How Fast are the Polar Ice Sheets and Shelves Melting?

The U.S. Geological Survey (USGS) has documented that the majority of ice fronts on the Antarctic Peninsula retreated during the late 20th century and are continuing in the early 21st century.  According to the USGS, EVERY ice shelf located on the southern section of the Antarctic Peninsula is retreating. The USGS is the first governmental agency in the USA to document the retreating ice.  While  the ice has been retreateing from 1947 through 2009, the MOST dramatic changes have occurred since 1990.

If the global warming trend continues, the retreat of the ice could result in drastic sea-level rises, which would threaten coastal developments, low-lying islands, areas in floodplains and could disrupt weather patterns worldwide.  The Antarctic ice shelves attach to the continental land mass and to the Antarctic ice sheet.  The Antarctic ice sheet covers about 98 percent of the Antarctic continent.  As the ice shelves break off, there is melting of glaciers and ice streams flow from the ice sheet to the sea.  That transition of ice from land to the ocean raises the sea level..

According to the U.S.department of the Interior Secretary Ken Salazar:

This study provides the first insight into the extent of Antarctica's coastal and glacier change, The rapid retreat of glaciers there demonstrates once again the profound effects our planet is already experiencing—more rapidly than previously known—as a consequence of climate change. The scientific work of USGS, which is investigating the impacts of climate change around the world, including an ongoing examination of glaciers, is a critical foundation of the Administration's commitment to combat climate change

This research is part of a larger ongoing USGS project that is studying the entire Antarctic coastline in detail, and this is important because the Antarctic ice sheet contains 91 percent of Earth's freshwater ice. The USGS study focuses on Antarctica, which is the Earth's largest reservoir of glacial ice.

In a separate study published in Geophysical Research Letters, the National Oceanic and Atmospheric Administration reports that ice is melting much more rapidly than expected in the Arctic as well, on the basis of new computer analyses and recent ice measurements (see URL http://dx.doi.org/10.1029/2009GL037820).