The Changing Arctic Climate
as Observed from Space
Josefino C. Comiso
NASA Goddard Space Flight Center
Josefino.c.comiso@nasa.gov
IPY Presentation for Informal Educators
GSFC Web, 16 October 2008
Scientific Motivations
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The Earth is warming and impacts of
anthropogenic activities is becoming more
apparent
Satellite data is needed to get a global
perspective of the problem
Early signals of a Climate change may come from
the polar regions because of feedback effects.
The Arctic is already showing such signals.
Impacts on the quality of human lives, on the
economy and the infracstructure are huge.
It may not be too late. Mitigation strategies must
be considered seriously.
Anthropogenic CO2
AES Drax in Yorkshire
pumps smoke out of the
tallest chimneys in the
country. The coal-fired
power plant emits more
CO2 – 22.8 million
tonnes annually – than
the 100 leastindustrialised nations
combined. Drax provides
7% of Britain’s electrical
power. Burning fossil
fuels to turn steam
turbines and create
electricity accounts for a
quarter of the world’s
greenhouse gas emissions,
and coal has the highest
carbon content of all
Culprit? Anthropogenic influence as
depicted by the CO2 Time Series
Antarctic Core Record for the Last 400,000 Years of Greenhouse Gases and Temperature + In Situ Data Since 1880
Natural climate variability
is associated with
Earth’s orbital
parameters and solar
effects. CO2, CH4 and
estimated global
temperature
0 = 1880-1899 mean
Hockey Stick - Earth’s Temperature Variations: Past 1000 Years
Surface temperature
trends from
meteorological
stations around
the world
• Rapid rise from 1910 to 1942
• Moderate cooling from 1942
to 1975
• Rapid rise from 1975 to the
present (satellite era)
• Global cooling during volcanic
erruptions
Sputnik
Launch
Trends in the Arctic Surface Temperature (1981 to 2007)
Trends in Ts >66.5°N = 0.64°C/dec
Trends over Sea ice = 0.35°C/dec
Trends over Greenland = 0.76°C/dec
Trends over Eurasia = 0.23°C/dec
Trends over North Am = 0.69°C/dec
>60°N for both Eurasia and North Am
Russia
Alaska
Canada
Greenland
Seasonal Trends in the NH Surface Temperature
Polar
AmplificationFeedbacks
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Ice-Albedo Feedback –
relevant to retreating
perennial ice cover and
also over land
Cloud feedback – positive
or negative, depending on
the height of clouds
Other feedbacks are
mainly positive
Yearly Arctic Ice Cover
during Maximum
Extents
1979-2007
Extent trend: -2.2%/decade
Areas trend: -2.5%/decade
Yearly Arctic Ice Cover
during Minimum
Extents
1979-2003
Extent trend: -10.1%/decade
Area trend: -11.4%/decade
2007
The Big Sea Ice Anomaly in 2007
2007 ice minimum area was
27% less than 2005 and
38% less than
climatological average.
Ref: Comiso, J.C., C. Parkinson, R. Gersten and L. Stock, Accelerated decline in the Arctic sea ice cover,
Geophysical Research Letter (in press).
Temporal Variations in
the ice cover, wind and
surface temperature
(March to May)
Data indicates significant
temperature and wind
effects. In August, there
was a cyclone in the region
that may have facilitated
anomaly.
Aug 07 Anom
Cold Weather Conditions in the Arctic in Winter
Surface temperature anomalies show cooling primarily in North America. Sea ice
concentration anomalies indicate positive ice cover anomalies in the Bering Sea
and Davis Strait and the effect is illustrated
in the ice cover in mid winter (1 March 2008)
Ice Concentration
1 March 2008
Bering
Sea
Russia
Canada
Greenland
Davis
Strait
Total Ice Cover/Monthly Anomalies
From 1978 to 1996,
the trend in the ice
extent was -2.2% per
decade. Since 1996,
the trend has
changed
to -10.1% per decade
suggesting a large
acceleration in the
decline.
Acceleration in the
decline makes it
difficult for ice to
recover because
of ice albedo
feedback.
-10.1%/dec
-10.7%/dec
Update to
2008 Arctic
Sea Ice
2008
2008
2008
Cluster Map
Multiyear ice Map
sub sonar
Wadhams
The
Wild
Card?
Multi
Year
Ice
from
1981 to
1998
Winter and
Summer
MY/Perennial
Ice Cover
Enhanced water
temperatures in 2007
Anomaly maps based on AVHRR
data from 1981 to 2007 show significant
warming of Arctic SSTs in 2007
IPY
measure
ments
Perovich and
the CRREL
Group
Summer ice melt
200
Beaufort Sea
1975
1994
1998
2006
2007
Total melt (cm)
150
North Pole
2000
2002
2004
2005
2006
2007a
2007b
100
50
0
Beaufort
North Pole
Surface melt
Beaufort
North Pole
Bottom melt
2007 Beaufort – huge increase in bottom melt
Monthly Snow Cover Extents and
Anomalies from 1979 to 2003
Permafrost in Alaska
Change in NDVI, Arctic Region
1981 to 2006
Himalayan Glaciers
Horn and Waxeggkees
Glaciers in the Austrian Tyrol
30 % of area and 50 % of volume was lost from1921 to 1994
Mendenhall Glacier in Alaska – observed to be
Thinning by 0.5 to 1 m per year
Observed Decline in Glacier Volume
Area of melt
increased
dramatically in
Greenland during the
last four years
Spring melt in Greenland in 2002
Estimates: Sea level equivalence
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Greenland ice sheet = 7 m
East Antarctic ice sheet = 65 m
West Antarctic ice sheet = 8 m
Antarctic Peninsula = 0.46 m
All other ice forms + glaciers = 0.45 m
Thermal expansion: the sea level goes up by 2 to
6 cm of every 1 K increase in Global Surface
Temperature
Saline sea Ice = 0 m; Perennial sea ice = .02 m
Effect of Sea Level Rise
(2000 census)
Four Regions: Areas under water
Summary
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Global warming is real. Met stations and satellite data show
enhanced surface temperatures that are amplified in the polar
regions.
Impacts of warming are now evident, the strongest being in
the Arctic. Reductions in snow cover, glaciers, and increased
melt in the permafrost and ice sheets are evident.
The perennial ice now declining at 11.4 % per decade shows
the most remarkable change. The 2007 ice minimum area
was 38% less than climatological average and 27% less than
previous lowest area in 2005. The 2008 perennial ice area
was almost as low as that of 2007.
The multiyear ice cover in winter is showing even more drastic
declines at 14% per decade. Ice is thinning in part because of
warmer ocean caused by ice albedo feedback.
Mitigation strategies are needed and needs to be implemented
before it gets too late.
End of Presentation
Some Mitigation Strategies
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Use of alternative energy sources: wind turbines,
solar/photovoltaic cells, nuclear, geothermal,
ocean, hybrid/hydrogen cars, gasohol/fuel crops,
etc.
Truly international efforts to reduce the use of
fossil fuels
Construction of energy efficient buildings and
public transportation systems
Conservation and greater public awareness of the
consequences of global warming
The Ozone Hole Success Story: A good
model for solving global Problems
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Scientists provided clear warning
Special interest groups denied story for years but
developed ozone-friendly technology
Media transmitted the message very well
Public was responsive and willing to help
US/European leadership was very effective
CFC-producing infrastructure quickly phased
out
Stronger Hurricanes
Katrina
More than $100B damage. 320 Million trees , corresponding to a biomass of 0.09 to 0.11 petagrams
of carbon were transferred form live to dead pools.(7% of US fossil fuel emission each year)
Super typhoon Chataan while
approaching Japan on July 4, 2002
AMSR-E data at 85 GHz
Stresses on Coral Reefs
Coral Reef off Fiji (Photo: Kevin Roland)
AMSR-E and SSM/I Multiyear
Ice Concentration
2007 is the
second
warmest year
observed from
meteorological
stations
Ttrends in the Northern
Hemisphere was considerably
higher than that of the
Southern Hemisphere.
Icebergs from the Jakobshavn Ice
Stream
Larson Ice Shelf Rapid Decline
January 31, 2002
March 17, 2002