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Arctic Climate Change: Where Reality Exceeds Expectations
Mark C. SerrezeNational Snow and Ice Data Center (NSIDC)Cooperative Institute for Research in Environmental Sciences at the University of Colorado at Boulder
Special Thanks: Julienne Stroeve, Andy Barrett, Ted Scambos, Drew Slater, Dave Lawrence, Tingjun Zhang
July, 1982: Global Warming? Bah!!
Ellesmere Island, near Lake Hazen
Peering into the future ….
Fi gure 10. 8
IPCC 2007
Arctic Amplification
Loss of Near-Surface Permafrost
Lawrence and Slater, 2005
Left: changes in multi-model mean freshwater budget terms for the Arctic Ocean with respect to 1950-1980 means: positive anomalies indicate an increasing source (or decreasing sink) of freshwater for the Arctic Ocean
Holland et al. 2007; Serreze et al. 2006
Acceleration of the Freshwater Cycle
Arctic sea ice is disappearing
Stroeve et al. 2008
Observed rate of loss is faster than expected
Adapted from Stroeve et al., 2007
The Northwest Passage: open by late August 2007
G. Spreen, L. Kaleschke, and G. Heygster/IUP Universitat Bremen, AMSR data from National Snow and Ice Data Center (left); unknown (upper right); Dave Kavanagh (middle right); D. Thoreson (lower right)
Manhattan1968
Gjoa1903
Cloud Nine2007
Impacts on Polar Bears
Model-Projected Arctic Amplification
Mark Serreze, Andy Barrett, Marika Holland
Model projection of 2-meter temperature anomalies by month and year for 70–90 degrees North latitude, compared to 1979–2007 means(CCSM3)
Latitude by height dependence of zonally averaged October–March temperature anomalies for 2050–2059, compared to 1979–2007 means(CCSM3)
Arctic amplification has emerged
Temperature anomalies, 2003–2007 minus 1979–2007
NCEP/NCAR, Climate Diagnostics Center
October
Observed Autumn Temperature Trends, 1960-2007
GISS Analysis
W. Abdalati
Greenland’s Changing Mass Budget
Surface Melt and the “Zwally Effect”
K. Steffen, M. Tedesco
Greenland’s Largest Glacier: Acceleration and Retreat
Ian Howat, Ian Joughin, Ted Scambos
Warming Permafrost
Russian Permafrost Temperature
-4
-3
-2
-1
0
1
2
3
4
1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000Year
Te
mp
era
ture
De
par
ture
(°C
) 0.2 m; Trend = +0.78°C/decade0.4 m; Trend = +0.79°C/decade0.8 m; Trend = +0.65°C/decade1.6 m; Trend = +0.55°C/decade3.2 m; Trend = +0.66°C/decade
Alaska: 4 to 6°C increase in 20th Century, 2 to 3°C in the last 30 years
Siberia: >3°C increase from mid-1950s to 1990
Canadian Arctic: 1 to 3°C increase in past several decades
Tibetan Plateau: up to 1.0°C increase since 1970s
IPCC 2007
Infrastructure ImpactsChersky, Russia
Qinghai-Xizang Highway bridge collapse
Alaska
Thermokarst in Yakutsk, Russia (Skiklomanov, 2005).
Methane Release from Arctic Lakes
Burning methane over a thermokarst lake in Siberia (K. Walter)
Methane bubbles trapped in lake ice
Lakes boiling with methane in
the Arctic
Talik Formation
Active layer
Permafrost
Seasonally frozen layer
Permafrost
Talik
(layer of unfrozen ground)
Chandler River, 50 miles S. of Umiat: Sturm, Racine and Tape: Fifty Years of Change in Arctic Alaskan Shrub Abundance
1949
Changes in Shrub Abundance: Chandler River, AK
2001
Concluding Comments
Even our earliest climate models projected that effects of greenhouse gas loading would be seen first in the Arctic.
Even eight years ago, attribution of observed changes was uncertain.
Despite strong imprints of natural variability, a role of greenhouse greenhouse gas loading now seems clear
A number of key changes are exceeding expectations from climate models. Could we lose the summer sea ice cover by 2030?
Much remains to be understood—the idea of “tipping points” has emerged as a key issue.
Not everything is rapidly changing (hydrologic cycle).