"the Greenland and West Antarctica ice caps are melting at approximately half the speed originally predicted"

Less than a year ago, we were inundated with reports like this one:

"If the current trend continues or gets worse, Antarctica could become the largest contributor to sea level rises in the world. It could start to lose more ice than Greenland within a few years," said Jianli Chen, of the University of Texas at Austin.

Chen's team used data from the Nasa mission to see how Earth's gravitational pull varied month to month between April 2002 and January 2009. Measurements taken over the south pole reflect changes in the mass of the Antarctic ice sheets.

The survey confirmed the West Antarctic ice sheet is melting rapidly with the loss of around 132bn tonnes of ice a year, but revealed unexpected melting in the larger East Antarctic ice sheet.

10 months later, we're hearing the scientific equivalent of never mind:

Estimates of the rate of ice loss from Greenland and West Antarctica, one of the most worrying questions in the global warming debate, should be halved, according to Dutch and US scientists.

In the last two years, several teams have estimated Greenland is shedding roughly 230 gigatonnes of ice, or 230 billion tonnes, per year and West Antarctica around 132 gigatonnes annually.

...

This movement, though, is not just a single vertical motion, lead researcher Bert Vermeersen of Delft Technical University, in the Netherlands, said in phone interview with AFP.

"A good analogy is that it's like a mattress after someone has been sleeping on it all night," he said.

The weight of the sleeper creates a hollow as the material compress downwards and outwards. When the person gets up, the mattress starts to recover. This movement, seen in close-up, is both upwards and downwards and also sideways, too, as the decompressed material expands outwards and pulls on adjacent stuffing.

Often ignored or considered a minor factor in previous research, post-glacial rebound turns out to be important, says the paper.

It looks at tiny changes in Earth's gravitational field provided by two satellites since 2002, from GPS measurements on land, and from figures for sea floor pressure.

These revealed, among other things, that southern Greenland is in fact subsiding, as the crust beneath it is pulled by the post-glacial rebound from northern America.

With glacial isostatic adjustment modelled in, the loss from Greenland is put at 104 gigatonnes, plus or minus 23 gigatonnes, and 64 gigatonnes from West Antarctica, plus or minus 32 gigatonnes.

These variations show a large degree of uncertainty, but Vermeersen believes that even so a clearer picture is emerging on icesheet loss.

"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," said Vermeersen, whose team worked with NASA's Jet Propulsation Laboratory and the Netherlands Institute for Space Research.

"We have concluded that the Greenland and West Antarctica ice caps are melting at approximately half the speed originally predicted."

I've concluded that these people are guessing... and that in fact they haven't a clue as to what's going on... In fact, I'll go out on a limb and predict that a year from now, they'll be revising their estimates once again...

Any takers?

Comments

[George]

If you are brutally honest,why does Co2, NO2, CCl4, and methane keep increasing in the atmosphere? How high will these greenhouse gases go? How long will they remain? What are the positive feedbacks? That will the world population be in 2050? Will they have increasing energy demands? When do we reach peak oil? Can you afford $10.00/gal gas?

[tim aka The Godless Heathen]

Why has Al Gore never once debated anyone about Global Warming?

And if Global Warming is such a upcoming catastrophe, why don’t all who believe, especially including one Mr. Al Gore, completely change the way they live their lives - no fossil fuel burning, no purchasing of products that supposedly contribute to Global Warming, etc. Rather than the complete opposite from the likes of Gore, with his multiple homes with huge energy bills, huge gas guzzling pleasure boats and SUV’s, traveling by carbon spewing, private jets…

Hell I would think that anyone who actually believed in Global Warming wouldn’t even want to contribute the unnecessary pollutants by being on the internet…but evidently…practicing what they preach just isn’t in their playbook. And they wonder why we don’t believe.

Last question, explain the past ice ages and the causes of subsequent global warming that eliminated them.

[chuck aka xtnyoda]

Excellent!