Transcript Slide 1
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] 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) Observed and Simulated Temperature Year Snow-Ice Albedo Feedback More solar energy is being deposited in the Arctic Ocean [Perovich et al., GRL, 2007] Ann. Review of Marine Science, 2009 Heat transport is also contributing to Arctic amplification [Graversen et al., Nature, 2008] Summer Heat Autumn Heat Arctic sea ice extent in summer has decreased by 7.4% per decade since 1978 [AR4 WGI SPM] Observed Minimum Ice Extent 2006 2008 2007 September Ice Extent 1980 2005 2007 Source: Annual Review of Marine Science, 2009 None of the models show trends comparable to observations [Stroeve et al., GRL, 2007] Minimum sea ice extent,106 km2 Observed and Simulated Minimum Ice Extent 10 8 6 4 Observations 2 IPCC AR4 Models 0 1960 1980 2000 2020 2040 Year 2060 2080 2100 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 SLR from 1993 to 2003 (mm/yr) Thermal expansion 1.60 ± 0.50 Glaciers & ice caps 0.77 ± 0.22 Greenland ice sheet 0.21 ± 0.07 Antarctic ice sheet 0.21 ± 0.35 Total 3.10 ± 0.70 From AR4 WG1 Table SPM.1 Loss from Greenland has nearly doubled since last reported [Allison et al., pers. comm., 2009] Discharge from many major outlet glaciers has accelerated markedly [Alley et al., Science, 2005] Jakobshavn Glacier West Greenland 2001 2006 1851 Source: Konrad Steffen Source: NASA Space Observatory Acceleration triggered by the arrival of warm ocean waters From Holland et al., Nature Geoscience, 2008 1991 2006 Model shortcomings limit our ability to make accurate projections of global sea level rise 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 + 0.2 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 And Meanwhile the Warming Continues Globe From AR4 WG1 Fig. 11.18 Arctic Climate Change John C. Fyfe Canadian Centre for Climate Modelling and Analysis