Recent climate, glacier changes in Antarctica at the ‘upper bound’ of normal

From the University of Washington some walkback?

This photo from December 2010 shows a one-meter long section of the West Antarctic Ice Sheet Divide core, with a dark layer of volcanic ash visible.

In the last few decades, glaciers at the edge of the icy continent of Antarctica have been thinning, and research has shown the rate of thinning has accelerated and contributed significantly to sea level rise.

New ice core research suggests that, while the changes are dramatic, they cannot be attributed with confidence to human-caused global warming, said Eric Steig, a University of Washington professor of Earth and space sciences.

Previous work by Steig has shown that rapid thinning of Antarctic glaciers was accompanied by rapid warming and changes in atmospheric circulation near the coast. His research with Qinghua Ding, a UW research associate, showed that the majority of Antarctic warming came during the 1990s in response to El Niño conditions in the tropical Pacific Ocean.

Their new research suggests the ’90s were not greatly different from some other decades – such as the 1830s and 1940s – that also showed marked temperature spikes.

“If we could look back at this region of Antarctica in the 1940s and 1830s, we would find that the regional climate would look a lot like it does today, and I think we also would find the glaciers retreating much as they are today,” said Steig, lead author of a paper on the findings published online April 14 in Nature Geoscience.

The researchers’ results are based on their analysis of a new ice core from the West Antarctic Ice Sheet Divide that goes back 2,000 years, along with a number of other ice core records going back about 200 years. They found that during that time there were several decades that exhibited similar climate patterns as the 1990s.

The most prominent of these in the last 200 years – the 1940s and the 1830s – were also periods of unusual El Niño activity like the 1990s. The implication, Steig said, is that rapid ice loss from Antarctica observed in the last few decades, particularly the ’90s, “may not be all that unusual.”

The same is not true for the Antarctic Peninsula, the part of the continent closer to South America, where rapid ice loss has been even more dramatic and where the changes are almost certainly a result of human-caused warming, Steig said.

But in the area where the new research was focused, the West Antarctic Ice Sheet, it is more difficult to detect the evidence of human-caused climate change. While changes in recent decades have been unusual and at the “upper bound of normal,” Steig said, they cannot be considered exceptional.

“The magnitude of unforced natural variability is very big in this area,” Steig said, “and that actually prevents us from answering the questions, ‘Is what we have been observing exceptional? Is this going to continue?'”

He said what happens to the West Antarctic Ice Sheet in the next few decades will depend greatly on what happens in the tropics.

The West Antarctic Ice Sheet is made up of layers of ice, greatly compressed, that correspond with a given year’s precipitation. Similar to tree rings, evidence preserved in each layer of ice can provide climate information for a specific time in the past at the site where the ice core was taken.

In this case, the researchers detected elevated levels of the isotope oxygen 18 in comparison with the more commonly found oxygen 16. Higher levels of oxygen 18 generally indicate higher air temperatures.

Levels of oxygen 18 in ice core samples from the 1990s were more elevated than for any other time in the last 200 years, but were very similar to levels reached during some earlier decades.

###

The work was funded by the National Science Foundation Office of Polar Programs.

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49 Responses to Recent climate, glacier changes in Antarctica at the ‘upper bound’ of normal

  1. Joseph says:

    One has to wonder if anything that the climate change science has claimed is robust enough to stand scrutiny under the standards employed in virtually all other disciplines?

    I work as a project manager and know for a fact that my Use Case has to be perfect before receiving the go ahead to start implementing. I also have to provide a huge amount of supporting data which is scrutinised by any interested party before receiving the final sign off, yet in climate change papers……no checks and balances.

  2. Chuck says:

    So despite his research that shows the contrary, he still believes in AGW.

    In the last few decades, glaciers at the edge of the icy continent of Antarctica have been thinning, and research has shown the rate of thinning has accelerated and contributed significantly to sea level rise.

    I thought there was nothing unusual about the rate of sea level rise and if anything it was slower recently.

    The same is not true for the Antarctic Peninsula, the part of the continent closer to South America, where rapid ice loss has been even more dramatic and where the changes are almost certainly a result of human-caused warming, Steig said.

    And exactly what is the evidence or does he just know that has to be the case?

  3. Latitude says:

    Who would have thunk it?…
    …more and more things are becoming normal

    ..and since when did sea level rise accelerate?

  4. ferdberple says:

    The same is not true for the Antarctic Peninsula, … where the changes are almost certainly a result of human-caused warming, Steig said.
    ===========
    Co-incidentally, this is the part of Antarctica where the most humans are located. Pumping out energy to try and stay warm. Are we seeing another case of frogs infected by researchers, mistakenly blamed on global warming?

    Shut down your generators and heaters in Antarctica and see what happens. Pretty safe bet temperatures in the camps will plummet.

  5. Tom J says:

    This is strictly a question. Ok, I recognize that that was a very stupid sentence to precede a question with, so let’s say we forget that I typed that. Anyway, has anybody ever done salinity measurements in that region and then kept an ongoing record comparing any changes to salinity in that region to salinity in the more open ocean. If the ice was melting at an unusual rate and contributing to sea level rise one might expect the salinity in that immediate region to be dropping particularly quickly relative to the more general ocean.

  6. ferdberple says:

    Levels of oxygen 18 in ice core samples from the 1990s were more elevated than for any other time in the last 200 years, but were very similar to levels reached during some earlier decades.
    ===========
    So, the LIA was cold, we know that. So the 1990’s were not unusual in comparison to the past. Everyone except The Team and the IPCC knew that as well. This looks like a case of infinite ability to state the bleeding obvious.

  7. Ian W says:

    ferdberple says:
    April 15, 2013 at 8:08 am

    The same is not true for the Antarctic Peninsula, … where the changes are almost certainly a result of human-caused warming, Steig said.
    ===========
    Co-incidentally, this is the part of Antarctica where the most humans are located. Pumping out energy to try and stay warm. Are we seeing another case of frogs infected by researchers, mistakenly blamed on global warming?

    Also as pointed out on this board only 5 years ago… There are active volcanoes all the way along the Antarctic Peninsula.
    http://wattsupwiththat.com/2008/01/22/surprise-theres-an-active-volcano-under-antarctic-ice/

  8. Pieter F. says:

    Meanwhile . . . add the Arctic and Antarctic sea ice anomalies and we get +608,000 sq.km. more sea ice than the benchmark (1979-2000 mean). The Antarctic is well above the mean, and the Arctic is within 1SD of the mean. Didn’t Al Gore predict that the Arctic would be ice-free in the summer of 2015? I need to reconnect with a few folks and prepare to collect on some bets.

  9. Bruce Cobb says:

    Looks like climate normal is the New Normal. The Alarmists, being somewhat slow, and currently in a state of d—al will continue on, in zombie-like fashion, of course.

  10. arthur4563 says:

    The big mystery is why he claims the warming in the peninsula was human-generated.

  11. Mike Haseler says:

    Chuck says: So despite his research that shows the contrary, he still believes in AGW.

    He believes that others believe that “Global Warming” is true. Others believe that he believes that “global warming” is true, because he believes that they believe that his belief that they believe is enough for him to say that he believes thus enforcing the belief of others that their belief is based on his belief.

  12. knr says:

    Having had the ‘magic’ one tree the data from which can be used to cover the whole world . we now have the ‘magic’ one bore whole whose data can be used to cover the whole of the Antarctica.
    Still at least it not ‘models’ this time , but given its Steig ,who has gone ‘all-in’ for the ’cause ‘ ,was there any other result possible than ‘its worst then we thought ‘.

  13. John Tillman says:

    Based upon measurements of soil radioactivity, the East Antarctic Ice Sheet has been stable for about 3300 years, ie since the Minoan Warm Period. The earth has been in a cooling trend since then, headed out of the current interglacial toward another glacial phase. Each succeeding peak of warmth has been cooler (Roman, Medieval & Modern Warm Periods) & each trough colder (Old Testament, Dark Ages & Little Ice Age Cold Periods).

    Here’s a recent study arguing for a climatic explanation of the collapse of Minoan civilization, based on ENSO proxies:

    http://www.clim-past.net/6/525/2010/cp-6-525-2010.pdf

  14. Bob Mount says:

    Thinning of sea ice in the Arctic and the Antarctic Peninsular is doubtless due to mankind – so get the scientists, explorers, tourists, military, trophy hunters, ice-breakers and record breakers off the ice asap!!

  15. Steven Mosher says:

    ‘Chuck says:
    April 15, 2013 at 7:55
    So despite his research that shows the contrary, he still believes in AGW.
    ###############################

    The research says nothing about the truth of AGW.

    In a nutshell. here is the theory.

    1. GHGs cause warming not cooling.
    2. Humans are putting more GHGs into the atmosphere.
    3. Over time the planet will warm, all other things being equal.

    Now, at its core the science says nothing about Ice in antarctica does it? At its core the science says nothing about whether it was warmer in the past or cooler. At its core, nothing you can find in antarctica can challenge it.

    Upon this core of the science, however, some folks have built some shakey arguments, particulary arguments about how fast it will warm or how fast it has warmed.

  16. Phil. says:

    Pieter F. says:
    April 15, 2013 at 8:24 am
    Meanwhile . . . add the Arctic and Antarctic sea ice anomalies and we get +608,000 sq.km. more sea ice than the benchmark (1979-2000 mean). The Antarctic is well above the mean, and the Arctic is within 1SD of the mean. Didn’t Al Gore predict that the Arctic would be ice-free in the summer of 2015? I need to reconnect with a few folks and prepare to collect on some bets.

    I wouldn’t be too eager to contact them were I you, since if you betted against the Arctic sea being ice free by then you’ll probably lose!

  17. Allencic says:

    Why is any so-called “climate research” still being done by the Warmists? It’s always the same result. It’s like asking the old question, “Do bears do you know what in the woods?” And then pay armies of researchers to go around the woods with scoops to get the exact same result.

  18. Chris M says:

    I suppose he feels he is risking his research grant by “dis-proving” global warming as a factor in the ice melt – thus the “yes – but I still believe so can I keep my grant money please?” statement.

  19. Genghis says:

    Stephan Mosher let me help you out.

    1. GHG’s cause warming in the lower atmosphere and cooling in the upper atmosphere.
    2. Humans are putting more GHG’s into the atmosphere.
    3. Over time the planets steady state temperature will stay the same, all other things being equal.

    See how easy that was : )

  20. DarrylB says:

    Not that I believe that AGW is significant, but I keep seeing a debate whether the rate of sea level rise is increasing or not. I would think that any change in sea level, regardless of an increase or a decrease in rate of rise is still an increase in sea level, and must be the result of some cause. There is no background rate of rise.
    Any comments?

  21. van Loon says:

    The Antarctic Peninsula is particularly sensitive to small changes in waves 3 and 1, since it reaches relatively far northwards. Such a small change has taken place at least since the IGY and has nothing to do with CO2.

  22. Steve Keohane says:

    Steven Mosher says:April 15, 2013 at 8:49 am
    3. Over time the planet will warm, all other things being equal.

    We know things are not equal over time, and certainly not all of them simultaneously, so #3 is moot.

  23. Kajajuk says:

    I cannot keep all this contractive info straight.
    What happen to the observation that the East Antarctica ice sheets are growing?
    http://www.co2science.org/articles/V16/N15/EDIT.php
    And this is from a so called “alarmist” site!

    And the West Antarctic Ice Sheet is warmer than ever?
    http://www.eurekalert.org/pub_releases/2013-01/nsf-pot010313.php

    I can certainly relate with people choosing a side and digging their heels in.

  24. Allencic said:
    April 15, 2013 at 8:59 am
    Why is any so-called “climate research” still being done by the Warmists? It’s always the same result. It’s like asking the old question, “Do bears do you know what in the woods?” And then pay armies of researchers to go around the woods with scoops to get the exact same result.
    ———————————-
    Except that bears and their byproducts are real.

  25. Kevin MacDonald says:

    Chuck says:
    April 15, 2013 at 7:55 am

    “The same is not true for the Antarctic Peninsula, the part of the continent closer to South America, where rapid ice loss has been even more dramatic and where the changes are almost certainly a result of human-caused warming, Steig said.”

    And exactly what is the evidence or does he just know that has to be the case?

    Acceleration of snow melt in an Antarctic Peninsula ice core during the twentieth century.

  26. agfosterjr says:

    The Jorge Montt Glacier on the north end of the Southern Patagonian Icefield got lots of coverage a year ago when time lapse video was released showing its record breaking retreat–82 feet per year (http://vimeo.com/33238262 and http://www.youtube.com/watch?v=hRhnLtFZxso). Some of the coverage made mention of Rivera’s explanation of fjord bathymetry being mainly responsible for the anomalous rate of retreat–the glacier floats for miles in deep water. But I have seen no MSM coverage of the beech logs discovered in 2010 by Rivera, et al, apparent remnants of a beech forest that got covered up in the LIA:
    2011:
    http://www.clim-past-discuss.net/7/3131/2011/cpd-7-3131-2011.pdf

    2012:
    http://www.clim-past.net/8/403/2012/cp-8-403-2012.pdf

    In fact the only mention I have seen of it outside the initial reports is here:
    http://climateaudit.org/2012/06/03/gergis-two-medieval-proxies/
    and here:
    P Gosselin in NTZ:
    http://notrickszone.com/2011/10/16/tree-rings-show-little-ice-age-and-medieval-warm-period-were-global/

    Precipitation over the ice fields varies between 4 and 8 meters of water equivalent per year. This is not the Antarctic desert. A core drilled at Pio 11, one of three glaciers which is growing rather than receding went down 50 meters, at which point ice lenses were replaced by water:
    http://www.glaciologia.cl/textos/rivera99.pdf
    18 O and deuterium analysis gave an age for the core of 6 years [sic], in agreement with estimated precipitation. Extrapolating from this core and calculating from currently measured precipitation it appears likely that the Patagonian Icefields are only two centuries old, give or take a century, that they clearly date from or since the LIA, and that at low elevations ice from the LIA covered up some small beech forests.

    And of course all this shows that the MWP extended to the SH and that the hockey schtick is a sham. –AGF

  27. HelmutU says:

    Why should I believe Mr. Steig? The same Mr. Steig, who manipulated the method so he could show the warming of the whole antarctic.

  28. Joe Public says:

    Steven Mosher at 8:49 am

    “In a nutshell. here is the theory.
    1. GHGs cause warming not cooling.
    2. Humans are putting more GHGs into the atmosphere.
    3. Over time the planet will warm, all other things being equal.”

    Humans putting more CO2 in a Greenhouse results over time in stronger, lusher plant growth, all other things being equal.

  29. agfosterjr says:

    DarrylB says:
    April 15, 2013 at 9:25 am
    ============================================================================
    The short answer is that SLR is not great enough to measure accurately. Traditional tide gauge measurements gave 2.1mm/year; satellites (except ENVISAT) showed 3.1 mm. Comparing apples to oranges we have acceleration, but knowing better, Church and White reanalyzed the gauge data and managed to come up with some slight acceleration, which of course they attribute to anthropogenic causes, else their analysis would have been a waste.

    A small bit of the long answer is that every cm of SLR should increase LOD by .1ms, enough to cancel isostatic rebound effects and then some, but this we do not see–like SLR, it gets lost in the noise. LOD is measured very precisely, but is affected annually by atmospheric angular momentum and decadally by core/mantle coupling. Catastrophic SLR would be easy to measure anyway, but it just continues its 80 year old trend, 2mm/year on average. Continental drift is faster. Coral grows faster. Dust accumulates faster. Populations grow hundreds of times faster than land lost due to SLR. SLR has always been the most easily detectable piece of the GW farce. –AGF

  30. TomRude says:

    That’s THE statement of the day: “The same is not true for the Antarctic Peninsula, … where the changes are almost certainly a result of human-caused warming, Steig said.”

    Yep, Global climate change is very selective: it does influence this 15% surface of Antarctica but not the 85% rest, it does influence some wind patterns but not others…

    Only meteorologically ignorants or dishonnests can subscribe to Steig’s comment without shaking their head in disbelief.

  31. Matthew R Marler says:

    “The magnitude of unforced natural variability is very big in this area,” Steig said, “and that actually prevents us from answering the questions, ‘Is what we have been observing exceptional? Is this going to continue?’”

    It is good to see this admission from him.

  32. Alec Rawls says:

    The same is not true for the Antarctic Peninsula, the part of the continent closer to South America, where rapid ice loss has been even more dramatic and where the changes are almost certainly a result of human-caused warming, Steig said.

    As Steig would know, the Antarctic Peninsula, especially near the tip, where the “rapid ice loss” has occurred, is a volcanic zone, which has contributed an unknown amount to ice melt in the region.

    http://www.sciencedaily.com/releases/2004/05/040527235943.htm

    http://a.cf9.si.edu/volcano.cfm?vn=390050

    Argument by exclusion (the warming has to be human-caused because there is no other cause to attribute it to) is always a weak argument at best, completely invalid at worst, but to invoke it when other possible causes are well known is really beyond the pale. We have seen worse from Steig, but this is still Steig.

  33. Matthew R Marler says:

    Steven Mosher: In a nutshell. here is the theory.

    1. GHGs cause warming not cooling.
    2. Humans are putting more GHGs into the atmosphere.
    3. Over time the planet will warm, all other things being equal.

    Now, at its core the science says nothing about Ice in antarctica does it? At its core the science says nothing about whether it was warmer in the past or cooler. At its core, nothing you can find in antarctica can challenge it.

    In fact, the *simplified* science that you outlined does not say anything in particular about any region in particular over any time span in particular. The “evidence” cited in support of the *simplified* science that you outlined consists (almost?) entirely of selected warming, melting, rainfall, drought etc extremes after they have happened. The mean global warming of the last 150 or so years was “predicted”, yet only the third of the warming epochs (1978-1998, appx) is “attributed to” the CO2 increase, with no a priori intellectual justification for selecting one out of three (like the Ancient Mariner who “stoppeth one of three), or showing that whatever caused the first two of the three has not simply recurred.

    The warming of a portion of Antarctica was presented as evidence of AGW because it was thought to be “unprecedented”. Here, a proponent of AGW who previously cited the selected warming as evidence for the theory has reported that the previously cited warming was not in fact unprecedented. That being the case, now you tell us that even “unprecedented” Antarctic warming should not have been cited as evidence in favor of AGW in the first place.

  34. Willis Eschenbach says:

    Steven Mosher says:
    April 15, 2013 at 8:49 am

    The research says nothing about the truth of AGW.

    In a nutshell. here is the theory.

    1. GHGs cause warming not cooling.
    2. Humans are putting more GHGs into the atmosphere.
    3. Over time the planet will warm, all other things being equal.

    Now, at its core the science says nothing about Ice in antarctica does it? At its core the science says nothing about whether it was warmer in the past or cooler. At its core, nothing you can find in antarctica can challenge it.

    Since in the real world other things are never equal, why would that be a statement about anything but a fanciful model planet, not a real planet?

    Upon this core of the science, however, some folks have built some shakey arguments, particulary arguments about how fast it will warm or how fast it has warmed.

    Since you admit that the “core of the science” you refer to only exists in a fantasy world with “all other things being equal”, and since in the real world a variety of homeostatic emergent phenomena affect the temperature in ways unmentioned in your “core of science”, I fear you are not talking about the real science about the real earth.

    I’m sure your ideas play well in the models, where indeed all other things may be equal … but out here in reality, not so much …

    w.

  35. Chad Wozniak says:

    @ John Tillman –
    Was there ever more profound proof that climate variability is entirely natural and AGW is untrue than what you say here? I don’t think so. Nice summary.

    Incidentally there is plenty of documentation in the historical record for the three prior warm periods you cite, to back up the soil radioactivity analysis. It’s pretty hard to get around that evidence by any sort of modeling or calculatikons. You’d have to destroy the world’s leading libraries to do that.

  36. Eric Barnes says:

    Steven Mosher says:
    April 15, 2013 at 8:49 am

    Now, at its core the science says nothing about Ice in antarctica does it? At its core the science says nothing about whether it was warmer in the past or cooler. At its core, nothing you can find in antarctica can challenge it.

    You’re onto something now mosher.

  37. TimTheToolMan says:

    Mosher writes “In a nutshell. here is the theory.

    1. GHGs cause warming not cooling.
    2. Humans are putting more GHGs into the atmosphere.
    3. Over time the planet will warm, all other things being equal”

    Fail at step one Mosher. GHGs facilitate energy transfer both to and from the atmospheric gasses that cant directly absorb or radiate IR energy (ie N2 and O2)

    That is all. GHGs do not cause warming although they may increase the temperature gradient between the bottom of the atmosphere and the top. With all things being equal. lol.

  38. Louis Hooffstetter says:

    Nice to see this but it’s too little, too late. Eric Steig’s reputation as a legitimate scientist was destroyed by Michael Mann’s statistical shenanigans in Steig, et al., 2009.

  39. Gary Pearse says:

    “Scientists Discover Undersea Volcano Off Antarctica

    Evidence of the volcano came as an unintended bonus from a research plan to investigate why a massive ice sheet, known as the Larsen B, collapsed and broke up several years ago.”

    http://www.sciencedaily.com/releases/2004/05/040527235943.htm

    Global warming? Yes. Anthropogenic Global Warming? Not so much.

  40. Jeff Alberts says:

    Pieter F. says:
    April 15, 2013 at 8:24 am

    Meanwhile . . . add the Arctic and Antarctic sea ice anomalies and we get +608,000 sq.km. more sea ice than the benchmark (1979-2000 mean). The Antarctic is well above the mean, and the Arctic is within 1SD of the mean. Didn’t Al Gore predict that the Arctic would be ice-free in the summer of 2015? I need to reconnect with a few folks and prepare to collect on some bets.

    Actually it went like this: In 2008, The Algore made a statement, probably a bit off the cuff, to a gathering in Germany, I believe it was. He said in 5 years, the Arctic would be 5 years. So, this year is the summer of Al’s discontent.

    FYI, there was a video of his statement which someone had recorded without Al’s knowledge. It was up on Youtube for a while, but he effectively had it cleansed from the web. At least I haven’t been able to find it again.

  41. Gary Pearse says:

    On the subject of glaciers: there hasn’t been ANY MSM reporting on the status of the worlds mountain glaciers “WGMS” that were so much touted up to 4 or 5 years ago. I suspect, in keeping with the flatlining and decline of the last few years in global temps that, on average, glacier retreats have probably begun to “pause”, too.

  42. Kajajuk says:

    Gary Pearse says:
    April 15, 2013 at 7:17 pm
    “On the subject of glaciers: there hasn’t been ANY MSM reporting on the status of the worlds mountain glaciers “WGMS” that were so much touted up to 4 or 5 years ago. I suspect, in keeping with the flatlining and decline of the last few years in global temps that, on average, glacier retreats have probably begun to “pause”, too.”
    ———————————————–
    I suspect the MSM “reporting” are selling something else of late, but the glaciers still weep…
    Unfortunately i could not find any “clean” reporting of the glaciers, that is to say, without a prescribed agenda of causation, sorry, no intent to offend only to refute the quip.

    http://sciencewriters.ca/2013/04/02/whats-behind-that-money-shot/
    http://glacierchange.wordpress.com/2013/02/14/tasman-glacier-retreat-update-2013/
    http://www.sciencedaily.com/releases/2013/04/130408122800.htm
    http://glacierchange.wordpress.com/2013/04/05/porcupine-glacier-retreat-and-lake-expansion-british-columbia/
    http://www.deccanherald.com/content/23845/retreat-himalayan-glaciers.html
    http://glacierchange.wordpress.com/2013/03/15/glacier-posts-through-march-2013/

    But relax, you can simply label the reporters and dismiss the reporting…

    “It is all rock and roll to me”
    kjjk

  43. The same is not true for the Antarctic Peninsula, the part of the continent closer to South America, where rapid ice loss has been even more dramatic and where the changes are almost certainly a result of human-caused warming, Steig said.

    I’ll take Steig seriously when he explains how ‘human-caused warming’ melts icesheets (Larsen A, B and C) surrounded by 200 to 400 km of permanent sea ice that doesn’t melt and that is rapidly expanding.

    See WUWT Sea Ice page.

    Hint: Glacial ice after some surface melt, has a much lower albedo than Antarctic sea ice.

  44. george e. smith says:

    “””””……But in the area where the new research was focused, the West Antarctic Ice Sheet, it is more difficult to detect the evidence of human-caused climate change. While changes in recent decades have been unusual and at the “upper bound of normal,” Steig said, they cannot be considered exceptional…….”””””

    So which is it Professor; is it “unusual”, or is it “normal (not outside upper bounds thereof)”, AKA “usual”, or is it “not exceptional” , AKA “not unusual” ?

    I’d say you have about covered the entire territory there , with your tarbrush like precision.

  45. Phil. says:

    Philip Bradley says:
    April 16, 2013 at 12:43 am
    The same is not true for the Antarctic Peninsula, the part of the continent closer to South America, where rapid ice loss has been even more dramatic and where the changes are almost certainly a result of human-caused warming, Steig said.

    I’ll take Steig seriously when he explains how ‘human-caused warming’ melts icesheets (Larsen A, B and C) surrounded by 200 to 400 km of permanent sea ice that doesn’t melt and that is rapidly expanding.

    The ice sheet is the permanent sea ice, when Larsen B collapsed it had direct contact with the ocean.
    http://earthobservatory.nasa.gov/Features/WorldOfChange/larsenb.php

  46. george e. smith says:

    “””””…..TimTheToolMan says:

    April 15, 2013 at 4:37 pm

    Mosher writes “In a nutshell. here is the theory.

    1. GHGs cause warming not cooling.
    2. Humans are putting more GHGs into the atmosphere.
    3. Over time the planet will warm, all other things being equal”

    Please sir m’seur executioner; I think I can see why your blade simply won’t drop down on my neck; It’s snagged right up there at # 3; all other things, will NOT remain equal !

    So a little drop of oil right there, and you will have my head off in a trice !

  47. jonnie26 says:

    where is the sea level drop that must have preceded the laying dawn of the current ice, after all it has all come off the ocean in the first place,

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