Aspen is running out of snow and the Rockies as a whole have seen a 20 percent decline in cover since 1980. Mer de Glace, the famous glacier in Chamonix, France, (host of the first Winter Olympics) has lost 250 feet of thickness in the past two years and Vancouver's ski season is a full month shorter than it was 50 years ago. These sweeping changes around the world are largely due to climate change's outsize effect on mountainous regions, including all of the 19 areas that have already hosted the 22nd Winter Olympic Games and every city hoping do so in the future.

At current warming rates, a new University of Waterloo study, released January 23, found that at best 11 of the 19 original sites of the Winter Olympics could reliably host the Games in the near future. That means that, if greenhouse gas emissions follow current trends, only six sites could still reliably host the games by the end of this century.

The Sochi Games are on target to be the most expensive Olympics to date, costing an estimated $51 billion, thanks in large part to the biggest artificial snow-making system in the world. To get snow to the slopes – which are technically in a subtropical region – Russians have had to move water up the mountain with some 400 generators, tapping into two new reservoirs, a move that environmentalists argue may cause ecological damage to the regions for decades to come.

But the Waterloo study authors argue that there are physical limits to even the most advanced snowmaking technology – namely, daily minimum temperatures need to remain below freezing. Given a projected 2.7 degree C rise in global temperatures over the next 70 years (the most conservative estimate by the United Nations Intergovernmental Panel on Climate Change), keeping enough snowpack to host the games will be all but impossible in Sochi; Grenoble, France; Garmisch-Partenkirchen, Germany; Chamonix; Vancouver; and even Squaw Valley. With a higher, but entirely possible, 4.4 degree C rise in temperatures the researchers add Sarajevo, Bosnia and Hercegovina; Oslo, Norway; Innsbruck, Austria; Turin, Italy; and Nagano, Japan, to that list.

"The cultural legacy of the world's celebration of winter sport is increasingly at risk," Daniel Scott, a Canada research chair in global tourism and lead author of the study said in a statement. "Fewer and fewer traditional winter sports regions will be able to host an Olympic Winter Games in a warmer world."