Google Earth is probably the best way to view the evidence of dramatic climate change in the form of glaciers. The reasons being that Google Earth has the best collection of satellite and aerial imagery, it has 3D terrain, there are many user-generated photos of the glaciers, and there are many collections of placemarks from scientists showing photos and video evidence of the changes.
Most recently, Google has announced a collections of placemarks from the Extreme Ice Survey project which includes dedicated scientists and extreme photographers who have been placing time lapse cameras around many glaciers and recording the dramatic changes, sometimes in just the course of a few months, of these glaciers which have been around for thousands of years. You can see the collection of placemarks of the Extreme Ice Survey here . Here is an example of the videos found in the collection:
AK-03 Columbia Glacier from Cliff from Extreme Ice Survey on Vimeo.
Google Earth 5 has a feature called historical imagery which lets you see other imagery for the same location. Unfortunately, many of the glaciers in the Extreme Ice Survey do not yet have much in the way of historical images. However, other people have created glacier KML files which show changes over time. See for example this collection by GEC member ‘blt’: Glaciers Melting, another story showing some data from the National Snow and Ice Data Center (the NSIDC has lots of Google Earth content).
And, for the most dramatic view of climate change visible in Google Earth, I highly recommend viewing the NSIDC view of ice melting at the arctic and antarctic poles from 1979 to the present.