The Changing Arctic:

1
The Changing Arctic Recent Events Global
Implications Martin O. JeffriesNational Science
Foundation Office of Polar Programs Division of
Arctic Sciences Presentation to the Seasons
and Biomes Workshop Fairbanks, AK, 27 September
2007
2
Increasing Greenhouse Gas Concentrations in the
Atmosphere
Source BBC
3
Greenhouse Gases and Increasing Global Temperature
Source BBC
Computer models can not simulate the 20th Century
global air temperature trend unless increased
atmospheric greenhouse gas concentrations are
included.
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Computer Simulation of Global Temperatures
Non-uniform geographic distribution of
temperature increase. Arctic amplification of
global warming.
Why arctic amplification?
Regional positive feedback processes.
Source BBC
IPCC Inter-governmental Panel on Climate Change
5
Albedo (?) The ratio of reflected solar radiation
to total incoming solar radiation.
A black object has an albedo of 0 (zero). That
is, all solar radiation is absorbed.
A white object has an albedo of 1 (one). That is,
all solar radiation is reflected.
6
16 August 2007
21 September 2005
Source National Snow and Ice Data Center (NSIDC)
5.3 x 106 km2
5.3 x 106 km2
August ice extent, 1979-2007
Arctic Sea Ice Retreat A Positive Feedback
Extent (106 km2)
2007
7
Sea Ice Loss The Real World Outpaces the
Virtual World
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Consequences of a Declining Sea Ice Cover
On 7 September 2007, the US Geological Survey
reported the results of a study that predicts
that by 2050 the polar bear population will be
reduced by 66. The reduction will not be evenly
distributed - polar bear populations in some
regions will not survive the loss of sea ice -
they will disappear completely. Changing polar
bear populations are a very visible and emotional
sign of ecosystem change.
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Natural Resources, International Trade and
Geopolitics
Source BBC
S.S.Manhattan, NW Passage, 1969
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People Communities
Shishmaref, Alaska
11
Source Vladimir Romanovsky
Arctic Coast
Central Alaska
Rising Ground Temperatures
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Thawing Permafrost Thermokarst Landscape
Change
Methane (CH4)
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Methane gas
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Bacteria make methane(decomposition)
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Arctic methane permafrost
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Methane Mobilized Another Positive Feedback
Source MOJ
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Increased Melting on the Greenland Ice Sheet
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