To date, most research associated with global climate change has focused on determining whether it really is happening, and trying to gauge how much -- and how fast -- average temperatures and precipitation levels will change.

But a researcher in Penn State's College of Agricultural Sciences, in a study funded by the U.S. Environmental Protection Agency during the last five years, has taken a different tact. His work assumes global warming is occurring and accepts the tendency of models that predict Pennsylvania will grow slightly warmer and wetter in the not-so-distant future. His research focuses on the effect of global climate change on Pennsylvania's agriculture, water resources and economy.

"My interest is primarily in the adaptation to climate change," says James Shortle, distinguished professor of agricultural and environmental economics. "There are a lot of people who are worrying about modeling climate change, trying to determine to what extent it is happening and looking at influencing climate change through pollution control, but my research is much more about how we should be adjusting to what we expect is happening."

Shortle doesn't think there is much doubt left about global climate change. "The evidence only continues to accumulate," he says. "Even the more credible skeptics are being converted. I had colleagues who said this is not happening, but I have seen those opinions change. People are having a hard time maintaining their skepticism of global climate change. The large societal risks cannot be ignored."

But the effects for Pennsylvania won't be all bad, according to research done by Shortle and his colleagues. "Climate change is likely to benefit our state's agriculture," he explains. "Higher levels of carbon dioxide in the atmosphere should stimulate photosynthesis and raise crop yields, while crops may also benefit from additional spring and summer rainfall and warmer temperatures."

Experts are uncertain whether climate change will enhance the Keystone State's position in the national and international agricultural markets. If Pennsylvania's growing conditions improve while those in other regions deteriorate, the state's production of crops and livestock could bring higher prices.

"There are clearly a number of factors that are going to influence agriculture in Pennsylvania," Shortle says. "My guess is that climate change will be the least significant. We need to distinguish between what's good for farmers and what's just good for crop production. Markets will change, and competition will affect farm profits, so we really must look at agricultural changes across the globe to determine what changes might mean to Pennsylvania."

Factors such as environmental regulations, new agricultural technology, nutrient and water resources management, and farmland preservation are important. "Of course, if we don't save enough farmland in Pennsylvania, future market demands won't matter much," Shortle says. "And pests are a wildcard in this kind of prognostication, because it may be that the same warmer, wetter weather that will boost crops also will benefit pests, and we may be dealing with more and different invasive pests than we do now."

If, as predicted, ocean levels rise, storm surges increase and the state sees more -- and more-severe -- hurricanes and other storms in coming decades, Pennsylvania's neighbors with shoreline and coastal plains, such as New Jersey and Maryland, likely will have to deal with inundation of wetlands and drastically increased beach erosion. "But the Keystone State won't get off unscathed, and we will have to deal with much less obvious changes in our ecosystem," Shortle says. "That's why we are involved in risk assessment now. Pennsylvania will have to adjust to the impacts of global climate change too, but it's harder to say what they will be.

"Changes are not likely to be radical, but we have to look simultaneously at human systems and physical systems -- they cannot be separated," Shortle adds. "Global climate change will have an impact on Pennsylvania's economic and social systems over time."

12/17/2004