Changing Earths Climate

Changing Earth’s Climate

Dr. Todd Albert Department of Geography School of Earth, Environment, and Society Bowling Green State University

Scienc e Signs

Science of Climate Change

Greenhouse Gasses

• Let sunlight in • Earth heats up and radiates heat • GHGs – don’t let Earth’s heat escape

Increased GHG Concentration

Earth’s “cooling” system is “clogged” Net effect: Earth warms

Newsflash:

GLOBAL WARMING SCIENCE IS NOT NEW

1824:

JEAN-BAPTISTE FOURIER DISCUSSES GREENHOUSE EFFECT

1861:

JOHN TYNDALL PUBLISHES THAT CO2 AND

1896:

SVANTE ARRHENIUS PROPOSES ANTHROPOGENIC GREENHOUSE EFFECT; BURNING FOSSIL FUELS WILL BUILD-UP CO2 AND LEAD TO

1897:

AMERICAN P.C. CHAMBERLAIN MODELS GLOBAL CARBON

1938:

G.S. CALLENDAR ARGUES THAT ANTHROPOGENIC WARMING IS UNDERWAY

1956:

GILBERT PLASS CALCULATES THAT CO2 EMISSIONS WILL HAVE A SIGNIFICANT EFFECT ON

1957:

ROGER REVELLE WARNS "LARGESCALE GEOPHYSICAL EXPERIMENT”; HE AND DAVID

1963:

CALCULATIONS REVEAL A WATER-VAPOR FEEDBACK WITH CO2

1967:

COMPUTER SIMULATION DETERMINES THAT TEMPS MAY RISE MORE THAN 4°F WHEN CO2

1980s:

WARMEST DECADE ON RECORD

1990s:

WARMEST DECADE IN 1000 YEARS

2003:

WILLIAM RUDDIMAN PUBLISHES THAT HUMANS HAVE CHANGED CLIMATE FOR THOUSANDS OF

Climate fluctuates naturally 18,000 years ago

Present

Glacier ice Sea ice

Glacial and Interglacial cycles (within an ice age)

180

800

600

400

200

Thousands of Years Before Present

Petit et al., 1999; Siegenthaler et al., 2005; EPICA Community members, 2004

0

Ice Ages and Hot Houses Hot house

Ice Age

Ice Age

Hot house

Cretaceous – a hot-house world • CO2 6-10 times present • Temps ~ 14oC warmer than present • Could this be an analog for the future? 85 Ma

`The balance of evidence suggests that there is a discernible human influence on global climate ' IPCC, Second Assessment Report, 1996

`There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human IPCC, Third Assessment Report, 2001

`Most of the observed increase in globally averaged temperatures since the mid20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.' IPCC, Fourth Assessment Report, 2007

`Warming of the climate system is unequivocal, as is now evident from observations of increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global mean sea level.' IPCC, Fourth Assessment Report, 2007

`…anthropogenic emissions of [CO2 and CH4] first altered atmospheric concentrations thousands of years ago… the estimated warming caused by these early gas emissions reached a global-mean value… large enough to have stopped a glaciation of northeastern Canada' William F. Ruddiman, 2003

Observations of recent climate change Global mean temperature Global average sea level Northern hemisphere snow cover 28

Global Instrumental Temperature Record 10 warmest years

29

Atmospheric CO2 (parts per million)

Reconstructing past climates

– – – – – – –

Deep ocean cores Isostatic rebound Ice cores Tree rings Coral cores Historical documents Others

31

Reconstructed NH surface temperatures

Reconstructed CO2 concentrations 380 370 360 350 340

Mauna Loa (1958 - present)

330

Siple Station (1750 - )

320 310 300 290 280 270 1750

1800

1850

1900

1950

2000

CO2 concentration after 50 years of unrestricted fossil fuel burning (600 ppmv)

Present CO2 concentration (386 ppmv)

300 270 240 210 180

800

600

400

200

Thousands of Years Before Petit et al., 1999; Siegenthaler et al., 2005; EPICA Community members, 2004 Present

0

Global warming facts (IPCC, 2007):

GLOBAL AVERAGE TEMPERATURES WILL RISE2 TO 11.5 °F BY 2100

Global warming facts (IPCC, 2007):

SEA LEVELS WILL RISE 7 TO

23” BY 2100, BUT…

Global warming facts (IPCC, 2007):

FUTURE MELTING IN GREENLAND AND ANTARCTICA IS UNKNOWN

Global warming facts (IPCC, 2007):

TEMPERATURES AND SEA LEVELS WILL CONTINUE TO RISE FOR CENTURIES

Global warming facts (IPCC, 2007):

11 OF THE LAST 12 YEARS RANK AMONG THE 12 WARMEST YEARS SINCE 1850

Global warming facts (IPCC, 2007):

HURRICANES HAVE INCREASED IN INTENSITY SINCE 1970

Global warming facts (IPCC, 2007):

ARCTIC SEA ICE WILL DISAPPEAR IN THE NEXT FEW DECADES

Global warming facts (IPCC, 2007):

HOT EXTREMES, HEAT WAVES, AND HEAVY RAINS WILL CONTINUE TO BECOME MORE

Global warming facts (IPCC, 2007):

GULF STREAM IS LIKELY TO SLOW, BUT NOT LIKELY TO STOP

Signs from the Earth

Predicted changes of human-caused warming

• For over 30 years, scientists have predicted increased greenhouse gasses will cause unnatural changes • By 2000: T T T T T T T

Antarctic sea ice and ice shelf break-ups Antarctic Peninsula warming Arctic sea ice melting Faster Arctic warming (11°F) Melting of small glaciers and ice caps Sea level rise And more…

Antarctic Sea Ice Break-ups

Larsen B, Mar-02 46

Larsen B, Mar-02 47

Larsen B, Mar-02 48

Larsen B, Mar-02 49

Larsen B, Mar-02 50

Larsen B, Mar-02 51

Larsen B, Mar-02 52

Wilkins, Mar-08

Arctic Sea Ice Melting

19 79

Arctic Sea Ice Melting

20 05

Arctic Sea Ice Melting

20 07

Arctic sea ice extent

Arctic sea ice extent

2007

Difference (°C) from 1961-1990 mean

Arctic is warming faster 2.0

All land area Arctic (land north of 65°N)

1.0

0.0

-1.0

-2.0 1860

1880

1900

1920

1940

1960

1980

2000 61

Small glaciers and ice caps are melting

2 004

1 941

62

Carroll Glacier

1 906 63

Carroll Glacier

2 004 64

McCarty Glacier, Alaska

65

Muir and Riggs Glaciers

66

Kilimanjaro

1970

2005

67

1993

2000

Kilimanjaro

69

Qori Kalis

1978

2002

70

Patagonia

1 928

2 004

71

Glacier thinning since 1970 (m/yr)

Adapted from Dyurgerov and Meier (2005)

72

Who cares? • • • • •

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

74

75

Sea-level rise

Sea-level rise 1. 2. 3. 4.

Thermal expansion Addition of water Freshening of water Melting ice sheets – Greenland: 7.4 m (25’) potential – Antarctica: 74 m (250’) potential • •

West Antarctica (7 m) East Antarctica (67 m)

West Antarctic Ice Sheet

Greenland satellite melt record

1992

2005 79

Greenland Melt Extent (April - September 25) 0.8 2002 2005

0.7 0.6 0.5 0.4 0.3 1992

0.2 1980

1985

1990

1995

2000

2005 80

14-Jun-2001

13-Jun-2002

17-Jun-2003

82

Basal lubrication

83

1 year of melt!

R. Huff, J. Box, S. Starkweather, T. Albert

Sea-level rise

Coastal population

Coastal migration

Sea level 18,000 years ago (-70m)

5m rise in sea level

7m rise in sea level

Florida’s coast if Greenland OR the West Antarctic Ice Sheet Melted

8m rise in sea level

10% of people worldwide live within 10 meters of sea level 25% of people in the U.S.

Manhattan

Manhattan +8m

70m rise in sea level

Additional consequences • • •

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

Mass extinction

97

Habitat loss

98

Coral bleaching

99

100

101

Solar+volcanic

102

All forcings

103

Likely consequences:

WHAT’S THE WORST THAT CAN HAPPEN?

Likely consequences:

150,000,000 PEOPLE DISPLACED; 10,000 TIMES WORSE THAN

Likely consequences:

SEVERE WATER SHORTAGES, ESPECIALLY WHERE SUPPLY DEPENDS ON GLACIERS

Likely consequences:

WIDE-SPREAD HUNGER DUE TO DROUGHT AND DESERTIFICATION

Likely consequences:

MORE THAN 1,000,000 SPECIES FACE EXTINCTION

Likely consequences:

DRASTIC ALTERING OF THE GLOBAL OCEAN CIRCULATION PATTERN

Likely consequences:

MELTING OF METHANE HYDRATE CRYSTALS COULD LEAD TO RUN-AWAY

Methane hydrates

112

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

Don’t remain happy in ignorance