Transcript Ellen Mosley-Thompson, Professor(9 MB

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
The Human Footprint on Earth
Image: NASA
Our Earth is warming!
Climate is changing differently across the globe!
Environmental conditions are changing!
- some changes are unprecedented for thousands of years
- some changes are occurring rapidly (years to decades)
rapid changes can pose severe challenges for adaptation
Global Temperature Change (ºC)
2001-2007 Mean Surface Temperature Anomaly (◦C) Global .54
2005 warmest
year on record
.6
.4
0.75°C
.2
0
-.2
relative to the 1951-1980 mean
-.4
1880
1900 1920
1940
1960
1980
Year
A.D.
Year A.D.
http:www.giss.nasa.gov/research/news
relative to the 1951-1980 mean
2000
ºC
(◦C)
Natural mechanisms influence climate
Natural mechanisms
•
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)
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
Carbon Dioxide & Methane Concentrations
Past, Present and Future
Dome C
IPCC 2000
Scenario A1B
for 2100 AD
3700
850
in the
2 remains
EPICA CO
Dome
C
ice
core extends back
atmosphere from
to 120 years
through70eight
glacial and interglacial
stages (800,000 years) recording changes
in the composition of Earth's atmosphere
1800
387
800
600
400
200
Thousands of Years (B.P.)
0
Today:
Today:
CO2 is 387 ppmv
CO is 378 ppmv
CH42is 1800 ppbv
CH4 is 1750 ppbv
Lüthi et al., Nature,
May 15, 2008
Many observed changes that are broadly consistent with an increase
in the radiative heating of Earth’s 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 world’s ice cover is responding dramatically.
Massive retreat
of low-latitude
glaciers today
2002
Gangapurna
Glacier
1957
Courtesy Doug Burbank, UCSB
~ 2 - 3 m thinning / year
1977
L.G. Thompson, OSU
Quelccaya Ice Cap, Peru
2002
L.G. Thompson, OSU
Kilimanjaro has lost 85%
of its ice cover since 1912
Thompson et al., PNAS, 2009, in press, November issue
Many observed changes that are broadly consistent with an increase
in the radiative heating of Earth’s 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 0.35°C 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
Many observed changes are broadly consistent with an increase
in the radiative heating of Earth’s 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”
“ 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)
> 600 reviewers
Approved by 113 governments
Global and Continental Temperature Change from 1900 to 2000 AD
observations
natural forcings
only
natural and
anthropogenic
forcings
IPCC Fourth Assessment February 2007
IPCC
(2007)
Projection for 2100 AD
2.0 – 4.5 oC
4
3
2
Northern Hemisphere
temperature (°C)
N.H.
Temperature
(°C)
for the
last 1000 years
1
0.4
0
0
-0.4
-0.8
1000
1200
1400
1600
Year
(A.D.)
Year A.D..
1800
2000
Global Temperature (°C)
5
4th Assessment
5
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.
4
3
2
This warming has already occurred
1
0.4
0
0
-0.4
-0.8
1000
1200
1400
1600
Year
(A.D.)
Year A.D..
1800
2000
Global Temperature (°C)
Future energy policy will determine this
Recent Assessments
Report of the Committee on Environment
and Natural Resources
National Science and Technology Council
May 2008
http://www.ostp.gov/galleries/NSTC
Reports/Scientific Assessment FULL Report.pdf
Report from U.S. Climate Change Science Program
2008
http://www.climatescience.gov/Library/sa
p/sap4-3/final-report/default.htm
Recent Assessment
http://www.globalchange.gov/publications/reports/
scientific-assessments/us-impacts
2009