At current rates of greenhouse gas emissions, which would see Earth's surface warm nearly three degrees Celsius above pre-industrial levels, 90 percent of Europe's ski resorts will eventually face critical shortages of natural snow, researchers said Monday. If the world warms 3C above mid-19th century levels and without artificial snow, 100 percent of ski resorts would face a very high risk of insufficient snow supply -- every other year, on average -- in the German and Austrian Alps, and in Tur