Climate change will substantially decrease the duration and thickness of wintertime ice cover on many North American lakes.

Seasonal or year-round ice cover is crucial for the health of lakes located in cold environs, but looks set to decline with continued emissions of carbon dioxide.

Terry Prowse of Environment Canada at the University of Victoria in British Columbia and colleagues estimated how warming expected in the coming decades will affect lake-ice cover in mid- to high-latitude North America, where most of the continents' ice-covered lakes are located1. Prowse's team used a regional climate model to analyse the effects of a scenario in which atmospheric concentrations of carbon dioxide rise to around 575 parts per million by 2050. Compared with the period 1961–1990, they estimated that average fall and winter temperatures across the region will rise by 2 °C to 8 °C by 2041–2070. Their lake-ice simulations suggest that by 2041–2070 the period of ice cover will have decreased between 15 and 35 days each year and the peak thickness of ice will be between 10 and 30 cm slimmer.

These changes will affect the quality and amount of sunlight reaching lake waters. Furthermore, the shorter lake-ice season could impact Arctic communities, who use frozen lakes and rivers as highways for transport.

Dibike, Y., Prowse, T., Bonsal, B., de Rham, L. & Saloranta, T. Simulation of North American lake-ice cover characteristics under contemporary and future climate conditions. J. Int. Climatol. doi:10.1002/joc.2300 (2011).