Global warming is casting a lengthening shadow over future Winter Olympics, boosting the risk that skiers will be competing on artificial or trucked-in snow, a new study suggests.
Out of 19 resorts that hosted the Winter Games from their inception in 1924 to 2010, just 10 or 11 will be "climatically reliable" by the 2050s, meaning that they can be depended on to have a bed of natural snow in February.
By the 2080s, as few as six of them would remain in this category, according to the probe, which bases these forecasts on trends in greenhouse-gas emissions.
"Internationally renowned Olympic sites ... simply would not be cold enough to reliably host the Games," the paper warns.
Afflicted Olympic venues would include Squaw Valley in the United States, Grenoble in the French Alps, GarmischPartenkirchen in Germany and Russia's Sochi, where the 2014 Games are set to start on Friday.
The investigation, headed by Daniel Scott at the University of Waterloo in Ontario, notes that over the decades, Games hosts have worked hard to overcome the uncertainties of weather.
Over the past 70 years, ice hockey, figure skating and curling have been moved indoors and bobsled and luge competitions shifted to refrigerated tracks.
But at the same time, average temperatures at Olympic venues have shot up.
The average daytime temperature in February in these locations soared from 0.4 degrees Celsius between the 1920s and the 1950s to 7.8 degrees in the early 21st century.
But only part of this rise was due to global warming, say the scientists. The rest was due to the readiness of the International Olympic Committee to award the Games to warmer locations.