November 28, 2010

The Braintrust Spins on Climage Change. Again.

From today's Sunday Pops at the Pittsburgh Tribune-Review:
New research suggests that all those predictions of markedly higher sea levels because of melting Antarctic ice sheets are wrong. In fact, the research says sea levels will fall — because of decreased gravitational pull and the fact that the bedrock will rise as the weight of the ice drops. The study comes out of Harvard, much to the chagrin, we're sure, of the Chicken Little crowd. Honey, throw another log on the fire — it's still cold outside.
But let's take a closer look, my droogs.

Here's the study's nearly incomprehensible summary:
Climate change could potentially destabilize marine ice sheets, which would affect projections of future sea-level rise. Specifically, an instability mechanism has been predicted for marine ice sheets such as the West Antarctic ice sheet that rest on reversed bed slopes, whereby ice-sheet thinning or rising sea level leads to irreversible retreat of the grounding line. However, existing analyses of this instability mechanism have not accounted for deformational and gravitational effects that lead to a sea-level fall at the margin of a rapidly shrinking ice sheet. Here we present a suite of predictions of gravitationally self-consistent sea-level change following grounding-line migration. Our predictions vary the initial ice-sheet size and also consider the contribution to sea-level change from various subregions of the simulated ice sheet. Using these results, we revisit a canonical analysis of marine-ice-sheet stability and demonstrate that gravity and deformation-induced sea-level changes local to the grounding line contribute a stabilizing influence on ice sheets grounded on reversed bed slopes. We conclude that accurate treatments of sea-level change should be incorporated into analyses of past and future marine-ice-sheet dynamics.
You will note, of course, that the study does NOT deny Climate change. It doesn't deny the temperature rising. It doesn't deny the ice sheet melting. Scaife's braintrust only wants you to make an artifical connection: the sea water won't be rising even though the "hoaxers" have said so - this Harvard study thus undermines another part of "global warming hoax" so we can be even more skeptical of the rest.

But does the study say what the braintrust says it says?


Take a look at some of the press following the report. Like this one from New Scientist:
The vast ice sheets of the Antarctic may be more stable than we thought, because a key piece of physics has been overlooked.

Glaciologists have long worried that the West Antarctic ice sheet will collapse over the next few centuries, raising sea levels dramatically. At present the ice sheet is grounded on underwater islands, which insulate some of the ice from the melting effect of the seawater upon which the rest of the sheet floats. But because the ice has started to melt because of climate change, more water is probably flowing underneath the sheet over the surface of the islands, accelerating its destruction.

The ice sheet has a defence mechanism, however. As it melts, sea levels around it will fall, say Natalya Gomez and Jerry Mitrovica of Harvard University and colleagues. That is counterintuitive, because the ice sheet will release extra water into the sea – but because the mass of ice has shrunk, its gravitational pull on the seawater will be weaker. Also, the bedrock will rise up as the weight of ice on it drops.

"You get a fall in sea level within 2000 kilometres of the ice sheet," Mitrovica says. This means there will be less water sloshing around the sheet's base, so it will last longer. "It will slow down the retreat," says Gomez. [emphases added.]
So this is a much more local thing than the Trib wants you to believe. Look again. The study is asserting something the Trib wants you to doubt: the temperature is rising.


rich10e said...

snore snore snore

EdHeath said...

Actually, good job on taking a complicated subject and showing how it's locally specific conclusions are being incorrectly and misleadingly generalized. Some people will catch and understand the truth, butt we shouldn't have to research newspaper stories or opinion pieces to find out the truth or any given situation.

Especially when the distortion is being used to further an agenda (and yes, this has to do with the Super Bowl domestic violence statistic as much as it has to do with Climate Change).