Effects of Past Low Lake Levels and Future Climate-Related Low Lake Levels on Lake Michigan, Chicago, and the Illinois Shoreline

摘要

The study concerned effects and adjustments resulting from the record-low levels of Lake Michigan during 1964-1965, and the potential effects of future low water levels resulting from expected climate changes. The low lake levels of the 1960s did not cause many major economic impacts at the time they occurred. The two major impacts discerned, damage to shoreline structures and encroachment of structures onto areas closer to the lake, developed during the low-level period, but both also resulted from a sequence in which the low water levels were followed by high levels. Climate scenarios based on three global climate model estimates showing a doubling of carbon dioxide (CO2) in the atmosphere, as well as scenarios based on extreme annual precipitation values from a 133-year period on the Great Lakes basin, were used to derive estimates of potential future low lake levels, which were then used for estimating future impacts. The degree of climate change and ensuing lake level will greatly affect the seriousness of the economic outcome, but the environmental and water resource effects are extremely serious under all the climate scenarios.