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Comments 52901 to 52950:

52901. chriskoz at 20:38 PM on 4 October 2012
       Modelling the permafrost carbon feedback
       Everybody here stipulates the consequences of C cycle disturbance we are causing. The disturbance in measured as just GtC, without actually qualifying the change of C oxidation/stability. What I mean here is that FF burning disturbance is far more severe than permafrost thawing disturbance. Because FF are sequestered in very stable form in 400Ma timeframe. That qualifies as at least 4000 times more stable as permafrost, which was likely thawed/refrozen in 100Ka interglacial cycles. That's why CO2 from FF is "far worse" than permafrost thawing for climate stability. That's why the Earth will have much harder time dealing with FF CO2: i.e. oceans that currently absorb some of it, will eventually degass it. While permafrost down to 3.5m may release CO2 that would eventually be effectively absorbed by the growing biosphere (i.e. lush forests may replace thundra if we return to hothouse) because the C in question is effectively part of the circulation in biosphere. So, when talking about carbon cycle changes, on a long run (that concious custodians of this planet should realy care, beyond 2100 which seams to be a limit of conciousness by politicians) one can ignore the effects of natural C feedbacks (that seem small by this study anyway) and concentrate on human disturbance that is unprecedented in millions of years.
52902. bvangerven at 20:05 PM on 4 October 2012
       The Economic Damage of Climate Denial
       The is one aspect missing in your article : You compare the cost of mitigation versus the – future – cost of adaptation. But not a word is said about who will pay the price in both cases. The cost of mitigation would be paid by the polluters. The cost of adaptation on the other hand would either be paid by the tax payers, or if the government completely fails to do its duty, adaptation will only be affordable for the rich elite, to protect their personal property, and the rest of us will be left in the lurch. This is also the main reason why representers of the fossil fuel industry plea for adaptation instead of mitigation. They are not really convinced that adaptation is cheaper, but it will be cheaper for their business.
52903. Falkenherz at 17:30 PM on 4 October 2012
       Climate time lag
       Thanks again, expecially Bob's comment (and Sphaerica's comment on the 1 W/m2->0,25 W/m2) clarify a lot for me. What I understand now is, my "thought experiment" is correct, but the figures I assumed in my example do not match to what we observe. So let's clarify what we observe now. See the graph "historical TSI re contruction" in the following link; http://lasp.colorado.edu/sorce/data/tsi_data.htm If I eyeball this, there has been an increase of TSI between 1700 to 2000 from roughly 1360,3 to 1361,3. This is the 1 W/m2 you are talking about, which translates into a "spherical" impact of 0,25 W/m2 (I don't know if that last step is challenged by sceptics, since we should talk about the sun energy which is overal captured from space on earth?). This also is Spaerica's point. So, reality tells us that an increase of TSI is 0,25 W/m2, and the lag to global temperature should be about 25-50 years, maybe even 150 years when the increment is small like this. Now, Bob, I understand that temperature rise should level off, if it would be just a lag. But you state "To get a situation where the atmosphere fails to show a response to the up-to-1960 TSI increase for 10-30 years, and then suddenly starts to increase, you need to argue a reasonable mechanism." I don't understand the part about "fails to show a response", but overall I believe this statement refers to the "hockeystick", right? So what you mean to say is, temp rises much higher/faster since roughly 1990 than ever before since 1850, and this cannot match to a TSI "lag pattern" from 1960 onwards? Turning to global temperature, I eyeball from this graph SPM.3 (http://www.ipcc.ch/publications_and_data/ar4/wg1/en/spmsspm-direct-observations.html) an increase since 1960 from roughly 13,9 to 14,5 Degrees. My problem here is, that the global temperature is only shown since 1850, not since 1700. Maybe you could put this into this long-term perspective? How much raise has happened since 1700, and how much since 1960? If the relations do not match, as you imply, then indeed we cannot assume a TSI lag. If it was a TSI lag, then we should see a leveling off, which means the raise of global temperature since 1960 to 2000 must be overall much less than the raise between 1700 and 1960, right? What I am basically trying to do, is finding the long-term perspective, because I suspect that everything happening in under 50 years could also have causes which we could attribute to "climate chaotics" besides the known GHG effects. (This of course not if we don't have an alternative possible explanation, one of which could be the here discussed lag.)
52904. Kevin C at 17:10 PM on 4 October 2012
       Nate Silver's Climate Chapter and What We Can Learn From It
       

       "In climate science, this healthy skepticism is generally directed at the reliability of computer models used to forecast the climate's course."

       It's worth reiterating that climate models are not the only means of making projections of future climate. Past climate tells us at least as much, and gives the same kind of answers. The Knutti and Hegerl 2008 graphic (below) provides a (now dated) illustration of this:

       

       There is a nice collection of empirical climate sensitivity estimates on this page. For a more recent work see Padilla et al 2011. So even if the models are complete junk (a claim which goes well beyond Silver's claims), we can still be confident that the short term temperature projections based on TCR and long term projections based on EQS are in the right ballpark.
52905. dana1981 at 15:23 PM on 4 October 2012
       Nate Silver's Climate Chapter and What We Can Learn From It
       Thanks OPatrick, I did tweet this post to Silver, so presumably he's aware of it. Would be interesting to hear his thoughts.
52906. OPatrick at 15:18 PM on 4 October 2012
       Nate Silver's Climate Chapter and What We Can Learn From It
       A clearly written review, which looks to be fair and balanced. I think a concerted effort to politely request that Nate Silver responds to this article might be in order. Perhaps he will have the integrity to do so.
52907. dana1981 at 13:27 PM on 4 October 2012
       Nate Silver's Climate Chapter and What We Can Learn From It
       Composer @1 - AIT is very vague about timeframes, basically just discussing potential consequences without saying when they might occur. I happen to think the vagueness was a fault of the film, but at the same time as you point out, it was factually correct in noting that those potential consequences are very real. So I think Silver's criticism of the film as "less cautious" isn't accurate - too vague or imprecise would be a valid criticism.
52908. skywatcher at 12:39 PM on 4 October 2012
       It's not us
       Carbon500, from your post here: I've seen a reproduction of this quote in quite a number of places - it seems to be a bit of a darling quote of the so-called 'skeptics' - a report from the early 20th Century indicating that conditions in the Arctic are notably warmer than in the late 19th Century. You quoted this as though it's somehow surprising or that it refutes anthropogenic causes for global warming. A 1920s observer in the Arctic might notice that, compared to the late 19th Century, glaciers had retreated somewhat and that sea ice was reduced in extent. An observer in the early 21st Centuey can observe that the same glaciers are considerably further back and continuing to retreat at a rapid rate [Some slightly readvanced in the 1960s-1980s in response to favourable conditions in the 1960s and 1970s]. A 21st Century glacial geomorphologist can observe that glaciers in Iceland, Norway, the Alps and elsewhere reached their greatest "Little Ice Age" extent in the late 19th Century (historical records, lichenometry etc) leaving large moraines behind. This is no surprise! We know there has been warming sice at least the late 19th Century. We have a pretty good idea of the causes of the warming through the 20th century: early warming had a large component of solar activity and a reduction in volcanic activity in addition to the initial component of post-Industrial Revolution greenhouse gas emissions. As we moved through the 20th Century, the GHG forcing increased to be the strongest of all the forcings, such that we cannot explain our current trajectory of warming if we ignore GHG physics (unless you believe in climate fairies, which I don't). The Arctic is continuing to respond to those forcings. The skeptics' claims that early 20th Century observations of the beginning of the thaw of the high Arctic, which is contiuing through the present day somehow contradicts our understanding of GHGs and climate, is frankly absurd. It's a transparent attempt to mislead the unwary reader by drawing a false parallel between the 1920s and today. We see that the Arctic is a much less ice-covered place than it was 40 (or 80, or 120 years ago), an observer in the 1920s saw that the Arctic was less ice-covered than in the 1880s. That 1920s observer would be astonished to see how little ice is in the Arctic now compared to the 1920.
52909. Composer99 at 12:39 PM on 4 October 2012
       Nate Silver's Climate Chapter and What We Can Learn From It
       With regards to Nate's criticisms of An Inconvenient Truth as quoted the OP: [...] sometimes [being] less cautious, portraying a polar bear clinging to life in the Arctic, or South Florida and Lower Manhattan flooding over. Films like these are not necessarily a good representation of the scientific consensus." As far as I know, as long humans continue to emit massive amounts of CO2 and cause further warming, the flooding examples will occur of necessity. Not having seen An Inconvenient Truth I am not in a position to say whether it exaggerates the timeframe in which, say, South Florida will be swallowed up by the ocean. But I am very confident that, failing decisive action by humans to cut down our emissions and sequester carbon, it will eventually happen.
52910. Composer99 at 12:33 PM on 4 October 2012
       The Economic Damage of Climate Denial
       Apart from any mathematical problems with Clyde's claims, there is also the conceptual problem - addressed in the OP already - that the global poor (especially those unaffected by state-level energy pricing in Maine) will suffer enormously more due to climate change than they could from any reasonable mitigation effort.
52911. scaddenp at 10:37 AM on 4 October 2012
       The Economic Damage of Climate Denial
       And further to Bob's comment, (and see my earlier comment), if you hit Chinese goods with carbon tax that matches that faced by local manufacturers (which you realistically have to do), then they will decarbonise as well. Or goods from places rich in renewables suddenly become more attractive than China. US can do this unilaterally. Please dont go into a "I dont wanna pay a tax so any pathetic argument will do" mode. If you dont want to pay carbon tax, then seek out the cheaper, non-carbon alternatives.
52912. JasonB at 10:23 AM on 4 October 2012
       The Economic Damage of Climate Denial
       And the great irony, of course, is that China is doing a lot -- massive wind rollout, massive nuclear rollout, and massive hydro.
52913. JasonB at 10:22 AM on 4 October 2012
       The Economic Damage of Climate Denial
       Clyde: "I have no problem with govt funding for research & development." So, rather than tax those who are actually responsible for emitting carbon, you'd tax everybody so the money can then be given out as funding for R&D? What's wrong with a market-based approach rather than asking the government to pick winners? As for China: per capita it's at 1/3 the emissions of the US. Why are you talking about them? As a total they emit a lot but that's only because as a total they account for a lot of the world's population. You could draw a line around the whole world that's not the US and say "Wow, look how much they're emitting, we shouldn't do anything to reduce our emissions" and it would make just as much sense.
52914. Bob Lacatena at 10:14 AM on 4 October 2012
       It's not us
       Carbon500, Sorry, but your gish-gallop is 100% silliness. My original point was: "And what evidence do you have that your anecdotal evidence is equivalent to what we are seeing today?" And you respond with yet more anecdotal evidence, in this case, a narrowly focused view of ice in one part of the world, as if that is then evidence that the entire globe is not warming. I'm sorry, Carbon500, this is a 100% fail. You're going to have to try a lot harder than just listing whatever papers you can find with google-search.
52915. Bob Lacatena at 10:06 AM on 4 October 2012
       The Economic Damage of Climate Denial
       Actually, no, China is as dependent on the world as everyone else. Right now China wants into the WTO, but won't follow the rules unless it suits them. That has to change. But China is not the huge, unstoppable economic power that everyone paints it to be. They need us like we need them, and they will suffer as much as anyone due to climate change. Acting like we can't make China do anything (not make, pressure and convince) is just one more excuse to do nothing.
52916. Bob Loblaw at 09:28 AM on 4 October 2012
       The Economic Damage of Climate Denial
       Clyde:"Nobody is gonna make China do anything" Yes. It's not as if we have any say in the matter. Like deciding not to buy stuff from China. That wouldn't work at all.
52917. Bob Loblaw at 09:02 AM on 4 October 2012
       Climate time lag
       Thanks, Riccardo. I had been trying to verbally describe what I would see in a graph, but I'm away from home at the moment so I couldn't easily do a graph myself. It helps a lot, I think.
52918. ranyl at 08:50 AM on 4 October 2012
       Modelling the permafrost carbon feedback
       Thanks Andy Interesting post pointing again to things having been underestimated by the models previously used to inform decision makers. Looking at figure 1, DEP2.6 the range seems like a lower limit ~0.23C to an upper limit of 0.8C by 2100. That is an additional temperature rise for 39ppm extra CO2. 39ppm is only at most 1/10 of a doubling from 390ppm, so a CS in the model acting as 2.3C. Therefore must presume this a low end estimate, and as CS could just easily be 4.5C (especially considering the skewed distribution of CS), 0.45C is just as likely. And even with complete cessation of CO2 emissions from fossil fuels in 2013 from figure 3, atmospheric CO2 remains the same just to due additional CO2 permafrost releases, so will be at least 390ppm all the way to 2100 even if that impossible extreme occured and that is despite there being strong CO2 sinks maintained in the model, when these do seem at considerable risk when the following are considered; peat drying, forest fires, mangroove degradation, aerobic methane release from the arctic, methane from permafrost world wide (as mentioned above), vegitative diseases (pests, fungus), hotter oceans, increasing weather extremes and mass biodiversity losses. Not sure if SO2 emissions are ceased in the model but many studies have shown that this heating effect is very signifiance at least 0.4C by 2050 if SO2 emissions were stopped today. Add in the heat in the system ~0.4-6C and 2C is an almost certainity even with a CS of 2.3C, and considering recent extreme events, 1.5C is a daunting proposition. The Pliocene, the best past analogy of today, albeit with a slightly cooler sun, suggests 350ppm means a significant climate shift resulting in an Ice free Northern Hemishpere and a much warmer climate with lots more water available for the water cycle, due to the ability of air to hold 8% more water per extra 1C in average temperature (that is a lot of extra water). Also there were wider tropics and a much warmer North Pole, therefore I pressume a meandering, blocking, severe extreme weather inducing jetstream situation and over time 20-25m sea level rise, how quick this will occur is debateable however 2m by 2100 does not look out of the question, and that this a lot of extra shallow tropical seas for storms to brew over. Therefore does any on here feel, that 1 trillion tonnes of CO2 emissions, or bascially adding 80% again of what we already have, is safe?
52919. dana1981 at 07:38 AM on 4 October 2012
       The Economic Damage of Climate Denial
       Clyde, you're missing the point that we're already paying high costs due to climate change (which will only increase), which are simply not reflected in fossil fuel prices. For example, look at agricultural productivity being hit by droughts and the associated food cost increases. Your objection is basically "I don't like taxes". Fine, then propose an alternative, for example a system like the one in British Columbia where the carbon tax is offset by reductions in other taxes. Opposing all solutions won't do us any good. We'll just get nowhere as the problem gets worse and the economy continues to suffer. US emissions only fell 1.7% in 2011 which is not nearly enough, and that despite the fact that natural gas prices are at an unsustainably low level. And by the way, you can't say three 8% increases add up to a 24% increase. That's completely mathematically backwards - 8% increases in three aspects of a budget will cause less than an 8% net budget change. As for your comments about China, see doug @19. China is already working to reduce its emissions. I do agree that we need all nations to get on board in order to solve the problem, but I also think is absurd and irresponsible for the main cause of the problem (USA) to point the finger at developing countries like China.
52920. KR at 07:35 AM on 4 October 2012
       It's not us
       Carbon500 - With regards to your extended reference, yes, ice extent certainly does vary based on a number of influences. Relevance? In regards to the graph you refer to, containing temperature data only from 1996, I would refer you to the Did global warming stop in 1998, 1995, 2002, 2007, 2010 thread. Cherry-picking short intervals proves nothing about long term trends - that's weather. If you look at those long term trends, however, at climate, you see something quite different (GISTEMP and 10 year averages).
52921. Carbon500 at 07:11 AM on 4 October 2012
       It's not us
       Response to Sphaerica from 'Inuit Perspectives on Recent Climate Change' - transferred to this thread at moderator's request. Sphaerica: Just to reinforce my point – more observations from the real world. Ice conditions in the Baltic Sea vary a lot from one year to another. The maximum ice covered area varies between 52,000 and 422,000 square kilometres(12-100 per cent of the total Baltic Sea area) Baltic Sea Portal: itameriportaali.fi/en/tietoa/jaa/jaatalvi/en_GB/jaatalvi Clearly the Baltic Sea has remained free of the malign influence of CO2. Here’s more: JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 106, NO. C3, P. 4493, 2001 doi:10.1029/1999JC000173 'Influence of atmospheric circulation on the maximum ice extent in the Baltic Sea' Anders Omstedt Swedish Meteorological and Hydrological Institute, Norrköping, Sweden Deliang Chen Department of Earth Sciences, University of Göteborg, Göteborg, Sweden This work analyzes long-term changes in the annual maximum ice extent in the Baltic Sea and Skagerrak between 1720 and 1997. It focuses on the sensitivity of the ice extent to changes in air temperature and on the relationships between the ice extent and large-scale atmospheric circulation. A significant regime shift in 1877 explains the decreasing trend in the ice extent. The regime shift indicates a change from a relatively cold climate regime to a relatively warm one, which is likely a result of changed atmospheric circulation. In addition, the analysis shows that a colder climate is associated with higher variability in the ice extent and with higher sensitivity of the ice extent to changes in winter air temperature. Moreover, the ice extent is fairly well correlated with the North Atlantic Oscillation (NAO) index during winter, which supports the results of earlier studies. However, the moving correlation analysis shows that the relationship between the NAO index and the ice extent is not stationary over time. A statistical model was established that links the ice extent and a set of circulation indices. It not only confirms the importance of the zonal flow but also implies the impact of meridional wind and vorticity. The usefulness of the statistical model is demonstrated by comparing its performance with that of a numerical model and with independent observations. The statistical model achieves a skill close to that of the numerical model. We conclude that this model can be a useful tool in estimating the mean conditions of the ice extent from monthly pressures, allowing for the use of the general circulation model output for predictions of mean ice extent. Finally, the globe is warming? Is it? http://data.giss.nasa.gov/gistemp/graphs_v3/Fig.C.gif
52922. Carbon500 at 07:00 AM on 4 October 2012
       Inuit Perspectives on Recent Climate Change
       Sphaerica: Just to reinforce my point – more observations from the real world. Ice conditions in the Baltic Sea vary a lot from one year to another. The maximum ice covered area varies between 52,000 and 422,000 square kilometres(12-100 per cent of the total Baltic Sea area) Baltic Sea Portal: itameriportaali.fi/en/tietoa/jaa/jaatalvi/en_GB/jaatalvi It would seem that the Baltic Sea has remained free of the malign influence of CO2. Here’s more: JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 106, NO. C3, P. 4493, 2001 doi:10.1029/1999JC000173 'Influence of atmospheric circulation on the maximum ice extent in the Baltic Sea' Anders Omstedt Swedish Meteorological and Hydrological Institute, Norrköping, Sweden Deliang Chen Department of Earth Sciences, University of Göteborg, Göteborg, Sweden This work analyzes long-term changes in the annual maximum ice extent in the Baltic Sea and Skagerrak between 1720 and 1997. It focuses on the sensitivity of the ice extent to changes in air temperature and on the relationships between the ice extent and large-scale atmospheric circulation. A significant regime shift in 1877 explains the decreasing trend in the ice extent. The regime shift indicates a change from a relatively cold climate regime to a relatively warm one, which is likely a result of changed atmospheric circulation. In addition, the analysis shows that a colder climate is associated with higher variability in the ice extent and with higher sensitivity of the ice extent to changes in winter air temperature. Moreover, the ice extent is fairly well correlated with the North Atlantic Oscillation (NAO) index during winter, which supports the results of earlier studies. However, the moving correlation analysis shows that the relationship between the NAO index and the ice extent is not stationary over time. A statistical model was established that links the ice extent and a set of circulation indices. It not only confirms the importance of the zonal flow but also implies the impact of meridional wind and vorticity. The usefulness of the statistical model is demonstrated by comparing its performance with that of a numerical model and with independent observations. The statistical model achieves a skill close to that of the numerical model. We conclude that this model can be a useful tool in estimating the mean conditions of the ice extent from monthly pressures, allowing for the use of the general circulation model output for predictions of mean ice extent. Finally, you state that the globe is warming? Is it? http://data.giss.nasa.gov/gistemp/graphs_v3/Fig.C.gif
52923. Riccardo at 06:58 AM on 4 October 2012
       Climate time lag
       Maybe it's easier to see these things graphically for the simplified energy balance model with a step-like forcing (thin red dashed line) applied at t=0. The red line is the energy imbalance and the black line is the temperature response. The time constant is 50 years. In this simple model the lag time is just the time taken to get about 63% of the effect. The response stats immediately and proressively slows down due to the decreasing energy imbalance, as expected.
       Moderator Response: This would be a great addition to the original post....
52924. Clyde at 06:37 AM on 4 October 2012
       The Economic Damage of Climate Denial
       dana1981 18 US carbon emissions decreased in 2011 mainly because of the move away from coal toward natural gas. My point (perhaps made poorly) was no tax was needed to reduce CO2 in the time frame. I have no problem with govt funding for research & development. IMO the fed govt (states can do as they please) shouldn't be raising taxes on anything. A carbon tax might be will intended in the beginning, Social Security was too. The fed govt now uses SS money for things other than SS. Talking about Maine's expected slight increase in electricity prices as a result of renewable energy completely misses the point of this post - that the costs of fossil fuels are not reflected in their market price, so previous electricity rates were artificially low. There's more than the "slight increase" in electric prices in the study. That's only part of the problem. Now lets move to a nation wide carbon tax scheme. I'm guessing gas/diesel will be included at some point. Either a direct tax on fuels or a mileage tax. That will increase the cost of everything in our daily lives. Using Maine's slight increase 8% in 2017. 1. Electric bill 8% 2. Fuel for vehicles 8%. *That will increase amongst other things, the cost of public transportation. 3. Grocery bill 8% Just three things a 24% increase. Before long a slight increase becomes a big increase. I'm guessing you know that will hit the poor the hardest. *Now some will say they poor can get tax rebates to help them deal with the increase. That money has to come from somebody. Not many (if any) folks aren't effected by higher gas/diesel prices & electric bills. Do you think companies won't pass the cost of production on to the consumers? Yet another 8% increase. DISCLAIMER: I used 8% just for a visual. I don't know the actual % without seeing the actual tax. The point being everything in our daily lives will cost more with a CO2 tax. When everything cost more it's no longer a slight increase. Your comment about China is an example of Tragedy of the Commons. It might be, but it doesn't make it false. Nobody is gonna make China do anything. Do you agree that for a CO2 tax to have the desired results some claim it will have, it has to be a global CO2 tax?
52925. Andy Skuce at 06:24 AM on 4 October 2012
       Modelling the permafrost carbon feedback
       Wyoming@4 I am not aware of any climate modelling studies that incorporate future methane hydrate releases. Modelling studies of permafrost feedbacks, such as the one covered in this post, are relatively recent, even though, compared with hydrates, the permafrost carbon is much more easily studied and observed because it on the surface and on land. Also, because hydrates are either buried under great thicknesses of permafrost or hundreds of metres of seawater, they likely will not become destabilized for centuries. In contrast, the response of the top few metres of frozen soils is likely to happen sooner. I'm more inclined to trust the opinions of David Archer than the Arctic Methane Emergency Group, on this issue. Having said that, I'm following the latest research with an open mind and I would very much like to see a modelling exercise that attempts to quantify the size and timing of methane hydrate releases and their effect on the climate. Recently, SkS conducted an interview with researcher Natalia Shakhova, that may be of interest. I'm working on a series of posts on subcap methane releases, which I think may prove to be more immediate in their climate impact than hydrate destabilization.
52926. DSL at 05:59 AM on 4 October 2012
       New research from last week 39/2012
       Thanks, Ari!
52927. Andy Skuce at 05:25 AM on 4 October 2012
       Modelling the permafrost carbon feedback
       Many thanks to Andrew MacDougall for showing up here and answering those questions. Incidentally, I wrote an SkS article some months ago on the DeConto et al paper that he referred to in his comment.
52928. Philippe Chantreau at 04:52 AM on 4 October 2012
       Modelling the permafrost carbon feedback
       Thanks for your participation Mr McDougall. Comments and clarification by real researchers are always greatly appreciated.
52929. Andrew MacDougall at 04:18 AM on 4 October 2012
       Modelling the permafrost carbon feedback
       To Answer the Questions of Kevin C: “1. If I understand correctly, the permafrost feedback isn't in CMIP3 climate models, so on this basis they are probably underestimating climate sensitivity. Is it in the CMIP5 models? (I'm guessing some of the the earth-systems models do take this into account.)” The permafrost feedback is not included in any of the CMIP3 or CMIP5 climate models. However, CO2 from permafrost does not contribute to climate sensitivity. Climate sensitivity is defined as “to the equilibrium change in global mean surface temperature following a doubling of the atmospheric (equivalent) CO2 concentration (IPCC glossary of terms)”. This definition specifically leaves out carbon cycle feedbacks. The climate sensitivity is determined by the direct radiative effect of CO2 and feedbacks from non-CO2 systems (ex. albedo, clouds, water vapour). 2. However long term sensitivity estimates based on past climate (in particular the glacial cycle) should already include this effect? The permafrost climate feedback presumably did play a part in glacier-interglacial carbon cycle feedbacks (Ciais Et Al. 2012 doi:10.1038/ngeo1324), and has been hypothesized to be responsible for earlier events in Earth history (DeConto Et Al. 2012 doi:10.1038/nature10929). 3. The authors attribute the reduced additional temperature impact of thawing under the highest emission scenarios to saturation of the IR bands. Presumably there is also an effect due to the logarithmic CO2-forcing relationship, but looking at the numbers I'm guessing this is a weaker effect? The saturation of IR bands is the mechanistic explanation for the logarithmic forcing from CO2. Also contributing to the muted temperature response in the high emissions scenario is the self-limiting nature of the feedback. That is, there is a point beyond which almost all the permafrost has thawed and all the carbon in the permafrost is decaying. At that point further waring will not contribute to a larger feedback.
52930. Wyoming at 02:49 AM on 4 October 2012
       Modelling the permafrost carbon feedback
       Andy, An issue that I am sure will be brought up questioning the total numbers on projected warming. There has been a lot of alarm (and some wild claims) regarding the CH4 emissions from the ESAS as observed by the Russian researchers and others. Since the paper does not take those emissions into account, nor these

       "Finally, this study does not consider any contribution of methane from methane hydrates, either from under permafrost or under ice sheets, nor from fossil methane currently trapped under an impermeable seal of continuous permafrost."

       There seems to be quite a few potentially significant methane emissions still to take into account. One would have to assume that the warming estimates in the above paper are very conservative still. Are you aware of any rigorous effort to provide a comprehensive estimate on total emissions (of all kinds at all locations) and projected warming. Recently there was a post on RealClimate regarding CH4 emissions, but it did not take into account any of the above either. There are a lot of people who are really interested in a warming estimate that takes all known sources into account. Thanks
52931. Bob Loblaw at 02:46 AM on 4 October 2012
       Climate time lag
       Falkenherz: First, I'll assume that at least part of what you are saying is a "thought experiment" scenario, rather than a thorough analysis of recent temperature changes and forcing factors. Thus, what I say will be simplistic if applied to the "real world" case. If we imagine a world were TSI increased until 1960, and then remained constant, the question is whether we can attribute a rapid rise in temperature in the (say) 1980-2010 period to that earlier (pre-1960) TSI increase. As you state, will the temperature continue to rise post 1960? The answer is yes, the temperatures will continue to rise post-1960, until a new equilibrium will be reached (25-50 years is not unreasonable), but we have to think about what that pattern of continuing temperature rise will be. - the rate of rise after 1960 should be expected to slow. After all, the 1960 rate of rise is based not only on the 1959-60 increase in TSI, but all the earlier TSI increases that have a lagged response. In addition, the rise in T due to the 1960 rise in TSI will be expected (as a first approximation) to follow an exponential decay sort of pattern: a larger immediate rise, followed by gradually decreasing rate of T rise as the system approaches its new equilibrium. So we've got two factors that say the rate of increase should slow: the ever-decreasing time-lagged "old" increase in TSI, and the nature of an exponential-decay-type response to the "current" or final step to the new TSI. - what will be very unlikely is a response post-1960 that will see little change, or a cooling, followed much later by a rapid rise in temperatures. Sphaerica has already commented on the chaotic nature and spatial variability of the response. To get a situation where the atmosphere fails to show a response to the up-to-1960 TSI increase for 10-30 years, and then suddenly starts to increase, you need to argue a reasonable mechanism. To accomplish this would require that a large amount of heat be stored somewhere else for several decades, and then be allowed to start working into the atmosphere and appearing as increased air temperatures. On the short term (a few years) El Nina/La Nina does just this sort of thing -shifting heat storage between the oceans and the atmosphere - which is a major reason why air temperature rise is not perfectly steady in response to the relatively smooth rise in CO2 forcing. We can see the result in ocean heat storage, however. For longer periods of time, there is no known physical mechanism that can do this. For El Nino/La Nina, the physical mechanism are fairly well-understood. For "skeptics" correlations with arbitrary cycles such as AMDO, no such physical mechanism has been proposed, let alone accepted. And if the mechanism exists for TSI, then it should also exist for things like volcanic activity, where we see pretty rapid response. It's back to the magic "now you see it, now you don't" disappearing/reappearing unnamed "possible mechanism" that purveyors of doubt want to believe will be under their Christmas tree next December.
52932. JoeT at 02:31 AM on 4 October 2012
       Modelling the permafrost carbon feedback
       I have a similar question to that of Kevin C. I would have thought that the logarithmic relationship IS the saturation effect. It seems to me in that case that the DEP 8.5 case would only be slightly higher than the DEP 6.0. Instead, it's actually lower. Perhaps you address this point again.
52933. Bob Lacatena at 00:17 AM on 4 October 2012
       Climate time lag
       Falkenherz, First, it is unclear to me what you are saying about assuming increased TSI to 1960. When you say it halts at +2 W/m2 in 1960, are you saying it then drops back to normal, or just that the increase halts at +2 W/m2, but that added forcing remains (constant) through to 2020? In the first case, then as with your long-lived-then-turned-off solar flare, the time-lag no longer applies because the forcing is gone and so the imbalance is gone. I think this is what you are saying, because if not then in 2020 you'd have a net forcing of +6 W/m2 (+4 CO2 and +2 solar). But with the solar forcing gone, you do not still have a time lag from the solar forcing that didn't yet raise temperatures. Its time has passed, and the opportunity to raise temperatures is gone. The forcing must remain through to the new equilibrium point. The moment the forcing ends, any remaining, unrealized temperature increase is "cancelled." [A separate issue, but I also question whether you'd get a +1 W/m2 in CO2 (or other) feedbacks so quickly from your solar forcing. That would be an increase in CO2 of at least 100ppm from "natural sources," which is clearly an indefensible proposition. But that's a quibble that's irrelevant.] If you are instead saying that TSI has remained increased by +2 W/m2 since 1960... then we're at that +6 W/m2 scenario, and honestly, I have seen absolutely nothing that suggests a solar forcing component that large. The best increase in TSI I have seen is 1 W/m2, but that's total input that needs to be divided by 4 to be spread over the surface of the earth (a sphere), leaving an increase of a mere 0.25 W/m2. Additionally, that increase is not constant over time (11 year solar cycle, with varying cycle strengths, one more element of chaos) so the time lag while such a forcing remained constant can be presumed to be even longer, perhaps by as much as a factor of 10. Additionally, the sun has been very quiet for the past 20 years. Depending on your baseline, you might even consider this a negative forcing, but at best it's minimal. Lastly, you ignore dimming aerosols, which in the dirtier air before 1980 added a substantial damping to all forcings, and continues to do so today, so your TSI increase must be presumed to be even smaller. For one estimate, see Huber and Knutti (2011). Bottom line, in reference to your statement that:

       ...you assume that the *entire* GW since 1960 is caused by CO2, as if a TSI lag was suddenly not there anymore...

       It's not there any more, if the increase in TSI is gone (the forcing is gone).
52934. Falkenherz at 23:45 PM on 3 October 2012
       Climate time lag
       I am not sure I understand your point or if you misunderstood my point; I understand your point as follows: Assume a solar flare that adds +8 W/m2 and it takes x years to get to the corresponding end-temperature of, say +4 Degrees. Assume now temperature is halfway through the process at x/2 with currently +2 Degrees, and the solar flare is now switched off; accordingly, temperature rise should stop at +2 and will slowly drop back to 0, the value from before. So far, so good. (But the chaotic climate system might as well let us see that "immediate no-more-warming response" with an additional delay, right?) Now, my point is: Assume TSI increased over the last 300 years in slow and little steps, then it halts at +2 W/m2 in 1960, compared to 300 years ago. Shouldn't temperature still rise until the corresponding balance of temperature is achieved (again, modified by climate chaotics)? And this lag I understood from the article can take between 25-50 years. That should be the TSI lag I meant. Now, assume also that CO2 increases since 1960 and adds +4 W/m2 in 2020. Assume also, that +1 W/m2 of that is part of the increased CO2 following temperature raise caused by TSI. So, we have a +3 W/m2 "extra" forcing from CO2 in 2020 (which represents the anthropomorphic part). If we have to assume the same lag times as above, it could take another 25-50 years to see the effect of that extra forcing. But right now, we probably only see the effects from the (ending) TSI-lag and maybe a little bit already of the "extra" CO2. I mean, we cannot even know what the last 50 years of CO2 forcing caused was part of the global warming, right? Correspondinly, the point of yours which I was doubting is, that you assume that the *entire* GW since 1960 is caused by CO2, as if a TSI lag was suddenly not there anymore. My point was, the GW since 1960 could still be caused by the earth going into equilibrium with the current level of TSI, and we might see only later the real effects of the extra CO2. (And from here on, I added a speculation on the arctic ice core which I omit now, because we should be first clear about this basic point). Where am I wrong?
52935. binntho at 20:30 PM on 3 October 2012
       Sea Level Isn't Level: Ocean Siphoning, Levered Continents and the Holocene Sea Level Highstand
       A very good article indeed. Thanks. I would be interested in another twist on sea rise: How quickly does meltwater in one place diffuse globally? In other words, if the Greenland ice cap is causing a global rise of 2mm/year (say), does that happen everywhere more or less at the same time or is there a noticeable time lag between the effect being measured in Iceland on the one hand and Easter Island on the other?
52936. littlerobbergirl at 20:22 PM on 3 October 2012
       Modelling the permafrost carbon feedback
       Its impressive they found a way through the morass of interlinked variables to get a result! So no amount of tinkering at the edges - changing drainage, encouraging healthy moss, grazing , allowing forest to grow, even gm moss with extra tannins - will make any difference? I still cant help seeing those vast peatlands of siberia as a massive waiting resource for sequestrTion and to grow our meat once brazil is a desert... Interesting snippet - the chap that described the enzymatic latch mechanism ( chris fellows of bangor) is doing the gm thing: http://www.newscientist.com/mobile/article/dn22313 He also mentions on his own site the possibility of more drying due to our new pattern of rubbish jert stream with many blocking highs which would increase loss from fire and oxidation ho hum
52937. Kevin C at 18:58 PM on 3 October 2012
       Modelling the permafrost carbon feedback
       Very interesting, thanks Andy. A few questions spring to mind: 1. If I understand correctly, the permafrost feedback isn't in CMIP3 climate models, so on this basis they are probably underestimating climate sensitivity. Is it in the CMIP5 models? (I'm guessing some of the the earth-systems models do take this into account.) 2. However long term sensitivity estimates based on past climate (in particular the glacial cycle) should already include this effect? 3. The authors attribute the reduced additional temperature impact of thawing under the highest emission scenarios to saturation of the IR bands. Presumably there is also an effect due to the logarithmic CO2-forcing relationship, but looking at the numbers I'm guessing this is a weaker effect?
52938. From Peru at 08:29 AM on 3 October 2012
       The Economic Damage of Climate Denial
       dana1981: Could it be possible to fix the broken link (the first one in comment nº4) to: Intergenerational Equity, Social Discount Rates and Global Warming http://www.econ.cam.ac.uk/faculty/dasgupta/pub07/climate.pdf Thank you in advance. By the way, do you (or anyone else) has some comments about the cases described in the two links above (comment nº4) where the discount rates can be not only very low, but even zero or negative?
52939. stonepig at 07:22 AM on 3 October 2012
       93% of Fox News climate change coverage misleading
       Mr Bostrom, thank you for the ins co reference. It will help me with some research I am doing.
52940. stonepig at 07:20 AM on 3 October 2012
       93% of Fox News climate change coverage misleading
       The latest issue of National Wildlife has a commentary from Obama in reference to their questions, but Rombot just sent them the platitudes of his party and refused to answer questions...and it is very disturbing. Gee, I hope someone asks during the debates. Rombot's position is so corporate it can hardly be believed...but believe it.
52941. JoeT at 06:32 AM on 3 October 2012
       2012 SkS Weekly Digest #39
       I would like to see more in depth discussion of how climate change affects drought and food production .. that is, more than "the wet gets wetter and the dry dryer". I'm still having a hard time understanding what the basic physics is and what assumptions different models make. I'll give an example: If you look at the August, 2012 paper published by Dai you can see in Figure 2, his prediction that the Sahel region in Africa will have more rainfall. But he writes: "Most CMIP3 models produce ... increasing precipitation over the Sahel in the twenty-first century1, although a few models do produce some drying over the Sahel under a uniform ocean warming." The model that Dai refers to that predicts increasing drying in the Sahel is by Isaac Held and co-workers at the Princeton GFDL. At the GFDL website, Held has a nice write-up about drought in the Sahel. In particular it is fascinating to see his graph showing that when the SST in the Southern Atlantic is greater than in the North, drought occurs. The question is, what happens when the ocean temperature world-wide increases? Will there be drought in the Sahel or not? Dai and Held seem to have different answers. That's not a problem. What I'd like to know is why do they have different answers? As part of this it would be nice to know what influence the movement of the ITCZ has on drought as in this fascinating article in Scientific American . What happens to the size of the Hadley cells? -- do they get bigger, smaller? Do they translate north and south with the ITCZ?
52942. scaddenp at 06:27 AM on 3 October 2012
       The Economic Damage of Climate Denial
       "Lets say America put in a carbon tax scheme. What good would it do for GW?" To maintain a level playing field for manufacturers, US would also have to tax carbon on imports that werent carbon-taxed at source. Goods made with non-carbon energy become cheaper than those built with coal. Thus US buying power becomes a strong incentive for exporters to US to switch from fossil fuel.
52943. Doug Bostrom at 05:46 AM on 3 October 2012
       The Economic Damage of Climate Denial
       Quite apart from being "green," there's the shame attendant with missing the boat. Here's a sad story of what happens when people are hopelessly entangled with the past: The world-leading UK windfarm built with little British involvement

       "We are hosting 18 French renewable energy companies here next month to show how we have helped develop two of the world's biggest windfarms. It would have been nice to have been able to show them some local [wind equipment] manufacturing."

52944. Composer99 at 05:25 AM on 3 October 2012
       The Economic Damage of Climate Denial
       

       Lets say America put in a carbon tax scheme. What good would it do for GW?

       Clyde, I think that there's a definite lack of imagination going on when one can ask this question. The answer is quite obvious: reduce American carbon emissions fast. Set leadership for the rest of the world to follow (one can imagine Chinese global warming pseudoskeptics arguing against taking action, in a mirror image of Clyde, on account of American inaction - to say nothing of how American obstructionism empowers pseudoskeptics elsewhere, such as Australia or Canada).
52945. Doug Bostrom at 05:09 AM on 3 October 2012
       The Economic Damage of Climate Denial
       Clyde, regarding your first point, you seem to be making an argument that market guidance by regulation is working as expected. I don't think that was your intention but the data you offer suggest that's the case. Concerning Maine, an odd choice. Maine already derives nearly half its electricity from renewables yet enjoys the lowest cost of electricity in New England, according to the EIA. Thinktanks don't seem to be tracking facts on the ground. Picking on Greece as a case study of fiscal norms w/regard to green energy is frankly absurd. The entire economic system in Greece is in a state of collapse. Offer a better example. China has installed an enormous amount of renewable energy capacity in the past decade, putting us to shame in that respect. Their stated objective is to modernize away from fossil fuel combustion for power generation and they're backing their words with action, far more and better than most of the rest of the world. That's balanced against an unprecedented economic juggling act; it's remarkable they're keeping all the balls in the air as it is. Lets say America put in a carbon tax scheme. What good would it do for GW? It would put a price on C02 emissions, stop us pretending that C02 costs nothing. Perhaps you didn't read Dana's article.
52946. dana1981 at 04:53 AM on 3 October 2012
       The Economic Damage of Climate Denial
       Clyde @18 - US carbon emissions decreased in 2011 mainly because of the move away from coal toward natural gas. Unfortunately the methane emissions associated with natural gas drilling aren't accounted for when looking exclusively at CO2. Talking about Maine's expected slight increase in electricity prices as a result of renewable energy completely misses the point of this post - that the costs of fossil fuels are not reflected in their market price, so previous electricity rates were artificially low. Additionally, Maine and other RGGI states have thus far experienced electriciy price increases no faster than the rest of the USA. Your comment about China is an example of Tragedy of the Commons. Sorry but you haven't provided any evidence to support your assertion that pricing CO2 "won't work", or even that doing so won't benefit the economy.
52947. Doug Bostrom at 04:47 AM on 3 October 2012
       93% of Fox News climate change coverage misleading
       Law and ethical behavior are a loose fit, are not necessarily in pursuit of the same objectives. For an interesting case of a conundrum produced by the collision of business objectives and implicit promises to shareholders versus the law, see this article: Insurance Companies Face Increased Risk from Global Warming. It's an ironic title, given that some insurance companies are confronted with a difficult choice about whether and how to actually face global warming:

       Insurers could be sued both by emitters that are trying to pass on liability, or by investors claiming they did not adequately disclose risks to the market. In 2010, the U.S. Securities and Exchange Commission (SEC) asked companies to report how climate change may affect profitability, potentially opening the The courts have yet to rule on whether greenhouse gas emitters can be tied to climate events. way for investor lawsuits.

       Fear leads to feigned ignorance:

       “Acknowledging climate risk would be a risk for [any] company in an American context,” says Andreas Spiegel, at Swiss Re. “There is the risk that the company or the managers would be held liable for their actions in relation to that.”

52948. Clyde at 04:30 AM on 3 October 2012
       The Economic Damage of Climate Denial
       Unlike 2009, the 2011 decline occurred during a year of positive growth in the Gross Domestic Product (GDP) Read more here. The 2011 decrease is only the fourth year since 1990 to experience a decline in carbon intensity of greater than 3.5 percent for the economy as a whole and only the sixth year since 1990 to experience an emissions decline. Since 1990, energy-related carbon dioxide emissions in the United States have grown much more slowly than GDP – in 2007 emissions were 19 percent greater than their 1990 level, but by 2011 were only about 9 percent above the 1990 level. GDP has increased by 66 percent over that same time period. ------------------------------------------ On September 26, 2012, the Maine Heritage Policy Center and Beacon Hill Institute for Public Policy Research released a study which found that Maine’s current Renewable Portfolio Standards (RPS) Law, which mandates the minimum and maximum amount of energy consumers must purchase from various sources, will raise the cost of electricity in Maine by 8% in 2017. Read more here. ------------------------------------ The electricity system came close to collapse in June when market operator LAGHE was overwhelmed by subsidies it pays to green power producers as part of efforts to bolster solar energy. Read more here. ------------------------------------------- Search Germany & France energy problems for more links. Taxing CO2 won't work. Shoving green energy down our throat won't work. Lets say America put in a carbon tax scheme. What good would it do for GW? If anybody thinks they can force China to do anything their not thinking clearly.
52949. John Russell at 04:06 AM on 3 October 2012
       93% of Fox News climate change coverage misleading
       MD + Bob Loblaw It's a basic requirement of business -- and a legal requirement, certainly in the UK -- that the directors of a company must maximise the profits for, and look after the interests of, the shareholders. However, it goes without saying that these aims must be accomplished within the law of the land; for overstepping the mark could bring the firm into disrepute and thus damage shareholder value -- which is exactly what the hacking scandal brought about for News International. Looking at the environmental angle, clearly these requirements can be interpreted in many different ways. A responsible company might come to the realisation that a short-term pursuit of profits could actually harm the long-term survival of the company and thus the interests of shareholders. Consequently, enlightened directors might realise that anything that damages their company's ability to, say, obtain raw materials or operate as usual, is something they should work to overcome. This is why, for instance, both insurance providers and food companies have accepted the science of climate change and are taking steps to engage actively in the fight to prevent it. There's more about this here from an organisation which seeks to encourage businesses to make a difference. I'm proud to have helped certain companies on that list achieve the highest positions in their sectors. It's never enough of course, but we can do our bit through our choices to keep the pressure on.
52950. Doug Bostrom at 03:30 AM on 3 October 2012
       The Economic Damage of Climate Denial
       Borehole disposal of nuclear waste looks to be quite promising. Ironically, thanks to the extreme efforts and liberal spending applied to the engineering of petroleum extraction the technical means to implement borehole disposal are largely understood and available. Looking at NRC incident reports, the current dominant crop of nuclear generation plants seem to be a case wherein our engineering prowess exceeds the foibles of human nature. We're capable of building these machines but arguably are barely competent to operate them. The three-way collision of nuclear plant complexity, large hazards attendant with less than perfectly scrupulous operation and the human tendency to sloth and apathy yields a result that is less than pleasing. Applying the current established track record of near-misses to a significant deployment upscaling of current nuclear plant design hints at a picture including a certain proportion of dramatic failures, assuming human nature is mostly immutable. That might be a tradeoff we need to accept. Simpler would seem to be definitely be better in this case, considering that we don't seem to be mentally equipped to operate what we're capable of building.

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