Climate Change is Contributing to Faster Rates of Lake Ice Loss in Lakes Around the Northern Hemisphere.

Lake ice phenology has been recorded for decades, providing us with long‐term records to investigate the impact of climate change in lakes since the Industrial Revolution. Here, we examine the trends and drivers of 18 lakes across the Northern Hemisphere, with 156–204 years of data, starting in the 1810s. We show that: (a) trends in ice phenology are faster than found by previous studies. Ice‐on is 11 days later per century, ice‐off is 9 days earlier per century, and ice cover duration is 19 days shorter per century; (b) there are significant breakpoints in the 1850s, 1870s, mid‐1890s, and mid‐1990s, after which trends in ice phenology are even faster, and associated with changing weather and climate; and (c) local air temperatures explain the most variation in ice phenology, on average 36.5%, followed by progressive climate change explaining around 17.5% on average, with teleconnection patterns explaining the least variation. Our findings support the assertion that broad‐scale climatic changes have led to more rapid lake ice loss in lakes distributed across the Northern Hemisphere, with potential widespread impacts on critical ecosystem services that lake ice provides. Plain Language Summary: Lake ice cover has been recorded for decades and has been shown to be sensitive to climatic change. Hence, we can use lake ice cover to investigate how climate change has affected lakes over the past ∼200 years. In this study, we explore 18 lakes across the Northern Hemisphere, with ice cover data starting in the 1810s. We find that ice‐on is increasingly later, ice‐off is earlier, and ice duration is shorter, with all these changes occurring at faster rates than previous studies showed. We discovered breakpoints in lake ice cover, after which the trends in lake ice phenology become faster than the trends before the breakpoints, and these breakpoints are related to changing local air temperatures and teleconnection patterns. Finally, we show that local air temperature influences the timing of ice‐on and ice‐off the most, followed by long‐term climate change and teleconnection patterns. Hence, we provide support for the statement that climate change has contributed to faster trends in ice phenology, with likely negative impacts on the important ecosystem services provided by lakes. Key Points: Trends in lake ice phenology are faster than shown in previous studies when including most recent dataSignificant breakpoints in ice phenology are associated with changing weather and climateWarmer air temperature explains most of the variation in later ice‐on and earlier ice‐off dates, in addition to shorter ice duration [ABSTRACT FROM AUTHOR]