Widespread loss of lake ice around the Northern Hemisphere in a warming world

Ice provides a range of ecosystem services, including fish harvest,
cultural traditions, transportation, recreation, and regulation of the
hydrologic cycle, to more than half of the world's 117 million lakes.
One of the earliest observed impacts of climatic warming has been the
loss of freshwater ice, with corresponding climatic and ecological
consequences. However, while trends in ice cover phenology have been
widely documented, a comprehensive large-scale assessment of lake ice
loss is absent. Here, using observations from 513 lakes around the
Northern Hemisphere, we identify lakes vulnerable to ice-free winters.
Our analyses reveal the importance of air temperature, lake depth,
elevation, and shoreline complexity in governing ice cover. We
estimate that 14,800 lakes currently experience intermittent winter
ice cover, increasing to 35,300 and 230,400 at 2degC and 8degC,
respectively, impacting up to 394 and 656 million people. Our study
illustrates that an extensive loss of lake ice will occur within the
next generation, stressing the importance of climate mitigation
strategies to preserve ecosystem structure and function, as well as
local winter cultural heritage.