Climate Change Impacts in Pennsylvania Brent Yarnal Department of Geography Penn State University

Overview Supporting science Present & future climate context Key climate impacts Some affected sectors

October US National Assessment of Climate Change Impacts Union of Concerned Scientists

Climate is changing across PA In the 20 th century:  Temperature increased 0.5 ° F  Rainfall increased 5-20% Since 1970:  Temperature increased ~0.15 ° F per decade  Annual days over 90 ° F increased  Winter snowpack decreased (c) Brian A. Morganti /

Source: IPCC 2001 HIGHER A1FI (940 ppm) LOWER B1 (550 ppm) Further warming depends on emissions

Current global emissions

Key climate changes Higher temperatures More extreme heat More precipitation More severe storms More floods More droughts

Temperature change above average Projected temperature changes for PA

Changes in average summer heat index

In the next several decades:  Doubling in days over 90°F in southern PA By mid-century:  50 days per year over 90°F in southern PA By late century :  Entire summer with highs over 90°F in southern PA Days with extreme heat

Precipitation 20 th century  Annual average precipitation rose 15% (6 inches) Future projections  Trend continues under either emission scenario Spring rainfall under the higher-emissions scenario

Hotter summers mean more evaporation, less soil moisture Droughts projected every 1-2 years in many areas Summer drought

Key sectors affected by climate change Agriculture Forestry Water & water resources Ecosystems Human health Recreation

New opportunities New risks & costs iStockphoto.com/Kalulu Agriculture & climate change

iStockphoto.com/lissart ©iStockphoto.com/Bronwyn8 Crops vulnerable to rising temperature iStockphoto.com/claylib

USDA NRCS Milk production declines in higher- emissions future

Forests Forests migrate Productivity increases

Dominant forest types for a doubling of CO 2

Black Cherry Lower emissions: 50% of habitat lost Higher emissions: 80% of habitat lost

Ecosystems Weakened ecosystems at risk Ecosystem functions impaired Biodiversity decrease

Bird habitat 25% reductions in forest habitat for  Ruffed grouse  American goldfinch  White throated sparrow iStockphoto.com/Flatcoater iStockphoto.com/BirdImages Jupiter Images

Water & water resources Uncertain water quantity Seasonal shift in streamflow Increased intense rainfall Decreased water quality

Projected changes in Susquehanna River flow

Human health Heat mortality increase Water-borne disease increase Vector-borne disease increase

Extreme heat – Harrisburg

Pollen allergens Higher temperatures + higher CO 2 levels  more pollen allergen production American Academy of Allergy, Asthma & Immunology Jupiter Images

Tony Tremblay James Estrin/The New York Times/Redux Air quality

Impacts on winter recreation Loss of ski industry Loss of snowmobiling iStockphoto.com/MentalArt

Snow cover Geoff Kuchera

Snowmobiling iStockphoto.com/N8K