Global warming is a fact, but its impact on Western Pennsylvania remains a matter of scientific speculation, a Carnegie Mellon University scientist said.
Nevertheless, noticeable change will occur here over the next 100 years, according to M. Granger Morgan, who heads the Department of Engineering and Public Policy. Dr. Morgan expressed reluctance to speculate but said local climate in 2107 could resemble the current climate of the Carolinas.
And if Greenland's glaciers continue melting, which Dr. Morgan said seems to be occurring faster than expected, oceans could rise many feet, which would threaten coastlines and create serious problems in New Orleans and Miami.
But the warming trend will be gradual.
"If you wait five years it will be a bit warmer on average than it is now," he said, noting it will become warmer and drier with possibly more intense precipitation. "There are potential surprises, and rapid rise in sea levels could be one of them."
Michael Rosenmeier, University of Pittsburgh assistant professor of geology and planetary science, studies climate change in geologic time, so he, too, was hesitant to predict the local impact.
But vegetation distribution could shift, he said. Plants that historically grew in warmer climates could thrive here, while trees and plants we're accustomed to seeing might find better habitat to the north.
New Hampshire, for example, could become a new habitat for oak trees that now grow in Pennsylvania.
"Since the last publication [of the Intergovernmental Panel on Climate Change] in 2001, they've really increased their estimates and the accuracy of those estimates," Dr. Rosenmeier said. "Bottom line, they're much more certain of human influence on temperatures and greenhouse gas emissions."
The panel's latest report, released yesterday in Paris, is good science done by brilliant scientists, said the two local professors who recommend immediate action to begin reducing greenhouse gas emissions.
It's already too late to prevent climate change, which has been under way for decades and will continue another 100 years, even if all greenhouse gas emissions halted tomorrow. But without corrective action, the long-term impact could worsen, they said.
Climate-change science has moved "by leaps and bounds" since 2001, Dr. Rosenmeier said, and the accuracy of climate-change models has improved.
"I don't want to say it's alarming, but it should ring bells and people should start addressing it," he said.
Global warming is caused by burning fossil fuels such as coal, oil and natural gas, which produce carbon dioxide emissions. Nuclear power does not produce greenhouse gases.
Carbon dioxide, unlike other pollutants, doesn't clear quickly from the atmosphere once emissions cease. It remains in the atmosphere, allowing sunlight to hit the earth but hindering heat from escaping.
"It's like filling a bathtub with a big faucet and a tiny drain," Dr. Morgan said of carbon dioxide in the atmosphere. "It just keeps accumulating."
He said new technology can be used to reduce greenhouse gases without outlandish hikes in energy costs, and carbon dioxide could be sequestered more than a mile underground. He also recommends a requirement that utility companies have a capped percentage of energy produced by fossil fuels.
Overall, the United States must begin using nonpolluting green energies.
"In an editorial I wrote for Science magazine, I complained that some power companies were trying to rush to build new coal plants and trying to get in under the wire," Dr. Morgan said. "But if they build them, we will be committed to 30 or 40 years of more emissions.
"Don't grandfather in new coal plants," he said. "If you build them today, we know they will cause problems in the future."
Dr. Morgan suggests a 20- to 50-year timetable to reduce and eventually eliminate greenhouse gases. Rapid action preventing use of fossil fuels would be expensive and not gain public support.
California leads the way in legislation to reduce greenhouse gases, with other states following its lead. But Pennsylvania is not one of those states. Dr. Morgan said the federal government should pass legislation and set timetables to reduce carbon dioxide. Then the United States could pressure other countries, including China, to reduce greenhouse gases worldwide.
"We have to lead but we need a carrot-and-stick approach," he said. "The carrot is technology to do it cheaply." Tariffs against polluting countries, including China, would be the economic stick.
"A majority of the good science on this issue was done in the U.S., but the Bush administration up until a couple years ago wouldn't even admit it was an issue."
Even large oil and utility companies are admitting there's a problem, he said.
While the U.S. economy can adapt to climate change, Third World nations with economies closely linked to climate could face economic disaster. "A lot of the world could be under water," Dr. Morgan said.
It's yet unknown whether other dramatic changes could occur. Will Amazon rainforests be destroyed? Will insects breed faster and cause more health and ecological problems? Will hurricanes and tornadoes get ever stronger?
"The biggest concerns from an American perspective are ecological impacts," Dr. Morgan said. "We love our national parks, but when climate zones move north, they won't look the same.
"We like polar bears in the Arctic, but when there's no ice, they will starve to death," he said. "For the American public, those are the big issues."Darrell Sapp, Post-Gazette
Fresh snow clings to the sides of the trees along Liberty Avenue in Gateway Center yesterday afternoon.
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Weather Page Forecasts, radar imagery and satellite photosSteve Mellon, Post-Gazette
About two dozen brave souls jumped into the chilly Monongahela River at the S. 18th Street boat ramp as part of the Pitts-Burrrrrgh Drowned Hogs' fund-raiser for Circle C Youth and Family Services yesterday. Click to a video report about their frigid frolic.
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David Templeton can be reached at email@example.com or 412-263-1578.