Iceberg Melting!

More than 2 trillion tons of land ice in Greenland, Antarctica and Alaska have melted since 2003, according to new Nasa satellite data that show the latest signs of what scientists say is global warming.
More than half of the loss of landlocked ice in the past five years has occurred in Greenland, based on measurements of ice weight by Nasa’s GRACE satellite, said geophysicist Scott Luthcke. The water melting from Greenland in the past five years would fill up about 11 Chesapeake Bays, he said, and the Greenland melt seems to be accelerating.

Nasa scientists planned to present their findings on Thursday at the American Geophysical Union conference in San Francisco. Luthcke said Greenland figures for the summer of 2008 aren’t complete yet, but this year’s ice loss, while still significant, won’t be as severe as 2007. Since 2003, when the Nasa satellite started taking measurements, Alaska has lost 400 billion tons of land ice.

Melting of land ice, unlike sea ice, increases sea levels very slightly. In the 1990s, Greenland didn’t add to world sea level rise; now that island is adding about half a
millimetre of sea level rise a year,
Nasa ice scientist Jay Zwally said. Between Greenland, Antarctica and Alaska, melting land ice
has raised global sea levels about one-fifth of an inch in the past five years, Luthcke said. Sea levels also rise from water expanding as it warms. Other research, being presented this week at the geophysical meeting point to more melting concerns from global warming, especially with sea ice.

Scientists studying sea ice are going to announce that parts of the Arctic north of Alaska were 9 to 10 degrees warmer this past fall, a strong early indication of what researchers call the Arctic amplification effect. That’s when the Arctic warms faster than predicted, and warming there is accelerating faster than elsewhere on the globe.

As sea ice melts, the Arctic waters absorb more heat in the summer, having lost the reflective powers of vast packs of white ice. That absorbed heat is released into the air in the fall. That has led to autumn temperatures in the last several years that are six to 10 degrees warmer than they were in the 1980s, said research scientist Julienne Stroeve at the National Snow and Ice Data Center in Boulder, Colorado. That’s a strong and early impact of global warming, she said.

(Source: The Times Of India)