UNIVERSITY PARK, Pa. -- Penn State researchers assessed the effects of changing climate conditions on agriculture, tourism, infrastructure, water resources, forestry, energy and human health in the 2015 Pennsylvania Climate Impact Assessment Update. The experts also made recommendations to help Pennsylvanians prepare and respond. The 2015 update was released by the Pennsylvania Department of Environmental Protection.

The 2015 update projects that given current emissions trends, the statewide average temperature will be 5-6 degrees Fahrenheit warmer by mid-century than it was from 1971 to 2000, with precipitation increasing by 8 percent annually and by 14 percent during the winter. Wetter winters and springs are expected, with more rain than snow.

Such weather trends will affect Pennsylvania’s natural resources and economy. Pennsylvanians should also be ready for new economic opportunities, especially in the agriculture sector.

Changing climate will have a mixed impact on agriculture. Dairy production would be affected negatively because businesses will need to mitigate heat stress to maintain milk yields and forage quality. Mushroom growers may need to provide less heating during the winter but additional cooling in the summer for mushroom houses. A warmer climate could stimulate a movement of poultry and hog production from southern states to Pennsylvania, expand double cropping beyond southeast Pennsylvania, improve chances of successfully establishing winter cover crops, and increase corn and soybean yields. At the same time, crop and livestock producers are likely to face management challenges due to new pests, weeds and diseases in a warmer climate.

Tourism and outdoor recreation will need to adapt to the changing weather. Commercial ski areas may incur higher snow-making costs as winters become shorter. Some rivers and streams would no longer be suited for cold-water fishing due to higher temperatures, changing availability of food sources, and drier conditions in some riparian habitats. However, because summers would be longer, recreational fishing activities could increase overall.

More floods will challenge Pennsylvania’s urban and rural infrastructure. Flood risks would be more substantial because of changing seasonable hydrologic conditions in most watersheds: wetter in winter and spring, and drier in summer. In the last decade, there has been a rise in peak flows in Pennsylvania’s river systems, especially in small-to-medium streams. This rise, coupled with the predicted increase of heavy storms, would create more extreme and frequent floods. In addition, more flash floods during spring storms would be likely because of wetter soil on mountains and runoff from snowmelt. Flood management methods, such as using pervious surfaces and wetland conservation, would continue to play a prominent role in coping with more severe floods.

Protecting water quality remains a big challenge for Pennsylvania. With more storms and floods, bank erosion and water channel degradation are expected to increase. Although most wetlands in the state would have stable or wetter hydrologic conditions on an annual basis, the seasonable swings in their hydrologic conditions would be more severe and affect the ability of wetlands to improve water quality. Protection of such wetlands is critical to “buffer” the water system from predicted impacts. In southeastern Pennsylvania, the quality of the tidal waters may deteriorate due to saltwater intrusion as sea levels rise. Fish and shellfish in these waters would be negatively affected because warming is likely to counteract the improvements in dissolved oxygen levels made under the Clean Water Act.

In the forestry sector, the state’s average tree growth rates should increase because of higher atmospheric carbon dioxide concentrations, longer growing seasons, and increased precipitation. No evidence has suggested that climate change has increased the death of trees in northeastern Pennsylvania; however, the survival rates of species such as sugar maple and aspen at the southern extent of their ranges could decrease. Forest managers should adopt a holistic approach to address climate change impacts together with other issues, such as insect pests, invasive species, and overabundant deer populations.

Overall energy consumption is likely to increase. Although heating fuel consumption would decline as winters become warmer, this decrease is expected to be outweighed by the increase in energy consumption for summer cooling. Ensuring reliable electricity delivery during potentially more frequent storms and hurricane events in the future is a concern. The report recommends that Commonwealth agencies encourage efficient building-integrated sources of backup power.

The health of Pennsylvania residents would also be affected. Given the longer warm season, individuals engaging in outdoor activities are more likely to be exposed to insect-borne diseases, including Lyme disease and the West Nile virus. People with respiratory allergies should take extra precaution as pollen and mold concentrations could increase. 

Pennsylvania needs to plan for these changes. The 2015 update reports that Pennsylvania has become warmer and wetter over the past 110 years, mainly due to human-induced increases in heat-trapping gases, such as carbon dioxide and methane. By examining the connections between climate, natural resources, human health, and economic development, Penn State researchers strive to help shape the roadmap for the Commonwealth’s response strategies. 

The Pennsylvania Department of Environmental Protection directed this statewide assessment on climate change under the Pennsylvania Climate Change Act of 2008. Penn State’s interdisciplinary team also prepared the original 2009 Pennsylvania Climate Impacts Assessment, and the 2013 Climate Impacts Assessment Update. The series of reports can be found online at:

• Pennsylvania Climate Impact Assessment 2009
• 2013 Pennsylvania Climate Impact Assessment Update
• 2015 Pennsylvania Climate Impacts Assessment Update

The report was authored by James Shortle, distinguished professor of agricultural and environmental economics and director of the Environment and Natural Resources Institute, with assistance from a multidisciplinary team of colleagues at Penn State. The co-authors (and the chapters they authored) include: 

• Raymond Najjar, professor of oceanography with a joint appointment in the Departments of Geosciences and Meteorology; and Paul Knight, a retired senior lecturer in meteorology, host of "Weather World," and a Pennsylvania state climatologist (Chapter 2: Past and future climate of Pennsylvania)
• David Abler, professor of agricultural, environmental and regional economics and demography, Department of Agricultural Economics, Sociology, and Education; and Armen Kemanian, assistant professor of production systems and modeling, Department of Plant Science (Chapter 3: Agriculture)
• Seth Blumsack, associate professor of energy policy and economics, Department of Energy and Mineral Engineering (Chapter 4: Energy Impacts of Pennsylvania’s Climate Futures)
• Marc McDill, associate professor of forest management, Department of Ecosystem Science and Management (Chapter 5: Forest Resources)
• Richard Ready, professor of agricultural and environmental economics, Department of Agricultural Economics, Sociology, and Education (Chapter 6: Human Health Impacts, and Chapter 7: Outdoor Recreation)
• Chaopeng Shen, assistant professor of civil engineering, Department of Civil and Environmental Engineering (Chapter 8: Water Resources)
• Denice Wardrop, senior scientist and professor of ecology and geography, Department of Geography, and director of Penn State’s Sustainability Institute (Chapter 9: Wetlands, and Chapter 10: Coastal Resources).