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  1. Eric,

    Thanks for the great article! Great addition to the Northern Hemispheric records…

    P.S. The group in Wisconsin-Madison (led by Elizabeth Colville and Anders Carlson I think) has a couple-year-old paper looking at the presence or absence of Greenland ice in the last interglacial through the determination of sediment sources discharged from southern Greenland. They came to the same conclusions that Greenland couldn’t have caused more than maybe 2 m of sea level. But that means Antarctica had to contribute a significant fraction.

    Comment by Chris Colose — 23 Jan 2013 @ 4:33 PM

  2. Eric, a big remaining issue seems to be the potential effect of warming currents on the outlet glaciers. Are you aware of any research characterizing those during the Eemian?

    Also, re the 1889 event you say it’s found “invariably,” but by that do you mean that it’s found in all the cores? My understanding had been otherwise.

    I have a few more questions but will read ref. 4 first.

    Erratum: Pfeffer et al. (2008) isn’t more recent that Cuffey & Marshall (2010).

    [Response: Cuffey and Marsall was actually 2000; now corrected. The melt layer I referred to is in every core I've ever seen. --eric]

    Comment by Steve Bloom — 23 Jan 2013 @ 4:39 PM

  3. Oops, I meant ref. 6.

    Comment by Steve Bloom — 23 Jan 2013 @ 4:41 PM

  4. Just to add, AFAICT ref. 5 doesn’t address currents.

    Comment by Steve Bloom — 23 Jan 2013 @ 4:55 PM

  5. Thank you!

    Comment by David B. Benson — 23 Jan 2013 @ 5:06 PM

  6. Eric,

    Very nice. One question. If Greenland could not contribute more than 2m to SLR, and there is only 3m of potential SLR present in WAIS, does that mean that East Antarctica was a major contributor?

    [Response: Yes. Unless of course one takes the low-end estimates of SLR at the Eemian, and uses the high-end estimates of the WAIS and Greenland ice sheets. Then you can just balance it without East Antarctica.--eric]

    Comment by Dan H. — 23 Jan 2013 @ 5:51 PM

  7. Can someone explain to me how the surface elevation is derived from the data? I am not clear how this esitmate is made.

    [Response: Air content data mostly. From the paper:

    Before surface melt began between 128.5 and 126.7 kyr BP, the air content at the depositional site had a stable level of 85 ml kg−1 compared to the present level of 97.5 ml kg−1. When corrected for changing local summer insolation, the air content difference suggests a surface elevation at the depositional site 540 ± 300 m higher at the onset of the Eemian (128 kyr BP) than the surface elevation at NEEM today.

    The paper goes on to discuss the corrections for ice flow, which are significant, because the ice at the bottom flowed from a site that was higher. So the actual elevation change they estimate is about 200 m (with a big plus/minus of 350 m!). -eric]

    Comment by John S. — 23 Jan 2013 @ 6:07 PM

  8. Great article, Eric. Thank you.

    What really baffles me is in the Milankovitch cycles, Antarctica seems to respond stronger to Arctic summer insolation (peaking in the Eemian) rather than to its own summer insolation (which was at a minimum during the Eemian).

    And during the glacial periods, when Milankovitch cycles minimize summer insolation over the Arctic and maximize summer insolation over the Southern Hemisphere, Antarctica is gaining ice mass.

    Is there a logical explanation for why Antarctica seems to respond opposite from what its own summer insolation suggests ?

    [Response: Classic answer to this is CO2. MOre complex answer is that it ain't just summer insolation intensity, but actually the radiation balance, which actually does peak locally (in Southern Hemisphere) at the right time. See Huybers and Denton, 2008, "Antarctic temperature at orbital timescales controlled by local summer duration". However, the magnitude of observed change isn't fully explained either way. So this is still an open question.--eric]

    Comment by Rob Dekker — 23 Jan 2013 @ 7:03 PM

  9. Thanks Eric for this detailed, yet accessible explanation of the findings and implications. But I am not sure if this is good news or bad news, regarding the stability of West and East Antarctica. I guess from an adaptation perspective, a steady & more predictable SLR contribution from Greenland is preferable than a much-harder to predict, potentially faster contribution from Antarctica. :/

    Just a small detail I noticed. You say that Greenland “is less sensitive to climate warming than some of the higher-end estimates suggest … though very much in line with more recent estimates (e.g. Pfeffer et al. (2008)).”

    However, Pfeffer et al 2008 do not assess the possible contribution from the Eemian-period, or even Eemian-type conditions. They only assess the potential contribution over the 21th century. Even a much slower rate of mass loss from Greenland could potentially yield several meters of SLR over centuries, I suppose.

    [Response: Agreed. My point in citing Pfeffer et al is simply that they do not believe the sensitivity can be as high as some (e.g. Hansen) have implied. But you are right that it's a bit apples and oranges, because even low sensitivity could give you lots of melt if you have enough time. This is almost ceratinly what happened during Marine Isotope Stage 11 (~400,000 years ago), when it wasn't any warmer than today (probably), yet the entire ice sheet may well have been gone. (you can read about stage 11 in Greenland here, where we are discussing a paper by Anne de Vernal and Claude Hillaire-Marcel, here--eric]

    Comment by perwis — 23 Jan 2013 @ 7:10 PM

  10. Another question, less basic : Do Antarctic ice cores also show melting events similar to what is found in the Greenland cores over the Holocene?

    [Response: Nope. Too cold in most places. And the warmer places where there have been cores drilled (e.g. Antarctic Peninsula) don't have ice of that (Eemian) age. Wait to see results from Fletcher Peninsula (on the Ant. Penin) though, currently being drilled by a British team. We may see very interesting things there.---eric]

    Comment by Rob Dekker — 23 Jan 2013 @ 7:12 PM

  11. Greenland Ice Cores Reveal Warm Climate of the Past
    http://www.sciencedaily.com/releases/2013/01/130123133612.htm
    adds a little, especially the graphic.

    Comment by David B. Benson — 23 Jan 2013 @ 7:14 PM

  12. Thanks for reporting on this really important paper.

    It seems very significant that the +6-7C for 127-121ky matches extremely clsely +6C for Antarctica from Sime’s paper http://www.nature.com/nature/journal/v462/n7271/full/nature08564.html.

    This to me, does seem to be highly indicative a global temperature rise at that time (+3C using 2:1), not purely a local insolation effect.

    Also I wonder what the implications for Arctic sea ice at such temperatures ?

    It would seem there would be a very dramatic reduction given the level of temperature sensitivity that has been observed recently.

    Comment by cumfy — 23 Jan 2013 @ 7:25 PM

  13. Justin Gillis at NYT touched on this issue a bit the other day, with article in Science Times and Green Blog there and while the concept of polar cities is gaining traction year by year, now comes this — vprivate email ….re Richard Alley mentioned in GILLIS temps rise article tells me today THIS: — danny

    http://pcillu101.blogspot.com

    Dear Danny,
    I presume that you are familiar with this one? Not an assessed result
    yet, just one paper

    Sincerely,

    http://www.pnas.org/content/early/2010/04/26/0913352107.abstract

    An adaptability limit to climate change due to heat stress –
    Steven C. Sherwood, and Matthew Huber

    Comment by Dan Bloom — 23 Jan 2013 @ 7:59 PM

  14. I just finished reading “The Whole Story of Climate” by E. Kirsten Peters. She shows the ice core temperature curves for the past 400,000 years and says to notice the sudden jagged lurches up and down. She says that the climate acts like a drunk walking down the street. It can fall in any direction at any time, so you can’t predict it just because you know that CO2 is increasing.

    What is your take on E. Kirsten Peters? Are there reasons for those sudden changes or is it purely chaos? E. Kirsten Peters seems sometimes to be slightly denialist but then not. I think she may have a point that there could be a lot of chaos involved, but there could instead be reasons for lurches that we cannot find because “the trail has gone cold.”

    E. Kirsten Peters says that some of the lurches happen as fast as 3 years from hot to cold or cold to hot. So we have been lucky, but she also says that agriculture, especially rice farming, supplied just enough CO2 to prevent a slide into major glaciation. That seems to be a contradiction of her other statement. So maybe we can engineer a stable climate. But at the end of the book, she says that we should learn to live with instability.

    ???

    [Response: Haven't read the book, but my impression from write-ups about it is that she falls into the confused trap of thinking "other things affect climate, so CO2 can't be important". That's just plain silly. The analogy with a drunk in the street is fine for natural climate variability, but the relevant point would then be that there is a car about to run him down, which rather changes the situation. --eric]

    Comment by Edward Greisch — 24 Jan 2013 @ 1:35 AM

  15. Two typos:

    1. “about climate form it” to “about climate from it”.
    2. “Eeemian” to “Eemian”

    [Response: Thanks; fixed! --eric]

    Comment by Michal — 24 Jan 2013 @ 7:03 AM

  16. Another important caveat worth mentioning is that the warming during the Eemian occurred over many centuries, with global surface temp likely no more than 1 degree C above pre-industrial.

    We are seeing significant changes in Greenland ice melt with ~0.8C rise in just a few decades.

    The more I learn about the Eemian, the more I shudder.

    Comment by Steve Brown — 24 Jan 2013 @ 7:45 AM

  17. Nice commentary on the new NEEM results Eric! However, if you look at Born & Nisancioglu, TC, 2012 you will notice that 4m of Greenland ice melt during EEM does not require a significant lowering of the ice surface at the NEEM ice core site. Unlike previous model studies we find that the northern most part of the Greenland ice sheet is particularly sensitive to a warm interglacial climate.

    http://www.the-cryosphere.net/6/1239/2012/tc-6-1239-2012.html

    [Response: Thanks Kerim. That's really interesting, and probably deserves another post.--eric]

    Comment by Kerim H. Nisancioglu — 24 Jan 2013 @ 8:10 AM

  18. Steve Brown -

    Actually, I see this as fairly good news, in that is shows that rapid collapse of the GIS is unlikely. A response based on in-situ melting would at least have the virtue of being slow on human timescales.

    On the other hand, it does point a finger at the WAIS as a bigger source of variability.

    And all of these studies are looking at the results of orbital forcing, not CO2-forcing. My impression (anyone feel free to correct) is that orbital forcing means more sunlight – basically higher daytime temperatures and warmer summers. GHG forcing is more about higher nighttime/winter temperatures, with polar amplification. This does mean that prior interglacials are not a perfect analog for current warming.

    Comment by Andrew Dodds — 24 Jan 2013 @ 8:20 AM

  19. Thank you for an excellent post. I am reading the article, and this is really good reference.

    Comment by Halldór Björnsson — 24 Jan 2013 @ 8:59 AM

  20. Andrew Dodds – It may be some good news for the estimate of the Greenland sea-level contribution, but there is good evidence that there was 6-9m of sea level rise around the Eemian climatic optimum in tandem with a +1C global average surface temp. The slight warming from the increase in N. Hemisphere insolation was amplified by the ice-albedo feedback loop. We are getting similar ice-albedo feedback warming from GHG forcing with at least +2C coming our way in the next century and only the thermal inertia of the ice-caps to act as a buffer.

    Comment by Steve Brown — 24 Jan 2013 @ 9:49 AM

  21. Will any of those who are not among the banned wander over to Tony’s place and point (gently of course) to the creative editing that leads his readers astray?

    [Response: Who? ;) --eric]

    Comment by Eli Rabett — 24 Jan 2013 @ 11:13 AM

  22. Eric, good write up. I would like to point out, however, that a study of ours reached the same conclusions reached by the NEEM project, which we published in 2011 in the journal Science (Colville et al., 2011, Science, v. 333, p. 620-623). Using marine sediment archives, we showed that a substantial Greenland Ice Sheet had to persist through the last interglaciation, contributing only 1.6-2.2 m to the sea level high stand of >4 m. From this data, we concluded that the Antarctic Ice Sheet had to contribute >1 m to the high stand (after accounting for ocean thermal expansion and Arctic ice cap contributions). It is reassuring to see that a later study using an entirely different geologic archive has arrived at the same conclusions as our study.

    [Response: Indeed. I did not mean to imply that this was a "first". It is merely a "first" with ice core data. --eric]

    Comment by Anders Carlson — 24 Jan 2013 @ 11:31 AM

  23. > [Response: Who? ;) --eric]

    You had to ask! Someone there just invited the whole gang here to help explain your papers.

    Comment by Hank Roberts — 24 Jan 2013 @ 2:57 PM

  24. I haven’t read the article yet, so forgive my ignorance. The rebound of the earth’s crust under Greenland was surely taken into account by these researchers when figuring melt volumes. That means that the more agressive melting likely under future higher temps and the lack of time for rebound may result in lower ice sheet elevations than seen during the Eemian despite equal melting, thus leading to more melt?

    Though the temperature difference between winter and summer would be greater under the NH solar-forced Eemian Greeland melting regime. Meaning what? Less melting today even though average yearly temps in Greenland may eventually be equal to the Eemian’s? You’re post today is very interesting, but I don’t have the knowledge to fill in the gaps.

    Comment by Andy — 24 Jan 2013 @ 4:04 PM

  25. Edward Greisch @14 — I know E. Kirsten Peters. While she has written some highly entertaining detective stories, I fear her (quite good) understanding of geology has not carried over to a particularly good book on climate. In particular, I’ll state that she doesn’t seem to understand D-O events including just how localized to the far north those were.

    [Response: Indeed, the rapid warming D-O events centered on the N. Atlantic region are often assumed (or prentended) to be global (which is totally wrong) by people trying to make claims without learning anything first. Don Easterbrook comes to mind. --eric]

    Comment by David B. Benson — 24 Jan 2013 @ 5:30 PM

  26. Another typo? “I’m prompted to do so by the publication in Nature today (January 23, 2012) of another new finding about Greenland melt. “

    [Response: That would explain my cheques bouncing! --eric]

    Comment by Mal Adapted — 24 Jan 2013 @ 9:12 PM

  27. Puzzling over “A key difference is that CO2 was not as high as today, but insolation forcing was much higher.”
    What might this mean, more or less melt should be expected? More summer insolation means less in winter; so, you might expect more extreme temperature differences between winter and summer. More CO2 means less differences between summer and winter, as well as less diurnal differences. I’m thinking insolation and CO2 work on different functions, and it probably would not be possible to categorically say one is more or less. Under higher insolation conditions, summertime highs could lead to more frequent melt events without drastically changing the mean annual temperature.

    I don’t suppose it is possible to detect differences in O18 within a year. If not, it may be difficult to tell the difference between generally warmer conditions, or just very warm summers. Is there a bias in how much precipitation falls in winter versus summer?

    Just puzzling.

    [Response: Please read the paper, or at least the abstract below. The key point is that direct solar radiation can provide lots of heat to surface, without the ambient air temperature being high. Go outside on a calm, cold, but very sunny day, and you'll get a sense of this. It turns out that these sorts of details matter. Here's another sort of striking comparison, to illustrate the point about insolation. CO2 forcing today is only ~2 W/m^2. Insolation forcing at the peak of the Eemian was ~40 W/m^2 in midsummer.

    Abstract from van de Berg et al.:

    During the Eemian interglacial period, 130,000 to 114,000 years ago, the volume of the Greenland ice sheet was about 30–60% smaller than the present-day volume. Summer temperatures in the Arctic region were about 2–4 K higher than today, leading to the suggestion that Eemian conditions could be considered an analogue for future warming, particularly for the future stability of the Greenland ice sheet. However, Northern Hemisphere insolation was much higher during the Eemian than today, which could affect the reliability of this analogy. Here we use a high-resolution regional climate model with a realistic ice-sheet surface representation to assess the surface mass balance of the Greenland ice sheet during the Eemian. Our simulations show that Eemian climate led to an 83% lower surface mass balance, compared with the preindustrial simulation. Our sensitivity experiments show that only about 55% of this change in surface mass balance can be attributed to higher ambient temperatures, with the remaining 45% caused by higher insolation and associated nonlinear feedbacks. We show that temperature–melt relations are dependent on changes in insolation. Hence, we suggest that projections of future Greenland ice loss on the basis of Eemian temperature–melt relations may overestimate the future vulnerability of the ice sheet.

    --eric]

    Comment by Chris G — 24 Jan 2013 @ 11:51 PM

  28. Eli ‘the most esalted’ Rabitt asked: “Will any of those who are not among the banned…”. Went there anyway. Won’t repeat the garbage sent here in the science site.

    Comment by jyyh — 25 Jan 2013 @ 1:43 AM

  29. Eric writes, inline #27:
    “CO2 forcing today is only ~2 W/m^2. Insolation forcing at the peak of the Eemian was ~40 W/m^2 in midsummer.”

    But averaged over the globe this difference is much smaller, or zero, right? What would that mean for (regional) ocean temps then and now, and for their potential impact on GIS melting?

    Comment by Lennart van der Linde — 25 Jan 2013 @ 2:15 AM

  30. Picking up on Chris G’s comment….

    I am curious whether whether ice core temperature estimates can be biassed high (perhaps significantly) due to higher amounts of summer vs winter precipitation.

    This is particularly important in interglacials where the orbital configuration provides the greatest potential difference both between temperatures and hydrological cycle comparing summer to winter.

    What are the assumptions used regarding the relative amount of summer and winter precipitation ?

    Comment by cumfy — 25 Jan 2013 @ 6:19 AM

  31. One clarification: the abstract said 8 C warmer than the average of the last millennium. That average is significantly different than the present temperature (say over the last decade). Their baseline is going to look a lot more like what we take to be pre-industrial.

    Ignoring the interesting issues related to surface temperature energy transfer compared to radiative transfer from insolation (which ought to account for albedo effects before comparing 2 W/m^2 with 40 W/m^2), a naive approach would be to adjust the temperature difference for the lapse rate from 8 C to 7 C and divide by 2 to account for Arctic amplification to get 3.5 C as the comparable global average warming above pre-industrial. Since BAU takes us well beyond that level of warming, feeling sanguine about future ice mass loss in response to these findings seems unsupported.

    Comment by Chris Dudley — 25 Jan 2013 @ 11:14 AM

  32. Prof. Steig writes:
    ” CO2 forcing today is only ~2 W/m^2. Insolation forcing at the peak of the Eemian was ~40 W/m^2 in midsummer. ”

    Is it not true that the 2W/m^2 CO2 forcing operates _all the time_ including in winter and at night ? What are the integrated effects of the Eemian insolation forcing as compared to current CO2 forcing over the entire year ? I have a rudimentary calculation for this, but I would appreciate detail.

    sidd

    [Response: Yes, of course. The mean annual change in insolation at the Eemian is tiny (haven't looked it up but probably less 0.5 W/m^2). But we're talking about melting, which is a summertime phenom, so the comparison I made is the most relevant one. Again, take a look at the paper I linked to in Nature Geosci. about insolation vs. temperature on ice surface mass balance..--eric]

    Comment by sidd — 25 Jan 2013 @ 1:58 PM

  33. Not discussed is that during the Eemian and Holocene, climate/weather was subject to much lower forcing then currently. And, during the Eemian and Holocene the level of forcing did not change as rapidly as ice sheet forcing has changed has over the last 30 years. With ongoing loss of Arctic sea ice, GIS forcing is likely to increase even more rapidly over the next 30 years.

    Changes in atmospheric circulation patterns resulting from changes in Arctic Sea Ice were likely a major factor in the 2012 GIS Melt Event. Unless there is an abrupt recovery of Arctic Sea Ice resulting in global atmospheric circulation patterns reverting to patterns typical of the Holocene, major Greenland melt events are likely the new normal. However, because high rates of forcing increase the number of extreme events, the GIS could see a large number of large melt events long before the average temperature approaches that of the Eemian.
    On Jan 23, 2013, as North America suffered intense cold, Ilulissat, Greenland was 41F. The day before it was 43F. The day before, it was 39F. The day before, it was 39F. Do I need to go on? For the most part these are not records, but mostly the records for these dates were set in the last 5 years. The 2007 sea ice melt was a sea change for the climate of Greenland. Record warmth, with the new records being broken every few years is the new normal for Greenland.

    Comment by Aaron Lewis — 25 Jan 2013 @ 2:01 PM

  34. Eric Steig wrote:
    ” the rapid warming D-O events centered on the N. Atlantic region are often assumed (or prentended) to be global (which is totally wrong) by people trying to make claims without learning anything first. Don Easterbrook comes to mind.”

    Didn’t Easterbrook provide evidence that supported his assertion of more widespread temperature increases from his own work with PNW glaciation? I am very curious what evidence you have that supports the statement that he is “totally wrong.”

    [Response: Start here perhaps: http://www.realclimate.org/index.php/archives/2006/11/revealed-secrets-of-abrupt-climate-shifts/ --eric]

    Comment by Matt Skaggs — 25 Jan 2013 @ 2:12 PM

  35. Eric, I am not trying to disparage the work of the team; I think it is a huge accomplishment. I’m simply trying to fill some holes in my understanding. And yes, I am familiar with the sensation of being warmed by the sun on a cold day, and, as Chris Dudley notes, I’m also aware that the magnitude of the effect is greatly affected by the albedo of the clothes I’m wearing.

    Lennart van der Linde, cumfy, and Chris Dudley have already stated part of what was in my mind.

    Other thoughts:

    On insolation and surface melt. I was wondering about 18O ratios, which is influenced by temperature of the atmosphere, and if, as you say, the surface can be warmed without greatly affecting the atmosphere, then we are talking about different things. Also, I’ve not yet read where surface melt is directly linked to ice sheet mass loss.

    If we are at 2 W/m^2 forcing currently, I think it is safe to say we will be somewhere more than that by the time we quit adding CO2 to the atmosphere. I’m more worried about where we are going than where we are, and I’m a little perturbed by the comparison of the insolation forcing unadjusted for ice albedo with the current forcing rather than probable future forcing. We are talking about potential future ice mass loss after all.

    Glacial outflow. It is my understanding that warmer ice is less viscous than colder ice. I think you don’t have to go very many meters down to reach a level where the temperature stays pretty consistently correlated with the surface yearly average. So, I’m wondering if being slightly warmer year round might have more of an effect than being very warm in one season. I don’t know if winter would be any colder or not during periods of high summer insolation.

    Precipitation bias. I don’t have access to the original article; so, I can’t tell if this was ferreted out with the climate model they used. For myself, I’m not going to guess whether there is a cool bias or a warm bias, but I do think it would be remarkable if the region received a uniform (or it least symmetric with hot and cold seasons) distribution of precipitation during a year. I doubt that a bias would be extreme enough to push the actual value outside of their confidence interval, but if it could be estimated, it would be interesting to know if the probability function were skewed toward the high or the low end.

    Having said all that, this seems like a nice solid piece that is compatible with Greenland being more stable than Antarctica, or at least the WAIS. That seems to be the growing consensus.

    Comment by Chris G — 25 Jan 2013 @ 3:59 PM

  36. Since this paper first came to notice by press release and Nature‘s online notice I’ve been looking at the headlines and stories in the larger media, gauging the reaction. There’s quite the spread of headlines on this story, many are quite extreme in the sense the headlines are communicating (though deliberate choice of words) that ice melt isn’t important anymore.

    Combine these stories with today’s press release from the RCN:
    http://www.eurekalert.org/pub_releases/2013-01/trco-gwl012513.php? , which taken out of context says there’s nothing to worry about, and those entities who want to scuttle any effort by the US government to take action on climate change have plenty of fodder the next few years by which to confuse the electorate.

    Communicating science to the general public is difficult enough, given the audience’s lack of specialized language in the subject field, but stories about ice melt seem especially prone to confusing, and exaggerated, headlines. Maybe this is because most people can identify with “ice” versus more esoteric topics (cosmic rays, chaos, sulfates, etc.), and so media outlets run with stories about “ice”. I do know that popular communication on this topic is a mess.

    Comment by freetoken — 25 Jan 2013 @ 5:41 PM

  37. GREENLAND
    By ANKER WEIDICK
    With a section on
    LANDSAT IMAGES OF GREENLAND
    By RICHARD S . WILLIAMS, Jr., and JANE G. FERRIGNO
    SATELLITE IMAGE ATLAS OF GLACIERS OF THE WORLD
    Edited by RICHARD S. WILLIAMS, Jr., and JANE G. FERRIGNO
    U.S.GEOLOGICAL SURVEY PROFESSIONAL PAPER 1386 – C
    http://pubs.usgs.gov/pp/p1386c/p1386c.pdf
    was certainly worth looking through.

    Comment by David B. Benson — 25 Jan 2013 @ 6:51 PM

  38. I found it helpful to compare the bedrock elevations:
    http://nsidc.org/data/atlas/news/bedrock_elevation.html

    Comment by David B. Benson — 25 Jan 2013 @ 10:52 PM

  39. Here is some nice stuff from Box and the usual suspects again
    http://www.arctic.noaa.gov/reportcard/greenland_ice_sheet.html

    I see that melting season is longer (27-45 days longer in S and NW Greenland), not so much just in full summer anymore

    And I note that we have an empirical test coming up of Gregoire et al. (Nature, 487, 2012) seeing that ELA has exceeded saddle altitude at 67N
    Fig 5.13 and Fig 5.14 ought to be compared with Gregoire Fig 3
    I wonder if Gregoire et al. thought they would live to see this test ?

    sidd

    [Response: I'm not so sure the saddle you refer to is comparable in nature to the saddle across Hudson's Bay that Gregoire et al. were modeling. Still, it is an interesting point. --eric]

    Comment by sidd — 26 Jan 2013 @ 1:34 AM

  40. Eric writes, inline @32:
    “The mean annual change in insolation at the Eemian is tiny (haven’t looked it up but probably less 0.5 W/m^2). But we’re talking about melting, which is a summertime phenom, so the comparison I made is the most relevant one.”

    Yes, but how about the potential influence of the oceans under strong CO2-forcing, such as today? Couldn’t that make up, at least in part, for the much smaller insolation? For example by melting arctic sea ice, by enhancing calving (as far as that goes) and by letting warmer air above the ocean reach GIS?

    This seems to be the line of reasoning of Jim Hansen to explain how the higher Eemian insolation could today be compensated by higher global mean CO2 forcing still reaching GIS. How plausible is this reasoning?

    [Response: All those processes are happening in reality, so Hansen is not wrong. I'm by no means saying that CO2 forcing can't and won't result in Greenland ice sheet mass loss. It probably has already, and certainly will in the next century. I'm merely saying that because the forcing (insolation vs. CO2) is very different, the Eemian really cannot be used as a direct analog. --eric]

    Comment by Lennart van der Linde — 26 Jan 2013 @ 3:34 AM

  41. What about the ocean thermal expansion during this period with +8°C ?

    “The sea-level rise is about 0.1 meters per Celsius degree change in temperature for the top well-mixed 500 meters at the surface of the oceans. This mixing probably has a time constant for absorbing heat from the atmosphere of about a decade.
    •The lower average depth of 3300 meters probably has a time constant for absorbing heat from the top layer of about 1000 years; heating it by one Celsius degree would raise the sea level by about 0.6 meters.”
    http://www.roperld.com/science/sealevelvstemperature.htm

    Comment by Elisabeth — 26 Jan 2013 @ 7:17 AM

  42. What about ocean thermal expansion during this period ?
    + 8°C in the Arctic, what does it means for global average temperature and for ocean thermal expansion ? +3 °C ?
    3°C x 0.6 meters/°C = 1.8 meters. +4°C ? 2.4 meters.

    Global sea leveal rise: + 4 – 6 meters
    Greenland contribution: +2 meters (2013 study)
    Expansion: +1.8 meters (or 2.4 meters)
    Moutain glaciers: ?
    Antarctica: ?

    “The sea-level rise is about 0.1 meters per Celsius degree change in temperature for the top well-mixed 500 meters at the surface of the oceans. This mixing probably has a time constant for absorbing heat from the atmosphere of about a decade.
    •The lower average depth of 3300 meters probably has a time constant for absorbing heat from the top layer of about 1000 years; heating it by one Celsius degree would raise the sea level by about 0.6 meters.”
    http://www.roperld.com/science/sealevelvstemperature.htm

    Comment by Elisabeth — 26 Jan 2013 @ 7:24 AM

  43. Does the article take into account the impact of contemporary anthropogenic soot on the albedo of Greenland and the Arctic? Isn’t anthropogenic soot half of the current warming problem in the Arctic?

    Comment by slow — 26 Jan 2013 @ 7:39 AM

  44. Elisabeth (#41),

    The global average temperature during the Eemian was similar to the pre-Anthropocene millennium though global average sea surface temperatures may have been slightly higher. The +8 C discussed here is for the extreme North, not the whole globe. http://en.wikipedia.org/wiki/Eemian

    Comment by Chris Dudley — 26 Jan 2013 @ 8:40 AM

  45. Prof. Steig: Fig 3 in Gregoire refers to the separation of the Laurentide and Cordilleran domes, not the domes around Hudson Bay, which are discussed later, but I agree that GRIS is not directly comparable to either. Nevertheless, it is interesting to note that just before separation of the two domes in Gregoire Fig. 3, saddle is dropping at 100m/yr over the last century. Fig. 5.14 in Box shows about 10 times smaller rate of altitude loss so we would be at the very beginning of the putative saddle collapse process.

    It would be interesting to rerun the Gregoire model for GRIS with Glimmer-CISM for ice and MAR for forcing according to regional reconstruction, as in Tedesco, and see what happens.

    sidd

    Comment by sidd — 26 Jan 2013 @ 12:36 PM

  46. gaa! Now I slip an order of mag. The correct statement is

    “Fig. 5.14 in Box shows about 100 times smaller rate of altitude loss so we would be at the very beginning of the putative saddle collapse process.”

    sidd

    Comment by sidd — 26 Jan 2013 @ 3:10 PM

  47. all rite, i officially cannot count. The Box graf shows 1m/10yr drop in altitude. The Gregoire paper shows 100m/yr over the last century of saddle collapse. That is _three orders_ of magnitude, not one or two.

    Moderattors, please feel free to delete my first, incorrect, “correction.”
    sidd

    Comment by sidd — 26 Jan 2013 @ 3:23 PM

  48. DarkSnowProject.org say

    Some of this soot is transported through the atmosphere and is deposited on glaciers, lowering their reflectivity, increasing solar energy absorption, increasing melt rates. Industrial activity including shipping also increases soot content of the atmosphere, eventually darkening snow and ice surfaces.

    Is this relevant to the Greenland melt?

    Comment by GeoffBeacon — 27 Jan 2013 @ 5:56 AM

  49. I think the answer to that question is the rationale for the DarkSnowProject’s existence

    The “Burning Question”
    While watching wildfires raging across his home state of Colorado, climatologist Jason Box was struck – could the dark wildfire soot contribute to the Greenland melting?

    Box is looking for funding to collect and analyze the data.

    Comment by WebHubTelescope — 27 Jan 2013 @ 11:07 AM

  50. I think the answer to that question is the rationale for the DarkSnowProject’s existence

    The “Burning Question”
    While watching wildfires raging across his home state of Colorado, climatologist Jason Box was struck – could the dark wildfire soot contribute to the Greenland melting?

    Box is looking for funding to collect and analyze the data

    Comment by WebHubTelescope — 27 Jan 2013 @ 11:08 AM

  51. > DarkSnow … Is this relevant?

    The DarkSnow info page, down at the bottom, says:

    “Questions and comments on the Dark Snow Project
    should be directed to:
    Jason E. Box, PhD,
    Associate Professor, Geography
    Atmospheric Sciences Program
    Researcher at Byrd Polar Research Center ….”

    Comment by Hank Roberts — 27 Jan 2013 @ 11:43 AM

  52. > DarkSnow
    Nice setup, takes donations via PayPal.

    Comment by Hank Roberts — 27 Jan 2013 @ 11:52 AM

  53. And Box’s recent research is linked from the DarkSnow page:

    http://www.the-cryosphere.net/6/821/2012/tc-6-821-2012.html
    The Cryosphere, 6, 821-839, 2012
    http://www.the-cryosphere.net/6/821/2012/
    doi:10.5194/tc-6-821-2012
    Greenland ice sheet albedo feedback: thermodynamics and atmospheric drivers

    Comment by Hank Roberts — 27 Jan 2013 @ 11:55 AM

  54. why would they park a front loader on a bridge?

    [Response: Good question! The front loader was on the bridge building up berms to try to save the bridge. Kind of a fools errand if you ask me, both because it was never going to work and because it was risking lives. What beats me is -- as you ask -- why did they then LEAVE it on the bridge. There are some impressive video e.g. http://www.greenlandmelting.com/1/post/2012/7/video-of-watson-bridge-at-kangerlussuaq-on-july-21-2012.html and http://www.youtube.com/watch?v=kKjXKAatiIs. I've stood on that bridge in normal conditions and it always gives me vertigo. There's also a video somewhere showing the loaders trying to save the bridge, and it's pretty obvious they should not be there; can't find it at the moment.]

    –eric

    Comment by tt — 27 Jan 2013 @ 5:43 PM

  55. Perhaps they were working on the bridge and went too long. Then they realized the bridge was too weak to support the machine to try to escape. They would park in the safest position and run for it before the bridge collapsed.

    [Response: Well, now we're both speculating about what "really" happened. Back to the climate aspect: this bridge was built in the late 1950s, so this was unequivocally the maximum flow it had had to deal with.--eric]

    Comment by Michael Sweet — 27 Jan 2013 @ 7:19 PM

  56. Found this video, looks like there had been some collapse (undermining?) of the bridge, involving the loader, prior to its abandonment. Looking at the berm, yeah, you have to wonder what that was supposed to accomplish. http://www.youtube.com/watch?v=WrIX-WzWA8k

    Comment by Chris G — 27 Jan 2013 @ 10:49 PM

  57. WebHubTelescope, Hank Roberts

    I was wondering if Dark Snow had any consequences for the Dahl-Jensen et.al. paper.

    Wildfires may have happened in the Eemian but I don’t suppose industrial pollution and diesel exhaust did.

    Is the answer to my question “Don’t know”?

    Comment by GeoffBeacon — 28 Jan 2013 @ 3:29 AM

  58. Eric, you say ‘…A key difference is that CO2 was not as high as today, but insolation forcing was much higher.’

    I imagine that the ‘bad’ side of that observation is that our present higher CO2 means the surface temperatures will persist higher over night, while an insolation forcing has most of it’s effect only when the sun is shining.

    So today’s higher CO2 is a gift that keeps on giving energy to the icecap 24/7, while insolation via orbital variations is mitigated partly by the day/night effect.

    Comment by Nigel Williams — 28 Jan 2013 @ 5:30 AM

  59. I don’t understand how one forcing is different than another. Why is the energy from CO2 different from a change in albedo. Is that standard metric of W/m2 an insufficient description of the processes?

    Comment by Jeffrey Davis — 28 Jan 2013 @ 9:08 AM

  60. Jeffrey,
    I’ll take a stab, although I’m sure there are others who could do better.

    A lot has to do with the distribution of the forcing. For instance, Eric refers to the 40 W/m^2 of insolation forcing during the Eemian in comparison to 2 W/m^2 due to current CO2 (and equivalent?) loading. The first number actually comes from the forcing as measured at 65 degrees latitude; globally averaged, it is zero. (The earth still casts the same size shadow; but the higher tilt exposes north and south extremes to more direct sunlight.) So, you only get regional effects directly. Now, if those regional effects cause other changes, such as a change in albedo (ice melts), then you can get global effects indirectly.

    In addition to spatial distribution, there is distribution over time. Polar winters are continuously dark; there is no positive forcing in the winter, and albedo counts for little.

    Also, the albedo state of the surface matters. Ice would reflect most of the 40-watt solar forcing, but when it melted, water would absorb most of it. I suppose when the earth was in a snowball state, orbital variations had little effect because a) most of the surface had a similar, high albedo, b) whatever effect they did have was not enough to raise the temperature of the ice enough to start melting. I guess this goes back to ‘feedbacks are everything.’ If high seasonal insolation occurs when ice is near a melting point, it can have a much larger effect than when it doesn’t.

    At a finer grain, you also have different absorption spectra for different surface materials. So, a given amount of energy in the solar wavelength band may or may not have the same effect as the same amount of energy in the IR band. There is a spectral graph here: http://frienergi.alternativkanalen.com/Water_Atoms.htm

    So, no, this measurement is fine for the broad strokes, but it is not enough to paint the whole picture.

    Comment by Chris G — 28 Jan 2013 @ 11:54 AM

  61. Geoff, did you ask at the Dark Snow website?
    I don’t know the answer to your question,
    but I’m not the right person to ask.

    Comment by Hank Roberts — 28 Jan 2013 @ 2:12 PM

  62. Dear RC

    I am thinking that regardless of these results sea levels are rising and EAIS, WAIS and Greenland are shedding additional ice into oceans at a increasing rate. By the end of the 21st century with BAU practices on going we are lookng at 1 ft to 1 metre of average sea level rise. Its nice to know that Greenland might be more stable but it looks like WAIS is not as its not grouned on rock as much for example.

    Still a bleak future

    Comment by pete best — 28 Jan 2013 @ 3:26 PM

  63. Elisabeth, #41, #42,
    I think you make an excellent point taking thermal expansion during the Eemian into account.

    Your assumption of Eemian global deep ocean warming of 3 C (wrt pre-industrial) may be a bit on the high side, although I could not find any evidence for or against that assumption. But logically speaking, if even Antarctica warmed significantly due to a higher of Arctic insolation during the Eemian, then warming (and thermal expansion) of the rest of the planetary oceans cannot be discarded.

    It seems to me that if your numbers are anywhere close to actual ocean expansion during the Eemian, then having minor ice in Antarctica seems likely, or at least well within the uncertainty margins of the observations.

    Comment by Rob Dekker — 28 Jan 2013 @ 7:32 PM

  64. Pete,
    While it is possible that sea level rise good increase to those rates, the current rate would only result in about 7 in. by 2100. Without a large contribution from either Greenland or Antarctica, those levels are a tad high. Eric’s work shows a more stable GIS, but the WAIS is only showing instability around Pine Island. Greater melt would need to occur in order to attain the higher levels you mention.

    [Response: WAIS is showing instability *everywhere*. The Pine Island Glacier area is simply the area where the changes are largest, and where the most intensive in situ research has been done. Note by the way that there is no such place as "Pine Island". That was the name of the ship, after which Pine Island Glacier and Pine Island Bay were named. --eric]

    Comment by Dan H. — 28 Jan 2013 @ 9:53 PM

  65. Rob (#63),

    Based on delta 18-O there does not seem to be much evidence for a warmer deep ocean in the last interglacial compared to now. http://en.wikipedia.org/wiki/%CE%9418O

    Comment by Chris Dudley — 29 Jan 2013 @ 11:09 AM

  66. New readers should review previous extensive contributions on sea level by “Dan H.” — https://www.google.com/search?q=site%3Arealclimate.org+dan+h.+sea+level

    Comment by Hank Roberts — 29 Jan 2013 @ 11:53 AM

  67. Eric,
    I am aware of the conventional naming, and probably should have phrased my response differently. Instability in the WAIS is largely confined to the Amundsen coast. The Thwaites glacier showed both rapid advances and retreats over the past three decades, which is likely due to oceanic changes.

    Those glaciers terminating in the Ross or Weddell sea are relatively stable. Granted, the ice shelves are a major player in their stability. Do you have any reason to suspect that these regions would exhibit changes similar to those in the Amundsen Sea?

    [Response: I didn’t mean to imply lack of knowledge on your part; was just adding detail in case readers go confused. Yes, you are right of course — it’s mostly the Amundsen Coast — but it’s all of the Amundsen Coast. Thwaites and PIG have both fluctuated, and both have been forced by the ocean. Together, they drain about 20% of the ice sheet, so they alone matter. I agree with you about Ross and Filchner Ronne — they flow into cold water and I don’t think instability there is nearly as likely and certainly not detectable now. For a different view though, see Hellmer et al. (written up here, for example: http://www.rtcc.org/weddell-sea-region-in-west-antarctic-could-be-on-brink-of-change/>/a>

    Comment by Dan H. — 29 Jan 2013 @ 1:25 PM

  68. Re #64

    7 inches, thats not the projections stated in the IPCC FAR report and they did not take into account anything but thermal expansion of the oceans. I believe it has been commented on here in several good articles. 1 Meter is not that high a probability for ice melt is accelerating (or certainly has been) in recent decades.

    Comment by pete best — 29 Jan 2013 @ 2:23 PM

  69. Google:

    … Instability in West Antarctic Ice Sheet

    http://www.utexas.edu/news/2012/05/10/ice_sheet/

    “… beneath the West Antarctic Ice Sheet (WAIS) near the Weddell Sea. The location, shape and texture of the mile-deep basin suggest that this region of the ice sheet is at a greater risk of collapse than previously thought….
    “… we could find no other region in West Antarctica more poised for change than this newly discovered basin at the head of the Filchner-Ronne Ice Shelf.”

    Comment by Hank Roberts — 29 Jan 2013 @ 4:26 PM

  70. Cite for that UTexas paper posted in the 2013 Sea Level Rise topic, rather than go further off Greenland discussion.

    Comment by Hank Roberts — 29 Jan 2013 @ 4:37 PM

  71. OK Eric,
    I think we are in agreement. Yes, others have speculated about what could occur, but this is largely guesswork at this time. By the time that we start seeing changes in these areas, it is likely that larger problems will have inundated us.

    [Response: Indeed. ---eric]

    Comment by Dan H. — 29 Jan 2013 @ 4:57 PM

  72. This is slightly off topic, so i ask the moderators to move the comment if it seems appropriate.

    I have been thinking about PIG/Thwaites in the context of CDW and retrograde submarine/sub-ice bed. As i understand the Schoof treatment of the Weertman instability, the temperature of ice/water interface is at the pressure melting point, which increases with depth. But we see that the melt is driven under PIG/THW by (warming) CDW which is hotter. As the bed becomes deeper inland, the temperature difference between CDW and pressure melting point increases, ie the heat available to melt ice at the bed is larger, so to me this would exacerbate the already very strong instability. Is this incorporated into a more modern treatment ?

    sidd

    [Response: This is indeed true, and is incorporated into modern treatments. Some of the thermodynamic arguments you are raising are treated in a paper or three by Chris Little (let me know if you can't find them), and are incorporated into a three dimensional-coupled-ocean-ice framework work by Olga Sergiekno. The latter is in review but I expect will be out some time in the next few months. --eric]

    Comment by sidd — 29 Jan 2013 @ 6:00 PM

  73. > likely … larger problems will have inundated

    Inundation-wise, literally, is -any- problem larger than the WAIS?

    I thought the WAIS the be-all and end-all of inundation sources but for the East.
    http://ars.els-cdn.com/content/image/1-s2.0-S0031018211002732-gr1.jpg
    http://www.sciencedirect.com/science/article/pii/S0031018211002732

    Looking at those deep images of the actual topography under the ice — the deep valleys with incised drainage channels all leading out toward the edges, and the smooth, broad fans of extruded glop around Antarctica — you can see the push the ice made shaped everything. Melting will reshape everything, no?

    Comment by Hank Roberts — 29 Jan 2013 @ 9:06 PM

  74. Thank you Prof Steig for the references. You were kind enuf to ignore my error, the sentence should of course read:

    “…the pressure melting point, which decreases with depth.”

    sidd

    Comment by sidd — 29 Jan 2013 @ 9:21 PM

  75. Prof. Box confirms my suspicions on GRIS SMB.

    “…in Greenland decanting a factor of 2 increase of meltwater runoff annually since 2000…”

    http://www.meltfactor.org/blog/?p=811

    annual doubling is fantastically fast. The thing will melt in place, not even counting saddle instability.

    Comment by sidd — 29 Jan 2013 @ 11:07 PM

  76. Jason Box responds to Andy Revkin’s comment on the Greenland-study:
    http://www.meltfactor.org/blog/?p=811

    Also reposted on Joe Romm’s ClimateProgress.

    Comment by Lennart van der Linde — 30 Jan 2013 @ 6:04 AM

  77. Lennart (#76),

    One thing that Box does not seem to pick up on is that Andy seems to think that 8 C of warming in unattainable. I think Andy may think that that is global warming rather than Greenland warming. But Greenland appears to have already warmed by about 3.5 C since the 1800′s http://www.nasa.gov/topics/earth/features/2012-temps.html so we could already be halfway to the conditions described in the new paper. Of course, the recent (2008-2012) warmth might be a spike but with Arctic amplification, an 8 C rise and greater is to be expected in the coming decades, contrary to Andy’s misconception.

    Comment by Chris Dudley — 30 Jan 2013 @ 8:36 AM

  78. Chris,
    Jason Box (and co-authors) estimate that Greenland temperatures would only rise 2-4C by 2100, with a possibility of exceeding natural variability. They maintain that these temperatures have been reached previously in the past 4000 years.

    http://icebubbles.ucsd.edu/Publications/Kobashi_2011_GRL.pdf

    Comment by Dan H. — 30 Jan 2013 @ 9:55 AM

  79. Dan H. ignores the rate of change.
    Dan H. claims the paper says “temperatures would only rise 2-4C by 2100″

    “Ice in our time” seems his message.
    As usual, what could be taken as a reassuring claim.

    Look at the Figure 1 in the Kobashyi article.
    Look at the rate of change.
    Look at the added forcing from CO2 which continues to increase.
    This is not natural variation.

    Look at their conclusion: “… that annual average warming at Greenland Summit will exceed 2–4°C above the 1970–1999 period by 2070–2099 …”

    Comment by Hank Roberts — 31 Jan 2013 @ 11:14 AM

  80. In case it is still of interest, regarding differences between forcings, I came across this article describing differences in precipitation patterns between solar and CO2 forcings.

    Original
    http://www.nature.com/nature/journal/v493/n7434/full/nature11784.html

    News version
    http://www.sciencedaily.com/releases/2013/01/130130132405.htm

    Comment by Chris G — 31 Jan 2013 @ 11:37 AM

  81. Someone could disagree with the conclusion reached in the Kobashi, et. al. paper, that the current temperature is not due to natural variation, and they list several reason why. However, to claim that they have reached a similar conclusion is clearly contracted by the paper. Figure 1 clearly shows no anomaly, and their conclusion states, “The current decadal average surface temperature at the summit is as warm as in the 1930s-1940s, and there was another smiilarly warm period in the 1140s, indicating that the present decade is not outside the envelope of variability of the last 1000 years. Excluding the last millenium, there were 72 decades warmer than the present one”

    Projections exceeding 2-4C where quoted from the IPCC AR4 report, not the Kobashi paper. Kobashi, et. al. stated, “a possibility of exceeding the upper bound (-28.7C) of the natural variabilty by 2100.” For reference, 2-4C above the 1970-1999 average is stated as -29.4 to -27.4C, such that -28.7C is clearly within that range. Taking bits and pieces of a report, and making preferential claims not support by the researchers should be discouraged.

    Comment by Dan H. — 31 Jan 2013 @ 12:32 PM

  82. DanH, Your interpretations are as poor as your explanations of them.

    “…. the conclusion reached in the Kobashi, et. al. paper, that the current temperature is not due to natural variation….” clearly tells us that your understanding of the paper is that the temperatures are NOT natural variation. Which of course is “clearly contracted” (sic – perfect typo) by your further ramblings. Nowhere does the study say as you do above, that “temperatures would only rise 2-4C by 2100″, in fact your later incomplete quote admits the paper states there is a definite possibility of temperatures exceeding 2-4C.

    Yes, “Taking bits and pieces of a report, and making preferential claims not support(ed) by the researchers should be discouraged.”

    Comment by flxible — 31 Jan 2013 @ 1:29 PM

  83. flxible,
    Forgive me for the confusing first statement. The paper clearly states that the current temperature is within natural variability. The paper states that there is a possibility of exceeding the upper bound of naturally variability (-28.7C), which is 2.7C above the reference period, and certainly within the 2-4C range. You are correct that the paper never states the possibility that temperatures will rise above 2-4C. There also exists the possibilty that temperatures will not rise above the two sigma level, and be constrainted below 2-4C above the reference. All this goes back to the statements that an 8C temperature rise in Greenland is unattainable.

    Comment by Dan H. — 31 Jan 2013 @ 3:13 PM

  84. Fig 1a in van der Berg et al. (2011) gives 550-575 w/m^2 summer 65N. Box at meltfactor shows GRIS albedo dropping from .73 to .53 in last decade, shall we say 100W/m^2 extra ? Now not so different from Eemian summer insolation anomaly of 50-100 W/m^2 ?

    Back to the Future!

    sidd

    Comment by sidd — 1 Feb 2013 @ 12:22 AM

  85. http://www.clim-past-discuss.net/8/4817/2012/cpd-8-4817-2012.html
    Clim. Past Discuss., 8, 4817-4883, 2012
    http://www.clim-past-discuss.net/8/4817/2012/
    doi:10.5194/cpd-8-4817-2012

    Causes of Greenland temperature variability over the past 4000 yr: implications for northern hemispheric temperature change

    T. Kobashi, K. Kawamura1, K. Goto-Azuma1, J.E. Box, C.-C. Gao, and T. Nakaegawa

    “… the past variability of climate forcings can explain at least 10% of the multi-decadal to millennial variability in Greenland temperature over the past 4000 yr. An average temperature trend for the Northern Hemisphere (NH) over the past 4000 yr was also inferred from the ice-core derived Greenland temperatures. Lines of evidence indicate that the current decadal average temperature of NH is likely warmer than at any time over the past 4000 yr….”

    Comment by Hank Roberts — 1 Feb 2013 @ 12:52 AM

  86. Dan (#78),

    Unfortunately GISTEMP has the following notice:

    “— Please Note —
    Due to technical problems with the GISS webserver, parts of our site content are not available.
    All interactive content, such as global temperature maps or station data plots using a web form, is currently disabled.”

    So, a more detailed investigation is not possible at this time. But, since the baseline for the Nature paper is the pre-industrial millennium and the 1800′s data seem to be an OK substitute for that based on fig. 1 of the paper you cite, I don’t see a big issue. 7 C above that period seems well within reach. I’ve corrected the Nature paper estimate of 8 C for changing altitude also mentioned in the abstract.

    Comment by Chris Dudley — 1 Feb 2013 @ 11:20 AM

  87. Ther goes DanH again, doing his dyslexic thing: “You are correct that the paper never states the possibility that temperatures will rise above 2-4C.”

    I never said that Dan. You were wrong when you stated it previously, and wrong again here, as Hank’s link points out.

    Comment by flxible — 1 Feb 2013 @ 11:30 AM

  88. That’s not dyslexic — it’s pretend agreement and Gish Gallop.

    Comment by Hank Roberts — 1 Feb 2013 @ 2:47 PM

  89. Just musing: Greenland known as the land of ice and fire. Any contribution from volcanism? Heat from below as well as from above?

    [Response: Nope. --eric]

    Comment by JimBrockd — 1 Feb 2013 @ 4:42 PM

  90. 82 flxible said, ” Nowhere does the study say as you do above, that “temperatures would only rise 2-4C by 2100″, in fact your later incomplete quote admits the paper states there is a definite possibility of temperatures exceeding 2-4C.”

    And our Hero Dan H immediately replied, “Forgive me for the confusing…” You left out CONTINUOUS and YEARS AND YEARS, but hey, baby steps, eh?

    Then Dan H courageously continues, “You are correct that the paper never states the possibility that temperatures will rise above 2-4C.”

    Wow, I gots to admit you’ve got guts. To turn “ONLY” (with emphasis!) into “never”. Yep, this pretty much describes your attitude towards “truth”….

    Comment by Jim Larsen — 1 Feb 2013 @ 5:37 PM

  91. re 89 JimBrockd – Iceland?

    Comment by Patrick 027 — 2 Feb 2013 @ 12:09 AM

  92. #89–JimD, that’d be Iceland, not Greenland. There’s never been surface vulcanism observed in the latter, though there was a paper in 2007 suggesting that there could be a magma hotspot. (Somewhere in the Northwest I think.)

    Comment by Kevin McKinney — 2 Feb 2013 @ 6:46 AM

  93. JimBrockd, I think you are confusing Greenland and Iceland.

    Comment by Marco — 2 Feb 2013 @ 6:51 AM

  94. How much effect might regional increases in GHGs in the Arctic have on the rate of GIS melt?

    http://arctic-news.blogspot.com/2013/02/dramatic-increase-in-methane-in-the-arctic-in-january-2013.html#more

    Comment by wili — 3 Feb 2013 @ 9:26 AM

  95. Wili, do you know what data is behind those “images by” Yurganov?

    I did the work of finding them several times before
    I don’t want to do the exercise again.

    I sure wish you would, instead of posting your alarm at the pictures.

    Whose data is used? Where in the atmosphere the methane is detected?
    Known reasons for the variation according to the researchers?

    The Arctic Methane Emergency people obscure that information.

    I can’t imagine why.

    Comment by Hank Roberts — 3 Feb 2013 @ 11:07 AM

  96. Where do you see any indication of “alarm” in my post?

    I asked a simple question. Please avoid attributing to others’ posts statements and sentiments they do not express. Such behavior is more befitting a troll like Dan.

    Yurganov is the main researcher mapping satellite data of methane concentrations over the Arctic. These concentrations are at 600 millibars, quite high in the troposphere, iirc. I’ll see if I can get the link directly to his site, since I agree that AMEG sometimes is rather…selective in their use of otherwise legitimate data.

    Comment by wili — 4 Feb 2013 @ 7:24 AM

  97. Ok, Wili, you’re not alarmed.
    Wait, you’re not?

    I am. That’s why I’m urging you to make more effort to explain.
    This is the third or fourth time around, on this same issue.

    When you post the AMEG/Yurganov pictures, please — give people the information you know about the source — the lab that actually does the work, and what they said about how it’s being used. We’ve been through that before.

    You’re writing for an audience, and for new readers who will come later.

    Comment by Hank Roberts — 4 Feb 2013 @ 12:14 PM

  98. This on methane is the reference I recommend:
    http://www.realclimate.org/index.php/archives/2010/03/arctic-methane-on-the-move/

    Now — the topic here is Greenland. What research is current that hasn’t been talked about yet? Spring is coming. What glaciers and areas of the icecap have been instrumented? Are we still using mostly aircraft flight since the satellite coverage isn’t good? Which countries are actively doing the research?

    And who’s got fishing rights in the new inland sea, once Greenland melts out?

    Comment by Hank Roberts — 4 Feb 2013 @ 12:28 PM

  99. The maps are from IASI but I have trouble finding them on their official site. Here is another site that collects and arranges these maps:

    https://sites.google.com/site/apocalypse4realmethane2012/home/iasi-2012-vs-2011-iasi-ch4-970-600-mb

    I do think it is past time that they adjust the scale so that everything over 1920 ppb is not bright red. Clearly things have now shifted, so we need to know how much of that bright red area is how far above 1920 ppb.

    My original question about all this remains–how much would a regional eruption of methane like this effect Arctic temperatures? Will winds tend to keep these elevated concentrations in the far north for a while, or will they quickly disperse over the globe. At that height, are they on their way to the stratosphere? If so, what effect might that have on the northern ozone hole this spring?

    Comment by wili — 4 Feb 2013 @ 1:35 PM

  100. This seems to be another place to search the original data:

    http://www.nsof.class.noaa.gov/saa/products/search?sub_id=0&datatype_family=IASI3X3&submit.x=22&submit.y=7

    Comment by wili — 4 Feb 2013 @ 1:38 PM

  101. I keep coming back to Fig 5b) in Tedesco(2012). This shows the cumulative SMB [Surface Mass Balance --ed.] from Jan thru Sep. Cumulative SMB used to reach a min. near the end of August, and remained substantially above zero for the mean for 1958-2011. The last three years 2010,2011,2012 show cumulative SMB going negative earlier in the year, and the minimum dropping very quickly, and occurring later in the year.

    1) I would like the graf extended to cover the whole year.

    2) individual years plotted separately.

    ( 3) And a pony…!)

    I poked around the University of Liege site but do not see the data for the reconstruction.

    I note that the run off anomaly was 350GT for 2011-2012, in comparison to GRACE mass waste estimate of 574GT. So a larger fraction comes from SMB than dynamic discharge. As has been pointed out in Gregoire and others, dynamic discharge thins the ice sheet and lowers the ice surface, plunging it deeper into the ablation zone. In this connection I see that Fig 6a in Tedesco shows ELA far below the saddle at 67N, but according to Prof. Box at meltfactor, ELA exceeded saddle height last year…

    sidd

    Comment by sidd — 4 Feb 2013 @ 3:53 PM

  102. Re- Comment by wili — 4 Feb 2013 @ 1:35 PM

    Methane is well mixed in the air.
    http://www.realclimate.org/index.php/archives/2010/03/arctic-methane-on-the-move/comment-page-1/#comment-164800

    Comment by Steve Fish — 4 Feb 2013 @ 3:57 PM

  103. Hank Roberts @98 — Check a bedrock elevation map of Greenland; no inland sea but rather a large lake.

    Comment by David B. Benson — 4 Feb 2013 @ 5:27 PM

  104. Re- Comment by sidd — 4 Feb 2013 @ 3:53 PM

    Acronym finder has 59 entries for SMB including Super Mario Brothers, Super Monkey Ball, and Shanghai Meteorological Bureau. Is it so hard to type out the whole thing just once?

    Should this be in the Real Climate Acronym Index?

    Steve

    [Response: ;) I think it should! I'll do that. Though it would be better if people would just write things out. Surface Mass Balance. I mean, learn to type, people. Smrtfone era is mking ppl dum--eric]

    Comment by Steve Fish — 4 Feb 2013 @ 10:13 PM

  105. David, inland lake of freshwater certainly to begin, but can that persist?

    I was expecting (can’t say ‘anticipating’) a saltwater connection through the area now “0 to 100 meters” above sea level (in this map) thinking the last deglaciation raised sea level up to 130 meters (and assuming isostatic rebound wouldn’t keep up with sea level rise).

    Has the deepest area of the basin been drilled down to whatever sediment underlies the icecap, do you recall? It might have an interesting record, if sediment from several cycles hasn’t been squeezed and scraped away by ice, but I haven’t found that.

    Same of course applies to Antarctica, I think we’re so far mostly looking at the edges.

    I’m well into science fiction scenarios here — if I’m going to stock that basin with fish ….

    Comment by Hank Roberts — 5 Feb 2013 @ 1:17 PM

  106. Answering one of my own questions, one ice core drilled at the center of the basin.

    The atlas shows two other channels I recall mentioned some time back, on the east and west coasts, where bedrock is also below the 100-meter height that would connect to salt water.

    The basin on the east side of Greenland — gray on the map, below present sea level — was mentioned somewhere as a site to watch for sea water eventually floating the ice off the bedrock and melting from the bottom up.

    Great atlas there, far more info on its website than the last time I looked.

    Comment by Hank Roberts — 5 Feb 2013 @ 1:28 PM

  107. Let me try to amend matters. SMB has been defined by the moderator. ELA is equilibrium line altitude, the altitude below which the ice is in net ablation and in net accumulation above.

    The reference to Tedesco is from The Cryosphere discuss,
    http://www.the-cryosphere-discuss.net/6/4939/2012/tcd-6-4939-2012.pdf

    this paper is under review for publication.

    More seriously, I made an error in attribution for ELA. Although Prof. Box writes at meltfactor.org, the article with present day ELA measurement is at
    http://www.arctic.noaa.gov/reportcard/greenland_ice_sheet.html

    My apologies for the carelessness and errors.

    I cannot attribute these to smartphone usage. I have no smartphone, do not text due to degenerating wrists and finger joints, and hence all my typing is on a full size keyboard. I think the discomfort of typing forces undue brevity, and is also clearly leading to errors. I shall try and do better, and confine my comments to times when I am physically more capable.

    sidd

    Comment by sidd — 5 Feb 2013 @ 1:34 PM

  108. More and new info, and there go my fiction scenarios for a big lake; it seems the Greenland ice didn’t melt last time ’round:
    http://blogs.agu.org/wildwildscience/2013/02/01/greenland-ice-core-may-rewrite-some-climate-books/

    “The big surprise from the NEEM core is that the Greenland icecap survived the warmth of the last interglacial quite well. It melted back a lot, and the spot where NEEM was located was about 150 meters lower then than now. In general there was still a big icecap in the Eemian, and it was quite a bit warmer than it is now.

    …. Sea level was MUCH higher in the Eemian, and many researchers believed this was due to the melting of ice in Greenland and in Antarctica. The NEEM core calls this into question, and it appears that the large rise in sea level may have come more from Antarctica.”

    Earlier page of info on the NEEM drilling project here:
    http://www.iceandclimate.nbi.ku.dk/research/drill_analysing/history_drilling/search_eemian/

    Comment by Hank Roberts — 5 Feb 2013 @ 1:44 PM

  109. So for Greenland — what’s different this time around?

    Rate of change in CO2 — much higher rate of change, we know that.
    How long? Up to the politicians, or the free market, or the people, who knows?

    Black carbon/soot on the ice surface — more? faster? different?
    Diesel smoke is a new factor (and oily stuff as anyone who’s worked around diesel smoke knows, nasty sticky stuff that floats on water — it doesn’t sink and wash away like smoke from forest fires, in my experience around diesel generators in camps.

    Soot from wildfires — I’d guess also more and faster than happened at natural rates of change.

    Dr. Box’s Black Ice will get some info about conditions.

    So this finding that the Eemian Greenland ice didn’t all melt suggests the Eemian sea level rise had to be Western Antarctic meltwater, so the Western Antarctic has to be looked at for faster change than so far expected.

    We’re changing air and ocean temperature — faster than nature ever did — so expect the Antarctic melt again, and faster this time.

    We’ve added black soot — faster this time, and more and different — to the Greenland ice surface, so that’s going to be a new forcing on Greenland. Now what?

    Comment by Hank Roberts — 5 Feb 2013 @ 3:26 PM

  110. Watts has outdone himself on the Arctic refreeze front with a post that basically contends that the cyanide doesn’t matter if you pour the koolaid fast enough.

    Comment by Russell — 13 Feb 2013 @ 7:44 AM

  111. Russell,
    Yes, using an artificially low point to make a comparison is highly biased, similar to plotting global temperatures starting in 1979. Since Arctic sea ice has shown a much wider divergence in summer rather than winter, it is to no surprise that more winter growth has been observed so far this year. A better graphic is to compare the current winter sea ice with past years.

    http://arctic.atmos.uiuc.edu/cryosphere/arctic.sea.ice.interactive.html

    As you can see, 2013 is currently 7th lowest of the past 10 years, and still climbing. By the time the melt season starts next month (or the following, if it stays cold longer), this years sea ice area may surpass te other three years. It will be interesting though to see how this one-year ice survives the summer. The one thing his posts does show is the large expanse of new ice.

    Comment by Dan H. — 14 Feb 2013 @ 5:38 PM

  112. #112–Strange, I’d have said that the graphic shows that 2013 is currently the 7th-lowest of the past 33 years.

    And I’ll add for good measure that this year has quite a bit of ‘climbing’ to do to surpass last year’s end-of-winter sprint. I don’t see it happening.

    Comment by Kevin McKinney — 15 Feb 2013 @ 12:28 AM

  113. #112–or 111.

    Comment by Kevin McKinney — 15 Feb 2013 @ 12:28 AM

  114. > biased similar to plotting global temperatures starting in 1979.

    Bogus:
    — equating Watts’s nonsense to climate papers
    — claiming Russell’s pointer is similar to your claim.

    This is spinning and twisting to post yet again a talking point.
    1979 isn’t picked for bias. Watts’s nonsense is.

    1979 … the starting date for most satellite-based global temperature estimates.

    Comment by Hank Roberts — 15 Feb 2013 @ 10:51 AM

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