With the global warming, will the Great Lakes level go up or down?

Answer 1

http://www.ucsusa.org/news/press_release/global-warming-great-lakes.html

Take a look at some of the effects that will happen in the Great Lakes region. The higher snowfall and precipitation will probably result in higher water levels.

Answer 2

That is a complex question that ultimately depends upon two main factors:
1. Inflow: Precipitation in the Great Lakes watershed is the main factor here.
2. Outflow: Evaporation and water out the St. Lawrence are the main factors here.

I'd say tha the biggest overall factor will be precipitation. If global warming increases precip, the lakes will rise, and vice versa.

Answer 3

They'll follow the sea level and go up with it.

But the shorelines of the Great Lakes are generally steeper than the coasts of the oceans. There'll be some flooding but it won't be nearly as bad as the coast.