The Great Lakes Geologic Mapping Coalition is a coordinated federal/state partnership between State geological surveys in Illinois, Indiana, Michigan, Ohio, Minnesota, Wisconsin, Pennsylvania, and New York and the USGS tasked with producing state-of-the-art, three-dimensional geologic maps of the region. Because these maps show in detail what lies beneath ground surface, they help governments, planners, industry, and communities develop energy initiatives, protect public safety, promote sustainable economic development, and protect water supplies and other natural resources. All of these issues are important as the region continues to further understand, mitigate, and prepare for the uncertain effects of global climate change.

Information gathered and interpreted for the mapping program directly is linked to climate change scenarios. In the face of warmer and drier climates, new knowledge will be acquired by the Coalition on evaluating water as an impacted resource. Maps will provide information on the location and yield capacities of underground water supplies for: (1) meeting growing energy needs, (2) protecting sensitive ecosystems, and (3) sensible growth and development balanced with environmental protection.

About 80% of water use in the region is for energy production. New ethanol, coal-bed methane, geologic CO₂ sequestration, coal-to-liquids, and IGCC coal plants either have been constructed or are included in near-future plans, each of which increases demand for water resources. Maps from the Coalition provide planners with detailed information on appropriate siting of these energy initiatives, and where they will not impinge on household, municipal, and agricultural water use. Regarding growth, development, and ecosystem issues, the maps and information provided by the Coalition position our states (as well as others) to adapt to a changing climate. These maps characterize water supplies for (1) supporting sustainable growth, (2) identifying aquifer recharge areas, (3) constructing, maintaining, and sustaining wetlands and other ecosystems, and (4) enabling effective land-and water-use planning by local and state agencies. The Coalition also addresses declining Great Lakes water level issues and associated shoreline problems, many of which are related to the response of near-shore geological materials and conditions to climate change.

Finally, maps reveal glacial and post-glacial geologic deposits showing a record of climate change during the past several hundred thousand years, and particularly in the last few thousand years. These sediments comprise some of the thickest, most widespread, and variable glacial materials in the United States. Past climatic changes are revealed well beyond the current 150-year period of human record keeping, and both long-and short-term trends are placed within a better perspective.