Scientists publish research, examine effects of climate changes on water levels

02/10/10 - A recent study on the Great Lakes revealed that lake levels are susceptible to climate change, putting the economy at further risk.The study was led by professor John King from the University of Rhode Island Graduate School of Oceanography and Michael Lewis, a visiting URI scientist working for the Geological Survey of Canada. Their study was published in December's issue of Eos, a science journal.

Prior to their scientific study, the general belief was that the high and low levels of the lake were due to glaciers advancing and retreating within the watershed of the Great Lakes. Their research focused on a period approximately 7,000 to 8,000 years ago.

"We came to the conclusion that the ice was already pretty far out of the watershed," King said. "The only way the lake levels could have gone down was due to a dryer climate than what we have now."

According to King, a big climate change is predicted to occur within the next 100 years. A drier climate will result in the lake levels falling below their overflow level.

Rivers connecting the Great Lakes will dry up, including Niagara Falls. The connection to the St. Lawrence Seaway will cease to exist, and Quebec, Montreal, Toronto, Chicago, Milwaukee and Cleveland will be affected.

"There's a fair amount of industry still in these areas and the main means of transportation is probably large ships on the Great Lakes," King said.

According to King, the economy based off the Great Lakes accounts for 25 percent of Canada's economy and about 15 percent of the United State's economy.

"Every inch or two that the lake level drops, you have to decrease the load by enough to lose tens of thousands of dollars to hundreds of thousands of dollars on every trip you make," King said. "If you have big changes, it pretty rapidly becomes non-economic to use big ships to transport things on the Great Lakes."

King pointed out that 80-90 percent of world commerce is "containerized stuff" transported by ships.

The National Science Foundation and the Canadian Geological Survey and Environment Canada funded King and Lewis's research. By conducting geophysical surveys using sonar to map the bottom of the lake, King and Lewis were able to observe the lake's features and note the elevation differences. Core samples were taken to study the stratigraphy of the lake.

"It's kind of like a layer cake on the bottom of the lakes," King said. "You get that mud core and then you get these studies on the fossils in there and the isotope composition that can radiocarbon date that material."

The core samples allowed the scientists to reconstruct what was happening in the environment during specific time periods.

The samples revealed that in the past, during a time period when lake levels were about 20 meters lower than they are today, forests grew on the floor of the Great Lakes. By collecting tree stump samples and arthropod fossils from the bottom of the lakes, King was able to date them.

"We could actually do studies on the tree rings that could reconstruct climate. We could look at the fossil pollen and reconstruct what the vegetation was like," King said.

King is also involved in habitat-mapping work in Narragansett Bay, Rhode Island, pollution studies in various areas, the Rhode Island offshore wind farm project and paleoclimate studies. He views the Rhode Island offshore wind farm project as "a habitat exercise with engineering aspects to it." In regards to his paleoclimate studies, he is currently in the midst of researching "a lake in East Africa and a lake in West Africa and looking at drought in both areas as well as how the climate system varies on long time scales."

Brad Hubbeny and Clifford Heil, two Ph.D graduates of the Graduate School of Oceanography were also involved in King and Lewis's Great Lakes research.