Great Lakes Ice

The Great Lakes have seen a 25% decrease in basin-wide ice cover since 1973, with all five lakes experiencing shorter ice durations. This trend, mirrored across the Northern Hemisphere, is linked to warming winter air and contributes to increased lake-effect snow, altered fish species competition, and risks to cultural heritage and safety. While natural patterns like El Niño cause year-to-year variability, long-term projections suggest further ice loss and surface water warming this century.

• Since 1973, the Great Lakes have experienced a long-term decline in ice cover, with an area-weighted average decrease of 25% across all five lakes by 2023. Lake Superior has shown the strongest trend of decrease.
• The duration of ice cover has decreased on all five lakes since 1973, with the reduction ranging from 15 fewer frozen days in Lake Huron to 49 fewer frozen days in Lake Superior. These decreases are most pronounced in shoreline areas.
• The decline in lake ice and warming surface waters create cascading impacts, including increased competition between warm- and cool-water fish species, higher risks of harmful algal blooms due to nutrient runoff from extreme rainfall, and a likely increase in lake-effect snow in northern zones of Lake Superior and Lake Michigan.
• Reduced ice cover negatively affects cultural heritage and safety, limiting access for ice fishing, skating, and ceremonial activities, while unstable ice has contributed to higher winter drowning rates in communities relying on ice access.
• The trends in the Great Lakes are part of a broader Northern Hemisphere pattern where lake ice duration has declined by over two weeks annually. Under a 2°C global warming scenario, the number of lakes in the Northern Hemisphere with only intermittent ice cover is estimated to increase 2.4-fold to 35,300 lakes.

APA

Sharma, S., Fujisaki-Manome, A., Gillespie, A., & Widhalm, M. (2024). Great Lakes Ice. Climate Central. https://www.climatecentral.org/climate-matters/great-lakes-ice-2024

Chicago

Sharma, Sapna, Ayumi Fujisaki-Manome, Alison Gillespie, and Melissa Widhalm. Great Lakes Ice. Climate Central, 2024. https://www.climatecentral.org/climate-matters/great-lakes-ice-2024.

Wikipedia

{{cite report |last1=Sharma |first1=Sapna |last2=Fujisaki-Manome |first2=Ayumi |last3=Gillespie |first3=Alison |last4=Widhalm |first4=Melissa |title=Great Lakes Ice |publisher=Climate Central |date=7 February 2024 |url=https://www.climatecentral.org/climate-matters/great-lakes-ice-2024 |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{sharma2024great, author = {Sharma, Sapna and Fujisaki-Manome, Ayumi and Gillespie, Alison and Widhalm, Melissa}, title = {{Great Lakes Ice}}, institution = {Climate Central}, year = {2024}, month = feb, url = {https://www.climatecentral.org/climate-matters/great-lakes-ice-2024}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }