If global warming occurs as scientists predict, it could be exacerbated by changes in Arctic thaw lakes and their basins, which make up the majority of the landscape on the Arctic Coastal Plain. That's why University of Cincinnati assistant professor of geography Wendy Eisner is leading a team that is developing ways to monitor these basins.
Eisner and the team are using radiocarbon dating, pollen analysis, ground-penetrating radar and remote sensing to devise models for the monitoring. She and co-investigator Ken Hinkel, UC professor of geography, will report on their preliminary findings Nov. 16 at the Land-Atmosphere-Ice Interactions conference in Salt Lake City. LAII is a component of the National Science Foundation's Arctic Systems Science Program. LAII research seeks to improve understanding of the role of interactions among land, atmosphere and ice in the functioning of the Arctic System, with an emphasis on improving the predictability of the Arctic System's responses to global change.
"The Arctic plays a crucial role in global change because it responds sensitively to changes in climate," said Eisner.
By 2100, the global temperature will rise 2.5 to 10.4 degrees Fahrenheit, according to predictions made earlier this year in a report from the Intergovernmental Panel on Climate Change. Hinkel was one of the report's contributors.
The thaw lake basins contain a lot of peat in the frozen subsoil. If global warming occurs, the permafrost could melt and peat would start to decompose, releasing greenhouse gases into the atmosphere.
"This could accelerate global warming," said Eisner. "If this scenario turns out to be true, we would probably want to do everything we could to keep these basins intact and storing, not releasing, greenhouse gases." On the other hand, the effect could be counteracted by other changes, Eisner said. Thaw lakes, which form atop the ice-rich tundra, cover about 20 percent of the Arctic Coastal Plain, and their drained basins cover an even greater area. Little is known about them. "It is not even known exactly how much of the landscape is composed of drained thaw lake basins," says Eisner. "Until now, no systematic examination of drained thaw-lake basins has been undertaken across the Arctic Coastal Plain."
Eisner and Hinkel, working with UC graduate student Liz Wolfe, in the first phase of their studies have found promising results using satellite imaging and ground penetrating radar to recognize and categorize the thaw lake basins. They have radiocarbon dated more than 30 basins in order to determine the age of the basins and verify that their classification scheme is correct. The oldest of the basins they examined dates back 5,000 years, while the youngest was 20-30 years old. They're also using satellite imaging to recognize and categorize thaw lake basins, with the help of geography department colleague Robert Frohn, a satellite imaging expert.
To get to this point, they first had to do legwork out on the tundra, verifying that the satellite images and ground-penetrating radar were giving them accurate information. They have trudged through rain, cold, snow, mud and water in two to three field trips per year in 2000 and 2001. In April 2001, the team drilled core samples using an 800-pound drill called a "Big Beaver." Samples taken earlier reached only to 18 inches, while the new mechanical drill reached several feet down to soil that is thousands of years old.
The team also includes James G. Bockheim of the University of Wisconsin, Kim Peterson of the University of Alaska at Anchorage, Frederick Nelson of the University of Delaware, Nick Balster, post-doc from University of Wisconsin, and Ben Jones, a UC undergraduate. The six-member, interdisciplinary team is collaborating in a three-year study funded by a $454,849 National Science Foundation grant.
Members of the team will return for additional field study in April and August 2002.