Research by Wooster Geologist Makes International News

Johannes Koch

Recent research by Johannes Koch, visiting assistant professor of geology at The College of Wooster, is making news around the world. Koch found that fresh, intact tree stumps near the retreating glaciers of Garibaldi Provincial Park (about 40 miles north of Vancouver, British Columbia) are providing new insights into the accelerated rates at which the rivers of ice have been shrinking as a result of human-aided global warming. To determine when the glaciers made their first forays into the forest to kill the trees and bury them under ice, Koch radiocarbon-dated wood from the stumps to see how long they have been in cold storage, and the answer was a surprising 7000 years.

"The stumps were in very good condition, sometimes with bark preserved," said Koch, who conducted the work as part of his doctoral thesis at Simon Fraser University in Burnaby, British Columbia. The pristine condition of the wood, he said, can best be explained by the stumps having spent all of the last seven millennia under tens to hundreds of meters of ice. All of the stumps were rooted in their original soil and location.

"Thus they really indicate when the glaciers overrode them, and their kill date gives the age of the glacier advance," Koch explained. "They also give us a span of time during which the glaciers have always been larger than they were 7000 years ago - until the recent warming released the stumps from their icy tombs.

"It seems like an unprecedented change in a short amount of time," Koch added. "From this work and many other studies looking at forcings of the climate system, one has to turn away from natural ones alone to explain this dramatic change of the past 150 years."