Climate Change Impacts on the Appalachian Trail. Lenny Bernstein, PhD. November 17, 2009

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1 Climate Change Impacts on the Appalachian Trail Lenny Bernstein, PhD. November 17, 2009

2 ATC Climate Change Resolution Approved by Board of Directors on Nov. 1, 2008 Commits ATC to: - Reduce its own carbon footprint - Promote the use of low-carbon alternatives for accessing the Trail - Educate ATC members and Trail visitors about climate change and its impacts on the Trail - Monitor climate change indicators - Support appropriate Federal and State carbon-reducing policies and partner with like minded-organizations 2

3 Assessing Climate Change Impacts on the A.T. Used Climate Wizard to estimate of amount of climate change - Developed by The Nature Conservancy, University of Southern Mississippi, and University of Washington - Downscaling program that looks at areas as small as 5 miles square (25 sq. mi.) - Provides historical climate data and projections of future temperature and precipitation using any combination of three climate models and three emission scenarios 3

4 Summer Precipitation Historic Average, Data Source: Climate Wizard 4

5 Evaluated Two Cases Moderate Case - CSIRO-MK3.0 model, Climate sensitivity = 3.1 o C - IPCC SRES A1B emission scenario 5

6 Projected Change in Summer Precipitation Moderate Case Data Source: Climate Wizard Model: CSIRO- MK 3.0 Emission Scenario: A1B 6

7 Evaluated Two Cases Moderate Case - CSIRO-MK3.0 model, Climate sensitivity = 3.1 o C - IPCC SRES A1B emission scenario More Extreme Case - MIROC 3.2 model, Climate sensitivity = 4.0 o C - IPCC SRES A2 emission scenario, 25% higher cumulative emissions ( ) then SRES A1B 7

8 Projected Change in Summer Precipitation More Extreme Case Data Source: Climate Wizard Model: MIROC 3.2 Emission Scenario: A2 8

9 Other Results Summertime temperature projected to increase over the southern half of the A.T. - Moderate Case: 3 o C (5.4 o F) - More Extreme Case: 4 o C (7.2 o F) Complete results at (see Topic 7, What Impacts will Climate Change Have on the A.T.?) 9

10 Impacts of Climate Change on the A.T. 1. Changes dues to more extreme weather 2. Changes in the distributions of plants and animals 3. Changes in the hiker experience 10

11 Changes in Weather Extremes Drought more likely - Water sources hikers depend on could disappear - Weaker trees more susceptible to insect attack - More treadway erosion More precipitation in heavy events; more runoff and erosion, less groundwater recharge More intense hurricanes could lead to more treadway erosion and more blow downs Warmer winter temperatures would increase the hiking season, but could lead to increased plant pest infestations and more dead trees Warmer, drier conditions could mean more forest fires; more blow-downs and dead trees could makes fires more intense 11

12 Changes in the Distribution of Plants and Animals Warming of the last 45 years has already caused boreal trees to migrate upslope in New England - Continued warming could make them locally extinct - Birds and animals that depend on these trees would also become locally extinct + Bicknell s thrush breed in red spruce; 25% of its breeding range is within 1 mile of the A.T. In Virginia, red spruce is found only at the highest elevation any further warming will increase the risk of local extinction Climate change, in combination with other global changes, could increase invasions by exotic invasives 12

13 Changes in the Hiker Experience Hotter summer weather likely to decrease trail use Water availability could become a serious problem for backpackers A.T. thru-hikers already starting about two weeks earlier - Walking with Spring adjusting to an earlier Spring 13

14 Using the A.T. to Study Impacts of Climate Change A.T. MEGA-Transect is a long-term study of plant and animal life along the full length of the A.T. - Also will monitor air and water quality - Will study visitor use patterns - Program has a dozen partners - Combination of citizen science and professional researchers - Just getting underway 14