Snowy season in many parts of Canada is off to a slow start. At the end of December, fewer than half of Whistler Blackcomb’s trails in British Columbia were open due to the lack of snow. And the Prairie provinces are expected to have a milder winter, with below-normal snowfall. While the amount of snow varies from year to year, a new study says snowpack – the volume of snow that is present on the landscape – in the Northern Hemisphere is on the decline because of climate change.Ivan Semeniuk is The Globe’s science reporter. He’s on the show to explain how this loss will impact not only ski season but also water supplies and agriculture.Questions? Comments? Ideas? E-mail us at thedecibel@globeandmail.com