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Comments 46701 to 46750:

46701. elsa at 04:47 AM on 30 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       Sphaerica

       I don't think I said that MA Roger agreed with doubting climatology, I think he said that one of the things the Economist did was doubt climatology, which it did.

       With regard to the models you can see from this article that there is a very wide spread of forecasts, which makes them less helpful than they would otherwise be, and the point has now been reached where the actual temperature is hitting the bottom 95% confidence limit.  What we are not told is the age of the models under investigation.

       With regard to the physical process you have not addressed the point.  Yes people have looked at actual temperature and CO2 concentrations but that does not supply an equation linking the two derived from physics.  All it is doing (and the models likewise) is fitting the data to the theory.  Of course such a theory will appear to be true.

       The argument whether CO2 is too small to matter lies at the heart of the debate between us.  I suppose at least you do say IMO!

46702. GCNP58 at 04:27 AM on 30 March 2013
       Earth Encounters Giant Speed Bump on the Road to Higher Sea Level
       

       The sample size is small, but has anyone looked at whether the effects of ENSO on sea level are amplified as global mean temperature rises?  The idea being the 1997-1998 ENSO event produced a modest dip and rise but the much smaller ENSO over the last few years produced a much larger decrease and increase.  Is the effect of ENSO on sea level nonlinear with temperature?  (I know, I'm asking you to do background research for me, but maybe you just know this from looking at the literature recently.)

46703. doubtingallofit at 03:37 AM on 30 March 2013
       To frack or not to frack?
       

       Why ignore the science on fracking and go with anecdotes when you don't do that with climate change?  Do any of you know what chemicals go into fracking?  And do you know how many years and how many wells were drilled before any claims of water contamination occurred?  (If you want to protect water, you have to put safety seals on all wells so the owner cannot contaminate the well, regulate all water well drilling, etc.  Should we go there?) I'm not seeing the science here.

46704. Bob Lacatena at 03:35 AM on 30 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       elsa,

       Quite rightly there is also a questioning of climatology...

       False (and MA Rodger is not supporting that point -- you are misrepresenting his position).

       ...they then use estimates of climate sensitivity derived not from a phsical process...

       False.  And false.

       ...if there is one thing that we all ought now to agree on, those models do not give reliable forecasts.

       False.

       You repeat a lot of myths.  It's time to start supporting your positions.  Most of your comments amount to little more than sloganeering.

       Finally:

       The answer is that the chnages in the composition of the atmosphere have been very small.

       See this.

       Or this.

       Or this.

       The argument that CO2 is too small to matter is possibly the most lame of all positions to take, and demonstrates an ignorance of the science that (IMO) disqualifies a person from participating in any rational, educated discussion.

46705. dana1981 at 02:43 AM on 30 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       elsa @20 - the only problem with the Economist article is that it's behind the times.  They barely touch on the critical accelerated warming of the deep oceans, and they don't recognize the flaws in the recent low sensitivity studies (which is not surprising, since they're not climate experts).  It's not "denialism", it's just incomplete research leading to flawed interpretations and conclusions.

       I will agree that 'denialism' is all about ignoring evidence.  The difference is that The Econimist isn't just ignoring inconvenient data, they just haven't yet caught up with the current state of climate research.

46706. elsa at 02:20 AM on 30 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       I agree with nealjking that the articles in the Economist (and yes shoyemore I have read both of them all the way through) are not particularly skeptical.  But as various others have noted above there is a hint of what most on here would call denialism.  I doubt that the Economist could change from true warmist to denier in one leap but there is definitely an underlying change of heart in there.  

       Quite rightly there is also a questioning of climatology, as MA Roger has pointed out.  As can be seen from Ed Hawkins' two graphs the current temperature is now outside the 75% confidence limit and touching on the 95% limit.

       (-snip-).  Scaddenp asks me by what physical process I arrive  at a climate sensitivity that is close to zero.  (-snip-).

       Moderator Response: [DB] Off-topic and sloganeering snipped.
46707. nealjking at 01:20 AM on 30 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       MA Rodger:

       My interpretation of the article in The Economist is that it is not nearly so skeptical or luke-warmist as you think. In particular, a fair reading of the last paragraph shows that the author is indeed expressing a concern about the actual state of the climate at 4 degrees C, not just the question of how precisely it will be known.

       In other words, the question it addressing is not the academic issue of scientific precision but rather the implications for people living in the world. It is, after all, a newspaper.

46708. Paul D at 22:57 PM on 29 March 2013
       CO2 is just a trace gas
       

       Is the trace gas thing still alive?

       Anyway, for a trace gas, it's amazingly important for life on the planet. Such tiny amounts supply us with food, trees etc.

       Plus, if you just look at the greenhouse gases in the atmosphere (like IR radiation), CO2 is the second most abundant, currently at about 9%.

       Moderator Response: [JH] The comment threads of each and every article posted on SkS are always live.
46709. MA Rodger at 21:58 PM on 29 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       shoymore @15.
       As Dana1981 says, the Economist article is not factually incorrect yet its analysis of those facts is in error. My own take is that the error is so bad, the article is entirely misguided.

       You will note that the context of concluding phrase "Hardly reassuring" that you quote (with to much assurance in my mind). The quote is not saying climate is a problem. It is actually saying climatology isn't up to the job.
       Such is the content of this article from the top 15-year flat temperatures to bottom. The author is continually exhibiting the symptoms of underlying denial.

       As for elsa, consider her/his flip from insisting ECS=0 to suggesting ECS assessments flip about far too wildly 'and you ought to see what I mean' when I tell you that elsa's position no longer fits comfortably alongside itself.

46710. Dikran Marsupial at 20:49 PM on 29 March 2013
       Tung and Zhou circularly blame ~40% of global warming on regional warming
       

       slasher@14 it is straightforward to show that argument is incorrect.  Let C' be the annual change in atmospheric CO2 (which we can measure directly) and Ea is annual anthropogenic emissions (fossil fuels are taxed, so we have good estimates of that) and En and Un are natural emissions of CO2 into the atmosphere and natural uptake of CO2 from the atmosphere (neither of which we can measure directly).  Fortunately, the carbon cycle obeys conservation of mass, so we know that

       C' = Ea + En - Un

       Technically there should also be a Ua representing anthropogenic uptake (i.e. carbon sequestration), but that is essentially negligible, so it has been neglected.  We can rearrange this to give

       En - Un = C' - Ea

       which means we can estimate the net natural carbon flux from things we can actually measure.  If we plug in the measurements, we get this:

       

       The green line is the natural contribution to atmospheric CO2, and we can see that it is not only negative (meaning the natural environment takes up more carbon from the atmosphere than it emits into it), but that it has been taking more and more carbon out of the atmosphere each year as time progresses. So if it were not for fossil fuel emissions, CO2 levels would currently be falling, rather than rising.

       According to the IPCC reports, the carbon cycle has actually intensified, with the natural fluxes both into the atmosphere and out of it increasing.  See below, the figures in red show the changes in the fluxes since the pre-industrial equilibrium. This shouldn't be too much of a surprise, if only because moving a substantial amount of carbon from the lithosphere into the atmosphere (via burning fossil fuels) means that there is more carbon sloshing about.  See the IPCC report for details, or better still, David Archers excellent primer on the carbon cycle.

       I suspect any further discussion of this topic should be on a more appropriate thread, such as this one
46711. barry1487 at 18:41 PM on 29 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       Elsa,

       "To claim that we know with 95% confidence (which actually the IPCC has never done) that the average temperature will rise by x degrees cannot sit comfortably alongside this statement."

       I think everyone here would agree. So where does this 'claim' come from? Pulled off a less than honest/accurate blogsite?

       
       There's no need to emphasise uncertainy where everyone here is aware of it. If we knew to a preciser degree what conditions would be like 30, 60 and 100 years from now, policy prescriptions would be easier to formulate. The perennial counter-argument of the 'skeptical' - that we have no certainty on the matter - somehow never seems to make it felt on them that this is cause for greater concern than better knowledge. Surely uncertainy means we should say, "it could be better or worse than our middle estimates," and therefore consider the full spectrum of risk. But when 'skeptics' say, "it's uncertain," they mean for us to hear, "it's going to be much less of a problem than we need to worry about." That's the rational disjoint in their whole thesis. Even skeptic Roger Pielke Senior advances this quite resonable proposition.

        

       "I don't think we know the consequences of what we're doing. But our footprint on the environment is more than just CO2: It's nitrogen deposition, it's the other black carbon, the aerosols, it's land-use change. And so we put all of these things together and say, "How can we come up with a policy that reduces our impact on the environment?" Because we don't know the consequences....

       The problem is, we don't know if we're pushing ourselves toward or away from some negative impact. That's the problem. We could be making ourselves actually less likely to have some drought pattern, but since we don't know, to me the prudent pattern is to try to minimize our impact."

       http://www.motherjones.com/environment/2008/10/qa-roger-pielke-sr

       Knowing less than Pielke and less than many here, I reflect that human industry has added 40% more CO2 to the atmosphere in a couple of centuries - an astonishing amount - and the surface temperature of the earth has definitely increased in that time. More uncertainty about causes and the future makes me feel more, not less concerned. The 'skeptics' have a much more rosy view of the future, but no good reason for it without being highly selective in their reading. The 'skeptical' blogs are their filter.

        

46712. Rob H at 18:05 PM on 29 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       (snip)
       Moderator Response: [Albatross] Off topic content deleted.
46713. Dumb Scientist at 13:00 PM on 29 March 2013
       Tung and Zhou circularly blame ~40% of global warming on regional warming
       

       Atmospheric CO2 increased faster after 1950.

46714. slasher at 12:17 PM on 29 March 2013
       Tung and Zhou circularly blame ~40% of global warming on regional warming
       

       significant deforrestation has not been replaced with other plants, significant deforrestation are in urban areas, the deforrestation reduces the co2 cycled through natural systems leading to more atmospheric co2

46715. Tom Curtis at 10:28 AM on 29 March 2013
       Watts Interview – Denial and Reality Mix like Oil and Water
       

       For what it is worth, from an email to A Scott:Scott,

       I also have been a little delayed in responding, the reason being I have been working on a comment at SkS, of which more later.

       I continue to believe you are trying too hard to find a problem. The reason for having linguistic conventions is so that you do not have to continuously restate details. That is, the convention of year zero BP exists so that scientists do not have to restate the start year every time the report on a new proxy or dating. It follows that if such a convention exists (and it does), if no further information is provided, that is sufficient reason to consider the ages to be stated relative to 1950.

       However, seeing you want to be obtuse (I'm sorry, but there is no better word), the facts are:

       1) Meese et al 1994 established the standard chronology of the GISP2 icecore, in which "The column Ice Age gives ages in years before 1950 AD, where "0" refers to summer, 1950." The chronology is called the Meese/Sowers chronology because it is correlated with the Sowers et al 1993 chronology of Voskok. That is the standard chronology used thereafter and reference to the Meese/Sowers chronology does not represent a revision after publication for any publication after 1994.

       2) Cuffey and Clow 1997 used the Meese/Sowers chronology, including the use of the 0 BP = 1950 convention beyond doubt, given that they state that "the age according to Meese/Sowers, given as years before 1950 AD. "

       3) Alley 2000 use the same chronology as Cuffey and Clow. We know this because:
       a) They do not mention using a different chronology for the data obtained from Cuffey and Clow, a severe lapse if they had in fact altered the chronology;
       b) Present = 1950 is the standard convention, and using a different convention without stating so would have been a significant lapse;
       c) Alley has confirmed the use of the Cuffey and Clow dating when inquiries were made;
       d) Comparison of the smoothed Cuffey and Clow accumulation rates with the reported Alley et al accumulation rates provides a best match on the assumption that Alley et al used the convention that 0 BP = 1950;
       e) Comparison of the Alley et al temperature reconstruction with the smoothed GISP2 d18O values gives the best match if you assume Alley et al used the standard convention; and
       f) The youngest gas age (indicating closure of the firn under compaction) for the GISP2 core is 89 BP, corresponding well with Alley's earliest date of 95 BP.

       I believe the last is relevant because prior to the closure of the firn, water vapour in the atmosphere can penetrate the firn contaminating the data. Once the firn is closed, the relative mass of ice and water vapour ensures the data is dominated by the former.

       Against this the only counter evidence is a NOAA page not constructed by Alley which is known to have at least one wrong date. Specifically, it says the start date of the data is -107,175 AD, whereas the earliest date in the data repository is 49981 BP (or 48,032 BC). Given that the NOAA page is out by over 50 thousand years for the start year, are you really going to rest your case on a 145 year discrepancy for the end year? On top of that, you have Easterbrook's claims, when he is not in the positon to know; and the caution of Alley's expression - which is not evidence that it is wrong.

       This brings me to the SkS post which bypasses the whole Easterbrook vs the evidence conundrum. In 2011, Kobashi et al created a new reconstruction of GISP2 temperatures using different data from the same ice core. Importantly, they brought the reconstruction up well beyond 1950, and included a direct comparison with Box 2009's reconstruction of site temperatures from regional weather data, and with the automatic weather station on site for the last two decades. In that post, I overlay Alley 2000 with Kobashi 2011, and the overlay clearly shows that onsite temperatures increased by just under 1.5 C between the end of the Alley 2000 data and the end of the 20th century. It further shows that the terminal date in Alley 2000 is in the 19th century.

       You may want to do that comparison yourself (along with those mentioned in 2 e & f above), but having done so, surely that is the end of the matter.

       Except (a prediction here), it won't be for Easterbrook. He will continue using a single proxy from a highly variable region in preference to using a large number of proxies from across the globe. He will continue to insist that (at best) only the global average temperature increase should be added to his terminal data rather than the actual temperature increase at the site as shown by regional thermometers and by a new analysis of the GISP2 data. Possibly he'll go one worse and insist on using the Greenland average air/firn temperature difference rather than the site specific difference as determined by data. All in all, he will continue to insist that Alley 2000 shows that modern temperatures (early 21st century) are very low relative to the Holocene average.

       I make the prediction with considerable confidence because he has been making the same refuted argument for many years, even though I know he has been advised of his mistakes. He is not interested in being accurate - he is interested in selling a message.

46716. scaddenp at 09:31 AM on 29 March 2013
       To frack or not to frack?
       

       I do note from those reports that in the areas where fracking seems to cause concern (and the names mean nothing to me so could be corrected here), the thermogenic gas is "wet". (contains other higher chain hydrocarbons, -butane, ethane, propane). Their presense is more strongly diagnostic and easier to measure than isotope studies which can get muddied by mixing of biogenic and thermogenic methane.

46717. scaddenp at 09:26 AM on 29 March 2013
       To frack or not to frack?
       

       gws - 14C would be no use in distinquishing biogenic coal gas from thermogenic methane - in both sources, 14C would be undetectably low.

       I followed the link but still scratching my head somewhat.The link I posted refers to analysis of aqifer that vroomie is worrying about and come up biogenic. I note that COGCC article does identify a well contaminated by thermogenic gas but tracing it to a leaking cap. There is not a lot of transparency around this data.

       I would be first to admit that I have next to no information on the fracking practise in the States. That extra chemicals (surfacants) are added is known to me, but that is common here too in geothermal. I would say that they pose managable risks involved with storage, transport and particularly in seepage from circulation pits. Is the risk from these any higher than that involved from other chemicals in common use in various industries? I dont see how the new chemicals  increase the risk of contamination of aquifers from the fracking process itself however. The key factors a casing seal and eventual well seal.

46718. shoyemore at 09:24 AM on 29 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       elsa,

       It is one of the few times I have read someone so wildly inaccurate in their assessment that they could not even aspire to being wrong. I do not think you read the same Economist article as everyone else. You are talking about an article whose second sentence is "But the problem is not going to go away.", and which finds the climate sensitivity debate "Hardly reassuring". Perhaps you should have read a bit farther than you did.

       ubrew2, the Economist is usually sound on the science, but is slavish in its promotion of fracking and natural gas as a "bridge fuel". Here, we can see the same trends as the housing bubble emerging. But fracking and bridge fuels are at least more "respectable" ideas than fake scepticism. Obama's new Energy Secretary seems to also hold to those views.

       Moderator Response:

       [JH] I deleted elsa's post because it was nothing more than sloganeering.

       [DB] Fixed typo per request.

46719. citizenschallenge at 08:35 AM on 29 March 2013
       The two epochs of Marcott and the Wheelchair
       

       I should have written

       ... around this Maginot Line

46720. gws at 08:28 AM on 29 March 2013
       To frack or not to frack?
       

       14C is not (yet) used in these studies. It would be challenging on methane anyway.

       @scaddenp: please follow the link in the post re water contamination. Thanks for the comment re 13C isotopes. OTOH, you are recycling a myth stating "that's been done safely for decades". Todays techniques are different and they do pose different challenges, particularly re fugitive emissions. Safety re water contamination is a different question.

46721. citizenschallenge at 08:27 AM on 29 March 2013
       The two epochs of Marcott and the Wheelchair
       

       "Magnon Line"

       hmmmm...

       Tragically, we won't be able to do an end run around it.

46722. citizenschallenge at 08:25 AM on 29 March 2013
       The two epochs of Marcott and the Wheelchair
       

       Thanks for reposting this article by Jos Hagelaars.

       Now I'm able to repost it,  yippy   ;)

       "Marcott et al. 2013 - A Collection of Examinations and Reviews"

       http://whatsupwiththatwatts.blogspot.com/2013/03/marcott-et-al-2013-collection-of.html

        

       Thanks for all the hard work you folks do !

       Cheers

        

46723. LarryM at 08:23 AM on 29 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       elsa@12:  Please read the rebuttal to the bogus argument that "CO2 is just a trace gas".  The difference between a CO2 concentration of 0.0% and the pre-industrial concentration of 0.3% is the difference between a frozen Earth and a nice comfortable Earth that can support a population of billions.  Small amounts of lots of things make a big difference.  It's not the percentage that matters, it's the doubling of it that matters.

46724. vrooomie at 08:23 AM on 29 March 2013
       To frack or not to frack?
       

       "... it seems strange to suddenly have a hue and cry about something thats been done safely for decades."

       What's been done for decades was simple water and sand fracking; what is recently being done is the use of many toxic chemicals in the frack fluid, some of which the oil corps *will not* iallow nformation on. To me that is a huge big red flag. "Gasland" is a good movie, and you ought to view it; the 'flaming faucet' isn't far from where I live, and I live smack dab in the middle of one of the biggest fracking frenzies in the country. given the lies we were told, vis--avis 'safety' in the Gulf (and in many other despoiled environments), I have little reason to believe fracking is as safe as the oil corps claim it is.

       I am *not* willing to bet my source of fresh water--in a  region where it is already scarce--to it possibly being ruined. And when  you ruin an aquifer--think the Imperial Valley--it's ruined. No more water. An average fracked well uses between 4-6 million gallons of fresh water (brackish/salt water won't work) and the vast majority of that is ruined for animal use, human and non-human. If ever there was a call for the precautionary principle, writ larger, I'm not sure of where. There is no substitute for water.

46725. ubrew12 at 08:12 AM on 29 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       I read the Economists' article and all I can say is dana1981 seems to be correct.  For example, the article gives pretty much equal weight between IPCC's 3C sensitivity estimate and Berntsen's 1.9C sensitivity.  It backs up Berntsen's estimate with other studies, and mentions even lower estimates several times.  The casual reader could easily come away with a 'feeling' the sensitivity is likely 2C or lower.  What the Economist omits is the many studies that point to a 4C sensitivity or higher.  This presentation of a false balance should be familiar to watchers of Fox News.

       From the Economist article "[if climate sensitivity is low] more adaptation rather than more mitigation might be the right policy"  It might be if mitigation costs are high, but what if they are low?  Why does a magazine that calls itself 'the Economist' omit the HALF of that equation they would seem most qualified to estimate?  By omission, the article maintains the myth that mitigation costs are high, and hence the 'adaptation' decision is solely dependent on those durned climate scientists and their tea leaves.

       From the Economist article: "If climate scientists were credit-rating agencies, climate sensitivity would be on negative watch"  But actually, if climate scientists were credit-rating agencies, then they would rate Wallstreet mortgage derivatives 'AAA' and sell them to pensioners.  The Economist missed an $11 trillion housing bubble, yet the credit-rating agencies that helped create it are still the 'gold standard' when it comes to judging value?  Such is the world we live in, apparently.

       The uncertainty about climate change is now essentially ALL on the side of evaluating economic impacts versus costs of mitigation.  Given its recent failings, I guess I can't blame the Economist for focusing on climate uncertainty instead.  But its no service to their readers.  The cost of mitigation is variously estimated to be 1% of GDP, which is pretty trivial.  And the benefits?  What is the benefit to keeping Manhattan and its credit-rating agencies from drowning?  Whatever that is, the Economist won't be talking about it.

46726. elsa at 08:01 AM on 29 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       The climate sensitivity seems to me what divides the warmists from the deniers. (-snip-).  Take on board the full implications of the statement "To illustrate that latter point, in the Norwegian study referred to earlier, an estimate of sensitivity using temperature data up to the year 2000 resulted in a relatively high sensitivity of 3.9 C per doubling. Adding in just a single decade of data, from 2000 to 2010, significantly reduces the estimate of sensitivity to 1.9 C." and you ought to see what I mean.  To claim that we know with 95% confidence (which actually the IPCC has never done) that the average temperature will rise by x degrees cannot sit comfortably alongside this statement.

       Moderator Response: [DB] Off-topic sloganeering snipped. Perhaps in the 2 years and 7 months that have elapsed you should have taken the time to actually learn something about the climate models (one of the basis for determining CS) you so thoroughly are uninformed about.
46727. Tom Curtis at 07:53 AM on 29 March 2013
       Most of the last 10,000 years were warmer
       

       Lanfear @25, I apologize for the delayed response.  It is with good purpose, however.  I have had the good fortune of rediscovering a recent paper (Kobaski et al 2011) showing a reconstruction of GISP2 data using a different method from Alley et al (2000).  That paper, based on the same ice core as used by Alley et al, carries the reconstruction through to about 1990, something they are able to do because of a higher resolution sampling.  Further, they directly compare their reconstruction to the Box 2009 reconstruction of temperatures since 1840 that is used in the main post; and with the AWS temperature record.

       The main post here uses the Box data under the assumption that temperature differences determined by the same method are likely to be correct in terms of relative position, but when compared to records determined by other methods there may be biases (possibly unknown) which distort the result.  Based on this principle, it adds the temperature difference between the decadal average of 1850-59 (corresponding to the end of the Alley et al temperature proxy) and 2000-09 (the present) to the Alley proxy.  Decadal differences are used because of the low resolution of the proxy.

       Kobaski et al discuss the issue directly, saying:

       "Before the two records are combined with the 4000‐year temperature record, it is necessary to make an adjustment, as firn temperatures are colder than air temperatures by 0.2°C to 2.6°C in Greenland [Steffen and Box, 2001] as a result of the surface radiative cooling and inversion as noted above. As the mean difference between the decadal average reconstructed Summit temperatures and the reconstructed Greenland temperature for the 1845–2005 period is 1.75°C, the AWS and reconstructed Summit temperatures are reduced by 1.75°C (Figure 1)."

       (My emphasis)

       So you are correct that the cause of the difference is the difference between firn temperature and the surface air temperature.

       As to the question about GISP2 temperatures and the MWP, that is more complex.  The Kobashi 2011 reconstruction shows greater variability in temperature due to its higher resolution.  As a result it shows some temperatues exceeding modern values in the MWP.  It also shows a significant peak in temperatures around 700 AD which significantly exceed modern values, although that predates the traditional dating of the MWP:

       

       (Kobashi et al 2011, figure 1.  Click on image for higher resolution.)

       I have attempted to overlay the Alley 2000 proxy data with the Kobaski 2011 reconstruction for comparison.  Doing so clearly shows the difference in resolution.  It shows some differences in the result as well.  Most notably, the 700 AD peak in Kobashi 2011 corresponds to a trough in Alley 2000.  I am certainly not expert enough to say which is likely to be more accurate where the two disagree.

       Despite the differences, the curves track each other reasonably closely closely to show.  The match should put paid to any doubts that the termination of Alley 2000 is around 1855, and that the 1855 temperature in Alley et al is approximately 1.5 C lower than modern temperatures at the same location:

       

       (Alley 2000 overlayed with Kobaski 2011.  Alignment was achieved based on the axis.  Click on image for higher resolution.)

46728. scaddenp at 07:08 AM on 29 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       Elsa, given a no-feedback sensitivity of 1.2, by what physical process do you propose to get a sensitivity close to zero??

46729. scaddenp at 06:59 AM on 29 March 2013
       To frack or not to frack?
       

       Distinguishing biogenic (from say coal beds) from thermogenic is not straightforward when biogenic source is too old for C14 to be of use. If you only have CH4 then thermogenic is lighter (d13 depleted) but it can be a difficult call. A better indicator of thermogenic gas is other hydrocarbons (eg ethane, butane) which would be unlikely biogenic gases. According to this report which looked at contamination discussed in the Gasland movie and did both geochemical and isotope studies, water contamination was from biogenic sources.

       And then you have the problem that fracking operations could theoretically at least mobilize biogenic methane.

       I havent seen Gaslands but I am suspicious of many anti-fracking claims. While needing a good regulatory environment (like all mining), it seems strange to suddenly have a hue and cry about something thats been done safely for decades.

        

46730. jja at 06:25 AM on 29 March 2013
       The two epochs of Marcott and the Wheelchair
       

       I'd call it the "Magnon Line" as a play on the Magnot Line since it embodies the beginning range of time that modern humans have taken dominance over Neanderthal and projects out to the end of humanity's pre-eminence on the planet (if we continue on this line).
       
       I think the A1B data should be dotted, and they should be using A1FI since it is the best fit to current emissions trends.  

46731. michael sweet at 06:07 AM on 29 March 2013
       Enhanced SkS Graphics Provide New Entry Point into SkS Material
       

       Jeff Masters at Wunderground weather in the US posted a blog that has a lot of Skeptical science graphs in it.  No new data but it shows that SkS is helping other scientists out.

46732. JosHagelaars at 06:04 AM on 29 March 2013
       The two epochs of Marcott and the Wheelchair
       

       @Tom Curtis

       I think you want much more from this short post than it was intended to be.
       For me the graph of Marcott et al, as presented in figure 2, makes it visible that the decreasing trend in temperatures starting around ~7000 BP was reversed somewhere before 1900 and this is backed up by the instrumental record. The same applies for the graphs of Marcott et al and the graphs of Tamino you copied here, they also show that this long-term decreasing trend did change.
       That's the main message of my post.

       I had no intention whatsoever to go into the details, like uncertainties, robustness, different algorithms or calibration methods as present or used in the Marcott et al reconstruction. I think I clearly state that the study is about the Holocene and if you don't want to call that graph a hockey stick that's OK with me.
       Other graphs with same message:
       http://www.skepticalscience.com/pics/c4u-chart7.png
       http://www.arcus.org/synthesis2k/synthesis/2k_Arctic_temperature.jpg

       In my opinion the slow decline since ~7000 BP would not have changed without the human influence. According to the CMIP5 data the total anthropogenic forcing in 1940 with reference to 1765 is 0.6 W/m². With a TCR of ~0.5 °C/(W·m²) this equates to ~0.3 °C. Certainly substantial.
       Data from PIK-Potsdam. See also this SkS post.

       The other message of my post is that if humans continue on this path we will generate a change in temperatures of the same order of magnitude as from the last deglaciation to the Holocene maximum according to the Shakun data and that this change will be very fast on a geological timescale.

       You may be right that my posts (this post is a translation of a Dutch original) at the Dutch version of ourclimatechange do take some, or a lot, scientific knowledge for granted. Something worthwhile discussing with Bart and the other co-bloggers.

       Please write your own post if you are not happy with mine. Reading your last comment #20, I certainly have the impression that your opinion about global warming is about the same as mine, we probably only differ in opinion about the presentation and/or the level of detail needed.

46733. jja at 06:00 AM on 29 March 2013
       New Research Confirms Global Warming Has Accelerated
       

       Question: 
       
       Does this data indicate that Trenberth's modeled global energy budget (http://www.skepticalscience.com/Tracking_Earths_Energy.html)  underestimated surface absorption and consequently underestimated Aerosol-cloud cooling?
       
       The AR-5 reduced its estimates for the value of negative forcing caused by aerosols.  Does this then indicate that there is a higher uncertainty for these values, potentially stronger negative forcing?

46734. Albatross at 05:55 AM on 29 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       For the most part, The Economist has doing a surprisingly good job covering anthropogenic climate change.  However, this was a very dissapointing piece by The Economist.

       As Dana noted climate sensitivity is complex (as is also evidenced by The Economist's long missive), and the inability of the article's author to correctly interpret the myriad of papers and data sources showed.  That they erroneously consider Nic Lewis to be a climate scientist was a huge red flag that the article's author was not informed enough to tell the real science from the chaff.  All in all, The Economist piece is an exercise in wishful thinking.

       Climate sensitivity is the fake skeptics' final fall-back position for inaction, so I can understand why they will cheer anything that they perceive to support their agenda. But even if climate sensitivity to doubling is "only" near 2 C, that does not disappear anthropogenic warming, nor does it disappear ocean acidification, nor does it disappear rising sea levels, loss of Arctic sea ice, receding glaciers or increases in certain extreme weather phenomena, nor does it change the fact that on our current emissions path we will likely quadruple CO₂ levels before 2100.

       Regardless of what equilibrium climate sensitivity is, we should be reducing GHG as quickly as possible because we have most likely already missed the boat to keeping warming to 2 C or less.

       Odd then, that some people seem to be trying to console themselves that everything will be OK or that aggressive action to reduce GHG emissions is not required by trying to argue for lower climate sensitivity.  That approach is very much backwards and amounts to nothing more than wishful thinking.

       Hopefully The Economist does better next time round.

46735. NewYorkJ at 05:37 AM on 29 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       Kevin,

       The recent article is hardly "anti AGW" either.  

       So what does all this amount to? The scientists are cautious about interpreting their findings. As Dr Knutti puts it, “the bottom line is that there are several lines of evidence, where the observed trends are pushing down, whereas the models are pushing up, so my personal view is that the overall assessment hasn’t changed much.”

       
       But given the hiatus in warming and all the new evidence, a small reduction in estimates of climate sensitivity would seem to be justified: a downwards nudge on various best estimates from 3°C to 2.5°C, perhaps; a lower ceiling (around 4.5°C), certainly. If climate scientists were credit-rating agencies, climate sensitivity would be on negative watch. But it would not yet be downgraded.

       Best estimate is still 3 C...but maybe it will be concluded to be 17% less.

       Both articles have their caveats.  Both also emphasize a skeptical angle with regards to best estimate climate sensitivity (the 2011 article describes it as "good news".  Failing to do so would be boring, and the media doesn't like boring.

       Clearly, this isn't the first time The Economist has had a skeptical angle in their articles, although they certainly have had better-quality articles on climate-related issues.

       tobyjoyce,

       It has already cited by contrarians around the web as though it was somehow supportive of their position.

       What deniers look for is movement towards their position from any realm (media, scientists, politicians, real or perceived), which is ultimately a strong desire not to legislate reductions in greenhouse gas emissions.  Even the perceived slightest movement warrants heavy spin, as they believe it helps with public perception, as in "hey look, the media is starting to figure out we're right".  

       My observations are that media on the whole has moved away from science in general, due in part to cost-cutting measures and the big economic downturn a few years ago.  What remains isn't as good of quality.  At the same time, denial is also on the decline over the last few years (public polls indicate that as well).  ClimateGate is virtually dead, and I'm not seeing as many contrarian views covered in media, other than the usual suspects.  Could be the whole ClimateGate thing killed contrarian credibility, and media felt duped in the end.  Deniers have to stretch these days to find something supportive of their movement.

        

46736. william5331 at 05:36 AM on 29 March 2013
       Arctic methane outgassing on the E Siberian Shelf part 2 - an interview with Dr Natalia Shakhova
       

       The age of the methane is of interest.  If it is found to be greater than the 50,000 years that can be measured with carbon dating, this would point to a geological source such as outgassing from coal, shale or liquid hydrocarbon deposits.  This would reinforce the idea that such seeps would be trapped under ice sheets as clathrates once the ice sheet had reached about 300m deep.  Over the roughly 100,000 years that glacials last, a lot of methane can accumulated only to be released when a milankovitch nudge starts the melt.

       It could be that no methane pulse would be seen in ice bubbles from Antactic or Greenland cores.  The half life of methane is about 7 years and much of the oxidation is due to hydroxyl ions in the upper atmosphere.  Whether this oxidation would continue inside the ice is a moot point.  However, the top 70 or so meters of a forming ice sheet still exchanges gas from the atmosphere.  The bubbles are not yet closed.  This would tend to blur or even eliminate a methane signature in ice bubbles even if it did occur in the atmosphere. 

       Another unsettling effect of methane release, especially on the continental shelf is the loosening of the sediment both by the melting of the "clathrate permafrost" and the expansion of the gas, turning the sediment into a fluidized bed.  Sudden slumps on continental shelves have been implicated in localized but very severe tsunamis.  Will the coastal people of the Arctic ocean experience some of these in the not too distant future.

46737. tobyjoyce at 04:34 AM on 29 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       I was disappointed overall with the tone of the Economist piece, because they are generally "sound" on the science of climate change. It shows that propaganda about a temperature "hiatus" and lower carbon sensitivity has gained some traction in the more rational media.

       It has already cited by contrarians around the web as though it was somehow supportive of their position.

       But look on the bright side - David Rose and the Daily Mail it wasn't. Not even close. 

46738. Kevin8233 at 04:33 AM on 29 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       NewYorkJ,

       Before you take the SUV out for a celebratory spin, though, it is worth bearing in mind that this is only one study, and, like all such, it has its flaws. The computer model used is of only middling sophistication, Dr Schmittner admits. That may be one reason for the narrow range of his team's results

       That is the statement from the previous article you reference.  Not exactly an anti AGW statement.  It looks like this other article was just a piece on this one paper.

46739. NewYorkJ at 04:19 AM on 29 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       Although deniers are trying to spin it otherwise (part of the message they're trying to sell that their movement is growing, and any material that they might spin as being skeptical is evidence of that), this isn't the first time The Economist has commented on climate science, or with a arguably skeptical angle.  In 2011, for example,

       The climate may not be as sensitive to carbon dioxide as previously believed

       Another area where The Economist article fails is being selective about the evidence they present.  The neglect, for example,

       Fasullo and Trenberth Find Evidence in Clouds for High Climate Sensitivity

46740. Bob Lacatena at 03:57 AM on 29 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       elsa,

       A zero climate sensitivity is so far beyond reality as to border on insanity.  That's like saying gravity might stop at any moment -- that the effect of gravity could turn out to be near zero.  A zero climate sensitivity is that insane.

       Best estimates for climate sensitivity today are still between 2.5 and 4 C per doubling.  Even the lowest in that range, 2.5 C, will turn out to be very, very bad for civilization, and at this point in time it seems vanishingly improbable that we will not shoot past and beyond a mere doubling.

       People don't seem to recognize how much of a change that minimum reasonable estimate represents.  And heaven help us if it's even just a little higher (like in that most likely case of 3 C or even 3.5 C).

46741. dana1981 at 03:45 AM on 29 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       I just thought it was strange for The Economist to try and tackle this subject because they clearly lack the expertise to properly interpret the research.  It seemed like they sent an intern to find a bunch of papers to reference, dumped them into an article, and didn't really know what to say about them.

       elsa @2 - given that climate sensitivity is indisputably different from zero, I guess you're agreeing that Zeke's statement is true.

46742. MA Rodger at 03:11 AM on 29 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       Climate Sensitivity - is it rather a strange subject for in-depth analysis by The Economist? Not really.

       Surely economists would do well to understand it. And even if it were not, in its Science & Technology section, The Economist does cover subjects that cannot be relevant to economics. For instance, last week it looked at the evolution of animals 500m years ago. Perhaps then, with all the economic gloom, an occasional diversion is good.

       The Economist did a poor job printing the article discussed by this post. They did also run a front-piece editorial which struck a better note, concluding "If the world has a bit more breathing space to deal with global warming, that will be good. But breathing space helps only if you actually do something with it."  Still, I don't think it makes up for the dreadful article.

46743. Jubble at 03:03 AM on 29 March 2013
       David Rose Hides the Rise in Global Warming
       

       I am a UK resident, and have submitted a complaint to the UK Press Complaints Commission.  They informed me they are already investigating the article due to an earlier complaint.  I let you know the outcome.

46744. elsa at 03:03 AM on 29 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       "Just how warm the world will be in 2100 depends more on how much carbon is emitted into the atmosphere, and what might be done about it, than on what the precise climate sensitivity ends up being."  That would only be true if the precise climate sensitivity was a postive number materially different from zero.  At zero the volume of CO2 in the atmosphere would make no difference to temperature. 

46745. elsa at 03:00 AM on 29 March 2013
       Making Sense of Sensitivity … and Keeping It in Perspective
       

       "Ultimately it was rather strange to see such a complex technical subject as climate sensitivity tackled in a business-related publication. While The Economist made a good effort at the topic, their lack of expertise showed."

       The Economist has published articles on science and technology for at least 40 years, indeed it usually has an entire section devoted to that topic.  For some years it has also taken the warmist line.  That they are now raising questions for the AGW side marks something of a turning point in my view.

46746. Bob Lacatena at 01:58 AM on 29 March 2013
       The Big Picture (2010 version)
       

       tcflood,

       I was hoping to have found a place where I could ask honest questions and have honest discussions.

       That's not how it looks to me, based entirely on your own posts.  You listed 5 common, low-level denial arguments that are very easily rebutted just by using the Search box and following the links.  None of them required interaction with or interjection by people who have a deep understanding of the climate science.

       Yet people engaged you anyway, and gave you a wealth of information that a trained chemist should be able to easily absorb.

       All you did in response was to change the subject and list more and more denial arguments.  I put a lot of time into creating this response for you, directly answering your question, in the fashion you requested (no math), using a frame of reference (chemistry) that should be right up your alley.

       You apparently did not even read it, let alone respond.  Instead, you decided to take your ball and go home in a huff.

       Your behavior suggests another agenda, that you were never really here to ask questions or to learn.  All you did was to clutter up this thread with off-topic denial sloganeering (all of which, if strictly subject to the site's Comments Policy, should be deleted).

       People responded, and you never once provided a counter-argument or delved more deeply into any subject.  You simply got angry, complained, or more often than that rushed to change the subject to yet another silly denial argument.

       Sorry, but based on your own behavior, visible to all, you'll get no sympathy here.  Your understanding of climate science is abysmal.  I know high school students with a deeper grasp of the science than you have demonstrated.  If you wish to be respected for your knowledge and understanding, then it needs to be adequately developed.

       Your decision to stop posting is probably the correct one.  However your decision to leave, without taking the time to learn exactly how much you fail to properly understand, is ill-advised.

       More people need to spend more time reading and learning instead of gettting angry because their ignorance is not given "due respect."

       Asking honest questions is always welcome.

       Asking questions with no intention of listening to the answers is not.

46747. John Hartz at 01:43 AM on 29 March 2013
       2013 SkS News Bulletin #5: Alberta Tar Sands and Keystone XL Pipeline
       

       chriskoz:

       I agree completely with your assessment of Andy Skuce's article, Keeping the Cork in the Oil Sands Bottle. In fact, I woiuld like to see it reposted on SkS. 

46748. CBDunkerson at 22:44 PM on 28 March 2013
       A Detailed Look at Renewable Baseload Energy
       

       Citibank recently did an analysis, discussed here, which closely matches my own expectations. This analysis suggests that the most likely scenario for global energy production in the short term is rapid growth of solar and wind power with natural gas as backup generation. This would slowly eliminate the concept of 'baseload' power... you'd have intermittent power from wind and solar and whenever demand exceeded the available intermittent power the natural gas plants would kick in temporarily to make up the difference. As time goes on the need for natural gas backups would then be eliminated by having a large enough smart grid to dispatch intermittent power from areas with excess to areas with a shortfall and/or various methods of power storage. Some areas will continue to rely on relatively steady power sources like hydro, geothermal, and nuclear which are already in place, but most generation will be from solar and wind.

       Barring some major new power innovation this path seems nearly inevitable to me. Wind, solar, and natural gas are all now cheaper in nearly every market than coal, oil, and nuclear, and this price gap will only get greater with time... and indeed wind and solar will soon be cheaper than natural gas as well. Hydro and geothermal are cheaper in some areas, but more expensive or impossible in others. Thus, economics will inevitably drive wind and solar to replace coal, oil, and nuclear. Natural gas compared to other fossil fuels is cheaper, probably less polluting (though more study of methane leakage is needed), and easier to quickly bring online and shutdown without tremendous inefficiency. Thus, it will logically fill the role of backup power source for most of the world until the infrastructure needed for fully renewable power is in place.

       If the future plays out this way then global carbon emissions will decline to safe levels long before we get to scenarios where we burn all available fossil fuels. Maybe we pass 560 ppm atmospheric CO2, but certainly not 1120 ppm. Of course, that could still result in very damaging AGW (especially if large methane feedbacks kick in), but we should be able to avoid the most catastrophic scenarios. Unfortunately, all that is based on current technology. Someone could come up with a cheap way to collect methane hydrates from the ocean in a few years and thus undercut solar and wind prices with a massive new fossil fuel source... at which point we're back to catastrophe unless governments actually respond intelligently and start putting a price on carbon.

46749. bouke at 22:24 PM on 28 March 2013
       To frack or not to frack?
       

       Chriskoz @3:

       The problem is that there is 'natural' fossil methane 50 meters down in some places, so the expected isotopic fingerprint would be that of fossil carbon. Also,  shallow methane is more likely to be present in areas where fracking occurs, because both may have the same source. Therefore, only a correlation cannot prove causation. The only way to know is to do a measurement before drilling, and one after.

       Also, even when you can prove a contamination is from a nearby well, the cause may not be the fracking process, but a leak near the top of the well. The latter can be mitigated by better regulation, the former cannot, so it is important to know what actually is the case. 

46750. Dumb Scientist at 21:15 PM on 28 March 2013
       Tung and Zhou circularly blame ~40% of global warming on regional warming
       

       The article linked to a radiative forcings chart that includes deforestation as a small "land use" component. It's negative because clearing rainforests to plant endless fields of identical crops increases the albedo, reflecting more sunlight and producing a slight cooling effect.

       I've already noted that deforestation also releases CO2 but in much smaller quantities than fossil fuel emissions. If deforestation before 1950 warmed the planet at the same rate as fossil fuel emissions after 1950, then why did atmospheric CO2 increase faster after 1950?

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