Climate Change Impacts in Pennsylvania
Brent YarnalDepartment of Geography
Penn State University
Overview
Supporting science Present & future climate
context Key climate impacts Some affected sectors
www.northeastclimateimpacts.org/pa
October 2008
2000
US National Assessment of Climate Change Impacts Union of Concerned
Scientists
http://www.int-res.com/abstracts/cr/v14/n3/
Climate is changing across PA
In the 20th 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 / www.stormeffects.com
Source: IPCC 2001
HIGHER
A1FI (940 ppm)
LOWER
B1 (550 ppm)
Further warming depends on emissions
Current global emissionsRecent emissions
1990 1995 2000 2005 2010
CO
2 E
mis
sion
s (G
tC y
-1)
5
6
7
8
9
10Actual emissions: CDIACActual emissions: EIA450ppm stabilisation650ppm stabilisationA1FI A1B A1T A2 B1 B2
1850 1900 1950 2000 2050 2100
CO
2 E
mis
sion
s (G
tC y
-1)
0
5
10
15
20
25
30Actual emissions: CDIAC450ppm stabilisation650ppm stabilisationA1FI A1B A1T A2 B1 B2
20062005
2007
Key climate changes Higher temperatures More extreme heat More precipitation More severe storms More floods More droughts
2010-2039 2040-2069 2070-2099
Temperature change above 1961-1990 average
Projected temperature changes for PA
Changes in average summer heat index
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 20th century
Annual average precipitation rose 15% (6 inches)
Future projections Trend continues under either
emission scenario
Spring rainfall under thehigher-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 CO2
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 CO2 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