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Friday, January 19, 2001

Climate prediction
could ease global
warming’s impact,
geologist says

Scientists merge resources

By Helen Altonn

The Earth could get hotter by 2 to 9 degrees Fahrenheit this century, causing sea level increases that could submerge islands and create havoc along coasts.

Providing this grim glimpse into the future is Jonathan Overpeck, geologist and director of the Institute for the Study of Planet Earth at the University of Arizona in Tucson.

"We don't know for sure but it's a real possibility," he said in an interview during an International Climate Research Conference last week at the East-West Center.

Overpeck said his work, analyzing climate changes over thousands of years and calculating future use of fossil fuels, suggests increased warming "will be closer to the high end."

This will have "huge implications" for the planet's inhabitants, with a sea level rise of possibly 10 to 20 feet, he pointed out.

Overpeck was among more than 100 scientists at the workshop comparing data in the rapidly expanding climate research field.

He said his institute is trying to provide information that can be used by policy-makers to deal with climate changes affecting water, forests, farming and many other interests.

People think immigration from Mexico is driven by the economy but climate also is a big factor, Overpeck said. Immigration has increased from that country because of drought.

Scientists are concerned with providing better predictions for planting, opening and closing dams, storing water, managing forests and coping with other problems, Overpeck said.

"Climate prediction will help us a great deal to maintain economic growth in the face of environmental changes."

Overpeck and his colleagues are interested in changes in climate over centuries, long before observing systems. They gather ancient data from tree rings, coral rings, sediments from lakes, ice cores and mountain ranges.

"All records suggest global warming has been unprecedented in the last 1,000 years," he said, explaining both natural and human factors are involved. "It isn't either-or."

But since the 1800s, he said, about two-thirds or three-fourths of the warming has been due to human activity producing greenhouse gases.

"I worry a lot," Overpeck said, noting in the last interglacial period 125,000 years ago, the Earth was only 2 to 3 degrees warmer, yet the sea level rose 12 to 18 feet higher than it is now.

Most of the Greenland ice sheet melted with only a couple of degrees more in temperature, he said.

Global warming can't be reversed, but it can be slowed to reduce the impact of climate and sea changes on society, Overpeck said.

He said petrochemical companies figured out solutions to destruction of the ozone and acid rain and he believes the same thing will happen with global warming.

"Big companies are starting to say this is a problem and they're thinking of technology to deal with it. ...

"The nice thing about it is that every one of these environmental issues has a solution that makes everyone happy. Global warming is just the biggest and the latest."

Space scientists merge
resources to detect
tiny changes in
Earth’s climate

By Helen Altonn

Space scientists in Honolulu last week learned more about what they need to crank up observing systems to improve climate predictions.

The National Aeronautics and Space Administration is planning satellite and Earth-based systems to detect the smallest signals of long-term climate changes, said Vikram Mehta and Eric Lindstrom.

"Things that seemed impossible to measure from space are becoming possible," said Lindstrom, a NASA oceanography program scientist in Washington, D.C.

He said satellites put up by the Department of Defense and National Oceanic and Atmospheric Administration will be converged into a national system capable of detecting small, subtle signals of climate changes.

Mehta, University of Maryland and Goddard Space Flight Center researcher, said, "We want to do better because of the impacts on society."

The scientists discussed the space agency's plans in an interview during an international Workshop on Decadal Climate Variability at the East-West Center.

NASA sponsored the conference with the International Pacific Research Center, operated by the United States and Japan at the University of Hawaii, and the Climate Variability & Predictability Project of the World Climate Research Program.

Enormous progress has been made in understanding climate since sailors measured ocean surface temperatures 150 years ago, Mehta said.

Early sailors would be astounded at today's technology, said Lindstrom, noting a sea level increase of less than half an inch now can be measured from space. "It's like measuring the thickness of a dime from the Empire State Building."

Mehta said people were laughing at the idea of measuring rainfall in space a few years ago, but now that's being done.

Salinity at the sea surface also is being measured by aircraft, which is difficult even from ships and people thought was impossible from space, Lindstrom said.

He said NASA is planning observing and communications systems that will revolutionize oceanography. Moving from weather to climate predictions involves a new set of requirements, he said.

Tiny signals of persistent cooling and warming could lead to droughts, flooding or other extreme climactic events with disastrous impacts on society, Mehta said.

People probably could ride out one bad drought, but not one after another, he said. Water will be the most important resource of the future, Mehta said.

Lindstrom said nations are collaborating in an integrated global observing strategy to help reduce critical consequences of climate changes.

"There are no national boundaries in this game. ... These climate phenomena span the globe and affect everybody."

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