Global warming?

Dr. Thompson's pictures show a dramatic melting of this glacier high above Peru in the Andes moutaines between the years of 1978 and 2000.

Earth has warmed one degree over the last century -- Why?

March 21, 2001
Web posted at: 2:15 PM EST (1915 GMT)

LESSON PLAN RELATED STORIES, SITES

Michael McManus
CNN NEWSROOM

WASHINGTON (CNN) -- One degree. On a thermometer, it doesn't seem like much at all. But that degree has sparked intense debate among experts who monitor the temperature on Earth.

In a new report issued by a leading group of scientists and meteorologists, research shows the planet has warmed one degree during the last 100 years. That report from the Intergovernmental Panel on Climate Change asserts that Earth will continue to warm between 2 and 10 degrees during the next century.

Those researchers believe that global warming could be boosting the planet's temperature. Global warming is a phenomenon of temperatures rising on Earth. Scientists have said that some human activities cause gases such as carbon dioxide, methane and nitrous oxide to build up in the atmosphere. Those gases trap heat closer to Earth's surface giving the planet a worldwide fever.

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Many experts say two chemicals -- carbon dioxide and carbon monoxide -- are most responsible for global warming. Cars, trucks and factories around the world emit those chemicals everyday. Once in the atmosphere, those chemicals act as big reflectors, bouncing back sun rays to the Earth and warming the planet.

But there are scientists, climatologists and weather watchers who believe that the warming trend is not an aberrant threat, but part of a natural cycle of warming and cooling on Earth. "We just haven't been around long enough to know if it's a fact," said CNN weather anchor Orelon Sidney. "The Earth is more than 4 billion years old and humans haven't been around that long. So this could just be a part of cycle."

The scientists who believe the Earth is warming say years of research is needed to determine why.

Dr. Lonnie Thompson, a researcher at the Byrd Polar Research Center located at Ohio State University, is among those attempting to discover the causes of global warming. He spends many months away from his home in search of answers.

Thompson's latest trek to the Andes Mountains showed substantial changes in a glacier.

"The glacier we have been studying has been melting at an unbelievable rate," Thompson said. "Where there was once ice, there is now a lake." Thompson photographed the new lake and glacier to show "obvious changes in our world because of temperature increase," he said. Thompson said a warmer earth could lead to more erratic weather. "If energy in the system -- the heat on the Earth's climate system --increases, then you're going to have more water vapor. More water vapor feeds more storms -- larger hurricanes, maybe larger snowstorms too."

As a meteorology student at the University of Maryland, Antony Chen is among those who would watch for those weather changes. He is part of the next generation of researchers who will have to figure out what's behind the cause of the temperature bump.

Chen says we have to look at the big picture then determine what changes people should make on the local level. "We need to know what's going on in the atmosphere, the magnitude of changes we are making to our climate system," Chen said. "Then we can start coming up with solutions."

Professor Bruce Doddridge is one of Chen's professors and is encouraged by the caliber of young people he's seen entering the earth sciences. "I'm impressed with the variety of smart and intelligent people coming through that can do this work," he said.

Doddridge concedes that there are many potential causes of global warming, but said he believes the new technology could help assess and solve the problem. "The issues are becoming more complicated," Doddridge said, "but I think the tools we have to work with are becoming more sophisticated."

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Special Report: Intergovernment Panel on Climate Change
University of Maryland
Dr. Lonnie Thompson's trip to the Andes
EPA Global Warming Site
National Oceanic and Atmospheric Administration

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