Scientists unlock 125 years of great lakes ice data to predict climate future and save declining fish species

Michigan researchers have created a groundbreaking dataset tracking Great Lakes ice coverage back to 1897, offering unprecedented insights into how climate change has transformed one of North America’s most vital freshwater systems over more than a century.

Published in Scientific Data, the research fills a critical gap in Great Lakes winter knowledge by using historical temperature records from weather stations across the region as a proxy for ice formation. While satellite data only covers the past 45 years, this new dataset extends the timeline to 120 years, revealing long-term patterns essential for understanding regional climate shifts.

“Lake ice is really part of the system, part of our life. It matters [for] our culture, regional weather, safety, everything,” said Ayumi Fujisaki-Manome, associate director for the Cooperative Institute for Great Lakes Research at the University of Michigan. The data is already proving invaluable for studying the decline of lake whitefish, an economically and culturally important species whose behavior under ice remains poorly understood.

The timing couldn’t be more crucial. Great Lakes temperatures have risen over the past two decades, frost seasons are shortening, and extreme weather events are becoming the norm. While this winter has brought some of the highest ice coverage in years following historic lows the previous season, researchers emphasize this volatility itself signals long-term climate transformation. The new dataset provides researchers, policymakers, and communities with essential baseline data to navigate an increasingly unpredictable environmental future.