Effects of Climate Change on Lake Ice Freeze Up Across the Northern Hemisphere: Historical Patterns and Future Predictions

Shifts in freeze up dates signal climatic change. We examined nine lakes in the Great Lakes region to forecast freeze up dates into the future. We also examined 75 lakes around the Northern Hemisphere to understand how and why freeze up has changed historically. Freeze up was later by an average of eight days in the Great Lakes region and nine days around the Northern Hemisphere in recent decades, with air temperatures being the primary driver of change in both studies. Date of freeze up on lakes in the Great Lakes region is expected to advance by an additional average of 11 days by the late 21st century. We highlight the importance of not only focusing on linear trends, but also examining the time series for potential abrupt shifts. Overall, winter ice seasons are becoming shorter which emphasizes the importance of mitigating climate change to protect our freshwater ecosystems.