Thursday, 9 September 2010

Polar Ice Loss Estimates Shrinking Faster Than Icecaps Themselves

source: dailytech
by: Jason Mick

Global warming proponents are forced to revise their predictions in the face of mounting evidence

Is the Earth warming? Recent studies have shown that some scientists believe that the Earth is experiencing climate change of the warming variety. And the body of collected evidence seems to support the hypothesis that the Earth is undergoing warming. The more interesting questions are "how much warming is occurring?" and "are humans causing it?"

On those issues there's still much debate and rancor, as illustrated by the recent embarrassing leak of emails from the University of East Anglia. The emails indicated a couple of particularly zealous advocates of anthropogenic global warming (AGW) theory suggesting a concerted effort to suppress publication and funding of studies that offered alternative or skeptical perspectives.

Now the premise that warming is posing an immediate threat has been dealt another setback, with top climatologists forced to yet again revise estimates of glacial ice loss after lower than expected melting.

According to the new study, over the last several years Greenland shed roughly 104±23 gigatons (billions tons) annually, and 64±32 gigatonnes from West Antarctica, according to an international team of climatologist led by Bert Vermeersen of Delft Technical University, in the Netherlands. Those estimates are less than half of previously published estimates of ice loss.

It goes on to state that each year sea levels are rising by approximately three-millimeters (0.2 inch), up substantially from 1.8mm (0.07 inches) per year in the 1970s.

The team says that past estimates badly missed the target as they failed to account for a phenomena called glacial isostatic adjustment. Glacial isostatic adjustment is a term for the rebounding of the Earth's crust that occurs at the end of an Ice Age. When the weight of the ice on the land is released, the land pushes minutely upwards changing the amount of sea level rise, and even the amount of ice loss itself.

The problem is that the rebound effect is sporadic and hard to predict. Professor Vermeersen comments, "A good analogy is that it's like a mattress after someone has been sleeping on it all night."

The previously overlooked effect explains why the amount of ice loss shown by satellites since 2002 was dramatically less than previously published figures --230 gigatons of ice per year for Greenland and 132 gigatons per year for West Antarctica.

Professor Vermeersen cooperated with a team of researchers at NASA's Jet Propulsation Laboratory and the Netherlands Institute for Space Research. He states, "The corrections for deformations of the Earth's crust have a considerable effect on the amount of ice that is estimated to be melting each year. We have concluded that the Greenland and West Antarctica ice caps are melting at approximately half the speed originally predicted."

With the revisions, ice cover loss is expected to only be contributing a third of sea level rise, rather than half, as previously published. The rest of the sea level rise comes from thermal expansion of the water.

The research was published in climatology's most prestigious journal, Nature Geoscience.

Most are not advocating scrapping research on global warming, ice loss, and potential human contributions to forcing. It is critical, however, to accurately assess the pace of climate change in order to formulate an economically feasibly response.

Some have criticized the carbon emissions reduction plan proposed by President Obama at Copenhagen late last year as being too economically damaging, particularly to developing nations. They point out that much of the talks were based on inaccurate figures submitted by the U.N.'s International Panel on Climate Change, figures which have since been revised.

Ultimately the depletion of oil stockpiles will lead to increasing prices, which in turn will lead to the adoption of emissions-free or reduced emissions modes of transportation like electric vehicles and hybrid vehicles. Likewise, new technologies like clean nuclear fission, nuclear fusion, and solar power stand to eventually offer inexpensive, emissions-free power as they refine.

The critical question for policy makers in governments worldwide is whether they have to push for the early adoption of these technologies before they become economically feasible. A major premature push could have a serious deleterious impact on their citizens' standard of living. But failure to respond to an impending crisis could be equally dangerous. Thus the new figures of reduced ice loss from NASA and the Netherlands university researchers offer critical insight, which politicians will hopefully heed when considering how much taxpayer money to devote to funding new technology to "fight" warming.

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