Global warming means big change here, expert says
Floods, droughts, stress on plants and animals, Penn State professor says.

By Ad Crable
Lancaster New Era
Lancaster Online
Published: Feb 03, 2007 12:02 PM EST

LANCASTER COUNTY, PA - Because of inescapable global warming, Pennsylvanians should brace for springs and summers filled with more flooded basements, and for heat waves and droughts that could make growing farm crops difficult, a Penn State professor and climate expert says.

And count on more winters like this one in Lancaster County, in which doomed flowers bloom in January, and mosquitoes potentially carrying the West Nile virus buzz around.

Michael Mann, director of the Penn State Earth System Science Center, discussed his take on what’s in store for Pennsylvania’s climate in the years to come in an interview Friday as fellow scientists from 113 nations released a sobering report for the United Nations on climate chage.

Mann, a meteorology and geosciences professor, served on that same Intergovernmental Panel on Climate Change when it released its last assessment five years ago.

This time, the scientists’ prediction of warmer temperatures and stormier weather ahead was more certain.

“There’s overwhelming scientific evidence now” that global warming is happening, is caused by man, and will have some effect on weather for decades, even if the world gets its act together and caps greenhouse gas emissions such as carbon dioxide, Mann says.

“We will see more droughts and flooding events,” Mann says. “We can never say one particular event is due to climate change. All we can say is the frequency of those type of events is likely to increase over time.

“We’re starting to see the loading of the dice.”

That is due mainly to warming of the sea surface, where most weather events originate.

Mann warns that even subtle changes in weather extremes will play havoc with Pennsylvania flora and fauna that take their cues from the weather.

“We’re changing the march of the seasons,” he says.

Unseasonable weather events could disrupt animals’ hibernation and migration signals, which they depend on to survive.

Flowers in backyards and in the wild could be fooled by abrupt changes in weather into opening prematurely, killing them in some cases.

More sweepingly, native plants, which evolved over eons in specific habitats, could lose their competitive edge with false starts.

Entire forest ecosystems might not be able to migrate fast enough to outrun environmental changes. Mann thinks, for example, sugar maple trees may be doomed in a warming New England.

Agriculture in Pennsylvania is in for a challenge, he predicted, with more frequent periods of dry weather and flooding reducing yields of such crops as corn.

Lancaster countians’ favorite beach retreats will certainly be subjected to more severe storms in the years ahead, Mann says.

Sea-level rises from melting ice sheets at either end of the earth are projected in the

United Nations report to be modest. Seas rising at those rates, Mann says, will mean more frequent storm surges in places like Atlantic City and Ocean City, N.J.

But he and other scientists, including those in a recent article in Science magazine, noted that only very recently has it been determined that the Greenland and Antarctic ice caps are melting at three times the rate they were only five years ago.

If that continues, more dramatic sea rises could cause unthinkable flooding of the U.S. Atlantic coastline, he says.

“Most of southern Florida and New York City would be submerged.”

Even though the Earth is already committed to troubling global change for decades, Mann is optimistic that reason and technology will combine to prevent a catastrophic climate change.

“I have optimism that we will find the technology that, in combination with more energy-conscious practices at corporate and individual levels, we can avert those dangerous thresholds.”

Alternative energy sources such as biofuels, more energy-efficient lightbulbs, hybrid vehicles and research into hydrogen fuel cells are all encouraging, Mann says.

But, he adds, “I think we don’t have time to argue.”

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