Three glaciers in the northern reaches of the United States have been shrinking in size, according to the U.S. Geological Survey. Officials with the USGS have been studying three “benchmark glaciers” since the 1950s to help understand changes in climate, and the news serves as yet another indication of how global warming maybe affecting the planet. The three glaciers are South Cascade Glacier in the Cascade Mountains of Washington State; Wolverine Glacier on the Kenai Peninsula near Anchorage, Alaska; and Gulkana Glacier in the interior of Alaska. Scientists found that, even taking into account seasonal changes, all three have experienced a net loss of ice since 1957, with the largest amount of shrinking occurring during the last 15 years.