June 25, 2001

Contact: Rex Buchanan, Kansas Geological Survey at KU,(785) 864-2106, or Lee Gerhard, (785) 864-3965

Book pins climate change mostly on natural processes

LAWRENCE -- A new book on global climate change states that geological and oceanic changes have had a larger impact on the world's climate than human activity.

"The evidence shows that there are constant natural changes in the climate, and in both directions, from warmer to cooler and from cooler to warmer" said Lee Gerhard, a geologist at the Kansas Geological Survey based at the University of Kansas and one of the editors of "Geological Perspectives of Global Climate Change."

The book was published by the American Association of Petroleum Geologists. Its editors include Gerhard and William Harrison, also a geologist at the Kansas Geological Survey based at KU.

The causes behind these changes are more difficult to discern but many of them are related to changes in earth's atmosphere and geology, according to the book, a collection of 18 papers written primarily by earth scientists. Some small-scale changes in climate are driven by factors such as volcanic activity, solar storms, and ocean currents.

The authors state a much larger factor in climate change, over the millions of years of geologic time, is the movement of the earth's land masses through plate tectonics (known more popularly as "continental drift"). Finally, the largest impact may come from such influences as the earth's distance from the sun or the amount of energy radiating from the sun.

"Human activities, such as increasing the amount of carbon dioxide and methane in the atmosphere, have very little impact on climate," said Gerhard. "These other natural processes influence climate far more, even over human history. Other processes, such as volcanic eruptions, meteor impacts, and other natural factors, are equally or more important than humans."

Regardless of the causes, a changing climate has dramatic implications for public policy, the authors state. The book explores such issues as disposing of carbon dioxide in deeply buried rock formations or the measures that should be taken in response to rising sea levels caused by the melting of polar ice caps.

"There is no way to predict whether we put the earth at risk by adding greenhouse gases to the atmosphere. . . . Nevertheless, prudence dictates tht we take firm steps to cut back the release of CO2 (carbon dioxide) into the atmosphere," writes Wallace S. Broecker, who studies ocean currents at the Lamont-Doherty Earth Observatory at Columbia University. "These steps will involve a combination of energy consesrvation, the implementation of nonfossil-fuel-based energy sources, and the capture and sequestration of CO2 from stationary power plants."

According to the book, the earth's geologic history is replete with examples of climate change. Some methods for measuring the change, such as cores from ice sheets in locations such as Greenland, are relatively well known. Others include studying fossils of beetles and tree leaves, or studying sponges that grew in ancient oceans.

"Geology offers important information about the earth's history, about the natural processes that have led to climate change," said Gerhard. "And one thing is clear from that history-that climate has always changed, and that natural processes cause those changes to vary greatly over time and in intensity."

 • Copies of the book are available from the Kansas Geological Survey, 1930 Constant Ave., Lawrence, KS 66047 (785) 864-3965 for $49 plus $6 per copy for postage and handling. Kansas residents should add 6.9% sales tax.