This is Arapaho glacier, the glacier that the city of Boulder owns.

The top picture is of Arapaho glacier in 1898.  The bottom is from 2003.  The glacier has retreated so much that it is no longer considered a glacier; it is now considered an ice field.

With increasing global temperatures, glaciers are at threat of going extinct all over the globe.  Global warming is a real threat. If significant measures are not taken to reverse the current trends, glaciers could completely disappear.

http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=16970

Here are pictures of other retreating glaciers:

http://www.worldviewofglobalwarming.org/pages/glaciers.html

The Pasterze, Austria's longest glacier, was about 2 kilometers longer in the 19th C. but is now completely out of sight from this overlook on the Grossglockner High Road. The Margaritzen-Strausee, a dammed artificial lake, now is in the place where the glacier terminus was in 1875. Measurements of the Pasterze began in 1889 and it has been pulling back the entire time, in approximate step with regional temperatures that have been increasing. The glacier is now about eight Km long and loses about 15 meters per year. However in 2003 the Pasterze decreased 30 meters in length and 6.5 meters in thickness. [1875 image, photographer unknown, is courtesy H. Slupetzky, from the University of Salzburg archives. Gary Braasch photo made Aug 14, 2004]