. Earth Science News .

NASA Mission Takes Stock of Earth's Melting Land Ice
by Staff Writers
Pasadena CA (JPL) Feb 13, 2012

Changes in ice thickness (in centimeters per year) during 2003-2010 as measured by NASA's Gravity Recovery and Climate Experiment (GRACE) satellites, averaged over each of the world's ice caps and glacier systems outside of Greenland and Antarctica. Image credit: NASA/JPL-Caltech/University of Colorado.

In the first comprehensive satellite study of its kind, a University of Colorado at Boulder-led team used NASA data to calculate how much Earth's melting land ice is adding to global sea level rise.

Using satellite measurements from the NASA/German Aerospace Center Gravity Recovery and Climate Experiment (GRACE), the researchers measured ice loss in all of Earth's land ice between 2003 and 2010, with particular emphasis on glaciers and ice caps outside of Greenland and Antarctica.

The total global ice mass lost from Greenland, Antarctica and Earth's glaciers and ice caps during the study period was about 4.3 trillion tons (1,000 cubic miles), adding about 0.5 inches (12 millimeters) to global sea level. That's enough ice to cover the United States 1.5 feet (0.5 meters) deep.

"Earth is losing a huge amount of ice to the ocean annually, and these new results will help us answer important questions in terms of both sea rise and how the planet's cold regions are responding to global change," said University of Colorado Boulder physics professor John Wahr, who helped lead the study.

"The strength of GRACE is it sees all the mass in the system, even though its resolution is not high enough to allow us to determine separate contributions from each individual glacier."

About a quarter of the average annual ice loss came from glaciers and ice caps outside of Greenland and Antarctica (roughly 148 billion tons, or 39 cubic miles). Ice loss from Greenland and Antarctica and their peripheral ice caps and glaciers averaged 385 billion tons (100 cubic miles) a year. Results of the study will be published online Feb. 8 in the journal Nature.

Traditional estimates of Earth's ice caps and glaciers have been made using ground measurements from relatively few glaciers to infer what all the world's unmonitored glaciers were doing. Only a few hundred of the roughly 200,000 glaciers worldwide have been monitored for longer than a decade.

One unexpected study result from GRACE was that the estimated ice loss from high Asian mountain ranges like the Himalaya, the Pamir and the Tien Shan was only about 4 billion tons of ice annually. Some previous ground-based estimates of ice loss in these high Asian mountains have ranged up to 50 billion tons annually.

"The GRACE results in this region really were a surprise," said Wahr, who is also a fellow at the University of Colorado-headquartered Cooperative Institute for Research in Environmental Sciences.

"One possible explanation is that previous estimates were based on measurements taken primarily from some of the lower, more accessible glaciers in Asia and extrapolated to infer the behavior of higher glaciers.

But unlike the lower glaciers, most of the high glaciers are located in very cold environments and require greater amounts of atmospheric warming before local temperatures rise enough to cause significant melting. This makes it difficult to use low-elevation, ground-based measurements to estimate results from the entire system."

"This study finds that the world's small glaciers and ice caps in places like Alaska, South America and the Himalayas contribute about 0.02 inches per year to sea level rise," said Tom Wagner, cryosphere program scientist at NASA Headquarters in Washington.

"While this is lower than previous estimates, it confirms that ice is being lost from around the globe, with just a few areas in precarious balance. The results sharpen our view of land-ice melting, which poses the biggest, most threatening factor in future sea level rise."

The twin GRACE satellites track changes in Earth's gravity field by noting minute changes in gravitational pull caused by regional variations in Earth's mass, which for periods of months to years is typically because of movements of water on Earth's surface. It does this by measuring changes in the distance between its two identical spacecraft to one-hundredth the width of a human hair.

Related Links
Grace at UT
Grace at JPL
Beyond the Ice Age

Get Our Free Newsletters Via Email
Buy Advertising Editorial Enquiries


. Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

CU-Boulder study shows global glaciers, ice caps, shedding billions of tons of mass annually
Boulder CO (SPX) Feb 09, 2012
Earth's glaciers and ice caps outside of the regions of Greenland and Antarctica are shedding roughly 150 billion tons of ice annually, according to a new study led by the University of Colorado Boulder. The research effort is the first comprehensive satellite study of the contribution of the world's melting glaciers and ice caps to global sea level rise and indicates they are adding rough ... read more

Japan's Fukushima reactor may be reheating: operator

Top US general meets Egypt's Tantawi amid NGOs row

Bird numbers drop around Fukushima

Japan passes $33 bln fourth extra budget

Watchdog group begins China Apple inspections

Russia to build powerful laser facility

Northrop Grumman Delivers 25,000th Electro-Optic Laser System to U.S. Army

Iran Launches New Home-Made Satellite into Orbit

Reform of EU fishing quotas urged

Engage China in water dialogue: Experts

Ocean microbe communities changing, but long-term environmental impact is unclear

Ocean warming causes elephant seals to dive deeper

NASA Mission Takes Stock of Earth's Melting Land Ice

CU-Boulder study shows global glaciers, ice caps, shedding billions of tons of mass annually

Putin receives 'prehistoric' water from Antarctic lake

Himalayan meltdown not so fast after all: study

5-10 percent corn yield jump using erosion-slowing cover crops

Shedding light on genetics of rice metabolism

Fresh city tomatoes, any time

Valentine's flowers inspected for pests

3D laser map shows earthquake before and after

Tree rings may underestimate climate response to volcanic eruptions

Chile to prosecute workers over lack of tsunami warning

Death toll in Philippine quake rises to 39

Nigeria army kills 12 suspected Islamists in flashpoint city

Inter-ethnic fighting displaces 40,000 in Kenya

Mali army tries to fend off Tuareg rebels as crisis grows

Chinese, Russian arms fuel Darfur abuse: Amnesty

Neanderthal demise due to many influences, including cultural changes

Why the brain is more reluctant to function as we age

Cutting-edge MRI techniques for studying communication within the brain

Entire genome of extinct human decoded from fossil

Memory Foam Mattress Review

Newsletters :: SpaceDaily Express :: SpaceWar Express :: TerraDaily Express :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News


The content herein, unless otherwise known to be public domain, are Copyright 1995-2012 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement