Many climate scientists believe the melting of glaciers worldwide is a sign the planet has entered the first phase of global warming. According to Rajendra K. Pachauri, "If you go to the Himalayan peaks, the rate at which the glaciers are retreating is alarming. And this is not an isolated example. I've seen photographs of Mount Kilimanjaro 50 years ago and now. The evidence is visible."
Riggs Glacier in Muir Inlet at Alaska's Glacier Bay National Park has greatly retreated. In 1941, the glacier was 2,000 feet thick. Now, vegetation grows on the mountains around the inlet where the glacier once stood. See before and after glacier photos here.