Climate Change and Great Lakes Water Resources

Hall, Noah; Stuntz, Brett

THE EARTH’S CLIMATE IS WARMING. This is the unequivocal conclusion of climate scientists. Despite the complexities of climatology, certain consistent themes emerge with implications for water availability: as the world gets warmer, it will experience increased regional variability in precipitation, more frequent heavy precipitation events, and will become more susceptible to drought. These simple facts could have a profound impact on the Great Lakes, as the warmer climate may reduce water supply and increase water demand within the region. Further, as other regions suffer from shortages in water supply and increased demand for water resources, they will look to divert Great Lakes water to slake their thirst. The science is compelling. Now the question for citizens and policymakers is whether existing laws and policies are adequate to protect the Great Lakes from the new pressures of climate change. Unfortunately, the answer is, “No.” However, the Great Lakes-St. Lawrence River Basin Water Resources Compact (“Great Lakes compact”), if enacted, would be an important step in improving Great Lakes water resource policy to meet the challenge of climate change. Part I of this report focuses on how climate change will impact water resources. It begins with a brief summary of climate change science. It then explores what a changing climate will mean for the Great Lakes, including possible lowering of lake levels, impacts on fisheries and wildlife, changes in Great Lakes shorelines, and reduction of groundwater supplies. Climate change will also reduce water supplies in other parts of the country, creating increased pressure to divert Great Lakes water to other regions. As the Great Lakes and other regions struggle with loss of water supplies, demand for water is expected to increase unless water conservation laws and policies are adopted.