Ice Core Paleoclimate Research Group

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Understanding Global Climate and Environmental
Change Ellen Mosley-Thompson, Professor
(Atmospheric Science) Director, Byrd Polar
Research Center The Ohio State University,
Columbus Ohio, USA
Ice Core Paleoclimate Research
Group Lonnie G. Thompson Henry Brecher Mary
Davis Paolo Gabrielli Ping-Nan Lin Matt
Makou Victor Zagorodnov
Graduate Students Liz Birkos Aron Buffen
Natalie Kehrwald David Urmann Lijia Wei
Funding provided by NSF Paleoclimate and
Polar Programs NASA Earth Sciences
(Glaciology) NOAA Paleoclimatology Gary
Comer Foundation OSU Climate, Water Carbon
Program
Image NASA
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Our Earth is warming!
(?C)
httpwww.giss.nasa.gov/research/news
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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
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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
  Earths surface

Smoke from fires in Guatemala and Mexico (May 14,
1998)
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?
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Carbon Dioxide Methane Concentrations Past,
Present and Future
IPCC 2000 Scenario A1B for 2100 AD
Today CO2 is 378 ppmv CH4 is 1750 ppbv
Lüthi et al., Nature, May 15, 2008
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Many observed changes that are broadly consistent
with an increase in the radiative heating of
Earths surface and lower atmosphere

• Recent and rapid melting of glaciers in
  non-polar regions around the world

Climatologically we are in unfamiliar
territory, and the worlds ice cover is
responding dramatically.
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(No Transcript)
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Massive retreat of low-latitude glaciers today
2002
Gangapurna Glacier
1957
Courtesy Doug Burbank, UCSB
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Quelccaya Ice Cap, Peru
1977
2002
L.G. Thompson, OSU
L.G. Thompson, OSU
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Kilimanjaro has lost 85 of its ice cover since
1912
Thompson et al., PNAS, 2009, in press, November
issue
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Many observed changes that are broadly consistent
with an increase in the radiative heating of
Earths surface and lower atmosphere

• 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

- Increase in global ocean surface temperatures
of 0.35C since 1979 - warming evident at all
latitudes over all ocean basins - to depths
of at least 3000 meters
- 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
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Many observed changes are broadly consistent with
an increase in the radiative heating of Earths
surface and lower atmosphere
- 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
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Warming of the climate system is unequivocal
Most of the observed increase in globally
averaged temperatures since the mid-20th century
is very likely due to the observed increase in
anthropogenic greenhouse gas concentrations.
Very likely means 90 confidence
A 3-year effort 152 authors (30 countries) gt 600
reviewers Approved by 113 governments
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Global and Continental Temperature Change from
1900 to 2000 AD
natural forcings only
natural and anthropogenic forcings
IPCC Fourth Assessment February 2007
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IPCC 4th Assessment (2007) Projection for 2100
AD 2.0 4.5 oC
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Global Temperature (C)
3
2
Northern Hemisphere temperature (C) for the last
1000 years
N.H. Temperature (C)
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0.4
0
0
-0.4
-0.8
Year A.D..
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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.
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Global Temperature (C)
3
2
1
0.4
0
0
-0.4
-0.8
Year A.D..
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Recent Assessments
Report of the Committee on Environment and
Natural Resources National Science and Technology
Council May 2008
Report from U.S. Climate Change Science Program
2008
http//www.climatescience.gov/Library/sap/sap4-3/f
inal-report/default.htm
http//www.ostp.gov/galleries/NSTC
Reports/Scientific Assessment FULL Report.pdf
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Recent Assessment
http//www.globalchange.gov/publications/reports/
scientific-assessments/us-impacts
2009