Global Warming
description
Transcript of Global Warming
*It is simply defined as the increase in the earth’s atmosphere by green house gases.
WHAT IS GLOBAL WARMING?
• Carbon dioxide • Nitrogen oxide • CFCs(Chloro fluro Carbons• Hydro carbons• Methane• Water vapour
Greenhouse Gasses
Causes of global warming:.
Deforestation
Rapid industrialization
Population explosion
Increase in GHG concentration
Main cause: CARBON DIOXIDE
Earth’s “cooling” system is “clogged”
Net effect:E A R T H H E A T S
U P
Increased GHG Concentration
• CO2 6-10 times present
• Temps ~ 14oC warmer than present
• Could this be an analog for the future?
Cretaceous – a hot-house world
85 Ma
Atmospheric CO2 (parts per million)
800 600 400 200 0
CO
2 (p
pmv)
Thousands of Years Before Present
Present CO2 concentration (386 ppmv)
CO2 concentration after 50 years of unrestricted fossil fuel burning (600 ppmv)
240
300
270
210
180
Petit et al., 1999; Siegenthaler et al., 2005; EPICA Community members, 2004
Tem
p.P
roxy
270
290
360
370
380
Car
bon
Dio
xide
Con
cent
ratio
n (p
pmv)
280
300
310
320
330
340
350
1750 1800 1850 1900 1950 2000
Mauna Loa (1958 - present)
Siple Station (1750 - )
Reconstructed CO2 concentrations
Climate fluctuates naturally
Glacier ice
Sea ice
18,000 years ago Present
12
Global mean temperature
Global averagesea level
Northern hemispheresnow cover
Observations of recent climate change
13
Global Instrumental Temperature Record
10 warmest years
• For over 30 years, scientists have predicted increased greenhouse gasses will cause unnatural changes
• By 2000:T Antarctic sea ice and ice shelf break-upsT Antarctic Peninsula warmingT Arctic sea ice meltingT Faster Arctic warming (11°F)T Melting of small glaciers and ice capsT Sea level riseT And more…
Predicted changes of human-caused warming
17
Antarctic Sea Ice Break-ups
Larsen B, Mar-02
18
Larsen B, Mar-02
19
Larsen B, Mar-02
Wilkins, Mar-08
Arctic Sea Ice Melting
1979
2005
Arctic Sea Ice Melting
2007
Arctic Sea Ice Melting
Ice
Exte
nt (
106 k
m2 )
Arctic sea ice extent
2007
27
Arctic is warming faster
1860 1880
-2.0
Diff
ere
nce
(°C
) fr
om
196
1-1
990
mea
n
All land area
1900 1920 1940 1960 1980 2000
-1.0
0.0
1.0
2.0
Arctic (land north of 65°N)
28
Carroll Glacier
1906
2004
1980
29
McCarty Glacier, Alaska
30
Muir and Riggs Glaciers
31
1970 2005
Kilimanjaro
1993
2000
33
Qori Kalis
1978 2002
1928 2004
Patagonia
• Glaciers and ice caps gone by 2100• Ice sheets melting too!• Over 40% of world’s water supply• Direct rise in sea level• Reflect sunlight
Who cares?
35
Sea-level rise
Temperatures and sea levels will continue to rise for centuries.Arctic sea ice will disappear in the next few decades Hot extremes, heat waves, and heavy rains will continue to become more frequent
Global warming facts (IPCC, 2007):
Sea-level rise1. Thermal expansion2. Addition of water3. Freshening of water4. Melting ice sheets
– Greenland: 7.4 m (25’) potential– Antarctica: 74 m (250’) potential
• West Antarctica (7 m)• East Antarctica (67 m)
WestAntarctic
IceSheet
39
1992 2005
Greenland satellite melt record
40
1992
2002 2005
1980
0.5
0.8
Mel
t Ext
ent (
106
km2 )
0.6
0.7
1985 1990 1995 2000 2005
0.4
0.2
0.3
Greenland Melt Extent (April - September 25)
17-Jun-200313-Jun-200214-Jun-2001
Sea-level rise
Coastal population
Coastal migration
Sea level 18,000 years ago (-70m)
Florida’s coast if Greenland OR the West Antarctic Ice Sheet Melted7m rise in sea level
5m rise in sea level
8m rise in sea level
• Fastest extinction rate in 65 M years (1000x normal rate)
• Increased poverty and hunger
• Increased disease– Air-borne (e.g. asthma)
– Insect-borne (e.g. malaria)
• More extreme weather– Droughts
– Flooding
– Heat-waves
– Storms
Additional consequences
46
Habitat loss
Mass extinction
47Coral bleaching
GREAT LOSS TO AQUATIC LIFE
CHANGE IN LIFE FORMS
Methane hydrates
Melting of Methane Hydrate crystals could lead to run-away greenhouse
Projected risks due to climate change
What can you do?
Reduce consumption
Plant trees
Drive less
Shop smart
Alternative energy
Be informed
Unplug
Improve efficiency
Don’t buy ocean-front property