Appendix F: Climate Drivers Table SUMMARY OF PROJECTED CLIMATE CHANGES FOR ALASKA Expected General Specific Change Change Climate Change Expected & Relative to Patterns of Change Source Variable Expected Reference Period Recent Changes Temperature Increase 2050: +3°C ±2° Large More pronounced in >95% IPCC (2007) 2100: +5°C ±3° autumn-winter, with very likely and SNAP winter increases of (sign) +8°C likely by 2100 Precipitation Increase 2050: 15-25% ± Large Fairly high % change, >90% IPCC(2007) 15% but high uncertainty and very likely and SNAP 2100: 25-50% ± low baseline precip; (sign) 20% drying effects of increased temperature and evapotranspiration may dominate Relative Little 2050: 0% ±10% Small Absolute humidity 50% SNAP Humidity change 2100: 0% ±15% increases About as likely as not Wind Increase 2050: +2% ±4% Small More pronounced in >90% Abatzoglou 2100: +4% ±8% winter and spring Likely and Brown (sign) (2011) Pacific Decadal to Unknown Major effect on Alaskan Natural Hartmann Decadal (comparable temperatures in cold variation, and Wendler Oscillation to climatic season; acts as a essentially (2005) (atmospheric circulation jump in wildcard within ongoing circulation) anomalies 1970s) climate trends affecting Alaska Extreme Warm 2050: 3-6x increase Large Increase in frequency Modeled Abatzoglou Events: Events in warm events; and length of extreme and and Temperature Increase/ decrease in cold hot events and observed Timlin and Cold events; decrease in extreme >95% Walsh Events 2100: 5-8.5x cold events (winter) due Very likely (2007) Decrease increase in warm to warming trend, but no (sign) events; 8-12x clear changes in overall decrease in cold variability events
Appendix F: Climate Drivers Table SUMMARY OF PROJECTED CLIMATE CHANGES FOR ALASKA Climate Variable General Change Expected Specific Change Expected & Reference Period Expected Change Relative to Recent Changes Patterns of Change Source Temperature Increase 2050: +3°C ±2° 2100: +5°C ±3° Large More pronounced in autumn-winter, with winter increases of +8°C likely by 2100 >95% very likely (sign) IPCC (2007) and SNAP Precipitation Increase 2050: 15-25% ± 15% 2100: 25-50% ± 20% Large Fairly high % change, but high uncertainty and low baseline precip; drying effects of increased temperature and evapotranspiration may dominate >90% very likely (sign) IPCC(2007) and SNAP Relative Humidity Little change 2050: 0% ±10% 2100: 0% ±15% Small Absolute humidity increases 50% About as likely as not SNAP Wind Increase 2050: +2% ±4% 2100: +4% ±8% Small More pronounced in winter and spring >90% Likely (sign) Abatzoglou and Brown (2011) Pacific Decadal Oscillation (atmospheric circulation) Decadal to circulation anomalies affecting Alaska Unknown (comparable to climatic jump in 1970s) Major effect on Alaskan temperatures in cold season; acts as a wildcard within ongoing climate trends Natural variation, essentially Hartmann and Wendler (2005) Extreme Events: Temperature Warm Events Increase/ Cold Events Decrease 2050: 3-6x increase in warm events; decrease in cold events; 2100: 5-8.5x increase in warm events; 8-12x decrease in cold events Large Increase in frequency and length of extreme hot events and decrease in extreme cold events (winter) due to warming trend, but no clear changes in overall variability Modeled and observed >95% Very likely (sign) Abatzoglou and Timlin and Walsh (2007)