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Reconstructing climate change through glacial geology and tree-ring analysis is the major research focus for Greg Wiles, assistant professor of geology at The College of Wooster since 1998.

A graduate of Beloit College, Wiles earned his master's degree from the State University of New York at Binghamton and his Ph.D. from the State University of New York at Buffalo.

Wiles is affiliated with the Geological Society of America, the National Association of Geoscience Teachers, American Association for the Advancement of Science, the American Quaternary Association, and the Society of the Sigma Xi.

Wiles' research has been published extensively, including "Dendrochronology and the late Holocene history of the Bering Piedmont Glacier, Alaska," which was published in Quaternary Research in 1999; and "Tree-Ring Dated Little Ice Age Histories of Maritime Glaciers from Western Prince William Sound," which appeared in The Holocene in 1999.

Wiles is the recipient of such honors as the Lamont-Doherty Earth Observatory Post-Doctoral Fellowship. In addition, he continues to conduct research funded by the National Science Foundation and the National Oceanic and Atmospheric Administration.

Past Q&A's

As environmentalists continue to warn us about the hazards of global warming, Greg Wiles, assistant professor of geology at The College of Wooster, attempts to shed more light on the subject. His research focuses on the retreat of glaciers and the variations in the sizes of tree rings. Wiles' objective is to develop a frame of reference to determine whether such warming is unusual or a natural part of a much longer cycle. He also speculates on some of the possible causes and effects of global warming.

What exactly is global warming?

Global warming is the observation that the Earth's surface temperatures are increasing. The observation is that average annual surface air temperatures of the earth have risen about 1° F since 1860 A.D. Like much of science, this story starts with an interesting observation and then scientists around the globe begin to ask questions like, "Why is it warming?" "Is this warming unusual?" "How will it impact the globe?"

Studying global warming and its possible causes is part of climate change research. One of the goals is to determine causes of the warming. Greenhouse Warming is a separate, but related issue - this term implies that the warming is due to increases in carbon dioxide, methane and other greenhouse gases.

How does geology in general and your research in particular suggest that global warming is taking place?

The retreat of glaciers, particularly at high latitudes, is one of the most obvious results of the warming. Studying the past changes in glaciers and their climatic significance is part of a growing field called Paleoclimatology. Our goal in studying glaciers is to understand how they have changed, particularly during the past 2000 years.

In order to determine whether global warming is due to Anthropogenic (people-caused) changes in the atmosphere, one needs to understand how a system, in this case glaciers, responds to natural climate changes. Then we will be able to better answer such questions as "Is the 20th century warming unusual over the past 2000 years or is it within the natural variability of the climate system?"

In addition to the record from glaciers, work with tree-rings shows warming during the past 100 plus years. This is particularly true for the interior regions and the northern treeline areas of Alaska.

Much of your research has taken place in Alaska. Are there more clues about global warming there than other parts of the world?

There are more than 100,000 individual glaciers in Alaska. These glaciers range from the very wet, relatively warm southern Gulf of Alaska coast to the high Arctic regions of the Brooks Range. This is a vast region of the planet covering a range in latitude comparable to the stretch between the Louisiana Delta and Northeast Ohio. Glaciers are found along this expanse and the vast majority of the glaciers are retreating at an accelerating rate. The presence of the glaciers and the fact that they are at higher latitudes (farther north) where warming and cooling are more dramatic makes Alaska a great place to examine the effects of warming and cooling on changes in glaciers.

How do geologists measure climate change?

We use proxy records. Proxies for past climate changes include the changes in glaciers, tree-rings, and the records from lake and ice cores. My students and I have focused on the study of the annual rings of long-lived trees and changes in glaciers. Annual layers of snow that turn to ice, annual growth layers in corals and layers of mud in lakes all contain information about past environmental conditions.

What impact might global warming have on the environment?

The impacts in high latitudes, particularly the Arctic, are profound. Decreases in sea ice during the past 40 years is well documented. This change affects the ecology and the climate of the north. A complex drama is underway where permafrost is melting in parts of the Arctic leading to the decline of forests, bark beetle infestations, and increased forest fires in these regions.

I think the impact warming will have on our region is a complex and open question. The interplay between climate change including the quasi-annual El Niños, and warming during the past 100 years all interact together to determine our climate. This is a fascinating field of study that has important implications in the fields of water resource management and agriculture.

Can the work of geologists such as yourself suggest ways to slow the pace of global warming?

If the warming is truly due to Greenhouse gas warming, anthropogenic emissions of greenhouse gases, then an obvious way to mitigate this change would be to cut back on emissions. The record of past climate change, particularly during the past 1000 years, suggest that the warming the world is experiencing today is unusual during this period. This information is taken seriously by experts who are charged with evaluating the cause of warming. Most would agree that anthropogenic emissions of greenhouse gases have some role in the warming.

I would emphasize that we are just beginning to appreciate the interconnectedness of the world's climate on a variety of time and spatial scales and that the causes of climate variation is an ongoing discussion. What complicates the story of recent warming is the anthropogenic contribution to an ever-changing climate. We have a major impact on the climate and related systems that is difficult to assess. One way to evaluate our role in climate change is to investigate the climate system from a paleo-perspective by using proxy records. This is the focus of our work.


Last updated: January 10, 2006 · For more information, contact John Finn