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Ice cap disappearing 30 years ahead of schedule

Antarctica seems to have lost about half a million square kilometers over the past couple of days. Seems to have been driven by the winds so the anomaly should fall back closer to zero over the coming weeks.

seaice.recent.antarctic.png
 
Am I right in interpreting the scale as "how long the ice has been there" eg, when it was last liquid water, and nothing to do with the common definition of "Ice Age"?

If so, they should have labelled it "Age of Ice" to avoid confusion :)

Also, how do they measure it? And where's the data between 88 and 08?
 
Crispy said:
Am I right in interpreting the scale as "how long the ice has been there" eg, when it was last liquid water, and nothing to do with the common definition of "Ice Age"?

If so, they should have labelled it "Age of Ice" to avoid confusion :)

Also, how do they measure it? And where's the data between 88 and 08?
Click to expand...
The ice can be measured by its thickness using a mixture of the satellite radars and tracking bouys. This year though a synthetic apateur radar on the Cryosphere 2 satellite has finalised comissioning and should be releasing data soon.

CryoSat ice mission gets clean bill of health

26 October 2010
Realising a satellite mission is a complicated task, with many milestones to pass before data are delivered to advance our understanding of Earth. However, scientists will soon have access to precious information on ice thickness as the commissioning of ESA's CryoSat draws to a close.
Click to expand...
http://www.esa.int/esaLP/SEMM2AZOBFG_LPcryosat_0.html

This should give us live data on ice thickness and hence age, as well as a clearer view of transportation and hopefully where the ice is full chunks or the partially melted 'rotten ice', it will also go along way to validating how good the PIOMAS thickness models of Zhang and co has been. .
 
Brace for over 20 meter sea level rise.

When was CO2 last at today’s level, and what was the world like then?
The most recent estimates35 suggest that at times between 5.2 and 2.6 million years ago (during the Pliocene), the carbon dioxide concentrations in the atmosphere reached between 330 and 400 ppm. During those periods, global temperatures were 2-3°C higher than now, and sea levels were higher than now by 10 – 25 metres, implying that global ice volume was much less than today36. There were large fluctuations in ice cover on Greenland and West Antarctica during the Pliocene, and during the warm intervals those areas were probably largely free of ice37,38,39. Some ice may also have been lost from parts of East Antarctica during the warm intervals40. Coniferous forests replaced tundra in the high latitudes of the Northern Hemisphere41, and the Arctic Ocean may have been seasonally free of sea-ice42.
Click to expand...

It also confirms that rapid extursions of geologically sourced CO2 can destabilise methane clatherates in sufficient quantities to be climactically significant.

The geological evidence from the 55 million year event and from earlier warming episodes suggests that such an addition is likely to raise average global temperatures by at least 5-6ºC, and possibly more, and that recovery of the Earth’s climate in the absence of any mitigation measures could take 100,000 years or more. Numerical models of the climate system support such an interpretation44. In the light of the evidence presented here it is reasonable to conclude that emitting further large amounts of CO2 into the atmosphere over time is likely to be unwise, uncomfortable though that fact may be
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Official statement from the UKs geological society.

Link

It only looks at 200 million years of climate history but it does focus on some undisputed facts.
The Paleocene Eocene Thermal Maximum 55 million years ago.
The Early Aptian 120 million years ago
And the Early Toarcian 183 million years ago.
Sea leves and CO2 during the Pliocene. The only coment on this is that there is a slightly different configuration of the continents since then with the Drake Passage being open and the Panama Ismuth closed.

So we can conclude that given the recent climate history of the earth a 20 meter sea level rise would be a fair expectation of only about 3 years more CO2 at current rates. We likely to be comiting to a methane feedback although some can argue this may yet be as much as 1000 years out or perhaps a lot closer, that methane feedback would like see a temperature rise in the order of 6C or greater (there are other mechanisms for methane feedbacks other than deep ocean clatherates).
 
ferrelhadley said:
Check out the CH4 readings on Ny-Alesund station on Svalsbard.
http://www.esrl.noaa.gov/gmd/ccgg/iadv/

None of the other stations show anything untoward so clearly a local event but still, gotta raise an eyebrow!
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worth keeping an eye on, but those data points are given as being preliminary, rather than verified, so it could be an instrument malfunction or problem with calibration etc.

it is exactly these sort of localised monitoring stations that would first pick up on any major releases from the methane clathrates (sp?) below the ocean, and / or permafrost melting though, so this would be pretty worrying if it was confirmed as being correct.
 
Here's an image that I found quite shocking. It's comparing the IPCC predictions for Arctic ice loss with the measured values:
IceFreeArctic.jpg
Source
So once again the IPCC has been shown to be too conservative in their predictions (just as they have on CO2 emmissions and sea level rise).
 
As terrible as that Svalbard data looks (and I see it's now being shown as confirmed) there may well be some other problem. There's an identical looking swing on the methane trace. Yet those massive changes aren't seen on other Arctic stations.
 
MikeMcc said:
As terrible as that Svalbard data looks (and I see it's now being shown as confirmed) there may well be some other problem. There's an identical looking swing on the methane trace. Yet those massive changes aren't seen on other Arctic stations.
Click to expand...
Yep, it is almost certainly merely a localised affair.

But I think it is very worth while bringing it to the attention of those who interperate the data and there is a small, very small, but real chance that this is something a little more serious than just a local phenomina. Given there are no NOAA reporting stations across North Russia and this is the area where Shakhova and Semiletov have been finding all the anomolous readings, Svaalsbard would be the first station on the NOAA network to pick anything up.

I think it is important to bring this to the attention of those who can grasp the significance but I do think it needsto be talked down as much as possible.
 
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