News Release, Kansas Geological Survey, May 24, 2001
Two of the book's editors, Lee Gerhard and William Harrsion, are geologists at the Kansas Geological Survey, based at the University of Kansas. The book was published by the American Association of Petroleum Geologists.
The book is a collection 18 papers, written primarily by earth scientists, about various aspects of geology and climate change.
According to several chapters in the book, the earth's geologic history is replete with examples of climate change. Those changes can be measured in a variety of ways. Some methods, such as cores from ice sheets in locations such as Greenland, are relatively well known. Others that are less well-known include studying fossils of beetles and tree leaves, or studying sponges that grew in ancient oceans.
Based on various geologic evidence, geologists say that temperatures in central Europe have dropped about 35 degrees Fahrenheit in the past 60 million years. During the Ice Ages that occurred about 1.5 million years ago, temperatures dropped about 10 degrees on average.
"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 Gerhard.
The causes behind these changes are more difficult to discern, say the authors, but many of them are related to changes in earth's atmosphere and geology. Some small-scale changes in climate are driven by factors such as volcanic activity, solar storms, and ocean currents.
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."
All of this--climate change and its sources--has dramatic implications for public policy. The book explores such issues as disposing of carbon dioxide in deeply buried rock formations, or the kinds of measures that should be taken in response to rising sea levels caused by the melting of polar ice caps.
"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 $49.00, plus $6.00 per copy for postage and handling. Kansas residents should add 6.9% sales tax on the entire cost of the order.