How might climate change affect Pennsylvania?

Average Temperature Plot

The term "Keystone State" may take on new meaning in the coming decades as Pennsylvania tackles an important issue, climate change. The state is the third highest emitter of carbon dioxide in the United States, preceded only by California and Texas. It is poised to experience change that could alter natural places like the John Heinz National Wildlife Refuge.

Over the next several decades, the climate in Pennsylvania may very well change from mild summers and snowy winters to much warmer summers and snow-less winters. Spring could start to arrive earlier as well. Even under the best projected scenario, one in which emissions are drastically reduced over the next decade, Pennsylvania residents will still experience hotter summers and warmer winters. Winters have already warmed 4 degrees F between 1970 and 2000. They are projected to rise between 3 to 7 degrees F in the next few decades, even more if emissions are not reduced. Overall, warming will be most dramatic in the southern part of the state.

Warmer winters will mean a lot less snow across the state and slushier (wetter) snow. There will also be a decreased average for snow-covered days across the state. This could spell trouble for popular winter recreation activities such as skiing and snowmobiling. Although ski slopes often make snow, if winters are too warm, the snow they make may simply melt or become too slushy to be sufficient for skiing. Snowmobile trails, which rely on natural snow, will likely not have enough snow to allow for this type of recreation.

Pine warbler at John Heinz National Wildlife Refuge

Hotter summers and earlier spring times may also cause challenges. An increased frequency of short-term (one to three month) droughts every one to two years will cause trouble for farmers. On the flipside, it is also predicted that heavier rainfall events (the type that often lead to flooding) will also become more frequent. The number of extremely hot days will also increase, especially in cities like Philadelphia and Pittsburgh, leading to an increased risk of heat-related illnesses including heat stress, heart attack, and death. "Philadelphia's Heat Health Watch/Warning system is a national model of public-health preparedness" and will become increasingly important in the coming years. Hotter summers will also lead to an increase in air pollution related to ozone and increased pollen production by plants (a problem for allergy sufferers and those with cardiovascular and respiratory diseases). Intense heat may also be problematic for wildlife found at the Heinz National Wildlife Refuge, forcing critters to find new ways to stay cool. Increased pollen production may also influence the composition of native plant communities at the Refuge in unexpected ways.

Agriculture, a $4 billion dollar a year industry for the state, will be especially challenged by a changing climate. Increased drought could lead to higher costs for farmers to irrigate their crops. Warmer weather crops such as watermelons and peppers might do better but cooler crops such as blueberries, raspberries, and some varieties of apples may struggle.  Higher average temperatures may also allow new agricultural pests and diseases to gain hold in Pennsylvania. Dairy farmers may incur increased costs as they come up with ways to reduce heat-stress in their cows, which can lower milk production.

The beautiful Pennsylvania maple-beech-birch forests may change over the coming decades to oak-hickory dominated forest systems, which are more tolerant of warmer climates. Ruffed grouse, the state bird, rely on this forest system and populations of these birds may decrease with decline of this forest type. Another forest system which may struggle is the spruce-fir system, often found on mountaintops. This system may be eliminated with warming temperatures, causing challenges for birds such as yellow-bellied flycatchers.

In order to reduce carbon and other greenhouse gas emissions by the 80% below 2000 levels that is needed over the next several decades, Pennsylvania has begun tapping into wind energy and biofuels, investing in green building certifications, improving building energy codes, and adopting tail-pipe emission standards.

What does this mean for the John Heinz NWR?

The John Heinz National Wildlife Refuge provides important wintering habitat for migratory birds, especially those that use the Atlantic Flyway. It also provides a home for the state endangered red-bellied turtle and the coastal leopard frog. Warming temperatures and potential changes in precipitation patterns may alter the way in which the John Heinz NWR staff manages the Refuge for these animals.


Photo: Pine warbler at John Heinz National Wildlife Refuge; Courtesy of USFWS

Union of Concerned Scientists. 2007. Pennsylvania: confronting climate change in the U.S. Northeast. Based on "Confronting Climate Change in the U.S. Northeast: Science, Impacts, and Solutions," a report of the Northeast Climate Impacts Assessment (NECIA, 2007). Washington, D.C., USA.

Union of Concerned Scientists. 2008. Climate change impacts and solutions for Pennsylvania: how today's actions shape the state's future. Cambridge, MA.

Data from The Weather Channel website: