As vessels of Earth's largest system of fresh surface water, the Great Lakes play a vital role in the hydrology, climate, and industries of the Great Lakes region, as well as in the lives of its residents. And yet, climate change could result in decreased water levels, an impact that would in turn impact commercial, agricultural, municipal, and recreational users of lake water. Climate change could present still other challenges and benefits to crop and livestock sectors of the region's agriculture industry, the health of its residents, and the vitality of its outdoor recreation and tourism industry.

A variety of climate models were the basis of the future conditions explored in this paper. Although reasonable in projecting change at a global level, these models are often less reliable in detail at the regional level. Nevertheless, the “what if -- scenarios generated by these models can be used to provide information that can be helpful in better preparing for climate change in the Great Lakes region and in considering strategies that could be helpful in addressing potential impacts of that change.