The Changing Arctic:
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The Changing Arctic: The Changing Arctic: Recent Events & Global Implications Recent Events & Global Implications Martin O. Jeffries Martin O. Jeffries National Science Foundation National Science Foundation Office of Polar Programs Office of Polar Programs Division of Arctic Sciences Division of Arctic Sciences Presentation to the Seasons and Biomes Workshop Fairbanks, AK, 27 September 2007
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The Changing Arctic: Recent Events & Global Implications Martin O. Jeffries National Science Foundation Office of Polar Programs Division of Arctic Sciences Presentation to the Seasons and Biomes Workshop Fairbanks, AK, 27 September 2007. CO 2. CO 2. CO 2. CO 2. CO 2. CO 2. CO 2. - PowerPoint PPT Presentation
Transcript of The Changing Arctic:
The Changing Arctic:The Changing Arctic:Recent Events & Global ImplicationsRecent Events & Global Implications
Martin O. JeffriesMartin O. JeffriesNational Science FoundationNational Science Foundation
Office of Polar ProgramsOffice of Polar ProgramsDivision of Arctic SciencesDivision of Arctic Sciences
Presentation to theSeasons and Biomes Workshop
Fairbanks, AK, 27 September 2007
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Increasing Greenhouse Gas Concentrations in the Atmosphere
CO2 CO2 CO2 CO2
CO2 CO2 CO2 CO2
CO2 CO2 CO2 CO2
CO2 CO2 CO2 CO2
CO2 CO2 CO2 CO2
CH4Radiative effect 20:1 NO2
Radiative effect 1:300
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Greenhouse Gases and Increasing Global Temperature
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
IPCC: Inter-governmental Panel on Climate Change
Non-uniform geographic distribution of temperature
increase.
Arctic amplification of global warming.
Why arctic amplification?
Regional positive feedback processes.
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.
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16 August 2007 21 September 2005
Arctic Sea Ice Retreat:A Positive Feedback
August ice extent, 1979-2007
Ext
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106 k
m2 )
2007
5.3 x 106 km2 5.3 x 106 km2
16 September 2007
Record minimum, 4.1 x 106 km2
Sea Ice Loss:The Real World
Outpaces the Virtual World
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.
279 species of migratory bird breed in significant numbers in the Arctic. Of those, 30 reach southern Africa, 26 reach Australia and New Zealand, 22 reach southern South America, and several species reach the Southern Ocean. Arctic Change has the potential to affect biodiversity far from the Arctic.
Arctic tern
Natural Resources, International Trade and Geopolitics
Northern Sea Route
Northwest Passage
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IDC
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S.S.Manhattan, NW Passage, 1969
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2 August 2007
People & Communities
Shi
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Arctic Coast Central Alaska
Rising Ground Temperatures
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Thawing Permafrost
Thermokarst
Landscape Change
& Methane (CH4)
Methane gas
Bacteria make methane(decomposition)
Arctic methane & permafrost
Methane Mobilized:Another Positive Feedback
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Increased Melting on the Greenland Ice Sheet
