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New studies show extent of Earth's ice melt

Thursday, May 03, 2012 - 03:23

May 3 - Two climate studies, each using satellite technology in different ways, have provided new insight into how fast ice is melting on Earth due to global warming. While climatologists have long known that rate of ice melt into our oceans has increased since records began more than a century ago, the new research shows just how much is being lost. Ben Gruber reports.

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According to research, Earth is losing ice faster than ever before. Gravitational data compiled over eight years from 2002 by University of Colorado Professor John Wahr, demonstrates just how much ice is being lost. (SOUNDBITE) (English) JOHN WAHR, PROFESSOR OF GEOPHYSICS AT THE UNIVERSITY OF COLORADO, SAYING: "What we found was that the world is losing an enormous amount of ice every year. Something like 550 billion tonnes of ice melts and goes into the ocean and raises see level. And over the 8 year period that amounts to a little bit more than 4 trillion tonnes of ice. And as you work it out, that's enough ice that if you change it into water, which it has been done, and you spread it over the United States that it a thickness of 1 ½ feet everywhere over the U.S. about that much water. You would be wading in that much water just from the ice that has melted from land areas over the last eight years." When ice sheets and glaciers lose ice - they also lose mass - and those changes in mass affect their gravitational pull. By measuring the ever-changing distance between a twin pair of satellites that orbit the planet, Wahr and his team were able to track those changes in gravitational pull and tell how much ice was lost. (SOUNDBITE) (English) JOHN WAHR, PROFESSOR OF GEOPHYSICS AT THE UNIVERSITY OF COLORADO, SAYING: "By looking at this change in distance you can figure out how much Antarctica weighs basically, how much mass is there. And then you can come back again next month and see if it has gained mass." Instead of gaining mass, Wahr says the research shows that Antarctica and other ice covered regions on Earth are losing mass faster every year. Climate researcher William Colgan is seeing the effects of this massive ice to water conversion on Greenland's glacial lakes. Colgan is using satellite imagery to create the most precise map of these lakes to date. (SOUNDBITE) (English) WILLIAM COLGAN, RESEARCH ASSOCIATE, CIRES, SAYING: "When you have an almost daily image of the lakes in Greenland what's really cool is that you can follow the size of a given lake through time, through one year, through many years. You can watch that lake grow, you can watch that lake shrink, and occasionally you can watch that lake catastrophically drain." A catastrophic drainage is when a glacial lake vanishes in a matter of hours. The increased weight of the lake due to ice melt causes the bottom to crack, and the water to drain out. (SOUNDBITE) (English) WILLIAM COLGAN, RESEARCH ASSOCIATE, CIRES, SAYING: "When we looked at what was happening to the lakes relative to what was happening with the melt that was occurring, it quickly became evident that in higher melt years when more of the ice sheet is melting because it is warmer there were more lakes at higher elevations and they were experiencing more of the catastrophic drainages." Colgan's lake research and John Wahr's global ice melt data both point to the influence of global warming. (SOUNDBITE) (English) JOHN WAHR, PROFESSOR OF GEOPHYSICS AT THE UNIVERSITY OF COLORADO, SAYING: "All I can really do and what my colleagues can really so is turn over our results to policy makers and they have to go with them and decide what to do. But I think clearly a good portion of that is to continue monitoring what is going on and try to figure out just what is causing it, what is going on, and what can we do to slow down those causes." And as the technology improves, so will the quality of the data although both scientists agree that there's already enough evidence of danger ahead for policy-makers to take action. Ben Gruber, Reuters.

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New studies show extent of Earth's ice melt

Thursday, May 03, 2012 - 03:23