Without major reductions in heat-trapping gas emissions, Pennsylvanians can say goodbye to ski resorts, snowmobiles, brook trout and eastern hemlocks, and expect many more heat-related health problems by the end of the century, according to a study on the effects of climate change on the Northeast.

		Graphic: Global warming in Western Pennsylvania

The two-year study, "Northeast Climate Impacts Assessment," released by the Union of Concerned Scientists yesterday in Pittsburgh and six other cities in the region, concludes that droughts and floods would occur more often and the state's dairy industry and corn and apple farmers would suffer significant and costly losses if carbon dioxide emissions continue to grow unabated.

"The message of the report is that although global warming is a serious challenge, it's one we can meet if we act quickly and boldly," said Nancy Cole, director of climate outreach for the Union of Concerned Scientists. "We can and we must meet the challenge, because the very character of Western Pennsylvania is at stake."

Ms. Cole said technologies already exist to reduce emissions by 3 percent a year and meet a goal of reducing heat-trapping gases by 80 percent by the middle of the century. Those technologies can help reduce emissions from electric power generation, which account for 40 percent of Pennsylvania's carbon dioxide total, increase the energy efficiency of buildings and reduce vehicle emissions.

"Pennsylvania is already investing in wind energy and that needs to continue, as do efforts to increase energy efficiency," Ms. Cole said. "Pittsburgh should serve as the hub for a green building boom, and invest in fuel-efficient vehicle fleets and smart growth development to reduce the amount of miles residents need to travel."

The peer-reviewed study by the union, a national public interest group, builds on projections made in October that showed the environment of the northeastern United States would be transformed and badly disrupted by climate change.

According to that report, Western Pennsylvania's climate will resemble the current climate in Alabama if emissions continue to grow, with 20 to 25 days each summer with above-100-degree temperatures and 60 days a year with temperatures above 90.

Average temperatures have already increased about 1.5 degrees Fahrenheit since 1970, the study says.

Even if substantial reductions of carbon dioxide begin now, some of the changes are inevitable. Pittsburgh's climate will still warm, and by 2100, will resemble that of present day Kentucky or Virginia.

"The largest uncertainty about what the climate will be like in 2100 is about what we will decide to do," said Jerry Melillo, director of the Ecosystems Center at the Marine Biological Laboratory in Woods Hole, Mass. "There's a tremendous amount of uncertainty related to what human activity will be like over this century, but right now we have a choice. It's up to you to decide if your children will live in a Pittsburgh like Pittsburgh or a Kentucky- or an Alabama-like Pittsburgh."

Leading scientists agree that the planet's climate is warming and that emissions from a variety of human sources have likely caused much of the change. Yesterday's report localizes those findings and details the effects in the Northeast of continuing emissions of heat-trapping gases, concluding that winters could warm by 8 to 12 degrees and summers by 6 to 14 degrees above historic levels.

Among the worst-case scenarios: Boston, Atlantic City, N.J., and New York City would be subject to disastrous flooding on a regular basis as storms exacerbate a projected sea-level rise from 1 to 2 feet; higher ocean temperatures would make the storied Georges Bank fishing grounds uninhabitable for cod and end lobstering along the New England coast; Philadelphia might average 30 days above 100 degrees each summer; parts of Massachusetts, New Jersey and Pennsylvania would likely become unsuitable for growing popular varieties of apples, blueberries and cranberries; and skiing in the Northeast would be possible only in western Maine.

In Pittsburgh and Philadelphia, the number of summer days of unhealthy smog levels would quadruple.

"The higher temperature health effects would be egregious for the very young and old," said Lewis Ziska, a plant physiologist with the U.S. Department of Agriculture and member of the assessment report's agriculture and health team. "In the 1986 heat wave in New York City, 46 died and 80 percent were above the age of 60."

Brian Hill, president and chief executive officer of the Pennsylvania Environmental Council, said that the state emits 305 million metric tons of carbon dioxide -- 1 percent of the world's total -- and so has an obligation to respond to calls for emissions reductions.

"Scientists are showing us what can happen if emissions continue, and the governor and Legislature need to act now," Mr. Hill said. He added that legislation has been introduced to address climate issues and the governor plans to announce his own climate strategy in the next couple of months.

Last month, the council released "Climate Change Roadmap for Pennsylvania" containing more than three dozen recommendations for reducing greenhouse gas emissions.

The full text of the "Climate Change Roadmap" is available at www.pecpa.org. The full text of the "Northeast Climate Impacts Assessment" report is available at www.northeastclimateimpacts.org.