Regional Impacts: Midwest and Great Lakes

Midwest Region

The following changes in climatic conditions have been observed in the Midwest in recent decades:

  • Average temperatures have increased, particularly during the winter.
  • Precipitation in summer and winter has been above average for the last three decades, the wettest period in a century.
  • Heavy downpours are twice as frequent as they were a century ago, and two record-breaking floods occurred in the past 15 years.
  • There has been a decrease in lake ice throughout the region and in the Great Lakes.

The following climate-related changes are projected for the Midwest:

  • Heat waves are expected to be more frequent, severe, and longer lasting.
  • Precipitation is expected to increase in winter and spring and to become more intense throughout the year, leading to more pronounced flooding/runoff conditions.
  • The likelihood of drought will increase in the summer, with water levels declining in rivers, streams, and wetlands.

Great Lakes Region

The following changes in climatic conditions have been observed in the Midwest in recent decades:

  • Water levels in the Great Lakes have been decreasing since a record high was reached in 1980. Lake levels are rising and falling a month earlier than during the 19th century. Lake temperatures have been increasing faster than surrounding air temperatures.
  • Since 1940 persistent low stream flows have increased, in some areas, by more than 50%. These increases are placing additional strain on stormwater infrastructure.
  • The frequency and intensity of severe storms has increased, resulting in negative economic impacts due to damages as well as increased costs of preparation, clean-up, and business disruption.
  • Average air temperatures increased by 2.3°F (1.3°C) from 1968 to 2002 in the Great Lakes region.
  • Since 1975, the number of days with land snow cover has decreased by 5 days per decade, and the average snow depth has decreased by 1.7 cm per decade. From 1973 to 2010, annual average ice coverage on the Great Lakes declined by 71%.

The following climate-related changes are projected for the Great Lakes:

  • Great Lake levels are expected to fall no more than a foot under a lower emissions scenario and between one and two feet under a higher emissions scenario. The greater the temperature rise, the higher the likelihood of a larger decrease in lake levels. There are also potential impacts on beaches, coastal ecosystems, dredging requirements, infrastructure, and shipping.
  • Stratification of lake waters will occur earlier and for longer periods during the summer, increasing the risk of oxygen-poor or oxygen-free dead zones that kill fish and other living things.
  • Aquatic ecosystem disruptions are likely to be compounded by invasions of non-native species. Native species are expected to decline.
  • By 2050, an average air temperature increase of 1.8 to 5.4°F (1 to 3°C) is projected. By 2100, an average air temperature increase of 3.6 to 11.2 °F (2 to 6.2°C) is projected. Winter temperatures will likely experience a greater increase than the summer months.

Learn More

Find more resources on the Midwest Regional Resources List.