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Comments 54951 to 55000:

  1. Why Arctic sea ice shouldn't leave anyone cold
    It's interesting to line this development up against natural influences. While we are higher in the solar cycle than in 2007, the current solar cycle is still one of the lowest on record. 2007 was a cooling year in the ENSO cycle, whereas this year we're had a bit of El Niño phase of the cycle, but not a strong one. There isn't anything to suggest from this that any natural influence should be causing unusual warming. Next time the solar cycle goes back to its more usual maximum or next time we have a strong El Niño 1998-style, we could see a very rapid loss of sea ice extent. What we are seeing this time is most likely the effect of long-term loss of multi-season ice depth that doesn't in the short term decrease sea ice extent, but results in needing a year that's not exceptionally above the norm to drive back ice area a long way, once the multi-season ice has thinned enough. GISS shows northern hemisphere summer is one of the warmest on record, but not the warmest.
  2. Will the Wet Get Wetter and the Dry Drier?
    Question: The"denial machine" now seems to be reduced to trying to prove the C.S. is small. I do not believe it is small, I think there is now good experimental evidence that the fast feedback CS is 3 deg C. BUT say the CS WAS at the lowest possible end, which we might take as 1.5 deg C. Why would this be an excuse for doing nothing about AGW? Does anyone have any crystal ball into denier logic that would help me out here?
  3. Will the Wet Get Wetter and the Dry Drier?
    JoeT - Sorry, I don't know the details of how these two models differ. What I can tell you is that the 19 model ensemble used in Seager (2011), linked to above, did not find a change over the Sahel that was statistically significant.
  4. Arctic Sea Ice Extent: We're gonna need a bigger graph
    Yes, no one really predicted it. Maybe we weren't being "alarmist" enough?
  5. Realistically What Might the Future Climate Look Like?
    garethman @42 It's great that you are taking these steps. Every little bit helps, but I'm sure you realize that not everyone can do the same. I suppose if everyone became a back-to-the-lander, our emissions would drop to near zero, but there isn't enough arable land to go around. Minifarms are not as efficient, for one thing, and then there is the problem of distribution. If everyone is a farmer, who is going to deliver food to where it can't be grown? Who is going to make new vaccines? I'm afraid we can't return to primitive agriculture without a massive loss of population.
  6. Realistically What Might the Future Climate Look Like?
    Tom @39, I googled "Antarctic Heat Island" and nearly choked. You should post an absurdity factor warning.
  7. Arctic Sea Ice Extent: We're gonna need a bigger graph
    shoyemore "Means the re-freezing will be almost as interesting as the melting." Never a truer word spoken. This years refreeze pattern is next years melt pattern. If refreeze starts later because the water is still warmer, their is less time for that ice to thicken over the winter and next year it melts out even quicker, more open water, more warming of the water more ... you get the idea. heijdensejan Yep, PIOMas really is following that exponential curve. However I think there will be some aspects of the Gompertz curve will happen as well. Exponential trend till it is 'virtually ice free' then leveling out like the gompertz curve before the last remnant goes. This isn't some weird math's. Its just that the last remnant is the ice along the north shore of Greenland & Ellesmere island. Weather patterns aren't usually conducive to that being cleared out easily and that is where the last remnant of the thicker ice remains. So it might hang around a bit. What is far more likely is that over the next 1-3 years the rest of the Arctic melts out substantially and earlier and that old ice is the last bastion. And importantly, that would include an ice-free North Pole. Not the final, truely ice free point. But perhaps a far more visceral 'tipping point'. The Year Santa Drowned. Although nobody wants the Arctic collapse to be happening, it might be our best hope in the short term to wake the world up.
  8. CO2 lags temperature
    David (and others), for a specific response to Humlum et al., 2012, I put up a quick demo of why their method will create misleading results: https://troyca.wordpress.com/2012/08/31/comment-on-the-phase-relation-between-atmospheric-carbon-dioxide-and-global-temperature/
  9. AGU Fall Meeting sessions on social media, misinformation and uncertainty
    JohnHartz #8 Thank you. I have already done the search. It’s not there. Neither is it on the Wayback machine, who took snapshots of SkS every week during the relevant period. (-Snip-) Lewandowsky mentions SkS in his list of eight “pro-science” ( -Snip-) sites used, and when challenged, said that perhaps Cook had deleted the link. There is no suggestion of anything underhand here. The link from the participating blogs to the commercial organisation who set up the survey was deleted once the fieldwork period was over. My interest in finding the link here was in reading the comments of bloggers. It is puzzling that Sceptical Science did NOT take part, given the great interest that Cook shows in Lewandowsky’s work. (-Snip-) ( -Snip-) (-Snip-) So it seems that Lewandowsky was mistaken when he said that SkS took part in the survey, and we’re left with the puzzle of how he obtained 1100+ responses from just six (possibly seven) blogs, given the sparse and largely negative comments from the couple of dozen bloggers who discussed the survey on the blogs concerned. ( -Snip- ).
    Response:

    [John Cook] Skeptical Science did link to the Lewandowsky survey back in 2011 2010 but now when I search the archives for the link, it's no longer there so the link must've been taken down once the survey was over.

    [DB] References to stolen intellectual property, statements about religions & ideology and general off-topic hypothesizing snipped.

  10. Matt Ridley - Wired for Lukewarm Catastrophe
    Joel@66: I think that shows that intuition is untrustworthy on this subject. Read Hansens' 2011 paper here, esp. figure 4a. Rypdal's method will allow you to deduce this figure for yourself. The temperature response to a given forcing history is the convolution of the derivative of this function with the forcing. You can see that about 40% of the response comes from forcing in the most recent 10 years, and 60% for earlier forcing. However, if the forcing is much more complicated than an impulse or a step, doing this calculation in your head is impractical. You actually have to do it before drawing conclusions on the results.
  11. Matt Ridley - Wired for Lukewarm Catastrophe
    Joel, 628ppm would be more like B1 scenario depending on what else was going on. IPCC prediction would be 1.1 -2.9 so I suppose they are luke-warmers too. I normally think of luke-warmers as those how somehow believe that climate sensitivity is less than 2.
  12. CO2 lags temperature
    thanks @Rob, clearly explained and the papers were helpful.
  13. AGU Fall Meeting sessions on social media, misinformation and uncertainty
    One further comment. Geoff Chamber's wrote at Bishop Hill:
    " Cook is quite clear in private correspondence that Lewandowsky’s denier / conspiracy theorist survey was something separate from the schemes he was cooking up with Lew. One possibility is that he contacted the commenters directly by email. This would be better survey practice, since it prevents commenters from exchanging views, as happened at Tamino’s, and also would avoid any possible bad publicity. Would it be considered unethical?"
    Clearly his questions have been answered already. Skeptical Science and John Cook are not associated with Lewandowski's study. Curiously, Geoff Chambers followed that comment by espousing his own, bizarre conspiracy theory. Given that he thinks the "... whole survey is a fuss about nothing ...", I have to wonder why he is making a fuss.
  14. AGU Fall Meeting sessions on social media, misinformation and uncertainty
    Further to my comment @12, and following up on John Hartz @13, I had a look at Lewandowski's data. Of interest to me is that 43 out of the 64 people who most strongly disagreed with global warming, as measured by their disagreement with the claim that:
    "I believe that the burning of fossil fuels on the scale observed over the last 50 years has increased atmospheric temperature to an appreciable degree."
    also strongly agreed with the claim that:
    "The claim that the climate is changing due to emissions from fossil fuels is a hoax perpetrated by corrupt scientists who wish to spend more taxpayer money on climate research."
    That is, 67% of the hard core "skeptics" surveyed are conspiracy theorists in the strict sense; even if their conspiracy theories are restricted to global warming. As it happens, however, 37 of those 64 had conspiracy theory ideation above average. That is, 50% of hardcore "skeptics" surveyed give significant credence to at least one, or some credence to at least 6 bona fide conspiracy theories other than those associated with climate change. Scary.
  15. Matt Ridley - Wired for Lukewarm Catastrophe
    Joel Upchurch at #65:
    Bernard J. @60 All you seem to have done is graph the IPCC A1F1 scenario. I don't know you seem to think that corresponds to any definition to the word proof.
    Really - "seem to have done"?! If you have a mathematical background you should be able to muck around and actually deduce how I arrived at the trajectory, or at least come to a pretty close approximation. I even gave you some clues. And note, I haven't at any time used the term "proof". What I did say is that:
    ...I constructed the curve...
    and that:
    ...I used the entire Mauna Loa dataset available at the time, and I used the data itself to determine the best projection, rather than directly assuming a linear, exponential, or other fit. I did this by using a process similar to that illustrated by Dana on this very thread, and by using the most parsimonious approach in that analysis to subsequently arrive at the 21st century extrapolation.
    To simplify, as it seems to escape your mathematically-trained attention, I used the entire Mauna Loa dataset, and the trend inherent in the data themselves, to arrive at the graph I displayed. And if that closely resembles the IPCC's A1F1 scenario, well, that probably reflects the underlying supposition of my analysis of a business-as-usual trend based solely on the pattern inherent in the Mauna Loa data. Call me cynical, but given your responses to me and to others here I can't help but question your argumentum ad auditorem claim to have a degree in mathematics. Are you sure that you didn't just take it as a first year subject (if that), and that you're inflating your experience in an attempt to redirect the thread?
    Moderator Response: [d_b] Easy there, please; no sense in being lured away from the subject at hand by irrelevancies.
  16. Matt Ridley - Wired for Lukewarm Catastrophe
    Composer99, nicely put. Saves me one debunking task. Joel, in #23, you asserted it was not plausible for emissions to increase at a sufficient rate to support large temperature rises. You ignored (and continue to ignore) such crucial issues as time delay to equilibrium, feedbacks, and economic/population issues that will lead to continued acceleration of both CO2 emissions and resultant warming at BAU. But in #28 you supported your assertion in #23 with the following statement:
    There is nothing in the actual C02 data that supports an increase to 792PPM of CO2 by 2100.
    Quite apart from the other evidence presented showing that this is patently absurd, I presented evidence that the IPCC have emissions scenarios that consider this entirely plausible, with A1FI and A2 passing 800ppm by 2100. In #62, you try and divert from accepting that you were wrong in your earlier statements by suggesting that the IPCC think 628ppm is plausible [of course they do]. Which was not the question. Let's not chase blimps here. Do you accept that the evidence presented shows that it is plausible for emissions to pass 800ppm by 2100? Or do you want to continue using your extensive mathematical skills to put naive linear trends through 30 years of data, and continue to ignore all other physical factors?
  17. AGU Fall Meeting sessions on social media, misinformation and uncertainty
    geoffchambers @6, a quick google search of SkS shows no hits for "Lewandowski" plus "survey". Beyond that, any questions you have should be directed to John Cook. For those who are interested, Lewandowki's paper is available online here. I note that, having read the methodology, the claims being made about it by various deniers are entirely unwarranted. It might justly be claimed that the paper has not sampled "skeptics" in general, or "skeptics who comment on the internet", but only "skeptics who comment on science based blogs" which may not be a representative sample. It may also be suspected that the number of "skeptics" participating may be to small to draw any significant conclusions. It is not clear to me where Lewandowski reports the proportion of respondents with low scores on the Climate Science part of the survey. More importantly, in my opinion, the title of the paper is not justified by the results, and is needlessly sensationalizing and offensive. Lewandowski found a -.866 correlation between free market ideology and acceptance of climate science, but only a negative 0.197 correlation between acceptance of conspiracy theories and acceptance of climate science. Clearly the link to free market ideology is the big result, and the limited link to conspiracy theory ideation should only be a footnote in this study. Having said that, the link between a significant group of "skeptics" and conspiracy theorizing is easily established by their own words, with suggestions that climate scientist fake data either to advance the cause of one world government, or to undermine the US economy, or simply to defraud tax payers all being common and all being, in the strictest sense, conspiracy theories. Of course, this only has bearing on those "skeptics", such as Monckton, who advance such theories; and is in no way a reflection on the more rational "skeptics" such as Jeff ID and Lucia.
  18. AGU Fall Meeting sessions on social media, misinformation and uncertainty
    To put Geoff Chamber's posts in context, here's the text of the Aug 31 post on Bihop Hill titled,"Landowsky's Survey." "Geoff Chambers has obtained Stephan Lewandowsky's survey data which can be seen as an attachment at the bottom of this post. Of course it's anonymised, so we are not going to get to the bottom of the question of the number of sceptics he approached, but you may be interested." Geoff and his cohorts at Bishoip Hill seem to be intent on making a mountain out of a molehill.
  19. Matt Ridley - Wired for Lukewarm Catastrophe
    Tom Curtis posted this at 9:50 am and it was unfortunatley accidentally deleted. I reproduce the text here:
    Joel Upchurch, I just did a few calculations based on your comment @28. Based on your projected temperature increases, I calculated that your estimate for CO2 concentration in 2100 is 490-620 ppmv. That later requires an average 2.56 ppmv CO2 groath over the remaining years of the 21st century, ie, a marginal increase over current levels. The former requires annual CO2 growth approx half that of current values for the rest of the 21st century. The median value requires no growth in emissions over current values for the remainder of the century. Your assumptions are simply absurd as a BAU model. More troubling, if you calculate the increase in temperature from the pre-industrial average using your your concentration estimates, we find an increase of 2.4 C over the preindustrial average for the lower estimate, and 3.4 C for the upper estimate. That represents a 1.7 to 2.7 C increase over current values. You only obtained lower values by ignoring the warming currently in the pipeline. (Note: The difference between my estimate and scaddenp's estimate at 58 is that I used a climate sensitivity of 3, while he used 2.8) Most importantly, the median value of 2.9 C is well above the 2 degree above pre-industrial average guardrail for "safe" global warming. Even your dubious luke warm values are way to hot.
  20. AGU Fall Meeting sessions on social media, misinformation and uncertainty
    Sorry, JH. Only JC can do that.
  21. Matt Ridley - Wired for Lukewarm Catastrophe
    Joel Upchurch @ 62: You claim of Tamino in one of his posts linked to upthread:
    He is actually demonstrating that Monckton's assertion of linear C02 growth is absurd. He wasn't trying to prove that CO2 accumulation is super-exponential. You are using what he posted out of context.
    However, over the course of his debunk of Monckton, Tamino concludes the post with the graph shared here before and some additional comments: log(CO2)
    It sure looks like log(CO2) has increased faster than linear, i.e., that CO2 concentration has increased faster than exponential. We can test this by fitting a quadratic curve to the residuals from our linear fit:
    residual fit
    Sho’nuff. CO2 has increased faster than exponential. Even using the shorter NOAA global dataset. And yes, the result is statisically significant. [Emphasis mine.]
    Suffice it to say that, while demonstrating CO2 concentration is increasing faster than exponentially was not the express purpose of Tamino's post, in direct contradiction to your assertion, he nevertheless does so. Colour me unimpressed, Joel.
  22. AGU Fall Meeting sessions on social media, misinformation and uncertainty
    @geoffchambers #6 I inadvertendly deleted your second post. I'm hoping that Daniel Bailey can restore it.
  23. AGU Fall Meeting sessions on social media, misinformation and uncertainty
    @geoffchambers #6: If you want to determine whether SkS posted a link to Lewandowsky's survey between Aug and Oct 2010, you can use the site's archive to access all of the articles posted during this time-frame. It is not incumbent on volunteer SkS authors to do this research for you. If you want to know how John Cook interacted with Stephan Lewandowsky on his survey, you best send a querry to John via email. He's a very busy person and no longer has time to read all of the comments posted on SkS.
  24. AGU Fall Meeting sessions on social media, misinformation and uncertainty
    I guess I'd have to ask, Geoff: Who's speculating, where are they speculating, who wants to know and why?
    Moderator Response: TC: The following is the text of Geoff Chamber's post, accidentally deleted by John Hart. I am posting it here as the natural response to Daniel's question:

    "Daniel Bailey Just about everyone at Lucia's blackboard, Bishop Hill, and Joanna Nova's. I've seen the names of Mosher, McIntyre Jeff Id, Andrew Montford, Anthony Watts, among others. Some of the speculation is about the identity of the sceptical blogs which Stephan contacted and which refused to cooperate. Some is about the data itself, which is now available at Bishop HillL My question is on the specific point as to whether Skeptical Science participated in the survey in any way. A simple yes or no answer will do."
  25. Matt Ridley - Wired for Lukewarm Catastrophe
    Joel Upchurch @63, I doubt very much that you have been told that discussing the IPCC's economic projections is of limits. You may have been told they are of topic on a particular thread - but that is not the same as saying they are of limits per se. In any event, I am not asking you to discuss the IPCC's economic projections. I am asking you to identify what you believe will happen so that you can be confident that CO2 emissions will not compound at greater than 3% annually over the next 90 odd years: a) Will economic growth be significantly less than 3%, and why? b) Or will the human population essentially plateau at current levels, and why? c) Or will carbon intensity decrease by 3% per annum compounding over the next 90 years without government regulation or a price on carbon? And if so, why?
  26. AGU Fall Meeting sessions on social media, misinformation and uncertainty
    I see John and Stephan are going to be convening a meeting together on Understanding & Responding to Misinformation in December 2012 There's a lot of speculation on the net at the moment about the Lewandowsky paper which  has been announced about scepticism and belief in conspiracy theories. (-Snip-) Could you, John Cook, please clarify whether SkS posted a link to Lewandowsky's survey between Aug and Oct 2010, or helped in any other way, eg by providing email addresses of potential respondents? many thanks Geoff Chambers
    Moderator Response:

    [DB] References to stolen intellectual property snipped.

  27. Matt Ridley - Wired for Lukewarm Catastrophe
    Joel Upchurch @66, why can we ignore it? Does the world end in 2100? Or is this just purely an intellectual exercise for you? More importantly, as is evident from your comment @28, you have been calculating the expected temperature increase from (approx) 2010 levels. In doing so you want to ignore the heat currently in the pipeline, and that in the pipeline at 2100, which is double dipping.
  28. Matt Ridley - Wired for Lukewarm Catastrophe
    Kevin C @ 61 As far as forecasting the temperature in 2100, then it seems to me that a pipeline cuts both ways. If there is 10 years of heat in the pipeline, then that means that we can ignore what we emit after 2090. I would like to discuss the Chinese situation. They are forecasting that their greenhouse gas emissions will peak around 2050 and start decreasing because of their switch to nuclear power.
  29. Matt Ridley - Wired for Lukewarm Catastrophe
    Bernard J. @60 All you seem to have done is graph the IPCC A1F1 scenario. I don't know you seem to think that corresponds to any definition to the word proof.
  30. Matt Ridley - Wired for Lukewarm Catastrophe
    scaddenp @58 Since the lukewarming argument is 2 degrees or less, 2.2 degrees as roughly consistent. I'm certainly not going to argue about 10%.
  31. Matt Ridley - Wired for Lukewarm Catastrophe
    Tom Curtis @ 59 I have been told in the past that questioning the economic models that the IPCC uses is off limits. If that is not longer the case, then I would love to discuss it. I find the economic models far more questionable than the science.
  32. Matt Ridley - Wired for Lukewarm Catastrophe
    skywatcher @57 I read Tamino's post again. He is actually demonstrating that Monckton's assertion of linear C02 growth is absurd. He wasn't trying to prove that CO2 accumulation is super-exponential. You are using what he posted out of context. I reviewed the IPCC scenarios and 628PPM by 2100 seems to fall between the A1B and B2 scenario, so I don't know why you think it is manifestly wrong.
  33. Realistically What Might the Future Climate Look Like?
    re: obese people and their carbon footprint department the Royal Society just published a special Geoengineering issue which contained an article on summarizing work studying which crops would reflect most sunlight back out to space. There are differences between different crops and between different strains of each crop when you examine the effect they have on local albedo. When civilization gets serious everything is going to be thrown at the problem. The issue contains an article on if it is possible for the planet to experience what specialists call a "runaway greenhouse effect", i.e. turning Earth into something like Venus by elevating the temperature so much the oceans boil away, which Jim Hansen said in a Bjerknes Lecture at the AGU that he thinks is a "dead certainty" if all fossil fuels are burned. The authors examined the issue, and the Royal Society publishers published the research because Hansen took a position. What a relief to discover that if you accept that the simple models employed are right, all that can happen and this is said to be a remote possibility by the modellers, is a "moist greenhouse", that wouldn't boil the oceans away. I think that event ends civilization and all or most all of life I'm still studying.... Schellnhuber says PIK examined the issue a bit as well and he also said, at the Australian 4 degrees conference in one of his speeches that what can happen is you heat the planet up slowly in human terms rapidly in geological terms and once you cross a line somewhere around 4-6 degrees I seem to remember the system takes off and doesn't stabilize until the temperature is far higher.
  34. Realistically What Might the Future Climate Look Like?
    Caldeira, and others, have pointed out many times that human engineered modifications to the atmosphere to cool the earth could cause unintended consequences. A severe drought or heat wave occurring after a nation, or group of nations, embarks on a modification program might be taken as an act of aggression by the suffering party. With conflicts due to unwelcome immigrations already taking place due to climate disruptions, and considering many well respected organizations predict these will only intensify as the climate becomes more unstable, this will only add another layer that could easily lead to catastrophic wars. Schellnhuber’s comment is surprisingly narrow-minded. Acidification of the oceans is not just a threat to corals but to the base of the food chain that most fish and all apex predators depend. These bureaucrats remind me of the discussions held by the collection of middle managers, phone sanitizers, and hairdressers as described by Douglas Adams.
  35. Realistically What Might the Future Climate Look Like?
    The "4 degrees" conference held in Australia was devoted to exploring what happens as climate warms beyond the 2 degree target adopted in climate negotiations. The conference was inspired by the Royal Society "4 degrees" conference held in the UK. Conference organizers mentioned that when they attended the UK conference 4 degrees of warming was regarded as something civilization could not allow to happen and hence was unlikely. By the time the follow up Australian conference was held the idea of 4 degrees or more was, incredibly, becoming far more credible. The conference has a website where many presentations are available in audio. This page contains links to the audios. John Schellnhuber's keynote speech Climate Change: The Critical Decade is particularly recommended. Schellnhuber gave another speech:Strange Encounters behind the 2 degrees C Firewall which is also very good. I've been studying both speeches and forget what is covered best in which. He was part of the group that came up with the original idea for the IPCC "burning embers" charts shown updated by Smith et.al. in the above post. one of his specialties is tipping points. In the "Strange Encounters..." speech he explains very well what the 2 degrees target meant. For one thing, although 2 degrees was declared in political negotiations to be "safe" according to Schellnhuber, it means the end for coral reefs worldwide. "But who needs coral reefs anyway?" He sadly joked. He offers the best explanation I have heard for why using the analogy that there is a limit in billions of tonnes of carbon that can be added in total to the atmosphere when talking about the solution to climate, as opposed to talking about restricting emissions to "x"% by some date in a given country. The prior Royal Society 4 degrees conference is well worth studying as well. This Wikipedia page contains links to the conference video presentation page as well as much other useful info. I'm travelling and don't have access to my home computer which has better links to all presentations of this conference but you can find everything with a tiny bit of work. Once people realize that 2 degrees was never "safe", and that the 2 degree target could well be out of our hands now, some minds turn from despair to geoengineering. I monitor a geoengineering group that is an exchange of views between some of the top researchers, i.e. Keith, Caldeira, etc., and this is what I feel. they aren't profit seeking cowboys- they are deeply concerned about what happens if say the Republicans suddenly wake up to the facts and immediately want to apply some wacked out scheme touted by such as Lomborg. They want to be able to say something about what scientific investigation of various techniques has shown might happen as civilization finds itself unable to face its present and becomes ready to try anything. Kevin Anderson's views are also worth study. Anderson is associated with the Tyndall Centre in the UK, which is sometimes billed as the UK's premier climate research institution. He feels climate scientists, and anyone who has been in any way minimizing how serious the problem we now face is need to be more explicit about what they know and feel in the future. an example of what he's critiquing: the Stern report he says contains fudged date and impossible assumptions as it concludes climate could be solved at reasonable cost, and he states categorically that most of his colleagues understand this but have been rather quiet.
    Moderator Response: [DB] The Royal Society 4 Degrees issue can be found here (many articles are open-access).
  36. Realistically What Might the Future Climate Look Like?
    We made a conscious decision a few years ago to act ourselves. I do not believe anyone has the political power or will to to anything, so action must come locally. We installed solar energy panels, switched to wood fired stoves, we grow our own veg and try and work from home as much as possible. I know this sounds smug, and I'm aware not everyone has the opportunity to change. But the financial benefit has been great. It helped put a child through University which was a major unpredicted benefit. Even if we just start with switching to LED lighting it will help, but one of the things that prevent people acting is that the problem is so huge, and that they expect the government or IPCC to act on their behalf. It's not going to happen, we have to pursuade everyone that they have the power to change things and every little helps. Measures to address climate change start at home, we must act locally.
  37. Matt Ridley - Wired for Lukewarm Catastrophe
    Joel: If you want to project a realistic temperature rise from CO2 emissions including warming in the pipeline from CO2 we have already emitted, there is a simple method of doing do. I did it <20 lines of R code. The method is spelled out in detail in this paper: Rypdal 2012 (open access). For a realistic future projection, you'll need to take into account that we probably can't maintain an increasing output of cooling aerosols, and China are working to reduce their aerosol output because of the health issues.
  38. Will the Wet Get Wetter and the Dry Drier?
    Rob Painting, As I wrote above, the results presented by GFDL differ in several ways from the very recent paper by Dai that can be found here. Would you know what assumptions go into the models that account for the differences. The Sahel region of Africa stands out in particular as one where the predictions diverge radically. Thanks.
  39. Arctic Sea Ice Extent: We're gonna need a bigger graph
    Most worrying is the fact that PIOMAS is following the exponential decline https://sites.google.com/site/arctischepinguin/home/piomas. Result ice free in 2015. Next year will be interesting
  40. Why Arctic sea ice shouldn't leave anyone cold
    A commenter over at Neven's ASI blog has offered up a very applicable & cogent argument. If if Arctic melts were as pronounced as Christy says relative to today then a graphical overlay of the two periods should be instructive. And that is just what deconstruct did. 1938 vs 2012 To highlight that difference, deconstruct also overlaid 1946 (representative of the colder mid-40s) with 2012: So that begs the question, which was the most comparable melt: 1938 to 2012...or 1938 to 1946? Enquiring minds want to know.
  41. CO2 lags temperature
    David Sanger - some recommended reading: 1. Interannual extremes in the rate of rise of atmospheric carbon dioxide since 1980 - Keeling 1995 2. The Carbon Cycle Response to ENSO: A Coupled Climate–Carbon Cycle Model Study - Jones (2001)
  42. Arctic Sea Ice Extent: We're gonna need a bigger graph
    I've been drawing simple bar graphs that track the minimum ice extent, area or volume for each year to date. With the PIOMAS August update (through 8/25) the results are striking: [LINK]
    Moderator Response: [DB] hot-linked URL. [RH] shortened link that was breaking page formatting.
  43. CO2 lags temperature
    David Sanger - this is much easier if you understand that the oceans are Earth's main heat reservoir. Arguably the greatest climatic effect greenhouse gases exert is that they trap more heat in the ocean. During La Nina the oceans accumulate more energy - as heat is buried in the sub-surface ocean, and during El Nino this heat wells to the surface and is smeared across the central and eastern equatorial Pacific. Due to these characteristics, and the surface air-sea exchange of heat, the Earth is cooler-than-average during La Nina, and warmer-than-average during El Nino. But there's more to the story, there are two large competing effects on carbon exchange during ENSO. In a La Nina phase upwelling of acidified deep water along the western coast of North & South America out-gasses CO2 to the atmosphere. But this is more than compensated by the wetter-than-average rainfall which falls over the continents and particularly the tropical river basins of the world. More rainfall over such a vast land area generally means more plant growth and a draw down of atmospheric CO2. During El Nino the much of the continental land surfaces are drier-than-average. This is because the upwelled heat on the Pacific equatorial ocean surface draws moisture away from the continents, and rainfall is focused over the ocean. CO2 out-gassing may shut off, but again this is more than compensated for by land vegetation. As drought sets in on the continents, vegetation dies and CO2 is released back to the atmosphere. Warming air temperatures also elevate respiration which, again, releases more CO2 back to the atmosphere. These natural short-term CO2 fluxes dwarf human fossil fuels emissions, but unlike fossil fuel pollution they do not increase incrementally year after year. It is, of course, more complicated than that. For example the distribution of rainfall is vitally important, but that is the general picture. Armed with that knowledge you can now under see that Humlum & co aren't telling us something we don't already know. They just lack understanding of the physical mechanisms which drive this and, allied to ideological bias, therefore come to conclusions unsupported by the evidence. As for large volcanic eruptions - they can reduce atmospheric CO2 because they stimulate enhanced plant growth on a global scale. This is accomplished by the volcanic aerosols high in the stratosphere increasing light-scattering which more readily penetrates the leaf canopy. In the absence of other limiting factors, more sunlight equals more growth and hence draw down of atmospheric CO2. You can see this in the graph you presented - after the Mt Pinatubo eruption (1991) even the El Nino of 1991-92 saw a decline in atmospheric CO2 - the opposite of the normal response.
  44. Arctic Sea Ice Extent: We're gonna need a bigger graph
    I keep a daily chart on the ice extent from IARC-JAXA. Like everyone else I had to make space at the bottom this year for the new melt. Deep Climate is projecting 3.56m km^2 for minimum. Deep Climate Projection One striking this is how long the melt season is becoming - from a V-shape to a U-shape in the chart. Means the re-freezing will be almost as interesting as the melting.
  45. CO2 lags temperature
    scaddenp @378 Thanks for the link. That explain a lot about the context. I should have thought to search the site first for "Humlum" KR @381 So if I understand the graph then he's just showing that (sometimes) if the measured CO2 increases a bit more quickly year over year, then the temperatures increase a bit more compared to the previous year, and if the CO2 increase from year to year is a bit more modest the temperature increase is a bit less (or could actually be a decrease since the y-axes have different zero-lines). Whatever is causing the variability from year to year (even noise?) could then affect both measures in a similar manner. And none of this has anything to do with why either measure is trending upwards. Is that close? skywatcher @379 so would effects of ENSO and volcanic activity account for the seeming lag in the graphs where temperature differentials from the previous year appear to increase or decrease 12 months or so before measured CO2 differentials from the previous year?
  46. Realistically What Might the Future Climate Look Like?
    I agree with Tom's commentary on Dale's opinion. Further, I want to point that Dale's "BS" acronym can be taken as inappropriate, inflammatory term that he should also apologise for. As Dale admits in his closing comment @40, his opinion (or more precisely his way of opining) is indeed inappropriate, not only for this site but for any decent site. If Dale adheres to his closing comment do do not opine on this site anymore, I will not be missing him.
  47. Matt Ridley - Wired for Lukewarm Catastrophe
    Bernard J. @46. I'm sorry, but without the supporting data all you have done is draw a pretty picture that you are asking us to take on faith. I have a math degree, so I don't think I will swoon if post [sic] the supporting data.
    A degree in mathematics?! As others have noted, your naïve treatment of the CO2 data is very much at odds with that claim. However, if it is true, you shouldn't need to see my supporting data. You should be able to see that I performed an analysis that fits the entire Mauna Loa record, and with a bit of application of that claimed degree in mathematics, very soon have a close replication of the graph. I'm extremely curious to see if you are able to replicate the graph, because Tim Curtin with his self-styled skill in statistics never managed what is in the end really a simple procedure. If this turns out to be beyond the skills of someone with a mathematical degree, I might provide a step-by-step description of the process in a few more days, but I really would like to see that you've attempted to arrive at a fit rather more sophisticated than a linear or an exponential fit - for goodness' sake, your own graph and Tamino's explanation should tell you that an exponential fit is rather off base, even with a regression coefficient of 0.98.
  48. Realistically What Might the Future Climate Look Like?
    Tom: I've already given my opinion, but it was deemed not appropriate for this site. I will not be giving it again. Thanks
  49. Arctic Sea Ice Extent: We're gonna need a bigger graph
    Reflecting the title, the NSIDC Sea Ice Index is already at the bottom of the graph above and still heading south. At the next update, the graph will have run out of room.
  50. CO2 lags temperature
    David Sanger - and other readers: The simple lesson from this particular paper is this: If someone de-trends the data, as Humlum did in that graph, they are no longer examining the trends, and therefore cannot conclude anything about them. This is actually a fairly common mistake - any number of papers have filtered out the trends, and then attempted to state conclusions about the very data they have excluded from analysis. Very sad...
    Moderator Response: [DB] Revised text per request.

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