Still warming after all these years (again)

Spread this excellent new video from the talented team at Skeptical Science far and wide. It explains why the latest denialist trope — no warming for 16 years — is rubbish. Take out the impact of the three biggest factors driving natural variations in the global average temperature — volcanoes, the El Niño Southern Oscillation and the solar cycle — and what’s left is the underlying upwards trend being driven by our CO2 emissions. The world’s warming, Australia’s burning, ice is melting and we did it. No room left for wishful thinking or complacency.

53 thoughts on “Still warming after all these years (again)”

  1. Isn’t this thread a contradiction in terms. You are suggesting that by removing “natural variability” i.e volcanoes, El Nino and solar cycles it can be shown that the planet is warming. These natural variations in climate ARE the drivers of our climate. Do you honestly expect that such complex mechanisms can just be fudged out of the equation to show a warming planet. What next, remove the 4000 PPM of Co2 that were present during the Jurrasic Period, but the global temperature was similar to today. Was that an erroneous result too?

    1. Mike I will suppose you to be asking an honest question despite the points you think you make being the substance of research and of denialism for years and years. Quite obviously you have been deceived by the misinformation we are so familiar with and have years of science to catch up, though that is not difficult given genuine examination.

      Do you know this old song or dance?
      “The Grand old Duke of Youk
      He had ten thousand men
      He marched them up the top of the hill
      and he marched them down again

      And when they’re up they’re up
      and when thery’re down they’re down
      and when they’re only half way up
      they’re neither up nor down.”

      Except for volcanoes what you call drivers of climate are not. They are natural variability with no trend, the 11 year sunspot cycle, ENSO and a number of other cycles right down to seasonal and daily variability. However, the disinformation campaign likes to cherry pick these cycles to claim the world is not warming or that it is all down to natural variability whereas they have no more influence on the trend of warming than the mythical Duke of York had on a military campaign.

      Of the money spent on determining the influence of natural variability most has been spent on earth and sun observing satellites. The result:
      the sun is on a very slight decline in energy output but this is too weak to offset the warming that is occuring, The 11 year sunspot cycles and the various oceanic cycles contribute nothing to global warming, nor do cosmic rays and the Milankovitch cycles are in a stable phase for about 40000 years. Stated simply natural variability cannot account for global warming. Nor any known drivers apart from human generation of greenhouse gasses, With respect to volcanism about which denialists continue repeating totaly untrue statements, the volume of CO2 emitted by all volcanoes in recent times is less than 1% of human emissions.

      A problem for statistical analysis is that all these noisy cycles, even the daily one have more amplitude than the total measured warming since 1750 say. To detect the trend then data has to be examined for a period long enough to enable removal of all known periodic behaviour and of course simple noise. A period of 27 years is considered a minimum. There are a huge number of papers and posts on this that have lots of science behind them unlike anything the merchants of doubt emit. Indicative examples of what the science has to say can be seen anytime at Skeptical science and a comparison with denialist efforts here The up down escalator

      Another place where a huge amount of effort is being made is in the gathering of proxy records through drilling of ice cores and sediments, isotope analysis and paleontology. In all these it is being shown with ever greater resolution and clarity that CO2 is closely allied with temperature change, usually lagging rather than leading in the past where human influence has been absent and the milankovitch cycles the main drivers. Now to that 4000ppm CO2 some time in the past.

      Denialists keep on throwing up this as some kind of argument without ever going to the trouble of checking up and consequently offering no details or mixing them up properly. In fact the 4000 ppm refers to a value for the late Ordovican period about 444 million years ago taken from Robert Berner’s GEOCARB model. This is about the time that life forms were just beginning to crawl out of the sea. Details would be a resolution of one point per 10 million years and a range or margin of error maybe between about 2500ppm and over 9000ppm, This was also aperiod when the sun was a good deal cooler than it is now. This is established through astronomical examination of the main sequence of stars. This relative coolness meant that the glaciation threshold was about 3000 ppm CO2 and in fact there was a mountain building episode (which withdraws CO2 from the atmosphere by the slow process of weathering, a 100 to 500,000 years is typical). As the oceans cooled there was also a huge increse in marine life drawing down even more CO2, and a glaciation that may have lasted about a million years.- just a short blip in an otherwise warm period.

      When you heard about 4000 ppm CO2 in the atmosphere did you search rhe scientific literature or reports on the same to find out what that was really about? That is what a real skeptic does. I found several accounts which are neatly summed up here at a basic and an intermediate level of comprehension.


      1. The source you quoted is found in the article I read. Link to the website. It cannot be asserted that there is a direct association between global temperature and global Co2 levels. Other parts of the graph demonstrate this. It is easy for anyone to say adding Co2 to the atmosphere causes a direct effect on global temperature. No it doesn’t. If that were the case the Co2 levels and global temperature would be linear. Skeptical science of course would find some way to bring those trends in line in much the same way that the drivers of our climate are being removed now. You simply can’t do it. It is a hyothetical suggestion i.e remove this, this and this and you are left with that. If only it were that simple. We are talking climate and weather here. This isn’t a science lab where you can just remove variables. It seems to me that these drivers of climate are being labelled as noise!! The climate is chaotic. What next, remove the effect of the 90 percent of Co2 that is produced naturally, or remove the effects of water vapour or methane to show the net effect of Anthro Co2. It is impossible. The method has been heavily criticised through the various opinions of climate scientists and it is my own opinion that the method is flawed because of the very nature of our climate.

  2. The Grand old Duke of York of course.

    On glaciation threshholds, the sun is over a very long period getting warmer so the glaciation threshhold gets less, maybe >3000 ppm CO2 444 million years ago to perhaps 250 ppm CO2 now. What gets me is that we are doing our level best to put all that carbon that has been withdrawn inbetween back into the atmosphere in the presence of a hotter sun.

  3. There is an interesting piece over at New Scientist in short “There is a growing awareness among climate scientists of the importance of natural variability in predicting climate change, especially in the short term, where it can completely obscure the global warming signal.”

    We need to look at the big picture and the longer term trends over the last 150+ years to really see what is happening

    1. The big picture is all we need for setting emissions policy, but the near term and regional snapshots are going to be increasingly important as we plan how to adapt to climate changes as they happen. That’s what the UK Met Office is trying to do with its modelling – but it’s a really hard problem (good SkS discussion here. Essentially, you have to initialise your climate model with current conditions (not trivial) and then forecast how the ocean is going to move heat around the planet (because the oceans are the biggest heat sinks/sources and 70% of the planet’s surface). Very much a work in progress…

  4. You comment that “Take out the impact of the three biggest factors driving natural variations in the global average temperature — volcanoes, the El Niño Southern Oscillation and the solar cycle — and what’s left is the underlying upwards trend being driven by our CO2 emissions”.
    Do I understand you to be saying (to take an extreme example) that if someone was providing a similar report in (say) the fifth year after Toba erupted, the report would be worded “Take out the impact of the Toba eruption…and what’s left is the underlying upwards trend being driven by our CO2 eruptions”? And then 100 years later be writing “take out the impact of the Toba eruption and what’s left is the underlying upwards trend being driven by our C02 eruptions.
    Just about Toba:
    Happened approx 70,000 years ago, said to be the largest volcanic eruption of the past 25 million years, appears to have induced a steep cooling period for six years that nearly brought humans to an end, and appears to have been followed by a 1000-year cooling trend.

    So, while freezing your butt off and wondering if any humans would survive, you’d be reading a report that said don’t worry, ignore the effects of Toba and the underlying temperature trend is upwards?
    For the report writers you comment on to remove the results of three of the really significant drivers of climate cooling and warming doesn’t make sense.

    1. The idea is to demonstrate that there is an underlying and very real upward temperature trend, being driven by CO2 accumulating in the atmosphere. This is not being done to in any way minimize the impact of the natural variations, but to explain why people claiming that global warming has somehow “stopped” or “gone away” over the last 15 or 16 years are very, very wrong.

      1. I understand that, I’m simply asking (by using an extreme example) that if C02/methane/water vapour/SOX emissions etc are drivers of warming/cooling, just as volcanoes and established weather patterns are, why aren’t they (in the case you comment on) all be added up to give an overall result?

        1. Well, the (unadjusted) global temp series is a result of all those things combined. But teasing out the relative contributions of all those factors helps us to work out what’s really going on.

          1. I agree it’s good to know what the short, medium,long term contributors to the annual average temp have been and might be. But any scientist surely loses street-cred if they produce a temperature number that isn’t what what your average human inhabitant is actually experiencing, or might experience. It would be like a financial advisor saying, great news, this year your retirement fund is $1m if we don’t factor in the the effects of the GFC, which by the way means you have only $500,000 in the fund.
            What does the unadjusted global temp series show about average temps over the past (say) 150 years – rising, falling, or staying the same?

            1. The temperature trend over the last 150 years shows a warming trend, but the IPCC only attribute human contributions to post 1950

  5. andyS January 13, 2013 at 8:22 pm

    the IPCC only attribute human contributions to post 1950

    Andy, when will you stop just making stuff up? What the IPCC actually said was:

    It is very unlikely that climate changes of at least the
    seven centuries prior to 1950 were due to variability generated within the climate system alone. A significant fraction of the reconstructed Northern Hemisphere inter-decadal temperature variability over those centuries is very likely attributable to volcanic eruptions and changes in solar irradiance, and it is likely that anthropogenic forcing contributed to the early 20th century warming evident in these records.

    (AR4, WG1, p.12)

    1. Likely that forcings contributed….

      This is a complete throwaway comment, the period prior to 1950 had minuscule co2 contributions compared to today.
      Do the IPCC also explain the period of cooling that preceded the period 1976 to 1998 when the modern warm period made itself apparent?

      1. The “cooling” of the 1950s and 60’s and early industrial era is well understood. Have you never heard of aerosols and the clean air acts?
        Note that China and India – the current biggest aerosol polluters do not have Clean Air Acts and may well be the major contributors to your now so called “Cooling phase”. (ie their pollution is in effect a solar reflector) – but underlying that – the warming continues and will dramatically increase (eg 1970’s, 80) once they clean up their act so to speak.

    1. The IPCC uses what it calls “calibrated language” to describe probabilities. For the fifth report (first part due later this year), “likely” is taken to mean 66-100% probability, “very unlikely” is 0-10% probability. In the context of the IPCC, these constitute expert judgements of the probability of an event. You could call that an opinion, I suppose, but it’s one that’s arrived at very carefully, as the guidance note on uncertainty for AR5 authors demonstrates.

    2. The terms “very unlikely” etc are defined in the Summary for Policymakers AR4 as:

      In this Summary for Policymakers, the following terms have been used to indicate the assessed likelihood, using expert judgement, of an outcome or a result: Virtually certain > 99% probability of occurrence, Extremely likely > 95%, Very likely > 90%, Likely > 66%, More likely than not > 50%, Unlikely < 33%, Very unlikely < 10%, Extremely unlikely < 5%

      So what the IPCC SPM is saying is that there is a greater than 66% chance that humans contributed something to the warming of the early 20th Century, although there is no quantification in the SPM on how much that may have been.
      Conversely, this could be read that there could be up to a 44% chance that humans contributed nothing to the early 20th Century warming

      1. I think you will find that the assessment of likelihood of human induced global warm warming has been substantially improved since AR4 to “Extremely likely” if not “virtually certain”.

        Incidentally the assessment of AR4 was NOT ” Likely” (that was the assessment in 2002) as you incorrectly state but ‘Very Likely” ie greater than 90% chance. AR4 was, at best, a very conservative document.

        I quote;

        “Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.[12] This is an advance since the TAR’s conclusion that “most of the observed warming over the last 50 years is likely to have been due to the increase in greenhouse gas concentrations”. Discernible human influences now extend to other aspects of climate, including ocean warming, continental-average temperatures, temperature extremes and wind patterns”

        By the way – these are universally accepted statistical conventions for describing probability – they are not unique to the IPCC, and as I demonstrated to you some time back, are part of a standard mathematics course for primary age children.

      2. “Conversely, this could be read that there could be up to a 44% chance that humans contributed nothing to the early 20th Century warming”

        Opportunist Andy? Your converse is extremely unlikely just to use the prevailing language. Rob has already mentioned land clearance and we know the effect of CO2 changes. we also know that coal use increased very considerably from the mid nineteenth century so your interpretation of probability has to be plain wrong but is of course consistent with the denialist strategy of playing the uncertainty game on the low side.

        1. If there is a 66% probability of X having some effect, then there is a 44% chance of it having no effect.

          So my 44% is “extremely unlikely”, according to you. However, the IPCC describe “extremely unlikely” as < 5% (see above comment)

            1. Good spot, thanks for the correction.

              Nevertheless, whether I chose 34% or 44%, it is nowhere near the 5% figure that is defined as “extremely unlikely” by the IPCC

          1. You don’t get it yet Andy. It is “extremely unlikely” well zero probability really, that humanity had zilch influence on temperature change prior to 1940 for the reasons already stated – land clearance, coal burning, railways and shipping, lots of concreting.
            So one must assume that there is uncertainty about non-anthropogenic factors, an increase in solar intensification has been discussed. Maybe it’s just insufficient data for greater certainty.

            1. Well, stylus claim that there is zero percent t chance that humans had any influence on the climate prior to,1950

              Actually, on a purely philosophical note, I would completely agree with you, for we know that by cutting down a small forest and planting a field of wheat will change the local climate and therefore by deduction the global climate.

              My point I am trying to make is that the IPCC logic can be inverted quite easily to make the statements I have made.

              It may seem boring but that it was IT engineers and denier types specialises in.

    3. Chris: The IPCC language in the summary for policy makers is also subject to the veto of any one policy maker. In the case of AR4 it emerged during the Copenhagen debacle that the scientific confidence that human activity was contributing to most of the temperature rise was 99%. Everyone but Saudi Arabia was prepared to sign up for that but Saudi Arabia refused to agree until that figure was lowered to 90%. This being the resulting official position it continues to be reiterated so one has to see past that sort of obfuscation.

        1. That is how the process works – they tend to the “least common denominator” – to get a consensus. Committees have their value. Here we have effectively every world govt (including the Saudis – whom it might be noticed have a lot to loose by this statement) represented and agreeing in 2007 that it is at least 90% certain that “Most of the observed increase in global average temperatures since the mid-20th century is ….. due to the observed increase in anthropogenic greenhouse gas concentrations”

            1. Are you really an idiot or just pretend to be one?

              (andyS’s comment deserves no better reply than what i have just given.

            2. Are you really an idiot or just pretend to be one?

              (andyS’s comment deserves no better reply than what i have just given).

            3. No I was being “ironic”. I know of course that the values given in the SPM of IPCC reports are formed by committee and not via any scientific process.value

              I was just glad that you pointed this out, Macro, and not me.

            4. For the casual reader (and the ill informed andy) I quote from the articles on the history and formation of the IPCC

              “The Intergovernmental Panel on Climate Change (IPCC) is a scientific intergovernmental body,[1][2] set up at the request of member governments.[3] It was first established in 1988 by two United Nations organizations, the World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP), and later endorsed by the United Nations General Assembly through Resolution 43/53. Its mission is to provide comprehensive scientific assessments of current scientific, technical and socio-economic information worldwide about the risk of climate change caused by human activity, its potential environmental and socio-economic consequences, and possible options for adapting to these consequences or mitigating the effects.[4] It is chaired by Rajendra K. Pachauri.

              Thousands of scientists and other experts contribute (on a voluntary basis, without payment from the IPCC) to writing and reviewing reports, which are reviewed by representatives from all the governments, with a Summary for Policymakers being subject to line-by-line approval by all participating governments. Typically this involves the governments of more than 120 countries.[5]”

            5. Note the last two sentences andy – yes governments get to have a say. After all, they should they set it up in the first place.

            6. We’ve been through andy’s egregious ignorance of – and arrogant disinterest in – how the IPCC works before, but he has chosen – deliberately – not to have learned anything.

              It is blatantly obvious to anyone with a functioning neuron that the committee component of the IPCC serves to make it a strikingly conservative institution, not an ‘alarmist’ one.

              However, being a troll means never having to know anything you don’t want to. So there.

              Thanks for demonstrating, for the umpteenth time, the level of integrity and commitment to veracity typical of the caste of Deniers, andy.

            7. I do know how the IPCC works. Why do you assume that I do not?

              Being a troll – does this extend to quoting the relevant pages from the IPCC and explaining to others what their terms mean?

              I am not really sure how I can improve – being referred to as a “denier” and a “troll” constantly doesn’t really help.

              Anyway, I have just ordered a new textbook on Bayesian Stats so hope to do some more “denial” in due course

            8. Wow; that’s like finding out the local pyro has ordered a 20 litre jerry-can and several boxes of matches.

              I look forward to your first peer-reviewed publication, I really do…

  6. andyS January 13, 2013 at 9:07 pm

    the period prior to 1950 had minuscule co2 contributions compared to today.

    Andy, you are forgetting the massive deforestation that occurred during the colonial and pre-colonial period. For instance, NZ lost approx. 50% of its pre-European forest cover prior to 1950, and that was after the Maori had themselves halved the extent of the pre-human forests.

    As for Europe,

    Europeans had lived in the midst of vast forests throughout the earlier medieval centuries. After 1250 they became so skilled at deforestation that by 1500 they were running short of wood for heating and cooking.

  7. I hope people have noticed the very interesting two part discussion on Seal Level Rise prediction at Real Climate by Stefan Rahmstorf

    part two

    A link at the beginning of part 2 takes you back to part one.

  8. So, andy feels slighted by being called a “denier troll”. Aw diddums. Quite simply, if you don’t want to be called that, then don’t behave like that.

    For example, bringing up a cold spell in China on the thread on the unprecedented heatwave in Australia. What was the purpose of that comment? I can see two possibilities:

    1. Claiming that it being cold somewhere in the world falsifies global warming. This is an argument from ignorance, the preserve of someone in denial as to the reality of global warming; or

    2. Intending to provoke the regulars here into adverse comment, knowing that it being cold somewhere does not actually falsify global warming. This would be pure trolling.

    I can’t for the life of me think of another explanation, but no doubt andy will be along with some convoluted reasoning as to why a mildly cold spell in a small region is somehow comparable to an unprecendented heatwave across an entire continent.

    1. I brought up the topic of the coldest winter in China in decades because I was told that “fire and ice” were off topic on the solar PV thread, and that Gareth would put up another thread to discuss this.

      If you think that it is a “mildly cold spell in a small region” when we have had extreme cold across China, India, Eastern Europe and Russia then it is not me that is in denial.

      I don’t take any offense to being called a “denier troll”. I have been called far worse things. However, when someone accuses you of trolling when you are quoting definitions of “very likely” from the IPCC, I just laugh.

      1. Andy, did you even bother to read the papers we referenced re how AGW can cause prolonged cold spells in the mid-latitudes, or were you too busy with your ongoing colorectal inspection?

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