Anthony Watts has now written not one, not two, not three, not four but at least five articles protesting the melting of the West Antarctic ice sheet. I've commented on two of those, here and here.
His latest is from a chap called Tom Sheahen, who rejects science because of his politics. He signs every denier manifesto he can lay his hand on. Yes, he's one of the 100 people who signed a CATO document formally rejecting science. Tom's also signed his name to other utter nuttery, telling the US Supreme Court that:
CO2 is not in any sense an unwanted by-product of the production of useful energy. Rather, the combustion of carbon based fuels to produce CO2, and the capture of the energy released by that process, is the whole idea....
Tom Sheahen gives a lesson in denier-speak
Tom's article is mainly one in which he translates normal language into "denier-speak". It's mostly a lot of vague arm-waving gobbledygook, though not as gobbledy or gooky as one of Anthony Watts' other darlings, Tim Ball. After explaining what people really mean in denier-speak, at one stage Tom writes:
Elected officials striving to be responsive to their constituents’ concerns are often pressured by advocacy groups who have latched onto an incorrect interpretation of words. Scientists are sometimes guilty of riding a bandwagon that formed when the public misunderstood and exaggerated their original meaning; perhaps it’s convenient, prestigious and financially advantageous to let that confusion continue uncorrected. The effect snowballs and leads to new laws being passed, with expensive new regulations. Years later, with nothing accomplished, people ask “Oh, is that what you really meant?” Then the blame game begins, after much taxpayer money went down the drain unnecessarily.
That's not a bad lesson in denier speak. It's got just the right tinge of conspiracy ideation and nefarious intent. Tom doesn't give any examples of new laws and expensive new regulations that have sent money down the drain unnecessarily, needless to say. It's all denier theatre.
The above paragraph, you'll have noticed, embodies the unwritten assumption that all deniers are so stupid that they don't understand the purpose of particular laws and regulations. In fact Tom makes that assumption (that deniers are stupid) more than once. Elsewhere he writes:
- The word “average” is easily misunderstood.
- In the absence of quotation marks, italics or capitals, ordinary citizens have no idea that the controversy is rooted in radically different meanings of the same words.
I expect now Anthony Watts will try to remember to put all controversial phrases in italics or between inverted commas, like Christopher Monckton does, so his dumb deniers will be know they must be translated into denier-speak. Will he be more precise in his use of "average" I wonder and specify whether he is referring to the mean or the mode or the median?
Tom Sheahen takes his deniers to Antarctica
Given that Tom's formally declared his allegiance to science denial it's a bit odd that he writes about geology - and then goes on to write about Antarctic ice. (Tom's name is also spelt as Tom Sheahan or Tom Sheehan in different places but it's the same chap AFAIK.)
What Tom's doing is having another shot at soothing the scaredy cats at WUWT. He's carefully explaining to them that terms used by geologists may have a different meaning to those same words used in general conversation. The words he picks are time-related.This is what Tom wrote:
Q. On TV I saw that the ice in Antarctica is collapsing, and that will raise sea level and inundate cities. Others reports say this will take thousands of years. How serious is the problem?
What you are witnessing here is a result of confusion between the public perception of the ordinary meaning of words, and the very special definitions used in scientific discourse.Tom apparently rejects the recent science that shows that parts of the West Antarctic ice sheet (WAIS) are slipping into the sea very quickly. He claims:
Geologists deal with changes in the earth that occur over epochs of millions of years. Anything that happens in less than 10,000 years is “sudden,” and something happening in only 1,000 years is “instantaneous.” To geologists, the word “collapse” is appropriate for a 10,000 year process.
A hot-topic in the media these days has to do with the West Antarctic Ice Shelf (WAIS), a region comprising about 8% of the ice covering Antarctica. Within that region, there are two glaciers that are sliding down to the sea at a steady pace, as glaciers always do. They comprise about 10% of the WAIS, less than 1% of Antarctic ice. This descent has been in progress for several thousand years, and is neither new nor man-caused. It will go on for a few thousand more, after which they’ll be gone. In the parlance of geology, those two glaciers are collapsing.
If that doesn’t sound to you like your usual meaning of the word “collapse,” you’re absolutely right. It’s a specialized geological term.
Unfortunately, the major media overlook the distinction of meanings, and then make the further generalization from two specific glaciers to the entire WAIS, and moreover to Antarctica in general. Scientists who point out the small actual glacier size (and volume of ice) are brushed aside in the rush to get a headline or a flamboyant sound byte that will keep the viewers tuned in. Words like unavoidable collapse carry a sense of foreboding.There is so much wrong with what Tom wrote that I won't bother with a listed rebuttal. Instead I'll point out that the melt of West Antarctica is happening. Not at a steady pace but at an accelerating pace. Not over 10,000 years but right now. And the West Antarctic ice sheet will add up to four metres (or more) to sea level when it's melted. The glaciers flowing into the Amundsen Sea alone will add a metre to sea level worldwide.
The groundline is moving back at nearly 2 km a year. Yes, that's right. Eric Rignot and colleagues have reported that over the nineteen years from 1992 to 2011:
- Pine Island Glacier retreated 31 km at its center - that's 1,632 metres a year on average.
- Thwaites Glacier retreated 14 km along its fast-flow core - that's 737 metres a year on average.
- Haynes Glacier retreated 10 km along its flanks - that's 526 metres a year on average.
- Smith/Kohler glaciers retreated the most, 35 km along its ice plain - that's 1,842 metres a year on average.
I haven't yet written about the other paper that hit the headlines at the same time as the Rignot paper. The second paper is by Ian Joughin, Benjamin E. Smith and Brooke Medley and was published in Science last week (16 May). Like Rignot14, they were studying the ice sheet in the Amundsen Sea Embayment, in particular the Thwaites and Haynes Glaciers. Here is a map, courtesy of AntarcticGlaciers.org . If you click to enlarge the image, you can see Thwaites next to Pine Island on the Amundsen Sea.
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| Credit: AntarcticGlaciers.org |
What the scientists found was that the collapse of WAIS has already begun. In the paper, when they refer to Thwaites Glacier they are also including Haynes Glacier and together they contribute almost half the ice losses to the Amundsen Sea (52 Gt/year of the 105Gt/year measured as at 2007).
The thing is that once Thwaites goes, so does most of the West Antarctic ice sheet from that area, which will eventually raise sea levels by anything up to four metres or so.
As reported in ScienceDaily.com:
The good news is that while the word "collapse" implies a sudden change, the fastest scenario is 200 years, and the longest is more than 1,000 years. The bad news is that such a collapse may be inevitable.
"Previously, when we saw thinning we didn't necessarily know whether the glacier could slow down later, spontaneously or through some feedback," Joughin said. "In our model simulations it looks like all the feedbacks tend to point toward it actually accelerating over time; there's no real stabilizing mechanism we can see."
What is apparently happening is that the warmer Circumpolar Deep Water (CDW) is thinning the ice that's on the continental shelf around Antarctica, which means that the glaciers aren't being held back to the same extent any more. From the paper:
Currently, elevated melt rates on the Amundsen Coast are largely driven by increased transport of warm CDW onto the continental shelf rather than by direct warming of the CDW (6). If the conditions responsible for this transport abate, melting should lessen. Thus, we simulated 100 years of high melt (m = 3 and 4) followed by reduced melt (m = 1) for the remainder of the simulation (Fig. 3B). Although the reduction in melt slowed the rate of loss, at the end of these 250-year simulations, losses were substantially greater relative to the sustained m = 1 simulation.Eric Rignot explains this in an article in The Guardian (well worth reading - h/t idunno):
...Ocean heat is pushed by the westerly winds and the westerlies have changed around Antarctica in response to climate warming and the depletion of the ozone. The stronger winds are caused by a world warming faster than a cooling Antarctica. Stronger westerlies push more subsurface warm waters poleward to melt the glaciers, and push surface waters northward.
The rapid collapse threshold - 1 mm/year of sea level rise
On the issue of how long this will take, the research suggests it could happen after a couple of centuries and probably in less than a thousand years. Which isn't all that long even on human time scales. And once she goes, she goes quickly. From the paper:
When simulated losses exceed 1 mm/year of sle [sea level equivalent], much greater losses generally follow within a few years. Using our basin-scale model, however, such rapid collapse is difficult to model, especially because interaction with other basins becomes increasingly important. Thus, we take 1 mm/year of sle to be a threshold that, once crossed, marks the onset of rapid (decades) collapse as the grounding line reaches the deepest regions of the marine basin. In our 250-year simulations, only the highest-melt, weak-margin simulation reaches this critical threshold. Therefore, we have extended the remaining simulations to determine when this threshold is reached (fig. S2 and Table 1). For all but the lowest-melt simulations (m = 0.5), the onset of rapid collapse begins within a millennium.
So what we need to watch for is the amount of loss a year. That's not all. The paper has some provisos.
An important feature of our numerical simulations is that they reveal a strong sensitivity to mechanical and/or rheological weakening of the margins, which can accelerate the rate of collapse by decades to centuries. Thus, future models will require careful treatment of shear margins to accurately project sea-level rise. Our simulations also assume that there is no retreat of the ice-shelf front. Full or partial ice-shelf collapse should produce more rapid retreat than we have simulated. In addition, we have not modeled ocean-driven melt that extends immediately upstream of the grounding line, which could also accelerate retreat.
That means, the ice could melt sooner rather than later. I'm thinking that it will be very important to keep a close watch on what is happening in West Antarctica over coming decades (and centuries).
There's 7 metres more waiting in East Antarctica
Eric Rignot warns that it's not just West Antarctica that's going to hit us with all this extra seawater. There's a marine glacier, Totten Glacier, in East Antarctica that will add seven metres (23 feet) to global sea level. He doesn't give a time frame but writes:
There is also a bigger picture than West Antarctica. The Amundsen sea sector is not the only vulnerable part of the continent. East Antarctica includes marine-based sectors that hold more ice. One of them, Totten glacier, holds the equivalent of seven metres of global sea level.
Controlling climate warming may ultimately make a difference not only about how fast West Antarctic ice will melt to sea, but also whether other parts of Antarctica will take their turn. Several "candidates" are lined up, and we seem to have figured a way to push them out of equilibrium even before warming of air temperature is strong enough to melt snow and ice at the surface.
Unabated climate warming of several degrees over the next century is likely to speed up the collapse of West Antarctica, but it could also trigger irreversible retreat of marine-based sectors of East Antarctica. Whether we should do something about it is simply a matter of common sense. And the time to act is now; Antarctica is not waiting for us.
What is the threshold for denialism?
One thing that I wonder, when I read papers like these two (Rignot14 and Joughin14) and then go across to WUWT to read how strongly they protest the facts, is why? Why do they pretend that ice doesn't melt as it warms? I mean, given all the caveats, this could mean a rapid rise in sea level within their lifetime, and easily within their children's lifetime. They can't all be 90 years old and childless. They can't all care so little about the future of human society. What is it that drives them to such an imbecilic reaction to strong warnings? There must come a day when deniers reach a threshold of fact that will be impossible to reject (leaving aside the certifiable nutters).
From the WUWT comments
emsnews is an ice age comether and he's wrong. Even a grand minimum won't stop global warming. emsnews says:
May 21, 2014 at 4:14 pm
Except if this is the beginning of another Maunder Minimum due to the sun, those glaciers won’t be suddenly or slowly melting into the ocean. Quite the opposite.
cnxtim copies and pastes the usual irrelevant, meaningless denier slogans and says:
May 21, 2014 at 4:53 pm
All this scaremongering is inexorably delivering the CAGW flock into the “chicken little idiot’ brigade in the eyes of the GP – and good riddance to them and their public purse budgets.
Frank K. is scared shitless but not about global warming or rising seas. He's a denier of the paranoid conspiracy persuasion and says:
May 21, 2014 at 5:02 pm
To add to what others have said, it is quite clear to me that the misuse of scientific press releases for political gain is deliberate. Global warming (or climate change, disruption, …whatever) has NEVER been about science, but rather a means to fundamentally change (and destroy) our ways of life. And the left wing, progressive zealots will not cease until their mission is acomplished.
george e. conant is overwhelmed by Tom's generosity in telling him not to be scared by Yahoo News items about hottest Aprils and global warming and rising seas, so much so that he can't help shouting:
May 21, 2014 at 5:11 pm
This may be off topic a wee bit BUT, I just scrolled through the Yahoo News Feed… OH MY GAWD, one article after another about Global Warming , all bad, all catastrophic , some already mentioned in these comments … I am seeing a ramping up of the Alarmism to levels just unbelievable. David Suzuki now demanding that politicians who are Climate Deniers should be (need to be) LOCKED UP… The Antarctic collapsing, Hottest April Globally , on and on …. WOW. And Thank you Dr. Sheahen, excellent article.
LogosWrench is another one who proves Tom's assumption about deniers and says:
May 21, 2014 at 5:19 pm
Now add to that our intellectual waste lands known as universities that teach words have no meaning apart from what the hearer desires. So there you go. Cooling is caused by warming and other such nonsense.
noloctd is a nasty as well as stupid denier who laughs aloud at the difficult legacy he's leaving his (presumably) nephew and says:
May 21, 2014 at 5:49 pm
A liberal family member has assured me that a Maunder Minimum like event will have NO effect this time because there is 400 PPM of CO2 in the atmosphere. He’s a soon to be grad student in something social sciency, but insists that he knows all about geology and the other sciences. He is convinced to the point of obsessive worry that humans are the cause of all climate change and that Antarctica will melt in his lifetime and innundate a good portion of the dry land, not just the coasts.
Alas, I can’t laugh too loudly as he’s family after all.
Oh, a real live normal rational person slipped in a comment. Chris says:
May 21, 2014 at 7:31 pm
Dr. Sheahen said” Within that region, there are two glaciers that are sliding down to the sea at a steady pace, as glaciers always do.
The “steady” pace has doubled from the 80 billion tons/year in the 2005-2010 time period to 160 billion tons/year during the latest measurements. I wouldn’t call that a steady pace, I’d call it a rapidly increasing pace.
The deniers did have a bit of trouble with the meaning of the word "average". So Tom's assumption about deniers was proven again. There were several comments, with various people explaining what different "averages" mean, for example, swifty is correct when saying:
May 21, 2014 at 9:27 pm
The midpoint of a range, when listed in ascending or descending order, yes, it is called the median.
I suppose since they are still debating grade school arithmetic, there isn't much reason to hope deniers will understand the intricacies of a melting cryosphere.
E. Rignot, J. Mouginot, M. Morlighem, H. Seroussi, B. Scheuchl. "Widespread, rapid grounding line retreat of Pine Island, Thwaites, Smith and Kohler glaciers, West Antarctica from 1992 to 2011".. Geophysical Research Letters, 2014; DOI: 10.1002/2014GL060140
Joughin, Ian, Benjamin E. Smith, and Brooke Medley. "Marine Ice Sheet Collapse Potentially Under Way for the Thwaites Glacier Basin, West Antarctica." Science 344, no. 6185 (2014): 735-738. DOI: 10.1126/science.1249055
