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Ice Core Paleoclimate Research Group
Lonnie G. ThompsonHenry BrecherMary DavisPaolo GabrielliPing-Nan LinMatt MakouVictor Zagorodnov
Understanding Global Climate and Environmental Change
Ellen Mosley-Thompson, Professor (Atmospheric Science)Director, Byrd Polar Research Center
The Ohio State University, Columbus Ohio, USA
Funding provided by: NSF: Paleoclimate and Polar Programs NASA: Earth Sciences (Glaciology) NOAA: Paleoclimatology Gary Comer Foundation OSU Climate, Water & Carbon Program
Graduate Students: Liz Birkos Aron Buffen Natalie Kehrwald David Urmann Lijia Wei
The Human Footprint on Earth Image: NASA
http:www.giss.nasa.gov/research/news
Our Earth is warming!
- some changes are unprecedented for thousands of years
- some changes are occurring rapidly (years to decades)
rapid changes can pose severe challenges for adaptation
Environmental conditions are changing!
2005 warmest year on record
0.75°C
(◦C) Year A.D.
Global Temperature Change (ºC).6
.4
.2
0
-.2
-.4
1880 1900 1920 1940 1960 1980 2000
Year A.D.
relative to the 1951-1980 mean
2001-2007 Mean Surface Temperature Anomaly (◦C) Global .54
relative to the 1951-1980 mean
ºC
Climate is changing differently across the globe!
Natural mechanisms influence climate
• Changes in the Sun
• Changes in the amount of volcanic aerosols in the atmosphere
• Internal variability of the coupled atmosphere-ocean system (e.g., ENSO, monsoon systems, NAO)
Natural mechanisms
Human factors also influence climate
Non-natural mechanisms
• Changes in the concentrations of atmospheric greenhouse gases
• Changes in aerosols and particles from burning fossil fuels (sulfate aerosols) and biomass (black carbon)
• Changes in the reflectivity (albedo) of the Earth’s surface
Smoke from fires in Guatemala and Mexico (May 14, 1998)
?? Pre-anthropogenic level
Lüthi et al., Nature,May 15, 2008
Today:
CO2 is 378 ppmv
CH4 is 1750 ppbv
Today:
CO2 is 387 ppmv
CH4 is 1800 ppbv
Thousands of Years (B.P.)
800 600 400 200 0
387
1800
850
3700IPCC 2000Scenario A1Bfor 2100 AD
CO2 remains in theatmosphere from70 to 120 years
Carbon Dioxide & Methane Concentrations Past, Present and Future
Dome C
EPICA Dome C ice core extends back
through eight glacial and interglacial
stages (800,000 years) recording changes
in the composition of Earth's atmosphere
- Recent and rapid melting of glaciers in non-polar regions around the world
Many observed changes that are broadly consistent with an increase
in the radiative heating of Earth’s surface and lower atmosphere
Climatologically we are in unfamiliar territory,
and the world’s ice cover is responding dramatically.
Gangapurna Glacier
1957
~ 2 - 3 m thinning / yearCourtesy Doug Burbank, UCSB
Massive retreat of low-latitude glaciers today
2002
Quelccaya Ice Cap, Peru1977 2002
L.G. Thompson, OSU L.G. Thompson, OSU
Kilimanjaro has lost 85%
of its ice cover since 1912
Thompson et al., PNAS, 2009, in press, November issue
- Increase in global ocean surface temperatures of 0.35°C since 1979
- warming evident at all latitudes over all ocean basins
- to depths of at least 3000 meters
Many observed changes that are broadly consistent with an increase
in the radiative heating of Earth’s surface and lower atmosphere
- Decreases in the area covered by seasonally frozen ground in
the high northern latitudes
- Reduction by about 2 weeks of the annual duration of northern lake
and river ice
- Recent and rapid melting of glaciers in non-polar regions around the world
- Dramatic decreases in the areal coverage and thickness of Arctic sea ice
- Rising sea level
- Increases in atmospheric moisture content (increased evaporation)
- Changes in extremes are consistent with warming
- increase in heat waves globally
- widespread increase in warm nights
- rarer occurrences of cold days, cold nights and days with frost
These many independent observations and the physical consistency
among them form the basis for the 2007 conclusion by the
Intergovernmental Panel of Climate Change (IPCC) that
“warming of the climate is unequivocal”
Many observed changes are broadly consistent with an increase
in the radiative heating of Earth’s surface and lower atmosphere
“ Warming of the climate system is unequivocal”
“Most of the observed increase in globally averaged temperaturessince the mid-20th century is very likely* due to the observed increasein anthropogenic greenhouse gas concentrations.”
* Very likely means 90% confidence
A 3-year effort152 authors (30 countries)> 600 reviewersApproved by 113 governments
observations
Global and Continental Temperature Change from 1900 to 2000 AD
natural forcingsonly
natural and anthropogenic
forcings
IPCC Fourth Assessment February 2007
4
3
5
0
Glo
bal
Tem
pera
ture
(°C
)
N.H. Temperature (°C)
IPCC 4th Assessment (2007)Projection for 2100 AD
2.0 – 4.5 oC
1000 1200 1400 1600 1800 2000Year (A.D.)
2
1
0
0.4
-0.4
-0.8
Year A.D..
Northern Hemisphere temperature (°C)
for the last 1000 years
4
3
5
0
Glo
bal
Tem
pera
ture
(°C
)
1000 1200 1400 1600 1800 2000Year (A.D.)
2
1
0
0.4
-0.4
-0.8
Year A.D..
Global average surface
temperature is heading not only
far outside the range of variation
of the last 1000 years but
outside the range experienced in
the tenure of Homo sapiens on
Earth.
Future energy policy will determine this
This warming has already occurred
Recent Assessments
http://www.ostp.gov/galleries/NSTC Reports/Scientific Assessment FULL Report.pdf
Report of the Committee on Environmentand Natural Resources
National Science and Technology CouncilMay 2008
http://www.climatescience.gov/Library/sap/sap4-3/final-report/default.htm
Report from U.S. Climate Change Science Program 2008
http://www.globalchange.gov/publications/reports/scientific-assessments/us-impacts
Recent Assessment
2009