruption to transport
(aircraft, ferries, trains)
Some early morning mists
especially at coast
May take a while to clear
impacted tourists
High levels of pollution due
to lack of wind
Breathing difficulties Thunderstorms may form
in evenings due to
convection
Flash flooding effects
homes and transport
Subsiding air traps pollutants Hospitals admissions
increase
Photo-chemical smog and
low level ozone trap heat
Increase in deaths from
asthma/breathing
conditions
37. • June to August 2003
• Over 2,000 died in the UK
between 4–13 August
2003.
• Highest temperature
recorded in Kent : 38.5°C
• Over 30,000 deaths in
Europe.
• £7 billion in crop loss.
• Railway tracks buckled.
The map shows the temperature variations
from normal in Summer 2003.
38. Storm eevveennttss iinn tthhee BBrriittiisshh IIsslleess::
BBoossccaassttllee 22000044
• August 16th 2004
• Large depression in Eastern Atlantic, sucking in
warm moist air – including the remnants of
Hurricane Alex
• Blew in from the sea in prevailing SW direction
• Met with SW wind and created convergence
• Also, intense uplift that morning in Cornwall
due to warm, sunny conditions – cumulonimbus
rose to 40,000ft.
• Intense, very localised storms.
• 200mm of rain in 24 hours, over 300mm per
hour at peak intensity.
• Most between midday and 5pm on the 16th on
high ground to the east.
• Already saturated catchment – rapid runoff.
• Boscastle lies in a deep valley just downstream
of the confluence of the rivers Valency and
Jordan.
39. SSttoorrmm eevveennttss:: BBoossccaassttllee 22000044 -- iimmppaaccttss
• 2 metre rise in river levels in one hour, floodwater velocity of 10mph.
• Est. 2million tonnes of water flowed through Boscastle that day.
• Debris caught under narrow bridge caused 3m high wave of water which
burst down main street when bridge collapsed.
• 84 cars recovered after being swept away; 32 never seen again!
• Significant structural damage – 58 properties affected, 4 swept away.
• 100 people air lifted to safety but no loss of life.
• 300 metres of sewers damaged or destroyed.
• Cost of damage estimated at £2million.
40. Storms eevveennttss:: BBoossccaassttllee 22000044 -- rreessppoonnssee
The flood management improvements in
Boscastle since the 2004 floods:
• Large relief culvert completed in April 2005 to
divert flood water from River Jordan.
• Widening and deepening of the River Valency
upstream of Boscastle..
• Car park raised in December 2006, using
stones removed from bed of River Valency
during widening and deepening works.
• Old stone lower bridge demolished – it was
over 100 years old and trapped 14 cars
beneath and behind it in the 2004 flood.
The cost of the River Valency works, car park and
bridge work is about £4.6 million, although it will still
not prevent a flood as severe as the 2004 event,
which has a chance of about 1 in 400 of occurring in
any one year.
41. The location ooff ttrrooppiiccaall cclliimmaatteess
Equator
The ITCZ influences the location of
tropical climates. Its northerly and
southerly limits are shown on the map.
Tropical climates are
located between the
Tropic of Cancer and
Tropic of Capricorn.
Tropic of Cancer
Tropic of Capricorn
ITCZ
ITCZ
42. TThhee cclliimmaattee ooff aa ttrrooppiiccaall rreeggiioonn::
tthhee MMoonnssoooonn CClliimmaattee
Monsoon is the reversal of wind direction
that results in a clearly defined wet and
dry season.
Locations that receive the majority of
their rainfall in one season have a
monsoon climate. They are found in
coastal regions of south Asia, Southeast
and north east Brazil, northern Australia,
West Africa.
Monsoon rainfall, Kerela, India
Gujarat, India July 2005 under monsoon
rains and suffering from serve floods
Gujarat before the start of monsoon
43. The cause of the mmoonnssoooonn cclliimmaattee -- IInnddiiaa
In mid- summer
the ITCZ has
move north over
India.
Air cools and sinks over ocean
Strong insolation causes
surface temperatures to
increase; low pressure causes
rapid uplift of warm air.
Moist air is sucked in
to replaced rising air.
Heavy orographic
rainfall can occur.
In winter the
ITCZ has
moved south.
The North
easterly trade
winds blow
south into
Equatorial Low.
Trade winds cause off shore
winds to blow across India
High pressure over
land as cool air
descends from the
Himalayas. Dry
conditions prevail.
44. TThhee cchhaarraacctteerriissttiiccss ooff tthhee
MMoonnssoooonn cclliimmaattee
March – May: Highest
temperatures and very dry. A
period of drought.
June – September: Heavy
rainfall. High humidity as the
temperatures remain hot.
October to February: Dry
season. Little precipitation.
Temperatures not as hot as
in March to May period.
Monsoon clouds over Lucknow, India.
45. Climate statistics ffoorr MMuummbbaaii && NNeeww DDeellhhii
Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec
Average
Temp.
(°C)
23.
5
23.5 26 28 30 29 27 26.5 26.5 28 27.5 26
Precipita
tion
(mm)
2.5 2.5 2.5 0 18 485 617 340 264 64 13 2.5
Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec
Average
Temp.
(°C)
14 16.5 22.5 28 33.5 33.5 31.5 30 29 26 20 15.5
Precipita
tion
(mm)
23 18 13 8 13 74 180 173 117 10 3 10
Mumbai
New
Delhi
46. SSuubb--ttrrooppiiccaall aannttiiccyycclloonneess
30°N
30°S
Sahara Desert
Namib Desert
Kalahari Desert
Equator
The Sahel
Prolonged period
of drought during
the 1980s. The
fluctuating location
of the ITCZ and its
progression south
linked to El Nino
events is one
cause of droughts
in this region.
47. TTrrooppiiccaall rreevvoollvviinngg ssttoorrmmss
Tropical depression
(winds less than 38 mph)
Tropical revolving storms
are very low pressure
weather systems with strong
winds and heavy rainfall.
They get their energy from
the sea and begin to die out
when they are over land.
Tropical storm (winds 39 – 73 mph)
Hurricane (winds >74 mph)
The aftermath of a tropical storm
49. TThhee ooccccuurrrreennccee ooff ttrrooppiiccaall rreevvoollvviinngg ssttoorrmmss
named storms
major
hurricanes
2005 was the worst year
on record for hurricanes
An average of 7.7 named storms and 3.6 major hurricanes since 1995 compares to
5 storms and 1.5 major hurricanes from 1970-1994.
50. FFoorrmmaattiioonn ooff aa ttrrooppiiccaall ssttoorrmm
Colder air sinks in the centre – the
‘eye’
Rising air spirals, cools and
condenses – cumulonimbus clouds
bring torrential rain and thunder
Strong upward movement of air
draws water vapour up
Warm (> 27°C), shallow (<60m)
seas
52. CCaassee ssttuuddyy:: HHuurrrriiccaannee KKaattrriinnaa 22000055
Hurricane Katrina first appeared on August 23 as a tropical depression just west of
the Bahamas.
August 25th Category 1* < 95 mph (< 155 km/ hr)
August 26th Category 2* 100 mph (160 km/ hr)
18 hours later Category 3* 115 mph (185 km/ hr)
August 28th Category 4* 145 mph (235 km/ hr)
Six hours later Category 5* 160 mph (255 km/ hr)
* on the Saffir-
Simpson scale
53. Case ssttuuddyy:: HHuurrrriiccaannee KKaattrriinnaa 22000055
The animated sequence
shows the path of Katrina
on the 29th August 2005
as it crossed the
Caribbean and moved
towards the southern
states of the USA.
Eventually it struck land
with devastating
consequences for the
people of New Orleans
and the surrounding
areas.
New
Orleans
54. LLaannddffaallll
Hurricane Katrina made landfall at 6.10am in Louisiana 29th August
Failure of the levées surrounding New
Orleans caused the greatest damage.
Winds speeds of 280 km per hour.
Red = hurricane force winds.
Up to 380mm of rain in places.
Storm surges, peaking at
8.5m high.
Strongest ever recorded hurricane to make landfall in the USA.
55. HHuurrrriiccaannee KKaattrriinnaa:: IImmppaaccttss
• By August 31st 80% of New Orleans lay
under water.
• 1.7 million people without electricity.
• $150 billion estimated total economic
impact.
• 1464 died in Louisiana.
• Almost everyone instantly unemployed!
• Estimated 600,000 pets killed.
• Lack of clean water, food and toilet
facilities.
• Oil and natural gas industry affected.
• Communications and transport
infrastructure damaged and failed.
57. MMaannaaggiinngg tthhee rriisskk
New Orleans waterfront
To repair the defences in New Orleans they:
• Repaired the levees – breached levees
repaired and all levees to be raised by 2010.
New floodgates to be built at canal entrances.
• Restored the wetlands – The $14 billion, 30-
year ‘Coast 2050’ plan to recreate the mixture
of swamp, marshland and barrier islands to
protect places inland as before.
How can New Orleans be prepared for another hurricane like Katrina?
• Preparation - National Hurricane Centre watches and produces warnings. It also runs a
‘hurricane preparedness week’ every year for the public. DHL also run schools workshops on
hurricane preparedness
• Evacuation – evacuation order given on 28th August 2005 by Mayor. However, it’s hard to
predict the path, very expensive and not everyone is able to leave. In advance of Hurricane
Gustav – which was heading for New Orleans at the end of August 2008 – the Mayor of New
Orleans ordered an evacuation to prevent a similar disaster. Over 90% of residents left the
city.
58. CCaassee ssttuuddyy:: CCyycclloonnee NNaarrggiiss 22000088
Convection increases,
Changes direction eastwards
April 27th: formed in
Bay of Bengal
May 1st
Convection decreases
Originally predicted to
hit Bangladesh or SE India
Landfall May 2nd Burma.
Peak winds of 215 km/h
Category 4
Dies outs May 3rd
59. Cyclone NNaarrggiiss MMaayy 22000088:: TThhee iimmppaaccttss
146,000 fatalities
1000s missing.
Many feared washed
out to sea
2.7% of projected GDP
predicted lost by event
1,163 temples
destroyed
Extensive destruction
of buildings, e.g. Labutta
town 75% buildings collapsed
700,000 homes
destroyed in delta
5 regions declared
a disaster area $10 estimated cost
65% of paddy fields
contaminated by
salt water
75% of health service
& 4,000 schools
damaged
75% livestock killed
100,000 fishing
vessels destroyed
60. Cyclone NNaarrggiiss MMaayy 22000088:: tthhee rreessppoonnssee
• 44 countries responded by
donating money to the relief
operation, food, shelter,
volunteers, water and medicine.
• Long term response has been to
restore quality of life through
projects working with farmers,
rebuilding school and health
centres and clean water supplies.
• Improving road infrastructure to
allow for quicker access to safer
areas in future disasters.
• Preparation to prepare people in
most vulnerable areas and
educate on appropriate response.
61. Climate on aa llooccaall ssccaallee:: uurrbbaann cclliimmaatteess
UUrrbbaann hheeaatt iissllaanndd eeffffeecctt
A micro climate is the climate of a small area. Temperature, precipitation, wind
and atmospheric gases are distinctly different in an urban area to that of a rural
area. An urban heat island describe how temperatures are highest at the centre
of the urban area and decrease towards the suburbs.
Urban areas are warmer because:
• Industries, homes & vehicles burn
fuel realising heat.
• Pollution from industry and vehicles
traps heat.
• Dense and dark coloured surfaces
of buildings and roads absorb heat.
• Small amounts of water and
vegetation so little energy is used in
evapotranspiration.
TTeemmppeerraattuurreess aarree ggrreeaatteesstt wwhheerree tthhee
bbuuiillddiinngg ddeennssiittyy iiss hhiigghheesstt
62. Urban climates: PPrreecciippiittaattiioonn aanndd wwiinndd
There is 5 – 30% more rain in urban areas than
in rural area due to a greater density of
condensation nuclei allowing for cloud
formation
There is 14% less chance of
snow in urban areas than
rural areas due to the
increased temperatures
Thunderstorms
are 25% more
likely urban areas
due to strong
convectional
uplifts of warm air
There is 10 times
more condensation
nuclei in urban areas
and this can lead to a
100% more likelihood
of fog in winter and
30% more in
Wind speed is summer.
20% less in
urban areas
are the building
act as barriers.
Tall buildings can
channel wind
resulting in strong
Prevailing winds blow pollution and rain gusts.
clouds. Consequently the west of
London was traditionally more desirable
63. UUrrbbaann cclliimmaatteess:: aaiirr qquuaalliittyy
Smog occurs during anticyclones. A
temperature inversion is causes as cool air
sinks to replace the rapid uplift of warm air.
Pollution is trapped below the warm inversion
layer causing a pollution dome to form.
Photochemical smog is caused as
above normal levels of nitrogen
dioxide and ozone are produced when
pollution and sunlight react.
65. EEvviiddeennccee ffoorr ppaasstt cclliimmaattee cchhaannggee
Climate varies on all time scales from the short –term (the recent retreat of
glaciers) to the long-term (deposition of desert sediments to form sandstone) in
response to random and periodic forcing factors.
Some of these could be due
to short-term changes e.g.
random variations in the
climatic systems.
Present day ice limit
Extent of glacier
retreat in little over
50 years
Ice limit in 1946
67. EEvviiddeennccee ffoorr ppaasstt cclliimmaattee cchhaannggee
Past sea levels
The ice ages brought eustatic change. Sea levels fell as huge volumes of water
were transferred to glaciers and ice caps. Subsequent melting would then cause
an increase in sea level. Such changes are termed glacio-eustatic.
Measuring sea level change
Accurate measurements can be made of past sea levels by observing one or
more of the following features.
1. Shoreline deposits such as shells, wood and peat found in marine cores.
2. Exposed rock outcrops containing marine fossils.
3. Vegetated tidal flats above the high water mark.
4. Exposed coral reefs.
5. Marine rocks displaying evidence of wind-borne erosion.
Past sea levels were up to 200m
above present during interglacials
and 100-150m below present during
glacials.
Other techniques include studying glacial
advances/retreat, ice cores, isotope
analysis, geology, pollen,
dendrochronology and
archaeological/historical data.
68. TThhee ccaauusseess ooff cclliimmaattee cchhaannggee
Climate change can take three forms:
1. Short-term change
Climate since the end of
the last ice age
(hundreds/thousands
years)
Very short-term: El Nino,
La Nina.
2. Long-term change
Global climate over billions of
years.
3. Paleoclimates
Climates from thousands /
millions of years ago.
69. GGlloobbaall wwaarrmmiinngg:: ccaauusseess
Shortwave radiation reaches
Earth’s atmosphere
Some is reflected
Some of the re-radiated long wave
radiation is trapped by water
vapour and “Greenhouse gases”
(CO2 CFCs, CH4, N2O)
Earth absorbs the radiation
Most gets through
Earth’s surface warms up and emits longwave radiation (re-radiates energy)
70. GGlloobbaall wwaarrmmiinngg ––
NNaattuurraall ccyyccllee vv hhuummaann iimmppaacctt
The current scientific consensus is that global warming is a real threat and it is a result of
human activity. However, some people continue to debate whether global warming actually
exists and/or whether it is as a result of human activity. The evidence for past climate
change is often cited to explain the current changing conditions.
Carbon
dioxide
emissions
since 1840
71. GGlloobbaall wwaarrmmiinngg
Most scientists agree that global warming is being caused by human effects
on the atmosphere, principally through carbon dioxide emissions.
Rank Country
1 USA
2 China
3 Russia
4 Japan
5 India
6 Germany
7 Canada
8 UK
9 Italy
10 South Korea
Top ten carbon dioxide emitters.
USA and China are the
two greatest emitters.
74. The effects ooff gglloobbaall wwaarrmmiinngg oonn
• Bangladesh is very
densely populated.
• Many fresh water
fishing resources are
under threat.
• Fishing generates
substantial income
and any intrusion of
salt water would
disrupt the economy.
• Storm surges are
also a threat;
cyclonic storms
occur frequently and
with devastating
effects.
BBaannggllaaddeesshh
Sea level threats to Bangladesh
76. Response ttoo gglloobbaall wwaarrmmiinngg oonn aa
iinntteerrnnaattiioonnaall,, nnaattiioonnaall aanndd llooccaall ssccaallee
National/Local
government policy
Public /
individuals
International
agreements
Rio Earth
summit
IPCC
Kyoto
UK policy Local agenda
21
Pressure
groups
Changing
lifestyles
77. CCooppiinngg wwiitthh cclliimmaattee cchhaannggee
–– EEaarrtthh SSuummmmiitt
In June 1992 at Rio de Janeiro in Brazil, the Rio Earth Summit, was the largest
environmental conference ever held. It attracted more than 30,000 people and
over 100 Heads of State. The aim of the conference was to address the growing
global environmental problems and to agree major treaties on climate change,
forest management and bio-diversity. A number of key principles came from the
Rio Declaration including:
A key outcome was The Framework Convention on Climate Change.
78. CCooppiinngg wwiitthh cclliimmaattee cchhaannggee ––
KKyyoottoo PPrroottooccooll
• On 16th February 2005 the 1997 Kyoto Protocol became international law.
• The Protocol was agreed in Kyoto, Japan in 1997 to implement the United
Nations Framework Convention for Climate Change .
• Industrialised nations who signed up to the treaty were legally bound to
reduce worldwide emissions of six greenhouse gases by an average of 5.2%
below their 1990 levels by the period 2008-2012.
• The agreement needed to be ratified
by countries accounting for at least
55% of 1990 carbon dioxide
emissions.
• The USA believes implementation
will have a devastating effect on it’s
economy. However, President
Obama has taken steps forward in
promoting renewable energy and
reducing carbon emissions.
80. Coping wwiitthh cclliimmaattee cchhaannggee –– IIPPCCCC
The Intergovernmental Panel on Climate Change (IPCC) was set up in
1988 to assess information regarding climate change and the impact on the
planet. Since 1988 it has produced four reports, the last in 2001.
It is involved in a monitoring programme which carries out the following
activities:
• Remote observation of the atmosphere at surface and trophosphere level.
• Monitoring and measuring ocean temperatures.
• Monitoring and measuring greenhouse gas levels in the atmosphere.
• Monitoring sea-level rise and glacial and ice sheet retreat.
81. • Climate change summit
held in Copenhagen in
December 2009.
• There was
disappointment
expressed by some
environmental groups
and observers at the
outcomes of the summit.
Demonstrators at the
Copenhagen summit
Photo credit: EPO on wikipedia.
83. Tackling cclliimmaattee cchhaannggee –– UUKK ppoolliiccyy 11
So what are the present UK policies?
• Sustainable energy usage, energy conserving
houses, grants for efficient gas boilers etc.
• Waste strategies including recycling to avoid
methane from landfill. Currently, in 2004 around 17%
of waste is recycled.
• Move to renewable sources of power, combined
heat and power systems and cleaner coal.
• Green transport strategies (clean lean burn)- car
engines, fuel efficiency, new fuels, car parking (e.g.
Winchester’s extended Park & Ride and MIRACLES
project) working patterns, public transport. Indirectly,
London’s Congestion Charging will help.
84. Tackling cclliimmaattee cchhaannggee –– UUKK ppoolliiccyy 22
• Air quality regulation- strict Environment Agency
and EU requirements.
• Planning regulations: encouragement of compact
cities and avoidance of urban sprawl e..g through
the Greenbelt policy. The map shows greenbelts in
the UK.
• Carbon emissions trading scheme - setting caps
on emissions in industry.
• Technological innovation - supporting research
and development into new long term options. In
March 2001, the Carbon Trust was launched to
promote low-carbon technology and innovation in
the UK.
• The Climate Change Levy (CCL) is a tax on the
use of energy in industry, commerce and the public
sector.
85. CCooppiinngg wwiitthh cclliimmaattee cchhaannggee
–– KKyyoottoo PPrroottooccooll
As an NIC, China is considered an Annexe II country, which means it is not required to
reduce emissions under the Protocol yet it emits more carbon dioxide than any nation
in the region and 50% of emissions from all LEDCs.
As with most LEDCs, China is more vulnerable to the effects of climate change than
MEDCs. It has increasing hazards of coastal and river flooding, drought, landslides,
storms and tropical cyclones. Rising sea levels could flood low lying areas along the
Yellow and Yangtze rivers and the Pearl river delta which would affect 70% of the
population and 80% of industrial output.
River transport
on the Yangtze.
86. CCooppiinngg wwiitthh cclliimmaattee cchhaannggee
–– LLooccaall aaggeennddaa 2211
To put sustainable development into practice at
a local level each local authority must create a
strategy. All local authorities must incorporate
sustainable development into every aspect of
their work. The strategies should not be
designed to work along side projects, they
should inform what the project should be.
Agenda 21 was established during the 1992 Rio Earth Summit. A framework
for future action on global sustainable development was agreed. However,
sustainable development cannot be achieved on a global scale unless it is
tackled at a local level, with all local authorities adopting Local Agenda 21 into
their strategies. 'Think Globally, Act Locally.'
87. CCooppiinngg wwiitthh cclliimmaattee cchhaannggee
–– LLooccaall aaggeennddaa 2211
With the cooperation of local business, schools, transport companies and
the wider community Oxford County Council has attempted to reduce road
traffic intensity along with its associated pollution. The city of Oxford has
been the main focus.
Strategies aim to reduce the 60% car use within the city and involve two
action plans – Travelwise and the Transport Action Plan. These include:
• Funding for the Sustrans cycle network across the county
• Increased funding for rural bus services.
• Green commuter plans from employers such as car share / bus
provision.
• Walk to school week.
• Provision of sustainable transport seminars for business
• Car free days.
88. Coping wwiitthh cclliimmaattee cchhaannggee ––
CChhaannggiinngg lliiffeessttyylleess
There are a many small changes to our lifestyles that can be made to
achieve a more sustainable society and help reduce climate change.
Energy and resources
Turn off electric and gas appliances such as TVs, lights and computers when
not in use. Insulate/double glaze your home to save energy. Use low
energy light bulbs and appliances. Only fill the kettle with the water you need.
Transport
Walk, cycle and use public transport whenever possible. Take fewer car
journeys and share cars.
Shopping
Avoid products with lots of packaging and reuse carrier bags. Buy
environmentally friendly products. Buy local food produce, think of food miles.
Reduce Waste
Reuse bags, bottles and containers. Have things repaired or try to fix
them. Recycle rubbish. Raise environmental awareness.
89. CCooppiinngg wwiitthh cclliimmaattee cchhaannggee
–– PPrreessssuurree ggrroouuppss
Friends of the Earth – www.foe.co.uk
The Climate Group – www.theclimategroup.org
The Carbon Trust – www.thecarbontrust.co.uk
Greenpeace – www.greenpeace.org
The Global Climate Coalition (guided USA against Kyoto) - www.globalclimate.org
World Wildlife Fund – www.wwf.org.uk
90. EExxaamm qquueessttiioonn
Explain the conditions that lead to the formation of
tropical storms. (6 marks)
Tropical storms can be formed where low pressure
weather systems occur over seas and oceans with
surface temperatures greater than 27°C. For
example in the tropical regions, (between the tropic
of Cancer and tropic of Capricorn), of the Atlantic
Ocean resulting in hurricanes and in the Indian
ocean where they are known as cyclones. They
require strong updrafts of warm moisture laden air
that cools and condenses to form cumulo-nimbus
clouds that bring torrential rainfall. The effect of the
coriolis force causes the rotation of the air mass
which is anti-clockwise in the northern hemisphere
and clockwise in the southern hemisphere.
2 specific
facts
Examples given
provided
Specific use
of
geographical
terminology
Good
explanation
to support
facts.
91. EExxaamm qquueessttiioonn
Essay question: Discuss the view that human activity is causing
climatic change.
Introduction
How is the climate changing?
What is global warming?
What evidence is there for climatic change?
Main Body
Evidence to suggest
change is due to human
activity.
Evidence to suggest
change is due to factors
other than human
activity.
Short term changes in climate
since last ice age and impact of El
Nino and La Nina
Paleoclimate trends
Sources of
methane
Source of green
house gases from
human activity and
their relative
importance.
Sources of CO²
Sources
of CFCs
Conclusion
Evaluation of
evidence and a
personal opinion
Editor's Notes
Atmosphere definition 1st. Diagram 2nd the boxes in following order, troposphere, tropopause, Stratosphere, stratopause, mesosophere, mesospause, thermosphere.