The rest of the media is finally catching up to my post from last month (see “Another AGU stunner: Evidence that Antarctica has warmed significantly over past 50 years“).
That’s because Nature published the peer-reviewed paper that was first reported at the American Geophysical Union meeting and Nature’s own blog (!), “Warming of the Antarctic ice-sheet surface since the 1957 International Geophysical Year” (subs req’d, abstract below).
Scientists know the Antarctic ice sheet is losing mass “100 years ahead of schedule” (see “AGU 2008: Two trillion tons of land ice lost since 2003” and “Antarctic ice sheet hits the fan“).
It is really only the warming of the West Antarctic Ice Sheet (WAIS) that you should worry about (at least for this century) because it’s going to disintegrate long before the East Antarctic Ice Sheet does — since WAIS appears to be melting from underneath (i.e. the water is warming, too), and since, as I wrote in the “high water” part of my book, the WAIS is inherently less stable:
Perhaps the most important, and worrisome, fact about the WAIS is that it is fundamentally far less stable than the Greenland ice sheet because most of it is grounded far below sea level. The WAIS rests on bedrock as deep as two kilometers underwater. One 2004 NASA-led study found that most of the glaciers they were studying “flow into floating ice shelves over bedrock up to hundreds of meters deeper than previous estimates, providing exit routes for ice from further inland if ice-sheet collapse is under way.” A 2002 study in Science examined the underwater grounding lines–the points where the ice starts floating. Using satellites, the researchers determined that “bottom melt rates experienced by large outlet glaciers near their grounding lines are far higher than generally assumed.” And that melt rate is positively correlated with ocean temperature.
The warmer it gets, the more unstable WAIS outlet glaciers will become. Since so much of the ice sheet is grounded underwater, rising sea levels may have the effect of lifting the sheets, allowing more-and increasingly warmer-water underneath it, leading to further bottom melting, more ice shelf disintegration, accelerated glacial flow, and further sea level rise, and so on and on, another vicious cycle. The combination of global warming and accelerating sea level rise from Greenland could be the trigger for catastrophic collapse in the WAIS (see, for instance, here).
You can read every thing a laymen could possibly want to know about what the study does and doesn’t show at RealClimate here. Andy Revkin blogs on the NYT coverage of the study with expert commentary here.
It bears repeating that this was not the only research presented at the AGU meeting to find that warming extends beyond the Antarctic’s Peninsula region. David Bromwich of the Byrd Polar Research Centre at Ohio State also presented at AGU his new study, “Surface and Mid-tropospheric Climate Change in Antarctica,” which found:
It is found that the statistically significant Antarctic Peninsula near-surface warming on an annual basis has spread into West Antarctica reaching as far as east as the Pine Island Bay-Thwaites Glacier region.
The warming is most marked in recent years with 2007 being the warmest year in the 1960- 2007 interval…. The warming over West Antarctica is maximized in the spring (SON) and in that season statistically significant warming stretches across all of West Antarctica and into northern Victoria Land. Weak near- surface warming is found over East Antarctica and the continent as a whole on an annual basis although continental warming in the spring is statistically significant and driven largely by the strong and widespread changes in West Antarctica.
Here is the abstract of the new Nature study:
Assessments of Antarctic temperature change have emphasized the contrast between strong warming of the Antarctic Peninsula and slight cooling of the Antarctic continental interior in recent decades. This pattern of temperature change has been attributed to the increased strength of the circumpolar westerlies, largely in response to changes in stratospheric ozone. This picture, however, is substantially incomplete owing to the sparseness and short duration of the observations. Here we show that significant warming extends well beyond the Antarctic Peninsula to cover most of West Antarctica, an area of warming much larger than previously reported. West Antarctic warming exceeds 0.1 °C per decade over the past 50 years, and is strongest in winter and spring. Although this is partly offset by autumn cooling in East Antarctica, the continent-wide average near-surface temperature trend is positive. Simulations using a general circulation model reproduce the essential features of the spatial pattern and the long-term trend, and we suggest that neither can be attributed directly to increases in the strength of the westerlies. Instead, regional changes in atmospheric circulation and associated changes in sea surface temperature and sea ice are required to explain the enhanced warming in West Antarctica.
So notwithstanding the amateur meteorologist-deniers who sometimes comment on this blog and elsewhere about how cold it is outside right now, the whole damn planet is warming and melting — even in places that are much, much colder than anywhere in the continental United States.
Related Posts:
- Startling new sea level rise research: “Most likely” 0.8 to 2.0 meters by 2100
- US Geological Survey stunner: Sea-level rise in 2100 will likely “substantially exceed” IPCC projections
- Report from AGU meeting: One meter sea level rise by 2100 “very likely” even if warming stops?
- Stabilize at 350 ppm or risk ice-free planet, warn NASA, Yale, Sheffield, Versailles, Boston et al
- Greenland ice loss soars: Bad for you, great for bottled water biz
- JPL’s new climate website: Yes, sea level rise has accelerated
- Debunking Bjørn Lomborg — Part II, Misrepresenting Sea Level Rise
- Inundated with Information on Sea Level Rise
- Sea levels may rise 5 feet by 2100
- Amazing AP article on sea level rise
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Oh dear, surprise, surprise. Its also warming at the south pole.
The report on the BBC site is a bit disappointing…
New evidence on Antarctic warming
http://news.bbc.co.uk/ 2/ hi/ science/ nature/ 7843186.stm
You may argue the worst kind of denialism is found in it…professional uncertainty!
Hello guys. Some times its alright to tell a white lie.
Especially if your probably right and your going to save the world by it.
Good post Joe and you are one of the few non-glaciologists to correctly note in recent years that WAIS is more unstable than Greenland. I was very pleased on reading your book six months ago to see that. The importance of Pine Island and Thwaites, called the week underbelly of the WAIS is that they are the only two significant outlet glaciers of WAIS that do not have large buttressing ice shelves. The large ice shelves buttress WAIS ice streams feeding into them, the smaller the ice shelf the less destabilization needed before the buttressing is reduced or eliminated. The thinning of these two glaciers, Thwaites and Pine Island in their floating ice sections in particular already indicate greater flotation and less buttressing.
Mauri:
Thanks. Turns out all you need to do to understand a subject is read the literature, attend talks, and then interview experts.
If we get 5°C warming and 1 to 2 meters of sea level rise this century, WAIS isn’t gonna last long.
Paulm:
I wouldn’t advocate white lies. The literature is pretty clear on this. I just advocate less media wishy-washiness, which I suppose is like advocating for less sex and violence on TV.
hi Joe,
As always, your website is the best.
Last time I mentioned tree death here in comments, I was accused of drinking koolaid.
That kind of hurt my feelings. I am quite serious and in fact, the decline of trees – and lately shrubs such as boxwood – has continued to accelerate visibly here in NJ. Pine trees aren’t just thinning – they are devoid of needles. Presuming the deciduous trees are suffering internally the same (which were the first alert I had, last summer) we’re going to have a very bare spring. We’ll see.
Here is an article in ScienceDaily.com with a link to the report, released just yesterday, by the US Climate Change Science Program. I believe the “abrupt change” that global warming “may” trigger according to the conclusions is in fact, already happening HERE and NOW.
http://www.sciencedaily.com/ releases/ 2009/ 01/ 090116142119.htm
Here is a section from Wikipedia on extinction:
“Most biologists believe that we are at this moment at the beginning of a tremendously accelerated anthropogenic mass extinction. E.O. Wilson of Harvard, in The Future of Life (2002), estimates that at current rates of human disruption of the biosphere, one-half of all species of life will be extinct by 2100. In 1998 the American Museum of Natural History conducted a poll of biologists that revealed that the vast majority of biologists believe that we are in the midst of an anthropogenic mass extinction. Numerous scientific studies since then—such as a 2004 report from Nature,[4] and those by the 10,000 scientists who contribute to the IUCN’s annual Red List of threatened species—have only strengthened this consensus.”
from http://en.wikipedia.org/ wiki/ Holocene_extinction_event
I found this site has many excellent reputable sources but if you just google 6th extinction you will find countless others:
http://www.well.com/~davidu/extinction.html
Joe, its all just a bit frustrating.
A new era has begun. Now is the opportunity to attain the broadest coalition for eliminating fossil fuel over time. Thirty-five years is a reasonable timetable that would very likely achieve 450ppm stabilization.
It has been demonstrated that the most cost efficient fossil fuel replacement is efficiency. Amazingly, the automotive industry is poised to free itself from gasoline. Does anyone doubt that in twenty years all new cars will be EV?
In the area of heating and cooling buildings, geothermal heats pumps are a market success. Insullation, window and roofing (white is optimum) technologies get better and better.
Concentrated solar is a reality, wind farms grow faster than the goal set for all alternatives. How wonderful if the first priority of the stimulus package is construction of a 21st Century grid capable of bringing the vast natural energy resources of the deserts and plains to all the people.
The temperature above 3 kilometers in Antarctica is 15 degrees C below the temperature on the sea level there. I think even in the southern summer the temperature doesn´t rise above 0 degree C up there, most of the ice of Antarctica doesn´t melt, only ice below 3 or 2 kilometers. And Antarctica has been without ice. That would mean that the melting of Antarctica happens via collapsing, just as you and mauri, perhaps, were thinking.
PaulK
You asked:
[Does anyone doubt that in twenty years all new cars will be EV?]
I do….unless you can fill in details on how that transfer to EV (all new cars) will occur and what will be the ‘real’ climate consequences if transmission grid and renewable power storage are not in place…and range problem and battery recycling is regulated, etc. etc.
John McCormick
John McCormick,
Good questions. Let me first amend my statement to all new cars will be plug in hybird or EV in twenty years. There is tremendous pent up consumer demand for these vehicles. Note that even in a very slow year, hybrids sold easily, limited only by battery availability.
All the manufacturers are committed to producing these vehicles. Look at other changes over a similar time period in car building. We’ve gone from rear wheel drive to front wheel drive, from points and rotors to electronic ignition. A/C, once a luxury is now standard equipment. Gas prices will continue to fluctuate, increasing the market for high efficiency.
Yes, modernizing the grid is of overriding importance, as noted in my original comment. Efforts in solar and wind are fruitless without it. It is one area where effective government action is necessary and more vital than any regulatory or carbon pricing regime.
Well I read what one of the authors had to say on RC and read the article here and anyone else see the cherry picking to get the ‘right’ answer?
I mean the auther himself said that:
1935-1945 was the warmest period
1969-2000 was cooling
1958-2006 was warming
so we can infer from that the temperature curve was cooling from 45 to 58
warmed from 58 to 69
cooled from 69 to 2000
* and this was not mentioned but all studies show cooling from 69 on to present *
45 was warmer than 2000
69 was warmer than 2000
58 was cooler than 2000
if 58 was better to use because it was longer
then 45 is even better because it is even longer than 58
so while the antarctic temp curve fluxs, over all cooling predominated except for a brief warming between 58 and 69.
And on another fun note, anyone notice that the warmest period for the antarctic is the same as the warmest period for the longest rural surface termperature record we have?
[JR: I take it you failed science, but aced "make stuff up." Your statements above are not true, and so your conclusions are not true.]
Gail,
I hail from the mid-section of New Jersey and it depresses the hell out of me to read your observations on the Pine Barrens. I left NJ in ‘79 but visited on and off until ‘89 but never around fall. I remember back in the 70’s the leaves turning around the last week of September and the first week of October. Can you tell me now when the leaves change their colors?
Rick
The authors of the Nature article posted a summary at:
http://www.realclimate.org/index.php?p=625
The article has the Nature URL in it.
Maybe the politicians will wake up when Washington, D.C. is under water. Hopefully,?! that will be before agriculture collapses. Any guesses on which happens first? My guess is that agriculture collapses first.
The president’s email address is president@whitehouse.gov, I think.
JR, please be specific. Where was I wrong? I used the information presented in the authors post on the study over at Real Climate.
Are you saying that he did not say that 1935-1945 was the warmest period within the century?
Are you saying the author was wrong to state that the studies starting in 1969 did not show cooling to the end of the century?
Which part is wrong? Which part of my logic was a failure to understand science?
If 1935-1945 is warmest then 1969 was warmer than 1957/8 but not as warm at 1935-1945.
If there is cooling from 1969 to end of century yet 1957/58 has warming till the end of the century, then there was a short period of warming from 1957/58 to 1969 only.
Therefore there was cooling from 1945 to at least 1957/58. From 1957/58 there was warming until 1969. From 1969 to the end of the century there was cooling.
So how is it wrong to point out that the warming took place during the 1957/58 to 1969 period which is only 11 or so years while the remaining time (55-11), 44 years was a cooling trend. So why is cherry picking 1957/58 better than picking 1969 or 1935-45? Both of those show cooling till the end of the century. The author states that 50 years is better than 30 or 20 but using that logic then 55, 63 if you run it out to the present is better than only that is only 50 years.
So how about some facts that I was in error in or that the author of the study was wrong about before you adhom me.
[JR: Please identify what specific claims you are reporting that "the author" supposedly made, with direct quotes and links. You have misstated what he wrote and mixed applies and oranges.]
Eric Steig
Ok, here is the link to Real Climate, http://www.realclimate.org where Eric Steig posted an article about the study that is:
So from 1969 to 2000 studies show cooling.
If 1935-1945 is warmest then 1969 was warmer than 1957/8 but not as warm at 1935-1945.
If there is cooling from 1969 to end of century yet 1957/58 has warming till the end of the century, then there was a short period of warming from 1957/58 to 1969 only.
Therefore there was cooling from 1945 to at least 1957/58. From 1957/58 there was warming until 1969. From 1969 to the end of the century there was cooling.
So how is it wrong to point out that the warming took place during the 1957/58 to 1969 period which is only 11 or so years while the remaining time (55-11), 44 years was a cooling trend. So why is cherry picking 1957/58 better than picking 1969 or 1935-45? Both of those show cooling till the end of the century. The author states that 50 years is better than 30 or 20 but using that logic then 55, 63 if you run it out to the present is better than only that is only 50 years.
Now I say again, using the authors own words, what did I get wrong? You’re the one that said I fail science so now you have the authors words, how did I fail?
[JR: Seriously, dude, read what you just posted!]
Oh, since the authors did say everything I said they did, how about an taking back calling me a liar?
[JR: But in fact what you just posted shows they didn't say everything you said that did. Try reading it again -- this time more closely.]
So let me get this straight: when the temperature goes up for several years in a row, that’s proof of global warming, but when the temperature goes down for several years in a row, its not disproof? It doesn’t even make you question the conclusions?