Arctic Climate Change John C. Fyfe Canadian Centre for Climate Modelling and Analysis

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

The Arctic has warmed at twice the global rate over the past 100 years [AR4 WGI SPM]

Human activities have caused significant warming in the Arctic [Gillett et al., Nature Geoscience, 2008] Temperature anomaly (K) Year Observed and Simulated Temperature

More solar energy is being deposited in the Arctic Ocean [Perovich et al., GRL, 2007] Ann. Review of Marine Science, 2009 Snow-Ice Albedo Feedback

Heat transport is also contributing to Arctic amplification [Graversen et al., Nature, 2008] Summer Autumn Heat

Arctic sea ice extent in summer has decreased by 7.4% per decade since 1978 [AR4 WGI SPM] Observed Minimum Ice Extent

September Ice Extent Source: Annual Review of Marine Science, 2009

None of the models show trends comparable to observations [Stroeve et al., GRL, 2007] IPCC AR4 Models Observations Year Minimum sea ice extent,10 6 km 2 Observed and Simulated Minimum Ice Extent

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

Thermal expansion1.60 ± 0.50 Glaciers & ice caps0.77 ± 0.22 Greenland ice sheet0.21 ± 0.07 Antarctic ice sheet0.21 ± 0.35 Total3.10 ± 0.70 SLR from 1993 to 2003 (mm/yr) From AR4 WG1 Table SPM.1

Loss from Greenland has nearly doubled since last reported [Allison et al., pers. comm., 2009]

Source: Konrad Steffen Source: NASA Space Observatory Jakobshavn Glacier West Greenland Discharge from many major outlet glaciers has accelerated markedly [Alley et al., Science, 2005]

Acceleration triggered by the arrival of warm ocean waters From Holland et al., Nature Geoscience,

Model shortcomings limit our ability to make accurate projections of global sea level rise Typical Climate Model Resolution From AR4 WG1 Fig. 1.4

Sea Level Rise by Year 2100? Gregory et al., Nature, 2004 Runaway melt of the GIS at ∆T > 3°C IPCC, 2007 Global SLR < 0.6 m m = 0.8 m Pfeffer et al., Science, 2008 Global SLR = 0.8 to 2.0 m Carlson et al., Nature Geoscience, 2008 SLR from GIS could be > 1.3 m

Models predict a “super recovery” of the ozone hole due to GHG emissions [Erying et al., JGR, 2007]

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 Poznań and reach an agreement in Copenhagen in 2009

From AR4 WG1 Fig Globe And Meanwhile the Warming Continues

Arctic Climate Change John C. Fyfe Canadian Centre for Climate Modelling and Analysis