This is Rob Dekker's Typepad Profile.
Join Typepad and start following Rob Dekker's activity
Join Now!
Already a member? Sign In
Rob Dekker
Recent Activity
Slightly OT, but I just came across this statement by the vice president of the Russian Geographic Society : "There should be a rise of a few more tenths of a degree in the average annual Arctic temperature for the development of minerals in the Arctic to be profitable, Chistyakov said." http://en.itar-tass.com/russia/706413 "This is a matter not only of hydrocarbons, but also of other resources, for instance, rare earth metals. Russia sets itself an ambitious aim to increase the output of rare earth metals and to assume the leading position in high-tech production." Who needs enemies of our planet's Arctic eco system and unique wildlife environment when you have the Russian Geographic Society as a friend ?
Toggle Commented Jan 17, 2014 on Bromine, chlorine and mercury at Arctic Sea Ice
Weather_West, thanks for bringing up the interesting "Ridiculously Resilient Ridge" (love the name!). This blocking high has been sitting there for almost a year now, caused the worst drought year in California's recorded history, and it shows no sign of relief. The SINGLE storm this raining season we had here in Northern California was a one-hour long tropical downpour (incidentally coinciding exactly with a soccer match of the U10 team I'm coaching) back in October. This is getting indeed quite "ridiculous". I did a bit of research, and found that interestingly enough there appears to be a "Ridiculously Resilient Trough" in the Antarctic about the same meridian, which is possibly causing extended sea ice cover around Antarctica) that's been there for almost two years now. I'll see if I can dig up a global picture of that (NCEP/NCAR).
Toggle Commented Jan 10, 2014 on Looking for winter weirdness 2014 at Arctic Sea Ice
Thanks VaughA. I guess he does not like me for pointing out common ground between the Francis and Barnes papers. That's OK. But I think I understand why he is venting a polarized view on this issue. Observational studies of trends on blocking events and jet stream are hard, and to find correlation of these with another effect (such as Arctic amplification) are harder yet, and then we didn't even talk about causation. Scientifically speaking we just starting with exploration of the data. After all, it's been only 15 years of so that sea ice cover started to reduce in very substantial fractions. Thus, it is not surprising that there are many serious climate scientists (Trenberth for one) who dismiss the link between Arctic sea ice loss and extreme climate events at this point, for lack of evidence, although they keep their mind open. But looking at Cliff's post, and the comments he gives (even disrespectfully disregarding Dr.Francis response on his own blog), it seems that Cliff has made up his mind on the issue, and is taking a very hard stand on one side. For a scientist, it's disappointing in my view. But since Dr. Francis' work has been highly publicized in public media, while the evidence for here theory is still rather thin and a bit fragile (just getting out of the noise) and has been pushed back again by papers like Dr.Barnes' results, it is also not entirely unexpected that he is a bit angry. In the process, I learned something about Cliff Mass, and the entire debate about the link (or lack thereof) between global warming and extreme weather events.
Toggle Commented Jan 10, 2014 on Looking for winter weirdness 2014 at Arctic Sea Ice
Thanks, idunno, for your reference to Chris Reynold's post on the discussion of the Francis versus Barnes papers. Chris' post is high quality (as usual) and I especially found Chris' graph of the increase in blocking patterns over time very interesting : http://farm9.staticflickr.com/8362/8343371824_dc4847afe5_o.jpg I took the liberty of using this graph in a second post on Cliff Mass' blog, who responded rather dismissive to my first comment, which was what I intended to be a applause of the constructive scientific debate on in the two papers on the issue of Arctic amplification in relation to extreme weather events. Since Cliff Mass did not even respond to Dr. Francis comment, and dismisses mine with the remark "You could not have read these papers very carefully", I'm not so sure if Cliff Mass is interested in engaging in any scientific debate.
We are all well aware of Jennifer Francis' work, and specifically the paper Francis and Vavrus 2012 "Evidence linking Arctic amplification with extreme weather in mid-latitudes". But at least I was not aware that there is actually a paper that challenges her findings, until I noticed this Cliff Mass blog : http://cliffmass.blogspot.com/2014/01/does-cold-wave-imply-anything-about.html The paper in question is Barnes 2013, by Prof. Elizabeth Barnes, Colorado State University (isn't that Trenberth's uni ?) Here is the pdf : http://barnes.atmos.colostate.edu/FILES/MANUSCRIPTS/Barnes_2013_GRL_w_supp.pdf Any way, I read the paper, and it is well written, clearly explained, thorough, it's results makes a lot of sense, and it does put some (significant?) constraints on Dr. Francis claims. Dr. Francis actually did put a comment in Cliff's blog on the Barnes paper. I also put in a comment, where I describe my opinion of the differences and common findings of both papers, and mention Neven's blog to Dr.Francis, as one site where we would love to have a longer discussion about blocking patterns, Rossby waves, and extreme weather events. I hope that comments gets through Cliff's moderation today, but if not, I'll post it in full tomorrow.
Somewhat OT, but I saw the movie "Frozen" (Disney) on New Year's Eve, and I can recommend it for anyone with a passion for snow/ice. Here is one inspiring scene : https://www.youtube.com/watch?v=moSFlvxnbgk So here is by new year's wish : Let 2014 be the year when we no longer hold back in using our skills, abilities and passions to learn, inform and debunk mis-information about our changing climate and the Arctic specifically.
Toggle Commented Jan 4, 2014 on Merry christPIOMAS at Arctic Sea Ice
After the devastating and almost scary 2012 melting season, I think we can all breath a bit easier now that 2013 appears to be the coldest melting season since 2001. Santa's home is saved for at least another year. And a special merry Christmas to Chris Reynolds, Wipneus, A-team and many other contributors over 2013 that make Neven's ASI blog the best place to get information on what is happening in the Arctic, the last remaining marine wildlife sanctuary and the canary in the coal mine of global warming. You guys rock !
Toggle Commented Dec 26, 2013 on Merry christPIOMAS at Arctic Sea Ice
wili said : should we be using these CryoSat numbers or the lower PIOMAS numbers when pointing out to people what is happening to sea ice? Which is more accurate? That is an excellent question in my opinion. Both Cryosat and PIOMAS heavily rely on modeling, albeit different models, with different input parameters, and both undoubtedly suffer from significant inaccuracies. I think that Cryosat' strength is in displaying details in the ice pack, but has questionable value for the overall mass of sea ice. After all, even a 10 cm mis-calculation of this radar system that is hovering a few hundred km above the planet surface will cause a 100 cm error in ice thickness and thus about 100 % error in ice mass/volume. Frankly, for a radar system, I don't know how they manage to estimate ice mass with any sort of accuracy at all. And I still do not understand why Cryosat does not present estimates for 'summer' ice mass. After all, during summer there are plenty of leads (open water) between the ice floes, which gives a great 'baseline' for the radar, so one would expect that the most accurate estimates of ice mass could be made only in summer. Still Cryosat explicitly ignores that season. Why ? PIOMAS on the other hand, has a hard time re-constructing details in the ice pack, such as ridging, false-bottoms in sea ice and re-freeze rates on a fragmented pack. But after decades of validations by in-situ ice thickness measurements PIOMAS must by now be the best model we have in estimating overall, large-scale ice growth under atmospheric and oceanic conditions, although these atmospheric conditions are also derived from models using satellite measurements. So maybe, with Cryosat being great in the details, and PIOMAS being great in the overall ice mass estimates, the two systems may complement each other very well. Maybe what is surprising is not how much these two systems differ, and which one to 'choose' or is 'better', but in fact how close they are, given that they produce numbers from completely different measurements and completely different models.
Neven, said : Rob Dekker, get over there and have a look (if you have the time) Sorry it took me so long. Hansen had previously estimated the heat flux of sea ice volume melted since 1995 to be 0.01 W/m^2. I posted a detailed comment on his article, which confirms that finding. It appears that the energy that was needed to melt sea ice over the past 18 years is not significant in the global energy balance. Thus direct effect of melting sea ice cannot be responsible for any significant planetary temperature change over that period. The IN-direct effect of melting sea ice (albedo feedback) IS significant (0.13-0.15 W/m^2). But of course, that is a WARMING effect (of the Arctic mainly), and thus opposite from claims 'hiatus' claimed.
Toggle Commented Dec 7, 2013 on The 'hiatus' and the Arctic at Arctic Sea Ice
In this time of political extremism, and media "balance" and industry mis-information and internet trolls, it is so refreshing to see clear rational thought and simple math as put forward by Bartlett reflected upon. Thank you Neven ! When we are faced with a finite resource like petroleum, of course it does not require exponential (some percentage per year) growth to get in trouble. In fact, linear growth and even no growth at all will deplete ANY finite resource over time. The question is not if fossil petroleum oil extraction from our planet can be done in a "sustainable" way as some oil companies are claiming. We already know that is NOT sustainable. Not under ANY consumption curve, exponential, linear, or flat. So the question is not IF, but WHEN will we switch to alternatives to fossil petroleum ? We HAVE TO at some point... When is that point ? We know that a finite resource like petroleum will probably follow some sort of bell curve. We also know that "conventional oil" already peaked in 2006 or so. Overall world oil extraction is still increasing simply because we are now digging into "unconventional oil" supplies, such as Canadian tar sands, shale oil and (most interesting to this forum) entering extreme places like the Arctic, to postpone the inevitable. But when extraction and thus consumption still increases, the problem only gets worse. To give some perspective on the time pressure we are under, consider that any new petroleum resource that we will discover and extract from now on will only postpone the inevitable decline to the right side of the Bell curve. For example, Prirazlomnaya (the first production rig in international waters of the Arctic) is drilling into the Prirazlomnaya which contains some 440 million barrel recoverable oil. Even at current rate of global oil use (some 88 million barrels per day), Prirazlomnaya will only delay the inevitable downslide on the bell curve by 5 days. Think about that. 5 days. As for all the 90 billion barrels of "undiscovered" oil that is supposed to be available in the Arctic, even at current extraction/consumption rate, we can delay the inevitable decline of fossil petroleum supplies by about 2.8 years. That's it. 2.8 years. Would we risk an ecological catastrophe in the last ocean on this planet that has until now been a sanctuary for wildlife due to it's ice cover, the ice cover that is disappearing because of burning fossil fuels in the first place, just so that we can stay addicted to a fossil fuel for 2.8 years longer ? My question is : Are we NUTS ? Change NOW ! Declare an Arctic sanctuary NOW ! And NO, Russia. It's NOT cool to throw anyone protesting against this insanity of Arctic oil exploration in jail without a trial. It's NOT cool to confiscate their vessel in international waters, and it is NOT cool to ignore an international court order to release the vessel and the protesters. It's NOT cool to drill in the Arctic.
Toggle Commented Dec 5, 2013 on In memoriam: Albert A. Bartlett at Arctic Sea Ice
Apologies, Neven, for my comment being off-topic. If there is a better place for my comment about Arctic protests, please direct me, and I'll take it there.
Since I prefer to discuss facts and science, it's not often that I state my opinion about environmental protests, since often this is a matter of opinion. But now that a Dutch vessel has been raided by the Russian authorities after Greenpeace staged a pre-announced protest, and the entire crew of 30 has been detained in a Russian prison for almost 2 months now, I do feel the need to point out that Russia is setting a dangerous president here, which would grant unprecedented liberty to drill the Arctic for oil if remained unchallenged : So let me say that I admire the Kingdom of the Netherlands in challenging Russia's actions here in front of the International Tribunal for the Law of the Sea (ITLOS). Under international laws (such as UNCLOS), you can't just go and raid a foreign ship in international waters, confiscate the vessel, take it's crew captive and throw them in jail, just because you don't like their presence ! Even if you believe that they are "Hooligans". There are rules for this, and Russia even ratified these under UNCLOS. If these actions by Russia go unchallenged, then the International Laws of the Sea seem to be considered null and void by Russia. And if Russia does not comply with them, why would anyone else ?
Thanks, idunno and especially Wipneus. Seems that the problem is resolved at NSIDC. The 11/03 update came through, and looks much more reasonable : http://nsidc.org/data/seaice_index/images/daily_images/N_daily_extent_hires.png
Seems that CT has an issue with the NASA data feed. Still, UBremen/AMSR2 is still quite different from NSIDC...
Does anyone know why there is such a big difference between the daily ice extent from NSIDC : http://nsidc.org/data/seaice_index/images/daily_images/N_daily_extent_hires.png from Cryosphere today : http://arctic.atmos.uiuc.edu/cryosphere/NEWIMAGES/arctic.seaice.color.000.png Look at the differences between Svalbard and Bering Strait... It seems that Bremen AMSR2 is in between these two : http://www.iup.uni-bremen.de:8084/amsr2/arctic_AMSR2_nic.png Which one has the most credibility ?
Thanks Neven ! I took my comments to Richard Telford's post.
You are right Pjie2. That did not quite come out the way I wanted. What I meant to say is that the increased summer solar irradiance in the early Holocene (some 20-40 W/m^2 more than present) is an order of magnitude more than the modern IR forcing caused by GHG emissions and influx from heat from lower latitudes on a warmer planet. Now, lots of adjustments (albedo differences, length of seasons, winter temps and precipitation etc) would have to be made for a fair comparison, but that first order assessment suggests that the Arctic summer sun of the early Holocene was much stronger than influence of our GHG emissions today.
About the Miller et al 2013 study, I'd like to express a word of caution regarding claims of early Holocene in the Arctic being warmer than today. For starters, the Arctic in the early Holocene experienced an order of magnitude higher level of solar irradiance than today's climate, even as enhanced by GHG emissions and overall global warming. But the main point of my note of caution is regarding the number of samples they base their evidence on. It appears that from the 145 dated specimens of mosses and lichens, the vast majority (some 135) dated back to less than 5000 years ago. Only 10 samples (4 mosses and 6 lichens) were carbon dead (older than 55,000 years or so). Now, it is of course very interesting that a couple of very old specimens were among their evidence, but I'd be very cautious in drawing such significant conclusions from so few samples. Especially since the majority of samples is much younger, and thus apparently the majority of the area was ice free less than 5000 years ago.
ColoradoBob, thanks a lot for the link to the recent Miller et al 2013 paper. http://phys.org/news/2013-10-unprecedented-warmth-arctic.html#jCp There has been some ambiguity in the past about whether the Arctic climate during the early Holocene was warmer or not than present. But when Miller et al 2013 shows that the mosses appearing from underneath the melting ice sheets of the Canadian Archipelago appear to be carbon dead, and thus older than 55,000 years, they are making a strong case that the current Arctic warming is beyond what we experienced during the entire Holocene, and it appears to date back to at least the Eemian (some 120,000 years ago) when sea levels were some 7 meters higher than today. Regarding "ammunition" against the Watts' type of crowd. Good luck. There are a virtual infinite amount of ways to deny, misinterpret, ignore, attack, or simply throw red-herrings at scientific findings like this. For example, note how internet entity " Linda Serena", (who's facebook account "https://www.facebook.com/Linda.Rittisat seems to be invalid, blocked or suspended) throws a red-herring by addressing the word "ammunition" in your post, and diverting attention to a McIntyre post. After which the discussion is about how credible or not McIntyre is. No more talk about the scientific evidence you put forward. See how that works with these guys ? Any way, let me just tell you that I appreciate you posting this evidence that the Arctic may be warmer now than it has been for 120,000 years.
NJ, if you want an answer from NSIDC's Walt Meier about your pet icebreaker theory, you could start by spelling his name right.
No Kevin, I don't. I do claim however that the correlation between their NAO pattern and the AMO definition is the result of linear detrending. If they use a physical AMO definition, like Trenberth's, then the correlation breaks down. Which they even admit to themselves in the Supplemental material. I understand that you are not convinced, and I am sorry that I could not explain myself better. Other papers fall in the same AMO trap, and the deniers are having a party with such papers. Take Zhou and Tung 2012 for example, which triggered this post : http://www.staatvanhetklimaat.nl/2012/10/17/new-paper-cuts-recent-anthropogenic-warming-trend-in-half/ That publication went all through the sceptic blogosphere all through to Marc Morano. See my remarks in the comment section of that blog post, where I first attempt to point out the issue with the detrended AMO. A follow-up of that paper in PNAS (Tung and Zhou 2013) was finally taken on by skepticalscience : http://www.skepticalscience.com/circular-argument-blaming-warming-on-amo.html Which pretty much nails it too. So for the future, please be aware of this "AMO trap". It's a way to attribute the non-linear global warming signal to the "natural " AMO. It WILL show up again and again, until we deal with it. Now I yield the floor for sure..
When you look at Trenberth's revised AMO index (figure 3 in Trenberth's paper) then it also becomes clear that the AMO is no longer a good physical explanation of the 16 year delayed NAO index. For example, Trenberth's AMO index suggests that Atlantic SSTs starter to rise rapidly since '95. So if Li et al's claim that NAO affects AMO with a 16 year delay which then affects global temperatures is still true, then we should see global temperatures go up rapidly starting about 2011. Which is OPPOSITE from what Li et al is claiming. It may still be that NAO index controls global temperatures with a 16 year delay, but whatever the physical mechanism may be that would accomplish that, it is not via Atlantic SSTs. So the physical explanation they propose is broken. What remains is a curve-fitting exercise of the NAO index over the non-linear trend of global temperatures, with no evidence that Atlantic ocean temperature patterns are involved.
Kevin, Trenberth's AMO index is obtained by SUBTRACTING the global SSTs from the Atlantic SSTs, and he explicitly advices AGAINST linear detrending. Here is Trenberth's paper on the AMO index : http://acacia.ucar.edu/staff/trenbert/trenberth.pdf/TrenberthSheaHurricanes2006GRL026894.pdf However, previous AMO indices are conflated with linear trends ... About 0.45C of the SST anomaly is common to global SST and is thus linked to global warming... ... The main difficulty with the traditional AMO index is that it is not possible to discriminate between variations arising from the THC and other phenomena with North Atlantic origins, and global anthropogenic changes. In particular, the recent warming of North Atlantic SSTs is known to be part of a global (taken here to be 60N to 60S) mean SST increase (Figure 2). While detrending [Knight et al., 2005] the AMO series helps remove part of this signal, the SST changes are not simply linear and a linear trend has no physical meaning. ... Accordingly, the global mean SST has been subtracted to derive a revised AMO index (Figure 3). Note that the reference they give ("Trenberth 2007") does not show up in the list of References, so if you don't already know that Trenberth adviced exactly against what they are doing, then you would never know. So Li et al explicitly IGNORED Trenberth's advice, and then still attribute their choice of AMO definition to him ! Ain't that something ?
In other words, re-read the paper, and assume that their AMO==DNHT. And surprise, surprise, all their conclusions still stand. Why ? Because a graph of the NAO index with 16 year delay is pretty similar to the graph of the linearly de-trended global temperatures over the past 100 years. And that's it. Neven, I apologize for an off-topic subject. I now yield the floor for discussions about the freezing season.
Kevin, Your conservative response to my criticism of Li et al 2013 is understandable. After all, we all tend to trust peer-reviewed scientific papers, especially when written by well-respected scientists. In a world where climate sceptic bloggers, "reports" by fossil-fuel funded "think-tanks" and political dominate media, peer-reviewed scientific papers seem to be the last stronghold that separates opinion from fact. And to a great extend that remains to be the case. But, that does not mean that we should uncritically accept every peer-reviewed paper blindly. In fact, there have been bad and even horrible papers in the past, and the only way to separate the good from the bad is by actually checking the science. Which brings us back to Li et al 2013. The physical effect they propose is that the NAO index (an atmospheric pressure difference) drives (with a 16 year delay) the temperatures of an area of the Northern Atlantic (the AMO), which then in turn affects the Northern Hemisphere Temperatures (NHT). Now, imagine for a moment that the SSTs over the area of the Northern Atlantic are EXACTLY following NHT. In other words, the NAO nor anything else has ANY influence over the SSTs in the Northern Atlantic, nor the AMO, nor the NHTs. If you do that, and re-read the paper with that "knowledge", you fill find that their conclusions still stand, and they still pretend to be able to predict NHT 16 years in advance. That alone should be enough evidence that they have messed up cause and effect, don't you think ?