Albuquerque Journal (Albuquerque, NM)

SCIENCE'S HOT TOPIC GLOBAL WARMING.(Dimension)

Byline: Stories by John Fleck * Graphics by Carol Cooperrider Of the Journal

Scientists trying to predict where the Earth's climate is going are looking to the past for clues about the future

LAGUNA DEL PERRO Geologist Bruce Allen can see an ancient lake stretching across the now arid Estancia Basin.

The windswept spot where he stood on a cold fall afternoon was once 150 deep in an ancient lake.

In his mind, he has filled that lake and then evaporated it a thousand times, reading ebbs and flows etched in the lake-bottom sediments.

Those ebbs and flows record ancient climates. You could think of Allen as a meteorologist of the past.

Nine times over a 12,000-year period, in the waning years of Earth's last ice age, the lake filled, then dried out again as Earth's climate changed.

There were no thermometers or rain gauges when Lake Estancia filled and dried and filled again. It is left to scientists like Allen to find the clues, to reassemble the record.

"Global climate change" is a hot topic these days, with satellite data and sophisticated computer simulations taking the temperature of our planet.

But to understand the future, you must know the past.

So while computer simulations of the greenhouse effect and analyses of shrinking rain forests and growing fossil fuel emissions drive much of the debate over the future climate of our planet, a growing number of scientists are peering backward, trying to understand climates of the past.

Here, that means slogging through the thick gray mud of the Estancia Basin with Allen.

In the relative shortness of our human lifetimes, we tend to think of what we have experienced as "normal climate." But research by scientists like Allen shows there is no such thing.

Climate is constantly changing it gets wetter and drier, warmer and colder.

Understanding those changes and how and why they occurred, researchers say, is essential to figuring out whether changes going on now are human-caused or the result of natural forces.

The Estancia Basin could be the poster child for the notion that climate can be a wild and temperamental thing. …

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