Ronan Kelly
Retired 2020
Himalayan glaciers: Meltdown ‘not so fast’ after all
Agence France Presse1
PARIS, FEB 10 -
Himalayan glaciers and ice caps that supply water to more than a billion people in Asia are losing mass up to 10 times less quickly than once feared, a study published on Thursday reported.
Based on an improved analysis of satellite data from 2003 to 2010, the findings offer a reprieve for a region already feeling the impacts of global warming. But they do not mean that the threat of disruptive change has disappeared, the researchers warned.
“The good news is that the glaciers are not losing mass as fast as we thought,” said Tad Pfeffer, a professor at the University of Colorado’s Institute of Arctic and Alpine Research and a co-author of the study. “The bad news is that they are still losing a lot of water. There is still definitely a serious problem for the Himalayas.”Much of that loss, it turns out, is taking place in the huge plains immediately south of the towering mountain range, where pumping from wells is draining ancient aquifers far faster than precipitation can replenish them.
...
http://www.ekantipur.com/2012/02/10...s--meltdown-not-so-fast-after-all/348683.html
Recent contributions of glaciers and ice caps to sea level rise
Thomas Jacob, John Wahr, W. Tad Pfeffer & Sean Swenson
Nature (2012) doi:10.1038/nature10847
Received 28 July 2011 Accepted 09 January 2012 Published online 08 February 2012
Glaciers and ice caps (GICs) are important contributors to present-day global mean sea level rise1, 2, 3, 4. Most previous global mass balance estimates for GICs rely on extrapolation of sparse mass balance measurements1, 2, 4 representing only a small fraction of the GIC area, leaving their overall contribution to sea level rise unclear. Here we show that GICs, excluding the Greenland and Antarctic peripheral GICs, lost mass at a rate of 148 ± 30 Gt yr−1 from January 2003 to December 2010, contributing 0.41 ± 0.08 mm yr−1 to sea level rise. Our results are based on a global, simultaneous inversion of monthly GRACE-derived satellite gravity fields, from which we calculate the mass change over all ice-covered regions greater in area than 100 km2. The GIC rate for 2003–2010 is about 30 per cent smaller than the previous mass balance estimate that most closely matches our study period2. The high mountains of Asia, in particular, show a mass loss of only 4 ± 20 Gt yr−1 for 2003–2010, compared with 47–55 Gt yr−1 in previously published estimates2, 5. For completeness, we also estimate that the Greenland and Antarctic ice sheets, including their peripheral GICs, contributed 1.06 ± 0.19 mm yr−1 to sea level rise over the same time period. The total contribution to sea level rise from all ice-covered regions is thus 1.48 ± 0.26 mm −1, which agrees well with independent estimates of sea level rise originating from land ice loss and other terrestrial sources6.
...
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature10847.html
Agence France Presse1
PARIS, FEB 10 -
Himalayan glaciers and ice caps that supply water to more than a billion people in Asia are losing mass up to 10 times less quickly than once feared, a study published on Thursday reported.
Based on an improved analysis of satellite data from 2003 to 2010, the findings offer a reprieve for a region already feeling the impacts of global warming. But they do not mean that the threat of disruptive change has disappeared, the researchers warned.
“The good news is that the glaciers are not losing mass as fast as we thought,” said Tad Pfeffer, a professor at the University of Colorado’s Institute of Arctic and Alpine Research and a co-author of the study. “The bad news is that they are still losing a lot of water. There is still definitely a serious problem for the Himalayas.”Much of that loss, it turns out, is taking place in the huge plains immediately south of the towering mountain range, where pumping from wells is draining ancient aquifers far faster than precipitation can replenish them.
...
http://www.ekantipur.com/2012/02/10...s--meltdown-not-so-fast-after-all/348683.html
Recent contributions of glaciers and ice caps to sea level rise
Thomas Jacob, John Wahr, W. Tad Pfeffer & Sean Swenson
Nature (2012) doi:10.1038/nature10847
Received 28 July 2011 Accepted 09 January 2012 Published online 08 February 2012
Glaciers and ice caps (GICs) are important contributors to present-day global mean sea level rise1, 2, 3, 4. Most previous global mass balance estimates for GICs rely on extrapolation of sparse mass balance measurements1, 2, 4 representing only a small fraction of the GIC area, leaving their overall contribution to sea level rise unclear. Here we show that GICs, excluding the Greenland and Antarctic peripheral GICs, lost mass at a rate of 148 ± 30 Gt yr−1 from January 2003 to December 2010, contributing 0.41 ± 0.08 mm yr−1 to sea level rise. Our results are based on a global, simultaneous inversion of monthly GRACE-derived satellite gravity fields, from which we calculate the mass change over all ice-covered regions greater in area than 100 km2. The GIC rate for 2003–2010 is about 30 per cent smaller than the previous mass balance estimate that most closely matches our study period2. The high mountains of Asia, in particular, show a mass loss of only 4 ± 20 Gt yr−1 for 2003–2010, compared with 47–55 Gt yr−1 in previously published estimates2, 5. For completeness, we also estimate that the Greenland and Antarctic ice sheets, including their peripheral GICs, contributed 1.06 ± 0.19 mm yr−1 to sea level rise over the same time period. The total contribution to sea level rise from all ice-covered regions is thus 1.48 ± 0.26 mm −1, which agrees well with independent estimates of sea level rise originating from land ice loss and other terrestrial sources6.
...
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature10847.html