MITZI PERDUE: Is global warming real? Yes

MITZI PERDUE: Is Global Warming Real? Yes

(July 28, 1998 1:16 p.m. EDT http://www.nandotimes.com) - Is global warming real? You can find experts who say that it's a clear and present danger. You can also find others who insist that the whole issue isn't worth worrying about.

Which of these groups should we believe?

Jonathan Overpeck, a scientist with the National Oceanic and Atmospheric Administration (NOAA) has some thoughts on this.

First of all, he doesn't have a high level of trust for the opinions of politically motivated people "who are not climate change scientists themselves and therefore lack firsthand knowledge."

Conversely, he would be inclined to trust what real climate scientists say. These men and women, he points out, have actually done the research. And more often than not, he adds, they've had their work published, which means it has been reviewed by other knowledgeable scientists. And, according to Overpeck, among these specialists, "There is a strong consensus that global warming is taking place." So the guys who know best say, yes, global warming is taking place.

Recently, Overpeck and an international team of 20 researchers worked together to summarize what we know about the climate changes that have taken place in the past 400 years. Their tools included analyzing and reviewing the growth of tree rings, examining lake sediments, studying written records and checking gas bubbles trapped inside glaciers.

Altogether, Overpeck and his colleagues used 30 different records to check and cross-check their results. What they discovered is that a Little Ice Age began around 1600 and continued until it reached its coldest around 1850.

Since then, the climate has warmed dramatically. Our climate is today warmer than it's been in 400 years.

So, according to the scientific evidence, global warming truly is taking place. But what are the likely consequences of this?

You've probably heard about the potential for coastal flooding, but there are other results to consider.

Rising temperatures, for example, are causing the Alaskan permafrost to thaw. "The permafrost is close to the melting point anyway," says Gunter Weller from the University of Alaska, "and it doesn't require much of a temperature increase to cause it to thaw."

In the last century, the permafrost in Alaska has warmed between two and four degrees. Since about 80 percent of Alaska rests on permafrost, the consequences are enormous. When ice masses in the permafrost thaws, the land underneath it becomes unstable. Soon there are pits and depressions, many of which are filled with water. This causes houses, roads and airport runways to become either unusable or in need of expensive repair. And as the thawing continues, the unstable ground could also pose problems for the Alaska Pipeline.

The problems don't end there. "A lot of the forests here are underlain by permafrost," explains Weller's colleague, Tom Osterkamp. "As the temperatures rise, the foundation for the whole eco system melts out from underneath it. The forest areas turn into marshes, fens or ponds."

If the forests aren't killed by standing water, they face a new threat. Insects that don't survive in colder temperatures are now gaining a foothold in Alaska. "There are unprecedented outbreaks," Weller points out. "The losses are higher than we've ever observed before."

Permafrost thawing may also contribute further to global warming. As the climate warms, dead vegetation that used to be locked in the permafrost, can now release its carbon and add to the green house gases implicated in global warming. This can effect everyone.

For climate scientists, the debate about global warming doesn't seem to be about "Is this happening?" Rather, it's "What is happening and what are we going to do about it?"

MITZI PERDUE writes about environmentally related matters weekly for Scripps Howard News Service.