Sea Levels Rising Faster Than Predicted Thanks to Global Warming
By Dave Porter
Reno, NV - At a California Institute of Technology news conference
Thursday, Eric Rignot of NASA's Jet Propulsion Laboratory told
reporters, "Greenland is probably going to contribute more and
faster to sea level rise than predicted."
Rignot's comments came on the heals of a researchers meeting of the
American Association for the Advancement of Science, which publishes
Science, where they said Glaciers around the world were disappearing
at an alarming rate.
The research is being published in Friday's issue of the journal Science.
In it, researchers say that rising temperatures due to global warming
are to blame for the glacier melt down that will cause the oceans to
rise more quickly.
Greenland's glaciers are dumping more than twice as much ice into the
Atlantic Ocean now as 10 years ago because glaciers are sliding off the
land more quickly.
Rignot explained that between 1996 and 2006, the amount of water lost
from Greenland's glaciers has more than doubled from 90 cubic kilometers
to 220 cubic kilometers a year.
To put the glacier melt into perspective, Rignot said that one cubic
kilometer is the amount of water Los Angeles uses in a year. Two-hundred
cubic kilometers of water is a lot of fresh water.
The researchers say that this could mean the sea level will rise faster
Julian Dowdeswell of the Scott Polar Research Institute at Britain's
Cambridge University wrote in a commentary in Science, At 1.7 million
square km (656,000 square miles), up to 3 km (nearly two miles) thick
and a little smaller than Mexico, the Greenland Ice Sheet would raise
global sea level by about 7 meters (22 feet) if it melted completely."
The study did not explore what is causing the rising air temperatures
in Greenland, but most scientists agree that human activity, notably
the burning of fossil fuels, is playing an important role in global warming.
The researchers used satellite data to track the movement of Greenland's
glaciers, which slide slowly down to the sea and deposit ice.
They calculated that Greenland contributes about 0.02 inch to the annual
0.1 inch rise in global sea levels.
Since 1996, southeast Greenland's outlet glaciers have been flowing more
quickly and since 2000 glaciers farther north have also sped up.
"One glacier that once was stable is now disappearing at the rate of
8.7 miles a year," Rignot said. "It takes a long time to build and
melt an ice sheet, but glaciers can react quickly to temperature changes."
Rising air temperatures are clearly a factor, the researchers told
the meeting. "This is clearly a result of warming around the periphery
of Greenland," Rignot said.
Over the last 20 years, the air temperature in southeast Greenland has
risen by 5.4 degrees.
Warmer air lubricates the bottoms of glaciers, helping them slide faster.
"Climate warming can work in different ways, but generally speaking,
if you warm up the ice sheet, the glacier will flow faster," said Rignot.
"And it may melt even more quickly in years to come," he added.
"The southern half of Greenland is reacting to what we think is climate
warming. The northern half is waiting, but I don't think it's going
to take long," Rignot said.
Rignot and other researchers noted that in some parts of Greenland,
increased snowfall is making parts of some glaciers thicker.
"A few years back, we thought ice sheets might grow because of increased
precipitation," Rignot said. "Now we see that rates of glacier flow are
changing. We think the process that is winning overall is the rate of