Reply to TLM

I received a rather lengthy comment from “TLM” on this post. My reply is too long for an in-line response, so here it is.

It begins:

TLM | July 13, 2012 at 9:54 am | Reply

Inevitably, because the internet is a largely US based phenomenon (particularly the Blogosphere), there is huge concentration on one unusual event in a relatively small part of one continent. Climate records are broken all the time and everywhere simply because we only have about 60 years of reliable data. At the moment in the UK we are suffering record levels of rainfall and low temperatures this summer. As far as I know nobody is seriously arguing that this is due to “global cooling” despite the predictable jokes in the pub.

The big argument is not about “New England” warming or “Old England” cooling it is about “Global” warming. Currently it looks like June and July are going to be pretty unremarkable in context looking at the whole globe.

Yes, records are broken all the time, and if this were just a war of “hottest ever” vs “coldest ever” it would be ridiculous. But there are two aspects which you have not addressed: the number and severity of record-breaking events.

I’m really not surprised that England shows low temperatures this summer — it’s a small region (much smaller than the USA) and they show greater variation, and indeed records are broken all the time. But I ask you: has England just had its coldest 12-month time span on record? Its coldest 6-month time span on record? One of Anthony Watts’ favorite comments is along the lines of “coldest March in 40 years!!!” He rarely (if ever) says “coldest March ever.” Is one of the cold months there in England the coldest on record? Did it break the old record by nearly 2F (1.1C) such as happened in March in Wisconsin? Is it anywhere near as record-shattering as the Moscow heat wave of 2010? Have the U.K. meteorological agencies referred to it as a “once in a thousand years” cold wave? That’s what you need to compare, since the Russian meteorological agency called their heat wave a “once in a thousand years” event.

You can always dig up cold events and even cold records, but sorry — your cold records just don’t stack up to the hot records being set, this last March in much of the USA, last summer in Texas and Oklahoma, 2010 in Russia, 2009 in south Australia. There’s a qualitative difference.

And if you look at the number of broken records — not just during the heat wave, but all this year in the USA, all last year, the years before that. This isn’t a “hot day” vs “cold day” argument, it’s a statistical property of the data record and there’s peer-reviewed research to back it up. Since the 2000s hot records have outnumbered cold 2 to 1. This year in the USA, that ratio is 10 to 1. There’s a quantitative difference. A big one.

So no, your “records are broken all the time” argument doesn’t stand up to scrutiny.

If you follow this blog regularly, you’ll also know that I have been one of the foremost advocates of emphasizing the trend over the fluctuations. But there comes a time when the extremes become so extreme, and happen so often, that they don’t just deserve mention, they have a noticeable — and too often, destructive — impact on human society. Welcome to the rest of our lives.

I have been reading the scientific literature since the last IPCC report as well as following many blogs both pro and anti and I just hold my hands up in despair.

I particularly dislike the tone of the comments on certain blogs where slagging of the other commentators seems to be more important than finding the truth, and I am afraid WUWT and this one are two of the worst. Both sides suffer from very bad cases of cognitive bias, always dismissing out of hand any argument that goes against their “belief system”.

I’m certainly willing to “slag” other commentators (I assume that’s British slang). What I don’t do is what Anthony Watts does — publish misinformation that can easily be disproven in order to do so. Like his SPPI paper with Joe D’Aleo which used faulty analysis to accuse scientists of outright fraud — but which I (and half a dozen other bloggers) easily showed wrong. When he does that, that’s when I “slag” him.

I don’t just “give ’em hell.” I give ’em the truth — they think it’s hell.

So what do we actually know?
1. The globe has warmed by about 0.5c since the first decade of the 20th Century, slightly more going back to 1850 if you extrapolate the very sparse data we had then over the whole globe.

No. The globe has warmed by about 0.8C (1.4F) since the first decade of the 20th century — 60% higher than your claim. Perhaps one of the reasons you understate global warming is that you have been misiniformed.

2. The ice cap is melting and summer snow in the NH is disappearing.
3. CO2 is a greenhouse gas that helps keep the atmosphere warm and the amount of CO2 in the atmosphere is rising due to man burning fossil fuels.

Some scientists have very reasonably linked points 1 and 2 to point 3 and are making great efforts to prove the linkage. Others have postulated very high sensitivty in this linkage which would lead to a global catastrophe. Actually, what few people understand is that the high sensitivity is not to CO2, it is to warming. Warming causes more warming, and cooling causes more cooling, whatever the forcing (CO2, the sun, volcanoes).

However, as far as I am aware, very few real scientists in the field are making the same great effort to disprove the linkage or the high sensitivity, and that is very, very bad for the science.

At the moment the very vital sceptical process is being left to amateurs and deluded deniers on blogs.

You should learn more about the history of global warming (I recommend Spencer Weart’s work). That happened in the early 20th century, and in the 1960s and 1970s and 1980s and even the 1990s. And yes, it’s still happening today although at a much reduced level.

Why the reduced effort, you wonder? Because the evidence is so strong. That’s how science works. Perhaps you’d like to complain about how few scientists are working their asses off to disprove the link between cigarette smoking and lung cancer.

When quantum mechanics was first proposed everybody went out of their way to try and prove it was wrong. And many scientists were slightly disappointed when the Higgs Boson was found, as disproving the Standard Theory would have been much more fun than proving it. So much so that they are demanding a 5 sigma proof! Climate scientist can only dream of such certainty.

The “5-sigma” issue has been discussed here before, more than once. In terms of the actual confidence level that can be ascribed to results it is not 5-sigma, because “sigma” refers to individual events rather testing the hypothesis. If you observe a hundred thousand events, which are deliberately selected to find what you’re looking for, then you’re gonna get some 4-sigma results just by accident, Higgs boson or no. In such a case, 4-sigma doesn’t mean anything like a p-value of 3 * 10^(-5). It means you need to adjust your statistics. Which is what the physicists do.

From where I sit there seems to be a gradully building body of evidence that the global troposphere temperature might not be quite as sensitive to warming as we first thought – the main item of evidence being that since 2000 the global temperature has not been following the track predicted by the early models despite a much faster rise in CO2 levels than predicted.

And yes, I have read your paper that it is all down to La Nina and volcanoes, and it is a good addition to the argument, but it is by no means proof – certainly not to 5 sigma!

It’s “only” 3-sigma. As I said earlier, the “5-sigma” requirement isn’t right. And let me ask you in all seriousness: if I told you that a train was speeding toward your own children but I could only prove it to 3-sigma, would you say, “I’ll wait until you get 5-sigma before telling them to get off the railroad tracks”?

That’s what’s at stake. Really.

And by the way — which “early models” are you talking about? What were their uncertainty levels? Were the forcing scenarios of those models realistic? What statistical analysis can you point to demonstrating significant departure between prediction and observation? Do any of those results attain the 5-sigma level?

But where are the peer reviewed papers arguing the contrary position? Why are all the scientists so afraid to test these theories really hard?

I’m afraid you’ve indulged in a bit of “slagging” yourself. Climate scientists are not “afraid” to test their theories really hard. That’s what they spend most of their time doing.

If global warming reverses, stops or even slows down then I am very worried this will discredit the scientific process irrevocably. Do you really want Watts, Spencer and Lindzen to be the only ones to have been on the correct side of the argument?

I’ll bet I can surprise you with this answer. Yes. If it turns out that I have been wrong all along, and they are totally right that global warming is “no problem,” no one will be better pleased than I.

Roy Spencer and Lindzen are minnows in the field and tainted by political and religious bias. Watts is an irrelevence whose argument is ruined by the crackpots and amateurs he allows to post articles on his site. We need real scientists doing real, challenging and absolutely vital, sceptical science. Scientists need to stop being afraid of being wrong!

You need to revise your beliefs about what climate scientists have been doing. You especially need to realize what it is that they’re really afraid of. It’s not fear of being wrong. It’s dreadful fear of being right.


90 responses to “Reply to TLM

  1. Who is TLM?

    Could the answer be in those initials?

    ‘The Lord Monckton’ maybe, after all he seems to think that Lindzen, amongst others, is on the right side of the arguments and TVMoB has been promoting that person who distracts lay audiences with non-science.

    • Don’t think so, he also calls Lindzen a “minnow” and “tainted”. Moreover, way too few misrepresentations of the science!

    • “Who is TLM?
      Could the answer be in those initials?
      ‘The Lord Monckton’ “

      ROFLMAO, well spotted, you got me!

  2. Good post, and little more to say.


    ” If it turns out that I have been wrong all along, and they are totally right that global warming is “no problem,” no one will be better pleased than I.”

    is overstating it a bit, as TLM’s point about discrediting the scientific process would then be a serious issue. But I guess we would all learn from our overconfidence and move on.

    [Response: I would gladly endure the damage to science’s reputation, to avoid the danger of global warming.]

  3. Spencer Weart’s history of this science is available here.

    Regardless of your angle of approach to global warming Weart’s book is highly useful.

  4. I’m glad TLM wrote his comment and I’m glad you took the time to explain the facts to him, Tamino. I think it will be a really useful resource to link to in future.

    Whether TLM is a ‘genuine’ sceptic or not will come out in his response. One thing is sure, he certainly received a more civil response here than if he’d written the exact same comment on a denial site.

    • Gavin's Pussycat

      John, civility is overrated. Here, TLM (and the rest of us) received a useful response.

  5. I’m not aware of any cold records in the UK, though there have been some rainfall records broken. It has been cool (though not by a lot, as the mins have kept the average up), but nothing really record breaking.
    It’s also, worth noting that also, the NW part of Scotland was very dry, as England & Wales (and Ireland) were getting all the rain. This is actually caused by the same large scale weather systems in that are causing the heat in the US.

    • Adam – December 2010 was the second coldest in the Central England Temperature Series since 1659 – and was followed by the warmest ever April.

  6. There are a few more scientific points worthy of mentioning:

    1) There is a terrestrial greenhouse effect that allows the temperature of this planet to be high enough to support liquid water. There is spatial and seasonal variation in the strength of the greenhouse effect, but on average it acts to allow the top of the atmosphere to radiate ~150 W/m2 less thermal emission to space than the surface emits. In simulations, the strength of the year 2000 greenhouse effect was about 6 W/m2 higher than the year 1850 greenhouse effect, owing to the increased opacity primarily from water vapor and CO2. The strength of this greenhouse effect is diminished somewhat after a volcanic eruption, since the water vapor decline (caused by shortwave reflection) outweighs the longwave absorption by the aerosol input.

    2) CO2 is the most important greenhouse gas in maintaining the structure of this greenhouse effect. The fractional contribution of the infrared opacity mentioned above is roughly 75% due to water vapor and to clouds, and 20% due to CO2, but CO2 doesn’t condense and precipitate out under the prevailing temperature conditions on Earth. Its concentration can rise and fall independently of temperature, and it can remain elevated over thousands of years as determined by its geological and oceanic sources and sinks. In contrast, if there were no water vapor in the atmosphere, evaporation would readily replenish the air column on timescales of weeks. Once too much water vapor is put in, it begins to condense and precipitate out. Thus, there is an equilibrium amount of water vapor in the air that is determined by temperature and is capped by the Clausius-Clapeyron equation. On average, the greenhouse effect is magnified by roughly a factor of 3 because of the longwave absorption by water, and this amplification mechanism works in a warming climate too.

    3) Atmospheric CO2 concentrations are now at ~395 ppm. This is roughly a 40% increase since the industrial revolution began. Although other factors such as solar irradiance, volcanoes, methane, ozone, etc must be accounted for, CO2 can explain a large amount of ~0.8 C temperature rise in the last century. The full warming effect, however, has been masked by the concurrent increases in sulfate aerosols which reflect sunlight to space, and delayed by the immense heat capacity of the ocean.

    4) There are now multiple lines of evidence that suggests climate sensitivity is higher than 2 C. The upper bound is difficult to nail down, since many climate observables are related to 1/sensitivity, and a gaussian distribution in this contribution gives no formal upper limit. For example, the peak cooling of a volcanic eruption is not much different if the “real” equilibrium sensitivity were 15 C or 10 C, but it is different if it was 1 C vs. 5 C. Combinations of paleoclimate evidence, observations, and perturbed-physics and multi-model ensembles (which are assigned credibility according to observations) and process-based understanding all indicates that climate sensitivity is significantly enhanced relative to the traditional “no-feedback” reference scenario, in which only the increase in Planck radiation is allowed to respond to a uniformly warming troposphere (this is an arbitrary but popular reference system).

    5) In order to be “right” in science, it is not enough that your conclusions are correct. Your reasoning and proposed process needs to be right too. Regardless of whether Lindzen or Spencer one day end up being right about a low sensitivity, they have not yet proposed any physical process or robust observation that is compelling for their current case. The scientists in Wegeners time had every reason to be skeptical of his ideas; he ended up being “right” but some of the original ideas were not convincing and demanded much more evidence. In contrast to the decades of observational, paleoclimate, and modeling work done on climate sensitivity, the results of Spencer and Lindzen are strongly dependent on minor and subjective choices (like what months you pick from in a satellite record), or often unjustified assumptions. Lindzen was wrong about the negative water vapor feedback in the 1990’s, and since proposed a high cloud related mechanism in 2001 (his “iris” hypothesis) which has not gained any traction either. He is now on to using satellite observations and regressing TOA radiant fluxes against temperature. The problem is that the satellite record has a lot of uncertainties, are not usually very long, radiation fluctuations are caused by much more than “temperature” (e.g., ENSO patterns), the coverage in these studies is not usually global, and the processes that govern internal variability and the forced thermodynamic response from 2xCO2 are different and have a different spatial structure. This gives rise to a whole host of practical issues using satellites alone to infer climate sensitivity. Other people have also tried though, and have come to different conclusions.

    6) At mid-range sensitivities, global warming is roughly linear in emissions at ~2 C per trillion tones of carbon emitted. What’s more, the perturbation of CO2 concentration lasts for thousands of years and the global temperature becomes “locked” into its new state even as emissions fall to zero. This makes global warming not only relevant at a socio-economic level, but it’s one that effects future generations and will be seen by a future geologist as an event comparable to, say, a glacial-interglacial transition.

    • Chris – The following question is off-topic for this thread, but I hope that if I just address it to you, Tamino won’t mind.
      The issue of water vapour being a “feedback not forcing” that you touch on above is one that I feel I should, but don’t, understand better, and that should be, but isn’t, explained better by those do so understand.
      Let me approach it this way:
      1. If the ONLY greenhouse gas on Earth was water vapour (all other things being equal), what would happen? What would the average global temperature be?
      2. In the situation in 1. , consider if the inherent ability of water vapour to absorb infra-red was increased. Is there a point at which that increase would cause a runaway global warming even if water vapour were the only greenhouse gas present?
      3. In other words, in respect to 2., is it the case that the statement “water vapour is a feedback, not a forcing” true not only because water vapour condenses back to liquid water but ALSO because water vapour’s inherent ability to absorb infra-red is below a certain threshold?

      • Hi Slioch,

        I’m helping out with some model simulations that are currently being performed at GISS to help address your first question, which takes CO2 from 0x to over 1000x present day levels.

        Thing is, once you remove all the other GHGs (really CO2, there’s not a whole lot of interest in the other gases in such experiments, because they don’t matter much), there’s not a whole lot of water vapor in the atmosphere. The impact of water vapor feedback eventually becomes negligible in the snowball limit. At some point you do get a snowball at low enough CO2, temperatures well below -30 C, and too low you can crash the model, but you’ll have to wait for some of these results. I don’t think it’s feasible to change the water vapor concentration in the model independently of these other “external factors” and keep that vapor distribution out to equilibrium (perhaps this is done in the most simplest of energy balance models that don’t have any thermodynamic responses, etc). There are simulations which remove all the water vapor (or double it) but within weeks it returns to its original value after evaporation or condensation processes take place.

        As for your second question, on the warm side, the runaway greenhouse threshold would definitely change if water vapor was a better greenhouse gas, though you can’t really be quantitative without accurate radiative transfer physics. The runaway threshold doesn’t depend too much on CO2 concentration…see my post e.g.,

      • Slioch asks how near or far the Earth is from suffering run-away GW from waper vapour? How much more powerful would H2O as a GHG have to be?
        Perhaps a better way of approaching this would be to ask a hypothetical question that didn’t break so many laws of physics. Perhaps:-
        “If the Earth only had H2O as a GHG, how much extra solar radiation would be needed to warm the Earth out from being a snowball and into being a steamed doughnut?” or “How much closer would the Earth have to be to the sun?”

      • Thanks Chris. Yes, I had seen you SKS article on runaway warming and I think it might be more appropriate to continue there (if at all), rather than clogging up this thread. But I’m away for a few days shortly, so won’t be able to do so for a while.
        Al — I’m quite relaxed about breaking a few laws of physics in a thought experiment if it helps me understand the consequences of those laws. Consider, for example the consequences if the freezing point of water was -20C, or even +20C. Varying insolation as you suggest would be interesting, but I’m not sure it would help me understand why at present water vapour is a feedback and not a forcing.

      • Pete Dunkelberg

        Slioch – “I’m quite relaxed about breaking a few laws of physics in a thought experiment if it helps me understand the consequences of those laws.”

        Somehow this doesn’t sound like a good plan.

        “…but I’m not sure it would help me understand why at present water vapour is a feedback and not a forcing.”

        This is terminology, not physics. It’s just about which came first. Add some CO2 … get lower albedo & more water vapor among other consequences. The CO2 started the ball rolling, so the other items are called feedbacks.

        P S ignore the muddled usage downthread. The energy in the system is all interchangeable and unlabeled. A joule is a joule.

      • Hi Slioch,
        My apologies.
        I do see now the nature of your primary enquiry for which my meddlesome adaptation of your hypothetical questioning is entirely unhelpful. Yet do be mindful that this was also the case prior to my meddlesome adaptation. Whether an influence of climate is forcing or feedback is in no way dependent on its inherent nature. Rather, forcing/feedback is defined by what is considered external/internal to the system under examination.

    • Pete Dunkelberg

      Chris: There is spatial and seasonal variation in the strength of the greenhouse effect, but on average it acts to allow the top of the atmosphere to radiate ~150 W/m2 less thermal emission to space than the surface emits.

      We’re all going to die! Or could you explain this another way? Let’s see … the TOA has a larger area than the surface …


      [Response: Have you calculated the ratio of TOA are to surface area?]

      • Pete Dunkelberg

        Gimme a break. The point is not that I need to go out and buy batteries for my old TI calculator. (*) The point is conservation of energy. The same amount of energy goes out as comes in, except for a slight temporary imbalance while we increase the GHGs. Or else the planet heats up until it blows away on the solar wind.

        (*) the point is also not that I need to be informed about google calculator. All I seek is a little physics. I’m sure Chris will explain his meaning if he is following replies to his comment.

      • I still don’t see what the problem is…

      • Pete, the surface budget is–forgive me, I know that we live here–a sideshow. From a conservation of energy point of view, it doesn’t matter what the surface does; what matters is TOA in and TOA out.

        According to Kiehl & Trenberth, the surface both receives and emits more than TOA. Seems impossible, doesn’t it? Yet that’s what measurement seems to show. I’m obliged to say (possibly by my own incomplete understanding) that it’s because some energy is ‘double counted’–first as incoming sunlight, then as down-welling IR. From this perspective, the surface ‘excess’ looks a bit like an artifact of energy accounting–but a necessary one, if you want accurate accounting.

        But hey, I’m just a musician.

      • Pete Dunkelberg

        Hi Chris, hi Kevin, OK I’m getting it. Due to the GHGs that intercept IR and re-radiate it in all directions, the surface catches a lot of down-welling IR rays that did not originate directly from the sun. Since we are (on average) in an equlibrium situation, the surface must give (radiate) as much as it gets. The down-welling radiation essentially is the greenhouse effect. So Chris, you mean (I now take it) that quantitavely the greenhouse effect is 150 wattts per sq meter. How did you say it?

        “There is spatial and seasonal variation in the strength of the greenhouse effect, but on average it acts to allow the top of the atmosphere to radiate ~150 W/m2 less thermal emission to space than the surface emits.”

        Cue an ode to the flexibility of language.

        So we agree that total energy in = total energy out, except for a slight imbalance while we adjust GHG concentrations. And of course you (properly understood) did not intend to say otherwise. My bad. And we have just about reached Arrhenius 101: to have an idea of what’s happening we have to balance the surface energy budget and the TOA energy budget simultaneously.

        This reminds me of the story of Ohm’s Laws that I read somewhere. As a roudabout way to make some point, Prof A told Prof B
        “When I teach electricity to certain classes I like to start with Ohm’s three Laws.”
        “What?” said Prof B, “I thought Ohm had only one law.”
        “No,” said A, “I find it works better to give them three laws: one solved for voltage, one solved for current and the third solved for resistance.”

      • “Ohm’s Three Laws…”


      • Pete, Slioch,

        Unfortunately it seems this thread has run its course, but I don’t know of a more appropriate forum to bring this to at the moment. You’re welcome to come over to my blog and leave comments there, since I have related posts up.

        A rather traditional “radiative definition” of the greenhouse effect strength is G = σTs^4 – OLR, where σTs^4 is the surface longwave emission at ground temperature Ts, and OLR is the outgoing radiation at the top of the atmosphere. On Earth, this difference amounts to ~150 W/m2; on Venus, it amounts to over 16,000 W/m2. The units “W/m2” represent a rate, and thus the greenhouse effect acts to reduce the rate at which energy is lost to space for any given temperature. A temperature gradient is established between the surface and upper atmosphere until a new equilibrium point is maintained and, eventually, the top boundary will emit to space at the same rate as the absorbed solar radiation.

        In equilibrium, both the top and bottom of the atmosphere energy budgets will be respected. The surface terms also include evaporation and sensible heating fluxes, which act in concert with the net infrared and solar radiation fluxes, in order to close the surface energy budget.

  7. Good post, Tamino. I know when I first really began to look into global warming six or seven years ago, I wasn’t sure what to make of it. There’s an awful lot of disinformation spread around. When I looked at the data myself, I realized that the climate is changing — and it’s changing quickly. This is supported by many lines of evidence independent of the temperature record — phenological data, historical ice & snow coverage data, glacial melt, sea level rise, etc. Once you realize that the climate has already changed considerably, it’s pretty obvious that it will only continue to change as more and more greenhouse gases accumulate. Which is what makes some of the future predictions especially alarming, yet realistic.

    One issue I recognized a couple years ago when there was much ado over the cold, snowy winters in the eastern US is that people’s perceptions of what is normal have already been distorted by the changes that have occurred. Something may be the “coldest in 20 years” but on a historical perspective be less significant in light of the fact that temperatures generally over the past 20 years have been warmer than the previous 100+ years. Global warming doesn’t mean every place will be warmer every day of every year — at least not at this juncture. After all, the global warming signal is still only around 1 degree, maybe a bit more on land areas.

    Getting back to the cold winter meme, there have been some cold winters recently (certainly not last winter here in the States, however!). However, there have also been some research that shows that this appears to be linked to changes in global atmospheric circulations patterns related to the decline in sea ice. In addition, there is observational data that shows the jet stream has shifted northward somewhat with time and slowed due to the effects of arctic amplification of warming. This has likely contributed to some of the increase in long-lasting, bizarre weather patterns that have been observed in recent years. Of course, it’s also useful to keep these recent winters in perspective. Last winter, NOAA released an updated plant hardiness map. I can say that the map, although more realistic than its 1990 predecessor, is already outdated here in northern Ohio — simply because it relies on 1981-2010 data and the climate even in the last 20 years has moved away from extreme cold. Using data from the local airport (which incidentally is in a rural area removed from UHI, and in a rust-belt region that has actually lost population in recent decades), the coldest extreme during the 70s and 80s was pretty uniformly between -10 and -15F, with some years closer to -20F. The old plant hardiness map had my area in the -10 to -15F zone. The recent update changes that to -5 to -10F. Yet, looking just at the past decade, the average coldest low has only been about -2F, so we’re already a half zone higher than indicated by the map. In addition, in recent years, only about every other year has even dropped below zero.

    But, from my perspective, climate change is real — and it seems to be accelerating. Nor is it just a US phenomenon or a “small part of one continent” as TLM puts it. Nor is it just a one-time deal. This summer has been extremely hot and dry. But each of the last two summers were also pretty darn hot. The summer of 2010 was noted for the record-shattering Russian heat wave, but it was also a warm one here in the states — in fact, the sixth warmest on record. Many states along the eastern seaboard record their hottest summer on record that year. Last summer was even more impressive — the 2nd hottest on record, with the extreme record-breaking heat wave & drought in the Southern Plains. This summer seems to be intent on sharing the wealth everywhere.

    • when there was much ado over the cold, snowy winters in the eastern US

      One should also note that the fake skeptics, as Tamino likes to call them. have a tendency to conflate “snowy” and “cold.” “Record-setting snow” somehow morphs into “record-setting cold” even when it’s not particularly cold.

      Of course, they’re not the same thing at all.

  8. I just wanted to add also that the observed conditions are certainly consistent with climate model predictions. This really is “what global warming looks like” at least here in the Great Lakes region.

    Take a look at this link, which discusses the future climate of Illinois:

    Look at how many of the indicators are present this year. The map that purports to show the future Illinois summer climate compared to locations much further south in the future looks impressive and almost inconceivable. But look at the temperatures this summer — heck, look at the entire year! A couple weeks ago, I looked at the figures for Detroit, MI. For the year, the temperatures in the Detroit metro area were comparable to 1971-2000 normals for Lexington, KY, for the same time frame, and nearly a degree and a half warmer than Greater Cincinnati Int’l Airport in Covington, KY. Given the excessive heat since then, it’s safe to say southeast MI has “dropped even further south.” Anyways, that’s what 4-6 degrees of sustained warmth means. It means shifting a location’s climate by 300 miles!

  9. Re after first section of TLM quote.
    The 2012 June UK temperatures were 0.3 deg C below average, the lowers June temp since 1991. It was the wettest June since records began in 1910. (The England & Wales rainfall records start in 1766. 2012 was equal wettest with 1860.) Bottom box on page @

    Re after second section of TLM quote.
    We Brits “slag off” rather than “slag” people. I think TLM is missing an “f” at that point in their comment.

    As somebody who has for over a decade been following the arguments of mock-sceptics, I still do not dismiss any sceptical argument out of hand. Okay, it is fair to say I approach what the likes of Lindzen et al present from a fairly negative viewpoint. But this is their own fault. They have “queered their own pitch.” A true sceptic would react far more dexterously to the criticism they get for their efforts. And in my experience, academics love a robust and genuine dust-up.
    And taking a genuine sceptical position to see where it goes, you might end up wrong but you sure have an opportunity to show off how good you are. It’s an attractive proposition, surely, as long as criticism is addressed properly.
    As for slagging folk off, in my view when the author stonewalls and exhibits wanton ignorance in the face of counter-arguments, they become ‘fair game’ for overly robust responses – ridiculing & making fun of their flawed argument. It is a thin line from there to ridiculing the author himself, a line I try not to make a habit of crossing. However, in the face of unbelievable stupidity I am less bothered by such niceties.

  10. climatehawk1

    Re “it’s just a U.S. phenomenon,” I think it is worth noting that according to the U.S. National Oceanic and Atmospheric Administration (NOAA), May 2012 was the 327th consecutive month in which average global temperatures exceeded the 20th century average for that month.

  11. Let me second Tamino’s post. As a geologist with a keen interest in climate science, I’m also a mountaineer and an avid skier. I’d like nothing better than to find out all the signals of warming are just a passing climatic blip and things will return to “normal” soon. The laws of physics strongly suggest otherwise as does the mounting evidence.

    • I can relate to your points! Despite hearing all the stuff about glaciers shrinking, for example, it was actually witnessing how much the Blackcomb glacier on Blackcomb mountain had shrunk over the years (and hearing from the old-timers that it hadn’t shrunk this quickly in the past) that raised my concern.

      I really want the deniers to be right!

  12. We need real scientists doing real, challenging and absolutely vital, sceptical science. Scientists need to stop being afraid of being wrong!

    Scientists want to be productive, it’s how their careers advance. Physicists see no reason to spend their time trying to publish papers proving that perpetual motion machines are possible. That would certainly be skeptical (of standard physics), challenging, and in its way vital (if such a proof were possible).

    In your own words, can TLM tell us *why* physicists don’t spend their time on such a topic?

    And how this might relate to climate scientists not spending their time trying to overturn the equally sound physics that underly climate science?

    Don’t limit yourself to “AGW”, which exposes a narrow and in its way ignorant understanding of climate science. Almost everything we know about climate science would have to be overturned (including numerous explanations of various paleo climate regimes, for example) in order for “AGW” to be “proven” false.

  13. One of the interesting insights from Mann’s book The Hockey Stick Wars was that he claimed to have originally approached his early research from a skeptical viewpoint. He claims to have set out to prove that recent warming was unremarkable in the historical context. If true (and I see no reason to doubt it), this is an example of why we don’t see “contrary” viewpoints in the literature. If you start from a contrary viewpoint and do the science right, the contrary viewpoint is rejected.

    • A more recent example of a serious study starting from a contrary viewpoint, doing the science right and rejecting the viewpoint would be Berkeley Earth Surface Temperature project. The nice thing about that one is that the initial viewpoint is pretty well document – if only by the cheque from the Koch Foundation.

  14. TLM: Why are all the scientists so afraid to test these theories really hard?

    tamino: That’s what they spend most of their time doing.

    Despite a few websites like this one, it is very difficult to get a grasp on the extent and depth of what climate scientists are doing by just reading the blogs. Perhaps it would help TLM if he/she subscribed to the Global Change series of the AGU:

    Although only abstracts are available there, scientists are generally very willing to make their publications available to interested readers. An email like the following inevitably produces the desired response:

    Dear Dr. XXXXXX:

    I would greatly appreciate receiving a reprint or PDF of your recently published article:


    Thanks very much.

    • Rattus Norvegicus

      It’s worked everytime I’ve tried it. Now that I work at a University, though I no longer have to go through this route. Just click on the link. Man this is great!

    • Another thing TLM might do is attend a scientific conference. There will be plenty of evidence of scientists “testing their theories really hard.” Scientific conferences, like most scholarly conferences, are not love-fests.

  15. doctorbunsenhoneydew

    TLM should read this article by the MET office explaining this summer’s weather.

    The U.K.s weather is famous for its changeable nature, it is the last place we should expect to see a clear indication of climate change. Ironically it is this variability that probably explains why we have climate data going back a lot further than most other parts of the world!

    There is also a branch of statistics called “exteme value theory”, which I know from experience is familiar to many climatologists. There are sound methods for analysing trends in the ocurrences of record events. While the discussion on blogs tends to be rather anecdotal, that doesn’t mean the climatologists are not using rigorous statistical methods.

  16. Thanks for the comprehensive reply! I am flattered that you thought it worth the effort. Your point about the extreme temperatures in the USA vs a bit of wet weather in lil ‘ol UK is well made. And it looks like I need to go and read Spencer Weart for a history of true climate sceptics.

    I posted a couple of further comments under “Thirteen” before I noticed you had replied here but your answer here pretty much covers the points.

    I would still like to see current temperatures plotted against some updated model outputs with revised sensitivity.

    [Response: A paper is being submitted soon which addresses such issues, including comparison of model results for temperature change and sea level rise to observations. Unfortunately I can’t say anything more until it goes through the review process — but rest assured I’ll report in full.]

    I am fed up of seeing Hansen’s 1988 graphs dragged up in the “other side’s” blogs all the time. As regards my temperature mistake, that was because I was using 30 year averages (average 1913-1942 vs average 1983-2012) that I had prepared for another post elsewhere. I agree that was misleading in this context – my apologies.

    Anyway, using the 30 year climate average method we only have another 15 years to wait to see if global warming has stopped! We cannot afford to wait that long, of course, which is why I would like to see a better investigation of the current 15 year global warming hiatus than is provided by blogs like WUWT.

    Keep up the good work!

    p.s. What is a “tone troll”?

    [Response: As far as I can tell, it’s someone who complains about the nasty tone of discussion, not because such complaint is needed but simply to divert attention from the real issue or to discredit one side (in a polite way). I don’t get the impression that you fit that category.]

    • “… I would like to see a better investigation of the current 15 year global warming hiatus than is provided by blogs like WUWT.”

      I’m not quite sure why 15 years is so magical. What about 14 or 16 years? Try WFT with 12, 13, 14, 16, 17, 18, 19, 20 years and see if you always get “cooling trends.”

      Here are some graphics that might be helpful:

    • “… I would like to see a better investigation of the current 15 year global warming hiatus than is provided by blogs like WUWT.”

      Really, there has been a lot. The apparent hiatus can be fully explained to within the measurement errors by just two factors:
      – Coverage bias in the Hadley and NCDC datasets, and
      – More La Ninas towards the end of the period.
      Once you take these into account, there is no evidence of a hiatus. None. The underlying warming signal is the same as ever. I’ve just finished a 4 part series examining this issue here. (The title is an homage to Tamino’s own work.)

      All this is known to scientists in the field – you can find it in the latest GISTEMP and HadCRUT4 papers if you look hard: Most of what I have done is illustrating what they already know. If you want my code to check for yourself, post a comment over at Skeptical Science and I’ll make it available.

      • Note: I meant trend uncertainties, not measurement errors of course. But the agreement is rather better than that.

  17. I also have a “it’s not just the US” comment, sadly in Danish but you can watch the movies yourself:
    There’s a lot of ice melting, apparently. Much more than normal. Summit measured + degrees recently. That’s a weather station at 3200 meters right on the inland-ice.

    To give an indication of the warmth in part of Greenland: Nuuk has an average temperature in July of 6.5 degrees Celsius. The first few weeks of July, the *lowest* temperature has been hovering around that temperature, often even being higher.

  18. There’s an increasingly credible line of research that absolutely links the UK’s record breaking summer with climate change (new rainfall records were set for England and Wales in April and June and the way we’re going likely July too). Funnily enough this came on the back of a 2 year ‘drought’ in parts of SE England.
    A number of groups are reporting on Artic sea ice loss causing the Jet Stream to weaken and stall. Well, it seems to want to stall directly over the UK which has been in the firing line of Atlantic weather systems for much of the time since late March.
    This is a similar scenario that gave us record breaking cold spells over recent winters, the Jet ‘stuck’ to the south of the UK allowing Artic air to flood down and stay there for long enough for new cold records to be set. It wasn’t the Jet moving south of us that was out of the ordinary, it’s how far south and how long it stayed there.
    The UK’s weather is too much governed by the position (and disposition) of the Jet Stream for these islands to be a good indicator of climate change but regardless of that, anyone who says our weather has been ‘normal’ these last few years has likely spent too much time in the pub.

  19. I understood that global warming was also global wetting and we are getting the wet bit in the UK.

    Doesn’t the atmosphere hold more water now?

    • Pete Dunkelberg

      > global wetting

      Alas that’s just a part of it. Try global bunched precipitation. Between flooding and the opposite people will Dai.

  20. Rather than cause this discussion to be spread over two articles, I thought I would post here in response to a reply by Tamino under “Thirteen”.

    Re looking at global warming over the last 15 years. I know it breaks all the “statistical” rules, but just simply eyeballing the graph of (annual average) temperatures shows a distinct change in the trend of global temperatures after 1998. In order to avoid a charge of “cherry picking” I could have said 10 years since 2002 – but to me the break in the trend is pretty clear.

    Everybody can see it so science needs to address it – otherwise the field is open to the likes of WUWT to draw their predictable conclusions. You already have a paper on it, so I know you thought it worth addressing.

    Re sea level rise accelerating or decelerating. My (admittedly very amateur) effort on this is on the couple of graphs linked to below. Very happy to be shot down in flames! I passed this by Dallas Masters at Colorado Uni and he said it was a fair representation of the data and he said I had used the right method to remove the GIA adjustment from their figures. I know you will dislike my use of a 5 year rolling linear regression, but whatever way you cut it it looks like sea level is currently rising at around 2mm a year (at the coasts – see below), rather slower than at the turn of this century when the rate was around 4mm a year.

    The GIA adjusted version is a good indication of the volume of water in the oceans and the effect from sea temperatures, but the one with the GIA adjustment removed is a better indication of the threat at the coasts.

    [Response: I quite understand that your interpretation based on visual inspection is very natural. The idea that there’s been a cessation (or even reversal) of temperature (or other) trend is regularly inquired about by real skeptics and hammered on by fake ones.

    I’ve done many posts (really, a lot!) about trends in temperature (and other) variables and this issue in particular. But clearly it’s a topic that bears repeating. So, I’ll do it again for the next post. After you’ve read it, let us know whether or not you find it persuasive. I’m confident you’ll apply a skeptical eye and not cut me any slack. Wouldn’t have it any other way.]

    • The eye is very easily decieved by the presence of the 1998 El-Nino spike. If you mask that year when you plot the data, there no longer seems to be a change in the trend starting in 1998.

      This suggests to me that it is an optical illusion caused by the spike rather than a genuine change in the long term trend (or a step change).

    • See, here is what I do not comprehend. The science of climate change is nearly 2 centuries old. We’ve known CO2 was a greenhouse gas for more than 150 years. The first prediction of anthropogenic warming is 116 years old. It’s not like this stuff is cutting edge science–on the very edge of truth and science fiction.

      And the evidence is not just that we see warming and feel we have to come up with an ad hoc theory. Hell, the prediction predated the warming. And there’s how it’s warming (the diurnal, seasonal and latitudinal dependence) and the fact that the stratosphere is cooling even as the troposphere warms. It is EXACTLY what we expect from a greenhouse mechanism.

      And it’s not as if the only harm is far off into the the future. A whole county in Texas burned last year. The western US is seeing probably its worst fire season ever this year–and early in the season, too! Half of the US is a disaster area due to drought. Siberia is burning. The area of the world in severe drought has increased by 27% in 30 years. And it’s all happening just where the models predict.

      Now contrast that to the denialosphere. They don’t publish. They don’t predict (at least not correctly and are never held accountable when they are wrong). Their arguments are easily refuted by anyone with a modicum of technical prowess, and seemingly abandoned, only to be resurrected on the next Gish Gallop around the track. They resort to threats, lies, and ideological insults.

      So how is it anyone believes them.

      • Susan Anderson

        Thanks Ray. You have a gift for putting simple facts simply, if with a bit of spice.

      • Didn’t have a whole county burn in Texas, but the total burned area was much larger than a typical county. In fact it was as large as…

        Rhode Island




        New York City.

    • Note that sea level rise is also heavily affected by ENSO (El Nino, La Nina). Thus, just like the temperature record, you rapidly will see changes in the trend that disappear when you correct for this aspect.

  21. KeefeAndAmanda

    Mainly to TLM and any other skeptic:

    I too am a lay observer (having only an undergraduate degree in mathematics) who has tried to find a way through this particular minefield, and in so doing, in order to simplify and generalize what I understand the science to be saying as much as possible, I have come up with the summary below.

    But before I present it, consider the book (that is partially available online as a Google e-book) “Solar activity and earth’s climate” by Rasmus E. Benestad, who obtained a Ph.D in physics from Atmospheric, Oceanic & Planetary Physics at Oxford University. Go to page 176. We read,

    “Any mechanism involving the albedo implies strongest response in the daytime temperature. Observations, on the other hand, suggest a reduction in the diurnal temperature range where the night-time temperature has increased more than the daytime temperature (Houghton et al., 2001). According to Svensmark’s hypothesis, the warming is due to the reduction in Earth’s albedo (reflected light), and therefore a long-term reduction in the low-level planetary cloud cover appears to be inconsistent with the observations.”

    That is, what Benestad says above is simply a polite way of saying that the reduction in the global diurnal temperature range where the global nighttime temperature has increased more than the global daytime temperature very strongly falsifies the hypothesis that essentially only more energy absorbed from the sun via less reflected sunlight (lower albedo) has caused the recent warming, this hypothesis being the main explanation put forth by those who are anti-AGW. (See the further below for how this falsification is very strong.) Benestad has written that each time he has confronted Svensmark about this Svensmark has refused to answer it in any meaningful way.

    To quote Benestad further:

    Quote: “I believe that some of Karl Popper[‘s] ideas about falsification can be useful.”

    The below summary demonstrating AGW to be true via the falsification of its negation was inspired by such falsification-based arguments already made by some climate scientists, like Benestad above. It’s wordy, but perhaps it is so because it does I think anticipate at least by implication all the possible objections to the conclusion that AGW is true.

    Apart from some more or less catastrophic release of heat from the interior of the planet, there generally and normally are only three possible ways to increase the total heat content of the planet’s fluidic system (atmosphere and oceans taken together as a system – see
    for an idea of what I mean):

    (1). More energy falls onto Earth from space (think the sun).

    (2). More of this energy falling onto Earth is absorbed – that is, less of it is reflected (think lower albedo, less reflected sunlight).

    (3). More of this absorbed energy is not radiated back out into space as infrared radiation – that is, more of it is trapped (think increased greenhouse gas activity).

    Side note: Any increased heating that could result from such claimed causal mechanisms as fewer galactic cosmic rays (with a claimed result of lower albedo), fewer reflective clouds, fewer aerosols from volcanic activity or human pollution, etc. can be viewed as ultimately being covered by this general case of (2). This condition (2) covers all those arguments made by those like Spencer, Lindzen, and Svensmark.

    Now consider these two sets of three statements applied over the long-term and applied globally:

    (A1). The nighttime warms slower than the daytime.

    (B1). The winter warms slower than the summer.

    (C1). The polar regions (especially the Arctic) warm slower than the equatorial regions.

    (A2). The nighttime warms faster than the daytime.

    (B2). The winter warms faster than the summer.

    (C2). The polar regions (especially the Arctic) warm faster than the equatorial regions.

    Now consider these two implication statements applied over the long-term and applied globally:

    (I1.) If global warming occurs just from either or both of (1) and (2), then each of (A1), (B1), and (C1) occurs.

    (I2.) If global warming occurs just from (3), then each of (A2), (B2), and (C2) occurs.

    As I understand it, the physics says that over the long-term and globally, (A2), (B2), and (C2) have occurred. This means that over the long-term and globally, the complete opposite of each of (A1), (B1), and (C1) has occurred. And as I understand it, the physics says that over the long-term and globally, (I1) and (I2) hold.

    (Yes, I know that these are simplifications and generalizations, but as I understand it, the science is such that these broad statements can be made and are true.)

    Let p -> q be implication (I1) with p being “global warming occurs just from either or both of (1) and (2)” and with q being “each of (A1), (B1), and (C1) occurs”, and let ~p and ~q respectively be the negations of p and q.

    Then by (A2), (B2), and (C2) having occurred we now have not only the falsity of q, but by a simple application of modus tollens (the form
    p -> q
    therefore ~p
    being a standard form) we have the condition p being falsified. That is, p implies and predicts q, but since what has actually happened is the complete opposite of each sub-condition of q, condition q is false and therefore condition p is false.

    This means that, since the condition of anti-AGW is essentially equivalent to this falsified condition of global warming occurring just from either or both of (1) and (2), anti-AGW is essentially falsified.

    I note that this is a very strong falsification of anti-AGW, since the condition of the complete opposite of each of (A1), (B1), and (C1) is a very much stronger negation of the conjunction of these three conditions than a simple negation of this conjunction. (For instance, a simple negation for each of these three conditions entails the false condition of the temperatures in question simply going up at the same rate. That is, the false condition of the temperatures in question going up at the same rate would constitute a weaker falsification of anti-AGW, but a falsification nonetheless.)

    By the process of elimination, and given that this falsification in question is a very strong one, (3) – which is essentially equivalent to AGW – is therefore to at least quite a large degree the explanation of the long-term global warming over the last half-century.

    The only way to continue to be anti-AGW in light of the above is to reject the science that says that over the long-term and globally, (A2), (B2), and (C2) have occurred and that (I1) and (I2) hold.

    Example: One way we see such rejection being made is in the cherry picking of regional studies showing that *in those regions*, (A2), (B2), or (C2) did not occur. But this rejection of a statistically general and global truth by cherry-picking a particular that is contrary to this statistically general and global truth is so obviously fallacious, I don’t see why anyone would actually try it – yet we see it tried all the time.

    This is about *global* warming or cooling, and so if regional studies are done, they must be seen in the *global* context if they are to done properly. These recent correctly done statistical/mathematical analyses at this site about what has recently happened in the US are a good example of regional analysis being done properly.

    One last point:

    Please do not make the mistake that so many still continue to make in their attempts to argue against AGW, this mistake expressed in the astonishingly wrong argument that causal relations in nature must form strictly or monotonically increasing functions (or strictly or monotonically decreasing functions). Due to the fact that many conflicting causal influences can be present in nature, temporary flat parts or downturns in an upward trending graph showing a relation between two conditions like global CO2 and global temperature can be perfectly consistent with and thus do not contradict the relation being a causal relation.

  22. You have a point, but there is change in direction later – somewhere between 2002 and 2005. You can actually ignore 1998 altogether if you wish, the reversal in the apparent trend is still there (I am aware that it is regarded as a statistical blip by most).

    In fact the trend slope of the linear regression for the last 10 years is more apparent at -0.0125c a year compared to -0.0025 for the 15 years – but of course a shorter period is less significant.

    I should point out that I am using the average of the anomalies of the first 5 months of 2012 as representative of the whole year. This of course will change if El Nino means higher temperatures for the rest of the year in which case the negative trends will be lower but they would need to be very high to turn either trend positive.

    • Do not look at a 10-year period in isolation. What was the slope from 1977-1987? 1987-1997? And now 1977-1997?

    • TLM, you’re going Down the Up Escalator. If you spend time at SKS as you indicated, you will know exactly what that means.

      Pointing to 10 year trends is a beginners pitfall, and also stock and trade for fake skeptics. You should read this post by Robert Grumbine:

    • TLM There have been many decadal scale slow downs in the past 30 years, but the long term warming trend continued; so why is the most recent hiatus different from the previous ones?

      You have computed the trend, but I would recommend you also look at the error bars on the trend, you will find that for a decadal trend they will probably be so large that it will be obvious that no meaningul inference should be made.

      As well as the escalator graph, SkS also has a temperature trend calculator which I suggest you investigate. It gives quadratic error bars on the trend (loosely speaking any straight line you can draw between then is not ruled out by the data as a plausible trend). You willl find that over the last decade there isn’t enough information to know whether it is warming or cooling. This is because there isn’t enough data in so short a window, so no infferences should be drawn on tha basis.

    • Chris O'Neill


      compared to -0.0025 for the 15 years

      Where do you get this negative trend from? Hadcrut4 and GISS give positive trends of 0.00844387 deg/year and 0.00906374 deg/year respectively.

      You must be using an obviously biassed or unduly influenced data set. Why do you make this choice? Aren’t you interested in the truth?

      [Response: I suspect he (?) is.

      I prefer GISS because they handle the Arctic better, and in fact that’s the goal with HadCRUT4. But HadCRUT4 doesn’t yet extend beyond end-of-2010. I also like GISS because, frankly, it’s American — like I am. But TLM is a Brit, and if you want anything British beyond 2010 that means HadCRUT3. Also, as far as I know it’s featured more prominently in the IPCC reports than GISS (or NCDC) data.

      I agree that HadCRUT3 is not as good a choice as others, but if a Brit chooses to examine it I don’t think we can rationally accuse him (?) of obvious bias.]

    • Chris O'Neill


      there is change in direction later – somewhere between 2002 and 2005.

      Interestingly, this is the time (2005) when HADCRUT3 and HADCRUT4 start to diverge.

  23. Oops, apologies for the spelling mistakes in the graph… (anomaly and temperature)… knocked up a bit quickly.

  24. “We need real scientists doing real, challenging and absolutely vital, sceptical science. Scientists need to stop being afraid of being wrong!”

    It seems to me that there is a misunderstanding on TLM’s part about how science is done. Research centers around the testing of hypotheses. But that testing (or experimentation) is not, or should not be, to prove the hypothesis but rather to disprove it. That is by far the most rigorous approach. I’m an immunologist so my knowledge of climate change is rudimentary at best but in my simple mind if I was doing global warming research and I wanted to test whether global temperatures have been increasing it would simply not be rigorous enough to repeat ad infinitum the measurements of temperature over a defined period using different methods; for me the BEST study was a classic example of non-rigorous hypothesis testing. Instead the rigor would come from asking what are the consequences of global warming? Increased temp should result in ice melting which should result in sea level rise. Do we see that? Increased temps are likely to change growing seasons of plants which should in turn affect populations of migrating birds and insects associated with them. Do we see that? And so on. Global warming, climate change, call it what you will one thing is for sure. Those involved have applied very serious rigor to the problem. And it has survived those tests alarmingly well.

    • Nobody is seriously disputing that it has warmed, and that the warming has continuing consequences for all life forms on the planet and for our cryosphere. But surely the best way to test the hypothesis of continued global warming is to measure directly how much the globe is warming. Or am I missing something? I did not mean that to sound trite, but direct evidence is always more persuasive than indirect or consequential evidence. Ask a policeman, or better still a jury!

      The argument comes down to how much of any current warming is due to our emissions of greenhouse gases and how much further warming we can expect as a result of that past warming. How is the postulated positive feedback manifesting itself in the temperature record? I was bemoaning the lack of discussion on current temperature trends and how they fit against the projections from current climate models. I only see current temperatures compared with Hansen’s (long since superseded) 1988 projections – which is not only misleading but rather stupid frankly.

      It looks like from Tamino’s responses that we can expect a paper covering that very point soon. I look forward to reading it.

      • TLM: I was bemoaning the lack of discussion on current temperature trends

        BPL: I’m not sure you’re clear on what a “trend” is. In statistical analysis, a time series has to have a significant slope to be called a “trend.” For climate time series, that means you typically need a sample size of thirty years or more.

        Got that? Thirty years, not fifteen, not ten. Here’s why:

  25. Sceptical Wombat

    I think it is very unfair to describe Lindzen as a minnow. He is after all a fellow of the NAS. Sure he is biased and his expertise in atmospheric physics is not directly related to climate change. However he clearly has the background and the intellectual ability to probe the science thoroughly. The fact that he has not come up with evidence supporting his bias which stands up to scrutiny is surely a strong indicator that such evidence does not exist.

    Actually, what few people understand is that the high sensitivity is not to CO2, it is to warming. Warming causes more warming, and cooling causes more cooling, whatever the forcing (CO2, the sun, volcanoes).

    I’m not sure what the point of this is but if TLM is saying there are net positive feedbacks then I would have to agree. However it is always important to understand that provided the feedback ratio is less than 1 the total effect will still be finite.

    • I’m not sure what the point of this is but if TLM is saying there are net positive feedbacks then I would have to agree.
      I am only trying to make it clear that the net positive feedbacks, if they exist, act independently of the level of CO2. If it warms then positive feedback, or high sensitivity, will mean that warming will cause more warming regardless of what happens to the original forcing (assuming that it does not actually reverse). For at least the last 10 years we do not appear to have seen “feedback” warming from the warming that happened in the 1980s and 1990s. I have yet to see a credible explanation of why that might be and it is beginning to look (to the sceptical layman) like the feedback is not as positive as has been suggested? Just a sceptical query – not a statement of belief.

      • @TLM
        As you say, when the impact of positive forcing is swamped in the atmosphere by prolonged La Nina (aided by a weak sun & added Chinese polution) short term warming feedbacks are shut off.
        What you are suggesting is that high sensitivity requires strong long-term feedbacks which should be now evident warming the planet, adding greatly to our CO2 forcing.
        Consider then a climate sensitivity of 4.5.
        If AGW with no long term feedbacks gives a sensitivity of about 2, the long term feedbacks would contribute 2.25 to yeild the 4.5 total. But 45% of this 2.25 (just like the CO2 forcing) will be its own short term feedbacks (which will disappear just like CO2 feedbacks in the face of ‘swamping’).
        Long-term feedbacks are a product of warming & as it takes decades for any forcing to warm the planet. So the warming that causes long term feedbacks will appear slowly over decades. We have still 40% and more of the warming from our present CO2 burden yet to appear so only 60% of long term feedbacks are yet started. And it takes decades, centuries for them to act fully so would we expect to see even 15% of those that have been started yet to be acting. And when the longterm feedback is acting, it too takes decades to warm the climate. Would 40% of those now acting have done their stuff.
        Given all that, would even a climate sensitivity of 4.5 be showing itself strongly? By these numbers here it would not. It would only be 6% of today’s total AGW.

      • For at least the last 10 years we do not appear to have seen “feedback” warming from the warming that happened in the 1980s and 1990s. I have yet to see a credible explanation of why that might be and it is beginning to look (to the sceptical layman) like the feedback is not as positive as has been suggested? Just a sceptical query – not a statement of belief.

        Since you read the denialsphere, surely you’re aware that we’ve been in an extended solar minimum? Those people were crowing for years that we were “entering a new ice age” because of these “Maunder minimum-like” conditions.

        Yet temps have stayed high, with nearly all of the warmest years on record being in the last decade.

        There are other random events which lead to fluctuations in global temperatures. Foster and Rahmstorf 2011 remove the effects of various events (ENSO, for instance) to unmask the trend due to increased forcing due to CO2 and find that it tracks theoretical predictions very accurately.

      • First, stop referring to 10 year periods as if they are sufficient to determine any underlying trend with any significance. They are not, as has been pointed out to you repeatedly. Over a 10 year period natural variability can easily overwhelm the underlying trend. Continuing to cite 10 year “trends” will very quickly wear out your welcome here.

        TLM: “net positive feedbacks, if they exist…”

        Ahem. Absolute humidity, meaning the total amount of water vapour present in the atmosphere, has in fact increased by ~4%, just as expected in a warming atmosphere. That means we have in fact seen an increase in the portion of greenhouse warming attributable to H2O.

        This should lay to rest any doubts you may have about the existence of net positive feedbacks.

        Northern hemisphere summer sea ice area, snow pack area, and land ice sheet surface reflectance has decreased, meaning northern hemisphere summer albedo has decreased.

        This should lay to rest any doubts you may have about the existence of net positive feedbacks.

        Northern hemisphere summer permafrost melt depth has increased, releasing more naturally sequestered CO2 and CH4.

        This should lay to rest any doubts you may have about the existence of net positive feedbacks.

      • Gavin's Pussycat

        I see a confusion here. We have currently an increase over pre-industrial of CO2 ppmv of 40%, that is, “half a doubling”, logarithmically. The equilibrium response to this we’re expected to see, for a mainstream sensitivity value of 3 degs/doubling, is thus 1.5 degrees.

        What we are seeing however is not the equilibrium response but the transient response, and its value from observation is more like 1 degree. The difference is due to the Earth’s thermal inertia, mainly of the oceans. It has nothing to do with feedbacks.

        Equilibrium sensitivity “without feedbacks”, CO2 only, would be 1.2 degs / doubling (a pretty hard value without ifs or buts), or 0.6 degs for 40%. The transient response would be even less. In the real world we’re seeing clearly more, which should tell you that this is the wrong explanation, and that there are real, solidly positive feedbacks at work.

      • Pete Dunkelberg

        Without getting to the semantics of “feedback” vs whatever, most of the warming goes into the global ocean, and some into reduction of total ice and even some into borehole temperatures. It continues.

    • If I understand his point, it’s that if we produce more warming via *any* mechanism (CO2, other greenhouse gases, solar mirrors, excessive nuclear fusion), the warming has the sensitivity that we’re ascribing to CO2. In other words, as you say, there are simply net positive feedbacks from warming.

      But to be more accurate, these definitions for sensitivities aren’t *quite* the same. At a minimum, CO2 has effects on the biosphere (which could lead to a change in albedo). There may be other things that I’m not thinking of that distinguish between a generic warming effect vs warming effects from additional CO2.

  26. Ray Ladbury
    The hope and wish that we can go on consuming as usual (or in many cases more than usual) is very strong. Far, far stronger than the wish to cut consumption. The deniers will always have an audience, especially among those who consume and those who sell the products to be consumed.

  27. Feel free to delete Tamino, but as a regular lurker I’d just like to interject to say what an interesting, informative and civilsed thread this is.

    [Response: I’d rather not delete Tamino. But I’m sure there are those who would.]

  28. Chris O'Neill

    I particularly dislike the tone of the comments on certain blogs where slagging of the other commentators seems to be more important than finding the truth

    Well TLM, the denialists were the first to do this in their defaming of climate scientists. What does that tell you about denialists?

  29. On TLM and Monckton.

    I was writing that post on a flaky laptop whilst being interrupted by problems installing a new version of a software package on my main machine. Having now read to the end of the ‘Thirteen’ post I can see that TLM gives far more credit to Skeptical Science than Monckton could ever bring himself to give. OTOH…?

    • I also doubt that Monckton would ever admit that he didn’t know enough Latin to know what “de facto” meant…

      • Horatio Algeranon

        Horatio somehow doubts The Lord would ever admit to not knowing anything.

        Is that even possible in principle?

      • What a near-miss, Horatio! You almost got “The Lord” and “principle” into the same sentence!

        (But I see that I have now beaten you to it!)

  30. Tamino: “I have been one of the foremost advocates of emphasizing the trend over the fluctuations. But there comes a time when the extremes become so extreme, and happen so often … ”

    Reference has already been made to the Central England Temperature Series [ ], (which like our pubs and castles goes back to 1659, quite a bit further than anything you guys can manage!) English records have been falling in that as well, but bizarrely: December 2010 was the second coldest since 1659 … and was followed by the warmest ever April 2011, and then this year by the fourth warmest March 2012. As far as precipitation is concerned, this April, May and June in England were the wettest since comprehensive precipitation records began in 1910 and followed a winter drought that caused widespread hosepipe bans just as the heavens opened in April.

    So, yes, it appears that things are getting more extreme, more weird, in many parts of the world, but these regional changes aren’t picked up by the global temperature or precipitation records. A 0.8C temperature rise may not sound very much to some, but if it is accompanied by one region suffering a scorching drought and blistering heat whilst another is ten feet under water and another is pelted with hail and ravaged by storms or buried in snow then it becomes more significant to those suffering the consequences. It would be really handy to have some metric – an index of regional variability of temperature and precipitation or some such – that could recognise and quantify the apparently increasing weird weather. It will be not so much the annual average temperatures and rainfalls that are going to cause devastation, but those extremes along the way that the averages may not even pick up on: but do we have a way of quantifying those extremes?

  31. Daniel J. Andrews

    You especially need to realize what it is that they’re really afraid of. It’s not fear of being wrong. It’s dreadful fear of being right.

    I’m stealing that.