Arctic Region

1
What is Happening in the Polar Regions and Why
Its Important
Ben Holt, Oceanography Group, ben.holt_at_jpl.nasa.go
v
Arctic Region Current Temperature at Barrow,
Alaska gt 27F
Antarctica and Southern Ocean Current Temperature
at South Pole gt -73 F
2
Global Temperature Changes Are Greatest in Polar
Regions
Current
httpwww.giss.nasa.gov/research/news
3
Sea Ice and Land Ice Differences Sea Ice
Ice freezes out from salty ocean Thickness
ranges from 0.5 - 5 meters Age 1-5 years Moves
with winds ocean currents Occurs in Arctic
Ocean Southern Ocean
4
Sea Ice Extent and Thickness Are Climate
Indicators
Colder climategt More Ice Warmer climategt Less
Ice
5
Arctic Sea Ice Extent is Diminishing
http//arctic.atmos.uiuc.edu/cryosphere/
Note decrease in both winter and summer
extent Most significant reduction is in SUMMER
due to increased melt
6
Arctic Sea Ice Extent Observations Compared to
IPCC Climate Models
Observations (red) show more rapid decline than
models When/If will Arctic become ice-free in
summer?
From Stroeve et al., Geophysical Research
Letters, 2007
7
Arctic Sea Ice Thickness Submarine and
Satellite Record
Sea ice thickness shows decadal thinning,
including recently
From Kwok Rothrock, Geophysical Research
Letters, 2009
8
Sea Ice and Land Ice Differences Land Ice
Glaciers, Ice Sheets, Icebergs
Slow accumulation of snow with little melt Snow
transformed to ice by pressure Thickness up to
4000 meters! Age up to 120,000 - 500, 000
years! Moves by gravity and basal slipping
9
Land Ice Mass Balance gt Accumulation Minus
Ablation
Change in Mass Balance Directly Impacts Sea Level
http//www.uky.edu/AS/Geology/howell/goodies/elear
ning/module13swf.swf
10
Ice Sheet Mass Balance Derived From GRACE
Gravity Mission
Greenland
Antarctica
Increase in mass loss on both ice sheets,
accelerating in latter years gt Ice sheets
contribution to sea level rise will also
accelerate
Reference Velicogna, Geophysical Research
Letters, 2009
11
Albedo Ability to Reflect Sunlight
White Shirt vs Dark Shirt
Ice/Snow Reflect Radiation Water Absorbs
Radiation
Increased warming gt more ice melt gt more open
water gt warmer water gtmore ice melt and so on
Reduction in Albedo Due to Warming Accentuates
Ice Melt
12
Greenland Recent Melt Features Lake, Runoff,
Moulin Images Courtesy of I. Joughin, U.
Washington
13
2009 NOAA Arctic Report Card lthttp//www.arctic.n
oaa.gov/reportcard/gt
Warming of the Arctic continues to be
widespread, and in some cases, dramatic. Linkages
between air, land, sea, and biology are evident.
Photo R. Kwok, JPL
Additional impacts gt Increase in shipping,
human activities including oil exploration, plus
need for maritime security.