CLIMATE CHANGE SCENARIOS FOR YUKON FLATS NATIONAL WILDLIFE REFUGE, ALASKA

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1 CLIMATE CHANGE SCENARIOS FOR YUKON FLATS NATIONAL WILDLIFE REFUGE, ALASKA Anna Springsteen University of Alaska and The Wilderness Society Wendy Loya The Wilderness Society

2 Climate Change in the Northern Latitudes Since 1950, temperatures have already risen 2.2ºC statewide and 3.9ºC in the Interior Changes in Precipitation suggest increases, although lack of monitoring makes it difficult to tell Need for closer examination of climate change in northern-latitudes

3 Global Circulation Models (GCMs) Used in IPCC 4th Assessment (2007) to look at potential climate change under several emissions scenarios. We chose 5 models to run under the A1B emissions scenario: Greenhouse gas emissions are expected to rise at rates similar to today but eventually decline due to the use of more renewables and more efficient technologies. 5 Models Echam5 Gfdl2.1 Miroc3.2MR HadCM3 CGCM3.1 - And a composite (average) of the 5 models. Global Emissions (Gt C / yr) A1B Past

4 Yukon Flats National Wildlife Refuge

5 Climate Change Predictions for the Refuge: Past and Future trends for Temperature and Precipitation Length of the Growing Season Change in Potential Evapotranspiration (PET) to estimate wetter or drier conditions

6 Temperature All 5 models predict temperature increases over time. Cccma y = (Year) Temperature (C) Echam5 Gfdl2.1 Hadley MirocMR Composite Regression of Composite Mean C C Year

7 Temperature Annual temperatures increase 9ºF by 2080, or about 1ºF per decade This is an increase from 22ºF to 31ºF on average Annual Temperature Change (ºF)

8 Temperature Winter temperatures increase 12ºF by 2080 This is an increase from -3ºF to 9ºF on average Winter Temperature Change (ºF)

9 Temperature Growing season temperatures increase 6ºF by 2080 This is an increase from 52ºF to 55 to 58ºF on average Growing Season Temperature Change (ºF)

10 Growing Season Date of freeze-up occurs 1.3 days later per decade Date of break-up occurs 1.3 days earlier per decade Thus, the growing season lengthens by ~3 days per decade to increase in length by 26 days Mean Modelled Length of Frost-Free Season +2.6 days per decade Length (Days) PRISM 152 days 167 days 178 days YEAR

11 Precipitation Annual precipitation increases from 10 to 13 to 15 inches. An increase of 0.5 inches per decade Annual Precipitation (inches)

12 Precipitation Winter precipitation increases 63% by 2080 This is an increase from 40 to 60 inches of snowfall Winter Precipitation (inches)

13 Precipitation Growing season precipitation increases by 33% This is an increase from 7 to 9 inches of rainfall Growing Season Precipitation (inches)

14 Potential Evapotranspiration (PET) Despite increases in Precipitation, conditions will become drier Due to warmer Temperatures and a longer growing season, the Refuge may become considerably drier -10 Water Deficit % Drier 25% Drier Time Period

15 Overview Warmer temperatures will be found in all seasons, along with an increase in precipitation. However, evaporation will increase water demand more than precipitation will fill it. In addition, because the growing season will lengthen by a month, the period over which water demand occurs will increase as well. Interior Alaska is projected to warm more in the next 40 years than it did in the last 150 and become drier by up to 25%.

16 Implications: Permafrost Thinning of discontinuous permafrost due to annual temperatures above 32ºF by Shrinking of wetlands - Unpredictable landscape changes

17 Implications: Forests Hotter, drier growing seasons: More forest fires Switch to more deciduous vegetation Potential for more invasive plant and insect outbreaks

18 Implications: Wetlands & Rivers Unpredictable freezing and ice break-up Earlier pulse of spring runoff, less or more runoff? Possible lower river levels and drying wetlands Warmer water temperatures affecting river and lake food webs

19 Implications: Wildlife Increased habitat for certain species, decreased quality habitat for others Extended breeding and rearing seasons How will weather variability change with climate--more extreme weather events?

20 Conclusions Climate models are not perfect and there are still many unknowns, but Climate change is already visible in interior Alaska. The combined warming and drying of the future are likely to cause stress on vegetation, wildlife, and people Need to plan for the effects of climate change in a quantitative way

21 Contributors Scenarios Network for Alaska Planning (SNAP) John Walsh Scott Rupp Bill Chapman Mark Olson

22 For More Information: Summary Available at: The Wilderness Society Website under "What's New" or Scenarios Network for Alaska Planning Website:

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24 Growing Season Mean Modelled First Date Below Freezing Date (Days since Jan. 1) days per decade PRISM Sep. 26 Day 269 Oct. 4 Day 278 sd=2.5 Oct. 9 Day 283 sd= YEAR Mean Modelled First Date Above Freezing Date (Days since Jan. 1) days per decade PRISM Apr. 27 Day 117 Apr. 20 Day 111 sd=4.2 Apr. 14 Day 105 sd= YEAR Mean Modelled Length of Frost-Free Season +2.6 days per decade Length (Days) PRISM 152 days 167 days 178 days YEAR

25 Potential Evapotranspiration (PET) PET (mm) Precipitation-PET (mm) PRISM Water Deficit % Drier 25% Drier Time Period

26 Precipitation Precipitation (mm) Cccma Echam5 Gfdl2.1 Hadley MirocMR Composite Regression of Composite Mean y = (Year) + 6 mm/mo + 10 mm/mo Year