In a Dec. 3 letter in the Brainerd Dispatch, Rolf Westgard claimed that the Earth's last big glaciers have melted. In support of his assertion, he referenced the past existence of ice sheets on lands many centuries ago.
People who study climate science refer to Mr. Westgard's "big glaciers" as ice sheets. They are very different from the common glaciers we think of today and can often see in high elevations. What about his assertion that all of these ice sheet have melted away? Well that is simply false. We have two large ice sheets that are in existence today. One is atop Greenland and another is atop Antarctica. These ice sheets are not, as Mr. Westgard suggests, "trivial in size". People that are interested in learning more about glaciers and how they differ from ice sheets can visit the National Snow and Ice Data Center ( http://nsidc.org/cryosphere/glaciers/questions/types.html ).
This may all seem like semantics but glaciers and ice sheets are very different and their impact on the Earth is different. An understanding of these differences is critical to understanding the Earth's climate.
Dr. John Abraham
Climate Scientist
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St. Thomas University
