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All IPCC definitions taken from Climate Change 2007: The Physical Science Basis. Working Group I Contribution to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Annex I, Glossary, pp. 941-954. Cambridge University Press.

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Comments 53001 to 53050:

  1. The Economic Damage of Climate Denial
    Clyde: Your claim "A carbon tax will not stop droughts & floods. No one can say any one drought or flood was caused by GW" fails for the same reason claiming "Regulation of smoking will not stop lung cancer. No one can say any one incident of lung cancer was caused by smoking". It is well established that rapid warming will increase both the quantity and severity of drought and flood events. The evidence reviewed on this site, in IPCC reports, and other literature make this, IMO, abundantly clear. Other evidence shows - wait for it - an increasing trend in these sorts of meteorological events (e.g. the Munich Re data which has been widely shared here and elsewhere). All other things being equal, in the absence of warming there would be no increasing trend in droughts or floods. Unless a carbon price (whether a carbon tax, cap & trade, or fee & dividend - and now that I come to think of it, why is it your only focus on this thread appears to be on a tax?) fails to reduce emissions - and given the success of, say, the sulphuric acid controls (a cap & trade system) we can be confident that a market-based mechanism (which includes Pigovian taxes such as a carbon tax) will do the job - it follows that pricing carbon will reduce emissions, hence preventing continued growth of drought & flood events. Your argument: You seem to think a tax is the only solution. Let the private sector solve the problem. The advancement in fracking technology just one example. Can somebody tell me how higher taxes will stop GW? Let's say a tax is passed. Folks & companies decide to pay the tax & carry on with the status quo. Will the govt having more money stop GW? is also, IMO, quite flawed, for two reasons: (1) Fracking enables additional extraction and combustion of fossil methane. Last I checked, methane and its combustion products (CO2 and H2O) are greenhouse gases. It is no solution to the problem of carbon emissions. (2) I find it odd that you would presume individuals, businesses, and other organizations would voluntarily pay more for the kinds of goods that would be affected by carbon pricing. As far as I am aware, in most North American jurisdictions people are pretty keen on lowering their tax burden. I can't imagine that carbon taxes or similar pricing mechanisms would not lead to similar tax-avoidance behaviour (in this case, by decarbonising).
  2. Climate time lag
    KR, There's an important point in your comment... that the time-lag results are non-linear. They will taper off as you get closer and closer to equilibrium. The fact that warming is relatively constant is actually a good argument that whatever the forcing is, it must be increasing continually in order for warming to remain linear. And the only forcing that is continually increasing is CO2. This by itself is one more strong argument that CO2 must be the cause, because the time-lag argument, rather than pointing to some past forcing (TSI) as a cause of current temperature increases, actually does the exact opposite, and points against any forcing that is not only currently active but still increasing -- of which CO2 is the only candidate.
  3. Climate time lag
    Sphaerica - It should also be noted that some of the 1940's drop is due to (a) limited ocean coverage during WWII and (b) changing techniques for ocean sampling. HadCRUT4 (with corrections for those issues) shows a hiatus until the mid-1970's, but much less of one than HadCRUT3, for example. I completely agree that a 0.25 W/m^2 forcing difference is minor compared to observed changes - that translates to a 0.075°C direct temperature change, or something like < 0.25°C with fully realized feedbacks. Insolation changes are simply too small to explain the last 50 years of climate change - not to mention being of the wrong sign. Falkenherz - There is no mechanism whatsoever that would allow past TSI changes to "come out of the woodwork" 50 years later. Temperature change due to any initial forcing shift taper off over time as the imbalance is reduced, but the ongoing rate of change in global mean temperature shows that the forcings are continuing to increase. The ongoing rate of change (close to linear over the last 40 years) is chasing an ongoing forcing change. Insolation has in fact been decreasing over that time, and if anything is reducing the rate of warming. Many 'skeptic' arguments to claim "it's the sun", but when you examine such claims you see almost no climate lag before the middle of the 20th century - and the invocation of a 50+ year lag suddenly kicking in once insolation starts to decrease. In other words, such arguments are purest fantasy, unsupportable in the real world.
  4. Nate Silver's Climate Chapter and What We Can Learn From It
    "I think the conclusion was mostly a result of Silver seeing that we're making such little progress on the policy front that there's no sense in scientists sticking their necks up..." I was thinking it may be because he cut his teeth at the Booth School of Business at Chicago, where Milton Friedman pioneered free market libertarianism. Although Friedman was in favor of Pigovian taxes (applied to negative externalities, ie a carbon tax), so who knows. Or it could be as simple as he cares about science and thinks it will lose credibility, which can be possible when analysis and advocacy mix. I completely disagree with this; I think it's possible to advocate using sceintific analysis, like Hansen does. I also think scientists are worried, as they should be, that nothing is getting done, which has forced them to be more vocal. But some "purists" find this argument irrelevant and feel that scientists should stay quiet.
  5. The Economic Damage of Climate Denial
    For example, look at agricultural productivity being hit by droughts and the associated food cost increases. A carbon tax will not stop droughts & floods. No one can say any one drought or flood was caused by GW. 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. You seem to think a tax is the only solution. Let the private sector solve the problem. The advancement in fracking technology just one example. Can somebody tell me how higher taxes will stop GW? Let's say a tax is passed. Folks & companies decide to pay the tax & carry on with the status quo. Will the govt having more money stop GW? Now to China. I work for a company who sells them scarp metal. We ship them barges of scarp metal monthly. They might be trying "green energy" in their efforts to provide electric. Their also building coal plants at a much faster pace than their green energy plants. Bob Law suggests not buying stuff from them. I don't know if he means on a personal level, or the govt to stop trading with them, maybe a combo of both? Go through your house & see how many things are made in the USA only. We going to stop buying stuff from anybody who don't have a carbon tax to our liking? Sphaerica says "China wants in the WTO, but won't follow the rules unless it suits them." My point made. For those who think a trade war with China will make (pressure & convince) them to do anything is wrong IMO. It has nothing to do with right & wrong with them. It's pride/prestige plain & simple. They won't allow anybody to tell them what to do. Some of you are suggesting that just because one (or more) country won't do something doesn't mean we shouldn't. If you want to tax American's (on the basis of GW) regardless of what any other country does, good luck trying to get that passed into law on the fed level.
  6. Climate time lag
    Bob, I'm not sure I entirely agree with you, because the same applies to CO2 forcing. Why the hiatus in warming from 1945 to 1980? The usual answer (one I accept) is the increase in dimming aerosols due to pollution/smog in that period, and that applies equally to any forcing (TSI or CO2). But I would still question how a 0.25 W/m2 forcing amounts to anything notable, particularly given the quiet sun for the past 15 years or so. That's why the deniers had to introduce the idea of cosmic rays and cloud nucleation, because the TSI alone wasn't anywhere near strong enough.
  7. Nate Silver's Climate Chapter and What We Can Learn From It
    chriskoz @7 - there does seem to be a bit of inconsistency with Silver acknowledging that uncertainty is an argument for action, but then at the end saying that climate scientists should stop advocating for action. I think the conclusion was mostly a result of Silver seeing that we're making such little progress on the policy front that there's no sense in scientists sticking their necks up, because they probably can't significantly speed up the process. He may be right about that, but you can't just quit trying to solve the biggest threat to humanity because you might fail.
  8. Climate time lag
    Falkenherz: Sphaerica has given you a couple of good diagrams. You can also see the effects of the 1:4 ratio in the equations in the text of the OP. Look at the one that has: S(1-A) = 4εσT4 ...and divide both sides by 4. The 4 disappears on the right, and we have S/4 on the left. ...now, you were asking about the "fails to appear" comment of mine, and said "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? That is basically it, but we don't even need to look back to the 1800s, just look at T through the mid-1900s to now. Look at Riccardo's graph, and let's assume that his 0 time value represents 1960, when TSI stopped rising. What we would expect is to see temperature rising like it does in Riccardo's graph - most rapidly in the first few years, followed by a tapering off and eventual equilibrium. What you would not expect is to see temperatures steady for a couple of decades, then see a sharp rise like Riccardo's graph - but delayed to start around 1980 or so. From Riccardo's graph, we see that the flux imbalance starts at time 0, and gradually drops as T rises (due to extra IR loss to space as T rises). If the atmosphere did not warm for 20 years, the flux imbalance (delta-F) would remain at 1.0 for 20 years, and that energy has to go somewhere. Since it is not appearing in the atmosphere, where would it be hiding? (You won't get an answer from "skeptics".) That's where you would have to provide a plausible physical explanation to explain the "missing" energy and why it doesn't start to affect the atmosphere until many years later. That's the difficulty in the argument that the 1980s-onwards warming is delayed from earlier TSI increases. It ignores physics. As for pre-1850: we don't show measured temperatures for earlier times because the direct measurements don't exist. Think about when the thermometer and the concept of temperature were invented, and then think about how long it might take to get decent global coverage, and you'll see the problem. Before 1850, proxies are required - things that we can measure now, like tree rings, sediments, ice cores, etc. that have a record from the past that responds to temperature (but isn't a direct measurement of temperature). That's how we fill in the gaps from the past, and that the sort of data that goes into Mann's work (and other similar studies) and shows the Hockey Stick.
  9. Nate Silver's Climate Chapter and What We Can Learn From It
    One thing that is interesting is that if anything, scientists have been getting less "alarmist" over time. That is, estimates of climate sensitivity have fallen, as have BAU emissions scenarios. Fake skeptics tend to be easy to identify, because they stick to the old predictions, and ignore the refinements. It remains entirely obvious that inaction is not an option.
  10. Nate Silver's Climate Chapter and What We Can Learn From It
    Thanks Dana for an insightful review of Silver's book. I have an impression that Silver simply does not make enough effort to understand the physics of climate science deeply enough to make accurate judgement. Therefore he falls into the traps of "equal balance" and the "debate", wheareas there is no debate. That impression is reinforced after reading Mike Mann's review you pointed above. Mike's comments are important not only because he's an expert but also because he is an insider to some extent: Silver consulted him before writing the book. Mike is disapointed that Silver misrepresented a few point from that consultation. For example "the uncetainty about the influence of GW on ElNino" was spelled out in the book as "we don't know much about ElNino phenomenon". To me, that's an indication that Silver tried to repeat something from that consultation but misunderstood it and consequently distort it. Mike also points a problem with Silver's view of uncertainty:
    "Uncertainty cuts both ways, and in many respects -- be it the rapid decline in Arctic sea ice, or the melting of the ice sheets -- it is cutting against us. Uncertainty, as many economists recognize, is thus a reason for action, not inaction! I'm surprised someone as sharp as Nate just doesn't appear to get that."
    That is at odds with one of your good points that Silver accepts William Nordhaus' view. So I don't know what Silver wanted to opine here: - that scientist are "exaggerating" so we have some more time to address the problem, or - that we should be addressing the problem now because that's the correct response to uncertainty that works both ways. To me, those two opinions are mutually exclusive and cannot possibly cohexist in this book.
  11. Nate Silver's Climate Chapter and What We Can Learn From It
    "That the observed rate of warming has most likely been a bit lower than the IPCC projection is also not surprising considering all the short-term cooling influences over the past decade." The link indicated here is misfiring You mentioned Chinese aerosols as a cooling influence. I would also mention the huge amount of ice that's melted this past decade. Your Figure 5 in this discussion http://www.skepticalscience.com/GRACE-and-glaciers.html illustrates how dramatic this effect is.
  12. Climate time lag
    Another good image:
  13. Climate time lag
    Falkenherz, On 1/4 TSI... Imagine drawing a circle on the wall -- the earth. In the middle of the room is a lightbulb -- the sun. The light that falls in the circle is the light received by the earth from the sun... it's in the shape of a disk. But the earth isn't a circle, it's a sphere. That light isn't falling on a disk but on the surface of that sphere. Since the surface is curved, it has a larger surface area than the disk. This means two things. First, that the same amount of light is falling on a larger area at the edges of there sphere: And second (because the sphere is rotating) that the light is falling on both the front and the back of the sphere. In the end, the computation is very straightforward. The light being delivered covers the area of a circle (πr^2) while the light being received is spread out over the area of a sphere (4πr^2). So the amount of energy received per unit area on the earth is energy-delivered-per-unit-area times area-of-delivery divided by area-of-receipt, or: energy * πr^2 / 4πr^2 = energy / 4 1361 * πr^2 / 4πr^2 = 1361 / 4 = 340.25 W/m^2 Interestingly, the only denier I've seen that has been foolish enough to dispute this is Postma, but even he comes up with the same answer... he just claims the logic of the geometry is wrong.
  14. Modelling the permafrost carbon feedback
    Thanks Andrew for those answers. I think it'll take me a while to grok the last one; my mental model of OLR clearly isn't sufficiently sophisticated at this stage. (It may of course be one of those things you never really understand till you've implemented your own.)
  15. 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.
  16. 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.
  17. 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.)
  18. 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.
  19. 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.
  20. 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.
  21. 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.
  22. 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.
  23. 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.
  24. 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.
  25. 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.
  26. 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.
  27. 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.
  28. 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.
  29. 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.
  30. 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.
  31. 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.
  32. 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?
  33. 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.
  34. 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).
  35. 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
  36. 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
  37. 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....
  38. 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?
  39. 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.
  40. New research from last week 39/2012
    Thanks, Ari!
  41. 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.
  42. 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.
  43. 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.
  44. 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
  45. 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.
  46. 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.
  47. 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).
  48. 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?
  49. 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?
  50. 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

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