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Ned Ward
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The odds are looking good for an El Nino to form over summer and recent updates hint toward a possible 'super' Nino event? Source? I usually get my ENSO forecasts from here: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf and as of now, they seem to be saying that close-to-neutral conditions will continue through this coming (NH) summer, with a possible moderate EN beginning in late summer. Where do you see hints of a "super Nino event"?
Michael Tobis continues to write about this topic: Climatifact: Seven Points in Support of Shakhova? Or not? Ahmed refers in the Twitter exchange to a paper in Rev Geophys, suggesting that Arctic thawing may release in excess of 50 GT of C, a very serious matter, amounting to something like 10% of our remaining margin to a best-guess warming around the best-guess dangerous threshhold of 2 C. This is in keeping with my prior understanding, and make no mistake, it is very bad news – it amounts to more than 50 billion tons MORE of fossil fuel that needs to be left in the ground for a given level of damage. But Ahmed refers to the paper in support of a very different assertion, that 50 GT of methane would be released. It’s commonly assumed as a rule of thumb that an abrupt methane release is from 20 to 70 times worse per molecule than the same amount of carbon released as CO2. So if true this would be very serious business indeed. 50 billion tons of methane would plausibly be civilization-ending and a massive extinction event. But the paper to which he points triumphantly says nothing of the sort. So I conclude that he doesn’t really know what he is talking about. Specifically he has already shown that he is confused about the distinction between methane releases and CO2 releases, something that someone on the climate beat ought to be clear about. THE MAIN ISSUE WITH THE CLATHRATE BOMB SCENARIO The fact that there’s a lot of methane under the sea floor is not in dispute. The question is whether there is a way to destabilize a whole lot of it at once. In order to justify this, Shakhova points to a possibility that some clathrates remain in the frozen phase even though they are at an unstable depth. This can occur if they are encased in water ice. A few nodules of this configuration have been identified, ironically because they are a threat to oil rigs, but they have NEVER been observed in the East Siberian sea, and it’s a long way from a few ounces to fifty billion tons. If fifty billion tons of the stuff were distributed just below the sea floor, the scenario proposed would not be wholly implausible. But there is no evidence of anything remotely like that, and no mechanism whereby it might exist. Anything which does not directly defend the existence of a large deposit of clathrates existing for millennia at pressures where they ought to have long since disintegrated is not a serious defense of the clathrate bomb scenario. And none of Ahmed’s points address this.
Toggle Commented Sep 8, 2013 on Arctic time bombs at Arctic Sea Ice
Large Ice breaking ships cause more damage to the Ice then everyone believes. [...] Ice Breaking ships are a main cause of Arctic sea ice loss is my feeling. No. Really, no. In the big picture of Arctic/Antarctic sea ice extent, the effect from icebreakers is too small to detect. Example calculations here
IJIS/JAXA is back! and they've filled in the past week of missing data. Latest extent is 5706719. This puts 2013 in 5th place, just 2k ahead of 2010, and 1.17M behind 2012. Last three days have averaged a respectable if unspectacular daily drop of 60k.
Toggle Commented Aug 23, 2013 on ASI 2013 update 7: cold and cloudy at Arctic Sea Ice
Neven writes: " felt a bit stupid for only suggesting that we need more research on the questions how Arctic sea ice (and NH snow cover) loss are affecting the jet stream and weather patterns, how much methane venting there is now and in the future from ESAS, and when the Arctic Ocean will be ice-free for a substantial time into Fall. I knew that technology-wise we need more buoys and other ways of monitoring ocean heat flux, and improvements in handling satellite data, but didn't have a clue as to how to describe the exact needs." --------------- Actually, Neven, I think your response was spot-on. Although they do ask about technology/instrumentation/methods, the focus should be on research questions, like your first three examples. Ideally, research questions should come first, and drive decisionmaking about the infrastructure, rather than vice versa. That's the way the funding agencies in the US want to work. If you go to NASA or NSF with a proposal to collect a lot of data and the science questions aren't the focus, it typically will get shot down by review panels. Something is more likely to get funded if the science questions are in the driver's seat. As someone who is very much on the "observational" side of science, rather than the "modeling" side, I have seen this firsthand from both sides (the proposer, and the review panelist)...
"My definition of tipping point (I stand corrected if I am wrong): The point that has been reach where returning to previous state is not possible unless an opposite force is applied." We're probably drifting further and further off topic, but ... I think the language here is a bit fuzzy. Both of the papers in Jai's last comment specifically say that Arctic sea ice has not passed a tipping point (and will not any time soon). By tipping point, they mean a point where the system becomes unstable, such that an initial decline in sea ice inevitably leads to further decline and the disappearance of most of the ice. According to the papers Jai cited, that doesn't really happen, or at least not any time soon. Consider three types of systems: 1. The system resists change. 2. The system changes in proportion to the force applied to it. 3. The system runs away, such that a small force sets in motion a self-sustaining process in which it drifts further and further away from its initial state. The two papers Jai linked to say that sea ice is an example of type 2 here. A certain warming (or cooling) will cause sea ice to decrease (or increase) to a new equilibrium, at which point the ice loss (or gain) stops. If you then reverse the forcing, the ice will go back to its previous state. The system moves when you apply pressure, and stops moving when you stop applying pressure. In this way of talking about it, a tipping point would be the point where behavior (3) takes over. For example, people have suggested that there is a tipping point for land ice caps (Greenland and WAIS). A small amount of warming could lead to initial melting of the ice, lowering the altitude of the ice sheet, which in turn leads to further melting, and further lowering. In that case, even if type climate stops warming, the disintegration of the ice sheet becomes self-perpetuating. But lots of people use the term "tipping point" in different ways, some of them very loose and ambiguous.
Toggle Commented Aug 16, 2013 on Arctic time bombs at Arctic Sea Ice
Back on the subject of methane. Jai writes: "The real issue is not air warming it is ocean warming at the shelf and the perilous condition of ESAS sediments and whether or not they a) contain a high volume of methane and b) are starting to release this methane because of ice loss." (1) A newly discovered source is not the same as a source that is new. (2) Quite a bit of ice has already been lost since the 1980s. Any new methane flux from the ESAS has not had much effect on the global atmospheric methane concentration, which is not increasing particularly fast. Jai: "The simple fact that the models and projections STILL have it wrong, that the people involved refuse to use PIOMAS but rather use extent as a predictive tool, and the excessive rate of volume melt indicates that we have already reached a tipping point." How do you know we've reached a tipping point? Did you even notice that the paper you just cited a few sentences ago (Eisenman and Wettlaufer 2010) specifically addressed the question of "tipping points"? There's a whole section of the paper dealing with this! If that's too much, the first sentence of their conclusion is written in pretty plain English and is easy to read. Short version: no, we haven't passed a tipping point and even a seasonally ice-free Arctic can be a stable state.
Toggle Commented Aug 16, 2013 on Arctic time bombs at Arctic Sea Ice
Jai, I feel like I'm chasing unicorns here. You keep citing papers, and then I spend a lot of time reading them and discover that they don't say anything along the lines of what you're claiming. You first introduced the idea of a "5C step change" in this comment: "In fact, I see that the actual trend indicates a step-change in temperature due to total sea ice loss by 2030 of 5C, This additional warming effect will be on top of the 2.5C/decade warming trend that we have previously seen." [6 Aug 2013 19:56] You then reiterated the "5C step change" claim: "In addition, you failed to respond to the 5C step change when we reach a June 1st 2030 0% sea ice extent." [6 Aug 2013 21:45] I said I didn't know where that came from. You then replied that it was in a paper that you had linked to: "The 5C step change brought about by a June 1st ice free state is in the paper I linked to you." [7 Aug 2013 22:06] So I looked back at the first comment where you mentioned the "5C step change" thing, and there were three papers linked there: (1) Screen and Simmonds 2010. That paper is about reanalysis data for the 1989-2008 period. It says nothing at all about a 5C step change or an ice-free June 2030. (2) Wang and Overland 2009. That paper models sea ice retreat over the next century. It doesn't predict an ice-free June in 2030, though it does mention the possibility of a nearly ice free September by the late 2030s. It doesn't refer to a "5C step change" in 2030, though it does mention that IPCC AR4 projects the Arctic to be 5C warmer than baseline in autumn by 2070. Note that that is the total warming, not an additional "step change" on top of the underlying trend. (3) Lawrence et al. 2008. This paper discusses the simulated rapid loss of ice that occurs in about half of models. It says nothing about June 2030, and nothing about a 5C step change. Figure 1a does show a temperature curve going from "-2" on the left axis to "+3" on the right axis, which could easily be mistaken for a 5C step change ... but only the right axis is temperature, the left axis is sea ice extent in million km2. When I pointed out that none of the papers you'd linked to supported the "5C step change" concept, you replied: "the 5C warming is found here [...] figure 1 shows expected temperature increases of 5C when the arctic is ice free in June." [14 Aug 2013 20:13] That's a new paper, it's not any of the ones you had originally cited. So why did you tell me (in the 7 Aug comment) that the source for the "5C" claim was in one of the papers that you'd already cited? OK, whatever. So I looked at the new paper (it's a preprint for Eisenman and Wettlaufer 2010). Figure 1 says that a model Arctic Ocean that is ice-free for most of the year will have temperatures in the mixed layer approaching 5C in September. But the annual mean looks like something around 1C, not 5C. I don't know what the current annual mean temperature of the mixed layer is, but it's probably somewhere between -1C to -2C, so this would represent a warming of up to 3C relative to present conditions. Needless to say, this is not "a step change of 5C on top of the existing trend". At this point I'm pretty much ready to give up. I keep reading the papers you're linking to, and not only do they not say what you claim they do, none of these papers contradicts the regional warming of 3C to 6C by 2060 that I originally proposed, and that you immediately rejected as not remotely possible. It would prevent a lot of wasted time on other people's behalf if you could just make sure that you're only citing papers that really say what you claim they do.
Toggle Commented Aug 16, 2013 on Arctic time bombs at Arctic Sea Ice
There's a pretty good article on this topic by Chris Mooney in Mother Jones: How Much Should You Worry About An Arctic Methane Bomb?
Toggle Commented Aug 14, 2013 on Arctic time bombs at Arctic Sea Ice
"by 2050" should read "by 2060", sorry.
Toggle Commented Aug 8, 2013 on Arctic time bombs at Arctic Sea Ice
Oh, and that 1.6C/decade that Lawrence 2008 found during "RILE"s isn't an addition on top of the warming trend, it is the trend after the RILE. Their model shows an average of 0.46C/decade before the RILE (quite close to this past decade's 0.48C/decade warming!) and 1.6C/decade after. So if you postulated 2 decades of 0.46C (2010-2030) followed by 3 decades at 1.6C, you'd end up with a total of 5.7C warming over the five decades. Which in fact is within the IPCC's projection of 3 to 6C warming in the Arctic by 2050. It's also worth noting that this is a model result, and one that according to Lawrence et al. only occurs in 50% of the models. There's no guarantee this will actually happen. At least, that's my understanding of what they say. I could be missing something.
Toggle Commented Aug 8, 2013 on Arctic time bombs at Arctic Sea Ice
"you failed to respond to the 5C step change when we reach a June 1st 2030 0% sea ice extent." I haven't found that yet, but you've linked to several papers in your comments and maybe I was looking in the wrong place. The closest match I can find is Lawrence et al. 2008, which claims that the NOAA CCSM model often shows "rapid ice loss events" when September sea ice extent drops by a couple million km2 over a few years. They say this results in an increased warming of ~3C in fall or 1.6C annually averaged. That's the closest I've seen in your links, though it's not 5C and I didn't notice anything about June 1st or 2030.
Toggle Commented Aug 8, 2013 on Arctic time bombs at Arctic Sea Ice
Jai writes: "That being said, you post a GISTEMP graph that clearly shows temperatures rising 3'C over the least 30 years and you then say that a 3-6C rise in the next 50 years is plausible?" Sorry, but you must not be reading it right. Temperatures have risen about 1.8C over the last 30 years, not 3C. To get 3C of warming you'd need to go back to the 1890s or so.
Toggle Commented Aug 8, 2013 on Arctic time bombs at Arctic Sea Ice
Jai Mitchell writes: "While the decadal average in the paper was 1.15C over this period. The reason this is low is because the majority of this warming has occurred since 1998. http://www.wwfblogs.org/climate/sites/default/files/SurfTempAnomaly,64oN-90oN-1880-2010.jpg "The rate of 1.15C/decade is taken from an average of a series that ended 5 years ago. The temperature profile of the arctic is growing exponentially and proportional to sea ice decline. The most recent decade has shown catastrophic sea ice collapse, this is not currently captured in the decadal temperature average of the paper." =================== I hardly know where to begin here. I apologize for the length of what follows, but so much is wrong or confused in Jai's comment that I don't see a way to keep this short. (1) You originally said "1989-2008 surface trends for the arctic are close to 2C per decade warming" and then later increased that to "2.5C/decade that we have already seen". The source you gave for that was Screen & Simmonds 2010. But Screen & Simmonds don't say that. They say 1.15C/decade. May I suggest that if you don't agree with Screen & Simmonds, don't cite them as a source for your claims? (2) If "the majority of the warming occurred after 1998" that would tend to increase not decrease the magnitude of the trend. I think you may be confused about how trends are calculated, because you keep referring to an "average". The figure that Screen & Simmonds report for 1989-2008 temperature is a trend, not an average. If the decadal average was higher for the later part of that period (which it was) that would tend to increase the trend, not decrease it. So your explanation for why Screen & Simmonds' trend is too low makes no sense. (3) In fact, Screen & Simmonds' trend is probably too high, as shown by the very graph you link to in the new comment. The graph appears to be a plot of the GISTEMP Land+Ocean temperature index for the Arctic. The version you link to truncates it at 2010, but the full data set through 2012 can be downloaded from NASA. The trend in GISTEMP's Arctic temperature for 1989-2008 is 0.7C/decade, or only about half of what Screen & Simmonds reported, and just over a quarter of your "2.5C/decade". Since you suggest that the problem with Screen & Simmonds was that their study period ended in 2008, we can extend it through 2012 ... but that decreases the trend slightly (to 0.66C/decade). (4) When you say "The most recent decade has shown catastrophic sea ice collapse, this is not currently captured in the decadal temperature average of the paper" ... well, the trend over the most recent decade (2003-2012) is even lower (0.48C/decade). =================== Continuing with Jai Mitchell's comment: "In addition, you failed to respond to the 5C step change when we reach a June 1st 2030 0% sea ice extent." =================== That's because I haven't seen any justification for a "5C step change" in 2030. I think that's highly improbable. =================== Jai again: "Even so, do you still think that a 3-6'C by 2060 is even a remote possibility?" =================== It seems likely to me. It assumes that warming is likely to increase, at a rate that is somewhere between a linear and exponential trend. Here's the same temperature data you linked to, but extended to the most recent year (2012). Blue line is annual temperature, red line is a LOESS smoothed version, yellow line is a linear trend over the past three decades: The linear trend is 0.6C/decade (as noted above, the trend for the most recent decade [0.48C/decade] is actually slower than the overall trend). Extrapolating that 0.6C/decade trend for five decades would give 3C warming by the 2060s. If one assumes that temperature will increase exponentially, extrapolating that to 2062 would give about 7.5C of warming. So my expectation (3C to 6C, which also matches the IPCC's projection) suggests that the temperature will increase at a rate that is faster than linear, but slower than exponential. That said, projecting a past trend in noisy data so far into the future is obviously unreliable. I'm just going through this to show that, yes, 3C to 6C warming in the Arctic over the next five decades is certainly plausible. =================== Back to Jai Mitchell one last time: "How does this change your perception of the comparisons between now and the last super interglacial of 400,000ybp when temperatures were close to what they are today for about 15,000 years and leading to the melting of the Greenland ice cap and the West Antarctic Shelf?" =================== I'm not sure what perception of mine is supposed to change. I was the one who originally pointed out here that GIS and WAIS basically melted away completely during MIS 11. If temperatures stay high for the next few millennia, I would expect that to happen again. Am I supposed to change that expectation, and if so, why?
Toggle Commented Aug 7, 2013 on Arctic time bombs at Arctic Sea Ice
Jai Mitchell writes: "1989-2008 surface trends for the arctic are close to 2C per decade warming." Actually, the paper that you cite says 0.5 to 1.6C depending on the season, or 1.15C/decade overall. and then continues: "on top of the 2.5C/decade warming trend that we have previously seen" How did the past decade's warming go from 1.15C/decade to "close to 2C/decade" to "2.5C/decade" within a couple of paragraphs? You've more than doubled the trend that was reported by the very paper you yourself cited.
Toggle Commented Aug 6, 2013 on Arctic time bombs at Arctic Sea Ice
... and of course, from the same play: That is, hot ice and wondrous strange snow
[...] we see The seasons alter: hoary-headed frosts Far in the fresh lap of the crimson rose, And on old Hiems' thin and icy crown An odorous chaplet of sweet summer buds Is, as in mockery, set: the spring, the summer, The childing autumn, angry winter, change Their wonted liveries, and the mazed world, By their increase, now knows not which is which [...]
Again, just to re-emphasize here. I think high-latitude methane sources will contribute to 21st century warming. I think we should keep a close eye on methane fluxes. I think we should start now (25 years ago actually) to reduce CO2 emissions so as to minimize 21st century climate change. But I don't see justification for portraying a scenario like this as realistic: Red line is ice core record, blue line is direct measurement up to mid-2013. In other words, actual history up to now. Green line is imaginary 50 Gton release of CH4 over a single decade. In the global atmospheric methane record, as of mid-2013, there is no sign of any such thing. CH4 levels are rising, but more slowly than a half-century ago.
Toggle Commented Aug 6, 2013 on Arctic time bombs at Arctic Sea Ice
Jai writes: "MIS 11 was much longer in duration at these temperatures." Yes. In the comment immediately preceding mine, Allen McDonnell had suggested that "duration" was the determining factor that had prevented a methane time bomb from going off during the Eemian interglacial, which he suggested was too short. So I pointed out that MIS 11 was a much longer interglacial. Apparently I'm being criticized by some for focusing on duration of warming rather than peak temperatures, and by others for focusing on peak temperatures rather than duration of warming. :-) Again, the total warming during MIS 11 was great enough to melt most or all of the Greenland ice sheet plus the West Antarctic ice sheet, with sea levels on the order of 10-20 meters above today's. That is a lot of warming, sustained for a very long time. I don't think there's any sign of a catastrophic 50-gigaton release of methane during MIS 11. Jai continues: "we are looking at the potential for an additional 6-14C arctic warming over the next 5 decades" Source? IPCC WGI chapter 11 (fig. 11.18) says approx. 3-6C for the Arctic by ~2060s. Where do you get 6-14C? Jai concludes with: "Even so, the evidence currently indicates that subsea methane clathrates HAVE been released during these interglacials." That's an interesting paper, though I'm no expert in that area. Taking it on face value, though: (1) It's not about interglacials (describes events that occurred *during* the last glacial cycle). (2) There was no 50-gigaton methane release (events they describe were more than two orders of magnitude smaller). (3) The study area is in deep waters of the tropical Pacific, not a shallow continental shelf in the Arctic. I'm not sure how that relates to this thread, but it does seem kind of funny that you began your comment by writing "Ned, It seems you are comparing two separate things."
Toggle Commented Aug 6, 2013 on Arctic time bombs at Arctic Sea Ice
Well, other interglacials saw periods of warmth that lasted longer, such as MIS 11 (during which Greenland ice sheet and WAIS pretty much entirely disappeared). Could a methane "bomb" survive through enough warming to melt all the ice in Greenland, but then explode now when we've not even managed to melt 0.5% of that ice?
Toggle Commented Aug 5, 2013 on Arctic time bombs at Arctic Sea Ice
Neven, I always look forward to these updates, and learn a lot from them -- you cover so many different points, it brings me up to speed on stuff I just wouldn't have time to keep track of otherwise. Thanks for doing this!
Chris Colose has an excellent post about methane at Skeptical Science: Toward Improved Discussions of Methane & Climate Some participants in this site have already commented over there, but others might not have seen it yet. In general, I agree with Chris's perspective on this issue. I think Arctic methane is a real but second-tier concern as an element of the terrestrial carbon feedback. I don't think there is any prospect of near-future "catastrophic" release of methane.
Toggle Commented Aug 4, 2013 on Arctic time bombs at Arctic Sea Ice
I do think there's a good chance that 21st century temperatures in the Russian Arctic will approach or surpass those from earlier in the Holocene. But as far as "methane time bombs" go, I think the absence of a "bomb" during previous interglacials -- including what Melles et al 2012 refer to as the "super-interglacials" -- argues against the likelihood of a "bomb" going off any time soon. The Arctic was *very* warm for long periods during previous interglacials, at some points warm enough for long enough to melt most or all of the Greenland ice cap. That's a lot of heat! But no "bomb" went off.
Toggle Commented Aug 4, 2013 on Arctic time bombs at Arctic Sea Ice
Early in this now-long thread, it was claimed that early holocene temperatures were warmer in the Arctic than today. It was never shown, though, that it was warmer specifically in the area we are talking about--the ESAS. First of all, there are good a priori reasons to expect that it was warmer in this region during the early to mid Holocene. Due to Milankovich geometry summer insolation in the Arctic was much higher than now, and other sites elsewhere in the Arctic are certainly believed to have had higher temperatures at that time. Paleoclimate data from the eastern Russian Arctic seem to follow this pattern. For example, Andreev et al 2004 examined pollen records from the Taymyr peninsula, at the western end of the region you're referring to: "TVII [i.e., reconstructed temperatures] were slightly warmer than today during the Allerød and 2–3°C colder during the Younger Dryas and became 0.5–1.5°C warmer than present again in the early Preboreal; two sharp decreases in TVII to the modern value occurred at about 9600 and 8500 yr BP; and after TVII fluctuated between 1.5 and 3.5°C above modern values." Andreev and Klimanov 2000 looked at pollen from seven locations across Arctic Russia. In general, they found a similar pattern of mid-Holocene warmth. The easternmost of their sites (Kazach'e) is closest to the ESAS. The warmest temperatures there (2C warmer than today) occurred at around 6000-4500 BP. Further east, at Lake El’gygytgyn, Melles et al 2012 report that the peak Holocene warmth was 1C to 2C above present temperatures. They also note that previous interglacials were substantially warmer (they refer to MIS 11c and 31 as "super-interglacials; with temperatures 4C to 5C above the peak Holocene temps, or 5C to 7C above current temperatures). It's worth keeping in mind that these are land temperatures. I don't think there are a lot of paleo reconstructions of temperatures in the East Siberian sea. Melles et al. 2012 notes that climate models suggest that past temperature changes in the Arctic Ocean in general would likely have been much smaller than those on the surrounding lands (see fig. 4). Sources: Andreev, A. A., and V. A. Klimanov. "Quantitative Holocene climatic reconstruction from Arctic Russia." Journal of Paleolimnology 24.1 (2000): 81-91. A.A. Andreev, P.E. Tarasov, V.A. Klimanov, M. Melles, O.M. Lisitsyna, H.-W. Hubberten, Vegetation and climate changes around the Lama Lake, Taymyr Peninsula, Russia during the Late Pleistocene and Holocene, Quaternary International, Volume 122, Issue 1, 2004, Pages 69-84. Melles, Martin, et al. "2.8 million years of Arctic climate change from Lake El’gygytgyn, NE Russia." science 337.6092 (2012): 315-320.
Toggle Commented Aug 4, 2013 on Arctic time bombs at Arctic Sea Ice
Water does in fact make it to the base of the ice sheet, even in Greenland, especially at low to mid elevations on the ice.