Arctic Climate Change

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Arctic Climate Change

• John C. Fyfe
• Canadian Centre for ClimateModelling and Analysis

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Three Main Points

• The Arctic interacts strongly with the global
  climate system
• The Arctic is changing rapidly, and faster than
  models have predicted
• The Arctic must be seriously considered in any
  mitigation strategy

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The Arctic has warmed at twice the global rate
over the past 100 years AR4 WGI SPM
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The Arctic has warmed at twice the global rate
over the past 100 years AR4 WGI SPM
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Human activities have caused significant warming
in the Arctic Gillett et al., Nature
Geoscience, 2008
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More solar energy is being deposited in the
Arctic Ocean Perovich et al., GRL, 2007
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Heat transport is also contributing to Arctic
amplification Graversen et al., Nature, 2008
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Arctic sea ice extent in summer has decreased by
7.4 per decade since 1978 AR4 WGI SPM
Observed Minimum Ice Extent
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Source Annual Review of Marine Science, 2009
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None of the models show trends comparable to
observations Stroeve et al., GRL, 2007
Observed and Simulated Minimum Ice Extent
10 8 6 4 2 0
Minimum sea ice extent,106 km2
1960 1980 2000 2020 2040
2060 2080 2100
Year
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Some Impacts of Sea Ice Loss

• Increased coastal erosion with longer fetch
• Increased primary productivity
• Diminished polar bear health and abundance
• Northern passage, shelf exploration and exclusive
  economic zones

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SLR from 1993 to 2003 (mm/yr)
From AR4 WG1 Table SPM.1
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Loss from Greenland has nearly doubled sincelast
reported Allison et al., pers. comm., 2009
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Discharge from many major outlet glaciers has
accelerated markedly Alley et al., Science, 2005
Jakobshavn GlacierWest Greenland
2001
2006
1851
Source Konrad Steffen
Source NASA Space Observatory
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Acceleration triggered by the arrivalof warm
ocean waters
From Holland et al., Nature Geoscience, 2008
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Model shortcomings limit our ability to make
accurate projections of global sea level rise
From AR4 WG1 Fig. 1.4
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Sea Level Rise by Year 2100?

• Gregory et al., Nature, 2004Runaway melt of the
  GIS at ?T gt 3C
• IPCC, 2007Global SLR lt 0.6 m 0.2 m 0.8 m
• Pfeffer et al., Science, 2008Global SLR 0.8 to
  2.0 m
• Carlson et al., Nature Geoscience, 2008SLR from
  GIS could be gt 1.3 m

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Models predict a super recovery of the ozone
holedue to GHG emissions Erying et al., JGR,
2007
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What Came Out of CoP-13 in Bali?

• Bali Declaration Emissions must peak or decline
  in the next 10 to 15 years, so there is no time
  to lose
• Bali Roadmap Negotiate and meet again in CoP-14
  in Poznan and reach an agreement in Copenhagen in
  2009

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And Meanwhile the Warming Continues
From AR4 WG1 Fig. 11.18
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Arctic Climate Change

• John C. Fyfe
• Canadian Centre for ClimateModelling and Analysis