Pennsylvania Climate Impact Assessment Report to the Department of Environmental Protection June 29, 2009 Authors: James Shortle, David Abler, Seth Blumsack, Robert Crane, Zachary Kaufman, Marc McDill, Raymond Najjar, Richard Ready, Thorsten Wagener, and Denice Wardrop This report was prepared by the Environment and Natural Resources Institute The Pennsylvania State University www.enri.cas.psu.edu 7000-BK-DEP4252 6/2009 Pennsylvania Climate Impact Assessment Table of Contents 1. Executive Summary 2. Introduction 3. Assessment Methodology 4. Climate Change and Uncertainty 5. Pennsylvania’s Climate Futures 6. Water Resources 7. Forests and Wildlife 8. Aquatic Ecosystems and Fisheries 9. Agriculture 10. Energy 11. Human Health 12. Tourism and Outdoor Recreation 13. Insurance and Economic Risk 14. Economic Barriers and Opportunities Appendices 1. IPCC Emissions Scenarios 2. Soil Moisture Model 3. Locations of Stream Temperature Measurements 4. The PHIM Model 5. IFSM Results for Agriculture in the Absence of Adaptation 6. Projected Habitat Maps for Pennsylvania for 36 Tree Species 7. Modeling Electricity Demand in Pennsylvania 8. Public Comment and Response Document 9. Agency Comment and Response Document - 2 - Acknowledgements This report is the result of the collective work of the authors. Lead authors for the components of the report are: Introduction and Methodology Dr. James Shortle, Distinguished Professor of Agricultural and Environmental Economics, Director, Environment and Natural Resources Institute Climate Change and Uncertainty Dr. Robert Crane, Professor of Geography, Director of the Alliance for Earth Sciences, Engineering and Development in Africa Pennsylvania’s Climate Futures Dr. Raymond Najjar, Associate Professor. of Meteorology and Geosciences Water Resources Dr. Thorsten Wagener, Associate Professor of Civil Engineering Forests and Wildlife Dr. Marc McDill, Associate Professor of Forest Management Aquatic Ecosystems and Fisheries Dr. Denice Wardrop, Assistant Director, Penn State Institutes of the Environment, Associate Professor of Geography and Ecology, Associate Director, Cooperative Wetlands Center Agriculture and Insurance Dr. David Abler, Professor of Agricultural, Environmental and Regional Economics, and Demography Energy, Economic Barriers Dr. Seth Blumsack, Assistant Professor and Opportunities of Energy and Mineral Engineering Human Health, Tourism and Dr. Richard Ready, Associate Professor of Outdoor Recreation Agricultural and Environmental Economics Insurance and Economic Risk Zach Kaufman, Research Assistant Department of Agricultural Economics and Rural Sociology - 3 - Research assistance was provided by Matthew Rydzik, Thomas Wilson, and Harrison Zeff. The final report benefited from comments on the draft report from Dr. Louis Iverson, U.S. Department of Agriculture, Forest Service; Dr. Robert O’Connor, National Science Foundation; Dr. C. Alan Rotz, U.S. Department of Agriculture, Agricultural Research Service. It also benefited from comments and/or consultation with state agencies: Pennsylvania Department of Agriculture, Department of Conservation and Natural Resources, Pennsylvania Department of Insurance, Pennsylvania Fish and Boat Commission, Pennsylvania Game Commission, Pennsylvania Department of Transportation, Pennsylvania Treasury Department, and Public Utility Commission. - 4 - 1.0 Executive Summary This report presents an assessment of the impacts of projected global climate change for Pennsylvania. This assessment was sponsored by the Pennsylvania Department of Environmental Protection (DEP) which, pursuant to the Pennsylvania Climate Change Act, Act 70 of 2008, is required to develop a report on the potential impacts of global climate change on Pennsylvania’s climate, human health, the economy and the management of economic risk, forests, wildlife, fisheries, recreation, agriculture and tourism. Act 70 also requires DEP to report on opportunities, and barriers to their realization, created by the need for alternative sources of energy, climate-related technologies, services and strategies, carbon sequestration technologies, capture and utilization of fugitive greenhouse gas emissions, and other mitigation strategies. The Fourth Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC) finds that “Warming of the climate system is unequivocal…” and that “Observational evidence from all continents and most oceans shows that many natural systems are being affected by regional climate changes, particularly temperature increases.” The report also finds that “A global assessment of data since 1970 has shown it is likely that anthropogenic warming has had a discernible influence on many physical and biological systems.” Most of the sectors considered in this report were explicitly mandated by Act 70 of 2008. Other sectors were added in consultation with DEP and recommendations from the Climate Change Advisory Committee (CCAC). Criteria for selecting additional sectors, and that guided the depth with which all sectors are examined included: (1) the importance of the sector to the state’s economic and social wellbeing, and ecological health; (2) the expected sensitivity of the sector to climate variability and change; and (3) the data and scientific results available to perform a credible assessment given the resources available for this study. The sectors are agriculture, ecosystems, energy, fisheries, forests, human health, insurance, outdoor recreation, tourism, water, wildlife, and the general economy. Ideally, the impact of projected climate change on any given sector is assessed using a mixture of approaches, including integrated quantitative modeling of the sector and extensive stakeholder engagement. The findings are based on readily available data, literature, and some preliminary quantitative analyses. A more in depth analysis would require significantly more time for compilation and analysis of new data. It is important to note in this context that there is limited scientific literature addressing the impacts of projected climate change in Pennsylvania. In consequence, this assessment largely interprets the implications for Pennsylvania of scientific literature that applies broadly and from which we can reasonably infer impacts in Pennsylvania. Such inferences make extensive use of relevant contextual data and information for Pennsylvania, and as is the case throughout this report, indicate the level of confidence in the conclusions. - 5 - 1.1 Pennsylvania’s Climate Futures General Circulation Models (GCM) have become useful tools for projecting the climate impacts of greenhouse gas emissions. We conducted an assessment of the reliability of a suite of GCMs for the climate averaged over the Commonwealth. Our overall findings using a variety of metrics based on surface temperature and precipitation are: • Individual GCMs differ dramatically in their ability to simulate the climate of Pennsylvania; • The multi-model mean produced a credible simulation of Pennsylvania’s recent climate, superior to the simulation of any individual GCM; and • The multi-model mean is slightly too cool and wet, and is slightly muted in its variability on sub-monthly time scales. The credible simulation of Pennsylvania’s past climate found in this evaluation implies that GCM projections for the region can provide useful information for the impacts of projected climate change. The spread across results from individual GCMs provides a rough estimate of the GCM error. Two plausible IPCC global emissions scenarios are used for our analysis of Pennsylvania’s climate future. One scenario assumes continued growth in global emissions throughout the 21st century. This “high” emission scenario is the A2 scenario of the IPCC Special Report on Emission Scenarios (SRES). The second, lower emissions scenario, assumes global emission’s growth is moderated to the middle of the 21st century and declines thereafter. This scenario is the IPCC SRES B1 scenario. Our main findings for the projected climate of the Commonwealth are: • It is very likely that Pennsylvania will warm throughout the 21st century; not a single GCM simulates cooling under the high (A2) or low (B1) emissions scenarios. • It is likely that annual precipitation will increase in Pennsylvania and very likely that winter precipitation will increase in both emissions scenarios. • Projected climate change for the Commonwealth over the next 20 years does not differ between the high and low emissions scenarios. Pennsylvania’s projected climate by the end of the century differs significant between the two scenarios. • By the end of the century, the median projected warming according to the A2 scenario is almost 4 degrees C (7 degrees F), which is nearly twice that of the B1 scenario. • By late century, the median B1 and A2 annual precipitation projections increase by six and 10 percent, respectively. Corresponding winter projections are eight and 15 percent. • Warming will lead to a longer growing season, with median B1 and A2 projections of nearly three and five weeks lengthening, respectively, by late century. Corresponding frost day decreases are nearly four and six weeks. • It is likely that Pennsylvania’s precipitation climate will become more extreme in the future, with longer dry periods and greater intensity of precipitation when it occurs. • There is substantial uncertainty in projections of future tropical and extratropical cyclones for Pennsylvania. Current research suggests fewer storms but with increases in intensity.