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