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Lorne Gunter: Good News On Polar Ice Melt You May Have Missed

You’ve almost certainly seen reports that the melt of Arctic sea ice this year, while not as great as the melts in 2008 and 2007, is nonetheless continuing the “death spiral” of Arctic ice. What I’m betting you haven’t seen, though, are any reports on a study released last week by Dutch and American scientists that shows the icecaps over Greenland and Western Antarctica are receding far more slowly than most global-warming scientists had thought. (See herehere and here.)

[First, an aside on Arctic sea ice: When alarmist stories began appearing in 2007 about the presence of open water at the North Pole and the rapider-than-expected depletion of Arctic ice cover, anyone who pointed out that reliable records of Arctic ice by satellite measurement went back less than 30 years was accused of being a know-nothing and a shill for Big Oil. So it is interesting to see in the Postmedia News story linked here and above, that the alarmists have now begun saying things such as “the four greatest melts since satellite measurements began in the late 1970s [emphasis mine] have occurred in the past four years.”

It’s interesting because it admits, indirectly, that scientists don’t know much about how much summer ice is normal in the Arctic, only how much is normal for the past 30 years. So it is impossible to draw conclusions about whether the current levels are distressing or not, since it is impossible to know for sure how today’s levels compare with those of a century ago or two or five. There are pretty good localized records from the 1950s on (although winds blow the sea ice around a lot up north, so even localized records are not always indicative of anything global) and there are notes from locals and explorers of unusual ice highs and lows from about 1800 on. Still, it is harder to raise the alarm when you can’t really say what went on before 1979 in reliable detail.

Moreover, there are disputes over just how much ice is up there now and whether or not the alarmists are measuring it accurately.

There is even some debate over why ice coverage was so low in 2007. After thinking the ice had melted in place (which could be blamed on global warming), NASA’s Jet Propulsion lab concluded last February that much of the lost ice had been blown out of the region by strong west-to-east winds. An ice dam that normally forms in the Nares Strait between Ellesmere Island and Greenland didn’t form that summer, so the winds just pushed an extra amount of Arctic ice out into Baffin Bay and ultimately the Atlantic.

So the claim that Arctic ice is in a death spiral, and the implications that this is a manmade catastrophe that must be contained by constraining carbon use, is in dispute, even if you have never heard about the counter arguments.

But let’s save all that for another day.]

Anyway, the latest Dutch-American research is interesting because it cuts in half or more the estimates of how much glacial ice is melting each year in Greenland and Western Antarctica, and those are the only two ice sheets in the world that really matter.

Up to 90% of the world’s ice is sitting on top of Antarctica. About 5% more sits on Greenland. All the other deposits – mostly mountain glaciers and the Arctic Ocean – amount to no more than 5%. So all these “Others” could melt without sea levels rising substantially. Their disappearance would cause other regional problems for wildlife, vegetation and indigenous populations. But that would not necessarily mean a worldwide climate catastrophe. We focus much attention on Arctic sea ice – largely, I think, because its current behaviour feeds into many scientists and reporters views of manmade global warming – when what we should be worried about is the stuff in Greenland and Antarctica.

Now according to scientists from NASA’s Jet Propulsion Laboratory (JPL), the Delft University of Technology in the Netherlands and SRON, the Netherlands Institute for Space Research, most estimates of how fast ice is disappearing from Greenland and the Western Antarctic are twice as high or more than they should be.

Using GPS satellites to measure the shape and contours of Greenland, the Western Antarctic and the surrounding sea and land masses, researchers discovered that most projections for ice loss failed to take into account “glacial isostatic adjustment.” Ice weights a lot. As it recedes, the land underneath rebounds, according to lead researcher Bert Vermeersen of Delft, “like a mattress after someone has been sleeping on it all night.” The depression left by the sleeper (and the ice) is both downward and outward, so when the sleeper rises, the mattress recovers up, down and sideways. So does the land under huge ice sheets.

In the last few years, most researchers – including those working for the IPCC, the U.N.’s Intergovernmental Panel on Climate Change – have assumed Greenland is losing about 230 gigatonnes of ice per year, while Western Antarctica is losing 132 gigatonnes. What the Dutch-American study concludes, in findings published in the September issue of the journalNature Geoscience, is that the loss is half that or less – 104 gigatonnes and 64 gigatonnes respectively.

Even these lower rates of loss can be put into further context. The eastern region of Antarctica, which is four times larger than the western portion, appears actually to be cooling and accumulating ice, rather than warming and losing ice. Since it is the single largest deposit of ice on the planet, that is significant.

The Antarctic ice mass is also so enormous that when a PEI-sized chunk broke off last year and the world’s media dutifully covered this as a tragedy brought on by manmade global warming, one scientist told me it was less then 1% of the ice in Western Antarctica, so a fraction of fraction of the continent’s total, more “like an icicle breaking off your roof.”

Of course will be those who doubt the JPL-Delft findings. Over the coming months holes will undoubtedly be picked in these findings as others with expertise in different aspects of glacial melt offer their opinions on what the authors may or may not have missed in their calculations. That is how science is supposed to work.

My bigger point is that most environmentalists, reporters, politicians and a distressingly large number of scientists have abandon scientific inquiry and pronounced the science to be settled on global warming/climate change. There is to be no debate. We are all just supposed to acknowledge their position as the only true faith and bow down to the Green idol.

But as the Delft-JPL study shows, it’s too early for that lock-step behaviour.

National Post, 17 September 2010