Evidence of Climate Change

Snow and ice reflect the sunrays back to the atmosphere. Without snow and ice, more water can evaporate into the atmosphere where it acts as a greenhouse gas. The ground will then absorb more heat. Snow and ice are melting at rates unseen for thousands of years, and this has profound climate consequences.

Spring snow cover has decreased since 1922 at an average rate of about two percent per decade in the Northern Hemisphere, including a steep five percent drop during the 1980s. River and lake ice don't last as long as they used to either. As permafrost melts in the vast northern tundra, trees locals colorfully call drunken trees are falling over and buildings are crumbling as the ground disintegrates beneath them.

Glaciers have been shrinking across the globe with a few exceptions. In Glacier National Park, for example, there were 150 glaciers in 1850. Today, there are 26. In Switzerland, the Tortin Glacier, which supported a local ski area, shrank so much that the Swiss put a city-block sized insulating sheet over the glacier's edge to slow its retreat. Sea ice is becoming smaller and smaller too especially in the Northern Hemisphere. Satellites have seen average Arctic sea ice shrink by 2.7 percent per decade from 1978 to 2006, with faster melting in summer. In summer 2007, the Northwest Passage north of Canada became navigable for the first time as the polar cap melted to its lowest level on record. 30 years faster than IPCC scientists had predicted. 2008's melt was second only to 2007. 

http://www.meted.ucar.edu/broadcastmet/climate/print.htm#page_2.0.0