Arguments
New Video: The Trouble at Totten Glacier
Posted on 17 April 2015 by Guest Author
This is a re-post from Peter Sinclair at Climate Crocks
The latest “This is Not Cool” video is the third in a trilogy of very important, and sobering, pieces I’ve posted over the last year. I didn’t start with a trilogy in mind, but the developments of the last few months have been jarring and momentous.
Chris Mooney wrote recently in the Washington Post, “A hundred years from now, humans may remember 2014 as the year that we first learned that we may have irreversibly destabilized the great ice sheet of West Antarctica, and thus set in motion more than 10 feet of sea level rise.”
He added, “Meanwhile, 2015 could be the year of the double whammy — when we learned the same about one gigantic glacier of East Antarctica, which could set in motion roughly the same amount all over again.”
The decades-long unfolding of this story – that vast areas of ice once thought to be invulnerable on time scales meaningful to humans, may in fact already be in the process of disintegration – is one that that the vast majority of humanity still does not understand, and that the media has been unwilling to track. It’s a realization that, one top expert told us, even seasoned ice sheet veterans find “shattering”.
For this video I used in-person interviews from December’s AGU conference, as well as a skype chat with Jamin Greenbaum of the University of Texas, whose recent research on East Antarctic vulnerability has been widely reported. Jamin pointed me to some Australian research from the same area. There was a huge volume of material, not all of which made it into this video, but which I’ll be posting in coming weeks to flesh out the picture.
The overriding message: we have a problem.
It is ironic that humans devised the means of irreversibly using up limited crustal stocks of fossil fuels to provide physical energy with the unintended consequence of causing irreversible rapid climate change. So now we have problems of the kind discussed here while we are losing the physical capability to address them. Oil is running out so fuel for aircraft will be posing a problem that will impinge on studies of what is happening in Antarctica and elsewhere.
Antarctic ice extent is at record levels and continues to increase. It has been found that the West Antarctic Peninsula, about 2% of the land mass, is being heated from below and not by global warming.
[Rob P] - Antarctic sea ice extent has accelerated, but so too has the loss of land-based ice volume from the Antarctic continent. And the loss of land-based ice volume is six times larger. Globally, the loss in ice volume is about 50 times greater than the gain in Antarctic sea ice volume (over the last decade). This is what we'd expect in a warming world.
The interesting thing about Antarctic sea ice is that the increases are concentrated in the vicinity of the polar gyres - suggesting that the wind-driven ocean circulation has played a part. Now that the wind-driven ocean circulation appears to have changed course, it will interesting to see what happens to the Antarctic sea ice.
[TD] Please read the post "Is Antarctica Losing or Gaining Ice?"--first its Basic tabbed pane, then its Intermediate tabbed pane. Then read the counter to the myth "Arctic sea ice loss is countered by Antarctic sea ice gain"--both Basic and Intermediate tabbed panes. The sea ice extent increase is in spite of the Antarctic ocean and air having been directly measured to be warming.
[TD] Your claim of global warming not contributing to West Antarctic Peninsula land ice loss is incorrect. See the post "Why Do Glaciers Lose Ice?" I suspect I know the source of your distorted claim that heating from below is what's causing land ice loss, but please do cite your source so commenters here can provide a correct interpretation of that specific claim. (Hint: For increased land ice loss to be due to heating from the land below, the heating of the land below must be increasing. The mere discovery of heating where nobody had looked before does not qualify as "increasing.")
Paisleg,
While the Antarctic sea ice is high, according to the NSIDC, it is currently lower than it was in 2014 so it cannot be record high. It is close to the record.
Since this post is about land based ice, and land ice is reponding to AGW differently than sea based ice I do not see your point. The land ice raises the sea level while the sea ice does not affect sea level.
Your claim about heating from below is simply false. Please provide a citation to support your absurd claim. Why do you believe such transparently false information? Think to yourself: why do you read material from people who deliberately mislead you with false information?
michael sweet @3, there exists a geothermal hot spot under the West Antarctic Ice Sheet (WAIS) that generates heat flows as high as 0.08 W/m^2, and even hotter spots just off shore of the Antarctic Peninsula, where the heat flows may be as high as 0.095 W/m^2 (See fig 8 of Shapiro and Ritzwoller 2004). There has been subice volcanism associated with the hotspot under the WAIS as recently as 200 BC (Corr and Vaughan 2008). Because of that volcanism, the geothermal heat flow under the WAIS cannot be considered constant, and will peak at higher values in the case of volcanic erruptions. I am not aware of evidence of recent erruptions, however. Such erruptions would have been detected from associated earthquakes. Consequently, absent specific evidence to the contrary, there is no reason to believe that there has been a recent increase in geothermal heat flow at that location.
Even if there had been, of course, it would be almost irrelevant. Specifically, the topography is such that water melted by volcanism at that location will potentially lubricate the flow of the Pine Island Glacier, but that although:
In addition, there have been recently discovered (Schroeder et al, 2014) geothermal hotspots associated with Mount Takahe, and underlying the Thwaites glacier. The average inferred flux is 0.114 W/m^2, with hotspots exceeding 0.2 W/m^2. Given the association with Mount Takahe, whose last known eruption was in 5550 BC, it is unlikely though possible that that heat flow has increased recently. Certainly the rate of change of the heat flow has not been measured.
More generally, and of necessity, all ice sheets are "heated from below", although that heating may not rise above 0.02 W/m^2, and changes in the heating are likely to be a tenth or less of that. What is more, basic physics indicates that reduction of the thickness of the ice is likely to result in a lower heat flow at the base of the ice (although the rate of change is, if you will forgive the pun, glacial). The exception is where reduction in ice mass triggers volcanism, which is an interesting potential feedback ;)
Paisleg appears to have made the standard denier jump from "there has been newly discovered geothermal heat flow under the ice" to "the geothermal heat flow under the ice has suddenly increased"; and from "there exists a heating source in addition to that from global warming" to "the heating from global warming is irrelevant to what is going on". But are non sequiturs, and in addition extremely unlikely to be valid inferences. He will also be entirely unable to provide any evidence that either inference is justified.
Indeed, he goes even further and assumes that because some ice is heated by geothermal sources, it follows that that ice is not heated by global warming (even though there is clear evidence for both the Pine Island Glacier and the Thwaites Glacier that they are). The final clause of his post, therefore, is certainly absurd. I am unsure whether you are reacting to just that clause (which is simply false, and absurd) or the the whole sentence, the first clause of which is not false. Hence my discussion.