"The vast ice sheets of Greenland and Antarctica are melting faster than previously estimated and that melting is accelerating, according to a new report that verifies 18 years of melting via two independent techniques.

Left unchecked, the extra water dumped into the oceans could push average global sea level six inches higher by 2050, the report finds. That would mark the ice sheets - defined as expanses of deep, long-term ice larger than 20,000 square miles - as the largest contributors to sea level rise, outstripping melting from Earth's other frozen reservoirs, namely mountain glaciers.

The new estimate of ice sheet melting and subsequent rise in sea level comes from an international team led by scientists at NASA's Jet Propulsion Laboratory. It outstrips more modest figures offered by the Intergovernmental Panel on Climate Change in 2007, the last time that international body published a comprehensive assessment of the ice sheets."

Brian Vastag reports for the Washington Post March 9, 2011. [2]