Global temperatures are expected to rise by up to three degrees Celsius in the next 50 years, melting glaciers, raising the snow line up mountains and crippling the ski industry, according to the U.N. Environment Program (UNEP) study.
\"The temperature changes will be more violent in the northern hemisphere during winter, so ski resorts are seriously at risk,\" said Rolf Burki, who carried out the research.
Slopes above 3,900 ft are now considered viable ski areas but, according to the report, in 30 to 50 years skiers will have to trek to altitudes of 4,900 to 5,900 ft.
And even up there, resorts will not be out of global warming\'s reach.
Environmentalists say Alpine glaciers and permafrost - frozen soil - could melt entirely by the end of the century if temperatures keep rising, making resorts more vulnerable to landslides.
Some scenarios suggest global warming could increase snow fall above 6,600 ft. Without a solid base of permafrost, that could raise the risk of avalanches, Burki told a conference that coincided with a major environmental meeting in Milan.
Most top Alpine resorts are high in the mountains but smaller, lower villages that depend on tourism for survival are already seeing global warming wreak havoc on winter sports.
Banks have stopped lending to Swiss resorts below 4,900 ft, worried they will never get their money from ski fields that will have to invest millions in snow-making equipment to stay viable over the next decade, Burki said.
About a third of Switzerland\'s resorts, mostly small fields where children learn to ski, are already struggling to survive.
Some top resorts like Cortina d\'Ampezzo in eastern Italy or Austria\'s Kitzbuhel are dotted with barrels blowing snow onto the lower slopes so people can ski back to town. But the cost of snow-making is too high for any but the richest resorts.
Laying the infrastructure of water pipes and turbines to make a 0.6 mile-long slope costs about $600,000. Puffing snow out of the system costs another $36,000 a year, said Burki, who researches economic geography at the University of Zurich.
\"Man is clever at creating technology to substitute nature but it only goes halfway,\" said Klaus Toepfer, executive director of UNEP.
\"Unless tough decisions are taken about global warming - from politicians to ski resorts themselves polluting less - skiing will look very different to future generations than it does now.\"