![Ecuadorian glaciers (BBC)](http://newsimg.bbc.co.uk/media/images/47678000/gif/_47678387_ecuador_volcano_226.gif)
(BBC)
As alpine glaciers around the world retreat, the link to global warming becomes clearer. Average air temperatures at the Ecuadorian glaciers have increase 0.6 degrees Celsius since 1939. That's a lot of heat for an ice sheet. The reliance of humans, and natural systems, on these water supplies simply cannot be overstated.