From PhysOrg we get the following:
As warmer winter temperatures restrict ice from freezing over, researchers believe the ice hockey stars of the future will have limited access to the frozen lakes and backyard rinks that have helped shape the careers of some of the greatest professional players, such as Wayne Gretzky; the Canadian considered to be the greatest of all time who started skating as a child on a rink in his backyard.
Their study, published today, 5 March, in IOP Publishing's journal Environmental Research Letters, calculated the annual start date and length of the outdoor skating season (OSS) from historical weather data across Canada and recorded how these have changed since the 1950s in tune with global warming.
Of the 142 meteorological stations studied, the researchers, from McGill University and Concordia University, found that only a few of the weather stations showed a statistically significant trend towards earlier start dates of the OSS; however, a much larger proportion of stations showed a statistically significant decrease in the length of the skating season over the past half century.
The largest decreases in the skating season length were observed in the Prairies and Southwest regions of Canada. By extrapolating their data to predict future patterns, the researchers envisaged a complete end to outdoor skating within the next few decades in areas such as British Columbia and Southern Alberta.
Their definition of the beginning of the OSS is the last in a series of three days where the maximum temperature does not exceed -5°C – it takes several cold days to lay the initial ice on the rink. Subsequently, the researchers counted the number of viable rink flooding days to estimate the season's length at each of the 142 stations.
Canada appears to have taken more of a hit from global warming compared to other countries in the world: since 1950, winter temperatures in Canada have increased by more than 2.5°C, which is three times the globally-averaged warming attributed to anthropogenic global warming.
The paper can be found here.