Study predicts less Great Lakes water loss

Oct 19, 2011

Previous research suggested a decline in future Great Lakes water levels, but findings from a recent scientific report may paint a different picture. 

Associated Press environmental writer John Flesher reports:

New research suggests climate change might not cause Great Lakes water levels to drop as much as previous studies have indicated. In fact, it might even cause them to rise.

Scientists at the NOAA Great Lakes Environmental Research Laboratory in Ann Arbor say they've devised a new way to predict future water levels. In a newly published journal article, they say it involves different methods of measuring evaporation of water from the soil and plants within the Great Lakes watershed.

Low water levels can cause heavy losses for shippers and other
Great Lakes businesses. They also affect the environment.

The lead author of the report was Dr. Brent Lofgren, and it was published in the Journal of Great Lakes Research.

 A NOAA press release details how scientists used new methods, accounting for evaporation in plants and soil surrounding the lakes:

Earlier studies used air temperature alone to estimate this variable. The new GLERL study uses an “energy budget-based approach” to better reflect the balance between energy coming in from the sun and energy given off from the Earth, which drives evaporation.

This approach also better represents the influence of greenhouse gases in the atmosphere on evaporation. The scientists applied this approach to computer models that predict lake levels and crunched various climate change scenarios. “The models show lower loss of water to vapor, meaning that more water is staying in the Great Lakes basin,” explained Lofgren.

While greenhouse gases add a small influx of energy to the land surrounding the lakes, they are much more effective at raising the temperature by hindering energy from leaving.

-John Klein Wilson - Michigan Radio Newsroom