Global warming less than we thought

Don’t have time to look closely, but here’s a taste of good news.

*abridged* New research from Oxford University shows the rate of global warming has been lower over the past decade than it was previously.

The paper, “Energy budget constraints on climate response”, to be published online by Nature Geoscience, shows the estimated average climate sensitivity – or how much the globe will warm if carbon dioxide concentrations are doubled – is almost the same as the estimates based on data up to the year 2000.

The study, which uses data from the past decade, also shows the most extreme rates of warming simulated by climate models over 50- to 100-year timescales are looking less likely.

The study used the most up-to-date information available to the AR5 from the IPCC, which is due to be finalised in September.

Victoria University climate scientist James Renwick said there was always a range of uncertainty and it had been hard to rule out the possibility that the climate sensitivity might be very large.

“Using the latest data shows that those very high sensitivities look much less likely, so we’ve been able to tighten the range of uncertainty, especially at the high end,” he said.

“We have much more comprehensive and reliable data on ocean heat content these days, and there haven’t been many large volcanic eruptions lately to obscure things, so that has allowed a better estimate of the range of climate sensitivity.”

via Lid lowered on global warming rate – Environment – NZ Herald News.

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25 Thoughts on “Global warming less than we thought

  1. Andy on 20/05/2013 at 11:48 am said:

    Victoria University climate scientist James Renwick said there was always a range of uncertainty and it had been hard to rule out the possibility that the climate sensitivity might be very large

    Typical weasel words. The probability of high sensitivities are looking much less then previous studies. This study is an important one because many of the well-known names associated with CS studies are co-authors, including Myles Allen, Gabi Hergerl and so-called sceptic Nic Lewis

  2. Andy on 20/05/2013 at 5:22 pm said:

    Judith Curry – mainstream ECS ~2 degrees C

    discusses the same paper

  3. Andy on 20/05/2013 at 5:30 pm said:

    Meanwhile, on Planet B

    Climate change: human disaster looms, claims new research

    Forecast global temperature rise of 4C a calamity for large swaths of planet even if predicted extremes are not reached

  4. Andy on 20/05/2013 at 10:24 pm said:

    There is more on Otto et al at Bishop hill with regards to the various reactions to this new paper

    • Richard C (NZ) on 20/05/2013 at 11:38 pm said:

      >”….with regards to the various reactions to this new paper”

      None more astounding than that of Steven Sherwood I would have thought (although I’ll have a look at BH eventually).

      I’ve spammed the following far and wide including ‘Emotional knowledge’ by Mike Jowsey but I think it is worth putting on the table again in this thread (at the risk of incurring wrath):-

      I’ve emailed Joanne Nova to check whether my eyes are deceiving me because she is very familiar with what Steven Sherwood’s climate viewpoint is in OZ, his papers, and what the MSM has reported of him in the past:-

      Hi Joanne,

      I never, in my wildest dreams that sensibility would prevail
      eventually, thought I’d see this from Steven Sherwood, and NEVER in
      the MSM.

      University of NSW scientist Steven Sherwood – a lead author on the
      next IPCC report – said the Nature Geoscience study [Otto et al] had
      found oceans were capturing heat more rapidly than expected over the
      past decade.

      [that’s highly contentious (but beside the point of this
      communication) and the latest data doesn’t support it – Balmaseda et
      at was out of date ending their study at 2009 and not doing a
      basin-by-basin analysis for example – upper Pacific and Atlantic
      actually cooling in the ARGO era
      data source
      It was just the Indian Ocean skewing the global aggregate, but the
      upper Indian hasn’t warmed since 4Q2010]

      ”By assuming that this behaviour will continue, they [Otto et al]
      calculate that the climate will warm about 20 per cent more slowly
      than previously expected, although over the long term it may be just
      as bad, since eventually the ocean will stop taking up heat,”
      Professor Sherwood said.

      But other research had pointed out the recent ocean heat storage may
      be part of a natural cycle that will eventually reverse, he said.

      ”So while their conclusions are interesting, they need to be taken
      with a large grain of salt until we see what happens to the oceans
      over the coming years,” he said.

      Read more:

      The Otto et al assumption that the atmosphere will in the far-future
      contain the heat at present going into the ocean after the ocean “will
      stop taking up heat” (as they assume – impossible anyway on
      respective specific heat capacity) and the assumption OHC will rise in
      the near-future without additional energy input when input is
      currently past solar peak is simply bizarre.

      But the jaw-dropping aspect to me, and the point of this email, is
      that Steven Sherwood is, on the face of it, talking sense –
      completely out of personal character – and warmist character n

      Is that how you see this Jo (or do I miss-characterize Sherwood)? And
      is Sherwood’s apparent new-found sense as I see it – in the MSM no
      less – as surprising to you as it is to me?

      Cheers Jo

      Richard Cumming (NZ)

      Jo replies:-

      Thanks, I too am trying to get those details now….


      # # #

      The thing is: ocean heat storage being “may be” “part of a natural cycle that will eventually reverse” is not, to my knowledge, the CO2-centric main-stream climate science view of which Sherwood is/was entrenched. It would be considered solar-centric cyclic minority view I would have thought.

      But Sherwood says: “..other research had pointed out” – what “other research” is he referring to? How many papers? Has anyone seen it/them? The only one I can think of off-hand is Abdussamatov (2012), certainly not main-stream CO2-centric. Is Sherwood actually acknowledging the scientific contribution of a maverick?

      Usually the first to bring such research to my notice is The Hockey Schtick blog but I don’t recall anything there other than Abdussamatov, being a regular viewer. I don’t think Real Climate would headline such research, or Skeptical Science. They tend to give such papers a solid ignoring or a cursory brush-off.

      Is Steven Sherwood being straight or is this a tactic to discount Otto et al I wonder?

  5. Richard C (NZ) on 21/05/2013 at 12:01 am said:

    >”Victoria University climate scientist James Renwick said there was always a range of uncertainty and it had been hard to rule out the possibility that the climate sensitivity might be very large.”

    I take this to mean by (cynical) inference and the implication of ” hard to rule out the possibility” that the the range of uncertainty was convenient for those pushing “very large” CS.

    >“Using the latest data shows that those very high sensitivities look much less likely, so we’ve been able to tighten the range of uncertainty, especially at the high end,” he said.

    Latest data, and therefore an update of realism, is always a good thing IMV. A continuous, perhaps real-time data feed to CS algorithms would be even better if that were possible. I don’t see why not given Otto et al updates 2000 CS to present (or whenever the study ends, maybe 2010/11?) and CS seems to be a time-varying derived metric rather than a fixed figure.

  6. Richard C (NZ) on 21/05/2013 at 4:40 pm said:

    Did I read somewhere, Matt Ridley I think, that for a lower CS of 1.3 C by 2060, half has already occurred?

    Answering my own question:-

    Matt Ridley:

    New Nature Geoscience paper v significant. If just 1.3C temp rise to 2060, half of which has happened already…

    • Richard C (NZ) on 21/05/2013 at 4:52 pm said:

      ‘Earth to Met Office: check your climate facts’

      Matt Ridley

      The latest science suggests that our policy on global warming is hopelessly misguided

      […] Yesterday saw the publication of a paper in a prestigious journal, Nature Geoscience, from a high-profile international team led by Oxford scientists. The contributors include 14 lead authors of the forthcoming Intergovernmental Panel on Climate Change scientific report; two are lead authors of the crucial chapter 10: professors Myles Allen and Gabriele Hegerl.

      So this study is about as authoritative as you can get. It uses the most robust method, of analysing the Earth’s heat budget over the past hundred years or so, to estimate a “transient climate response” — the amount of warming that, with rising emissions, the world is likely to experience by the time carbon dioxide levels have doubled since pre-industrial times.

      The most likely estimate is 1.3C. Even if we reach doubled carbon dioxide in just 50 years, we can expect the world to be about two-thirds of a degree warmer than it is now, maybe a bit more if other greenhouse gases increase too. That is to say, up until my teenage children reach retirement age, they will have experienced further warming at about the same rate as I have experienced since I was at school. […]

      Now contrast the new result with the Met Office’s flagship climate model, the one that ministers and their advisers place most faith in. Called HadGEM2-ES, it expects a transient climate response of 2.5C, or almost double the best estimate that the Oxford team has just published. Indeed, the latter’s study concludes that it is more than 95 per cent certain that the response is below 2C, considerably short of the Met Office model’s estimate.


    • Mike Jowsey on 21/05/2013 at 5:07 pm said:

      Richard, we all knew that the house of cards would crumble. This starts with the house being divided. This is a tipping point perhaps. 😉

  7. Barry on 22/05/2013 at 7:48 am said:

    IMHO, this is the biggest (and best) news in the climate field since COP15 fell over.

    As Judy Curry points out, 2 of the 14 authors are lead authors of the all-important Chapter 10 of AR5 which will estimate climate sensitivity. It confirms a plethora of other recent studies which warmists were struggling to describe as outliers.

    The Otto paper reduces the “best estimate” for ECS from 3 to 2 – a massive 33% decrease. Even more importantly, its best estimate for the new-fangled TCR is only 1.3, suggesting that positive and negative feedbacks almost balance out during the 50-100 years after CO2 reaches 560ppm.

    Richard Tol and others have shown that the effect of global warming is beneficial on balance until it reaches 2.2°C above the pre-industrial level. Only then do the negatives outweigh the positives.

    Matt Ridley notes that this paper (if correct) means that the next couple of generations – including James Hansen’s many grandchildren – will experience exactly the same gentle warming trend that the earth has seen over the past 50 years. Forget about “catastrophic” or “dangerous”. Start thinking in terms of “benign” and “golden ages”.

    The Herald’s reporting of this breakthrough is downright dishonest.

    • Andy on 22/05/2013 at 10:24 am said:

      Barry – I would agree with those sentiments. “Climate Sensitivity to CO2” is the cornerstone of the CO2-AGW theory, and this does seem like a fairly major paper.

      I would also note that Nic Lewis is a co-author, who has doggedly pursued this issue, presumably as a hobby.

      Skeptical Science refers to Lewis as a “retired accountant, not a climate scientist” or similar derogatory terms (not that being a retired accountant is a bad thing, I’m sure you know what I mean)

      So presumably Nic Lewis can now call himself a “climate scientist”, having a paper in Nature co-authored by such luminaries as Myles Allen and Gabi Hegerl

      Dave Frame was a colleague at Oxford with Allen. I would hope he might have something interesting to say about this paper in the NZ sphere at some point.

  8. SimonP on 23/05/2013 at 3:15 pm said:

    It is good news that estimates are becoming more precise and that the more extreme projections ar looking less likely. Alexandar Otto has a good summary of his own paper rather than relying on less-informed sources:
    Nic Lewis’s paper is here:
    All these new estimates do is delay the warming by roughly 15 years. Matt Ridley’s “rational optimism” has obviously been unaffected by the crash of Northern Rock. He probably should have stuck with evolutionary theory and survival of the fittest 😉

    • Andy on 23/05/2013 at 3:28 pm said:

      James Annan seems to have different views

      This looks like a pretty unreasonable attempt to spin the result as nothing new for sensitivity, when it is clearly something very new indeed from these authors, and implies a marked lowering of the IPCC “likely” range. So although the analysis does depend on a few approximations and simplifications, it’s hard to see how they could continue to defend the 2-4.5C range

  9. Andy on 25/05/2013 at 11:13 am said:

    There is a very interesting paper from Nic Lewis at Bishop Hill which looks at where Otto et al differs from his study.

    It turns out that both papers get 1.3 degrees c for TCS but the ECS values differ.
    Lewis gets 1.6 to 1.7 for ECS whereas Otto et al get 2 degrees.

    It turns out this difference is due to use of Leviticus et al.

    • Richard C (NZ) on 25/05/2013 at 1:36 pm said:

      >”It turns out this difference is due to use of Leviticus et al”

      Levitus et al Andy – Leviticus et al is the Bible.

      But yes, Levitus et al’s pentadal data is highly problematic as Bob Tisdale has exposed.

      My question though is: the premise/assumption used for “heat-uptake estimates” in respect to CS methodology, specifically the “heat-uptake” part. SkS have a recent post on this and although there’s some sense in comments – Gates, Painting, Brookes – except they miss-attribute a posited change (unsubstantiated) to the output side of the sun-ocean-atmosphere system when the change has been on the input side, they also neglect Trenberth’s lags. Rob Painting’s conjecture however, IS on the side of conventional thermodynamic energy flows, laws of convection, energy gradients, observational scientific literature etc, they just don’t have the observational or calculated evidence to support it (I’m keeping an open mind in case it turns up). The SkS post title is (and actually Nuccitelli’s POV is contrary to the Gates/Painting faction’s POV, see below and my 3 part series):-

      ‘Another Piece of the Global Warming Puzzle – More Efficient Ocean Heat Uptake’

      Basically what they (the SkS/Nuccitelli faction and IPCC/Rahmstorf/Schmittner) are saying is that anthropogenically forced heat that is missing from the atmosphere (the warmists dilemma) has instead been absorbed by “More Efficient Ocean Heat Uptake”. Is this SkS POV the same as the Otto et al “heat-uptake” assumption?

      If it is, what that assumption is in effect, is that an anthropogenically-forced energy flux in the direction air to sea (air => sea, or the IPCC’s AR4/5 “air-sea fluxes”) accounts for all or most of the energy accumulated in the ocean since about 1950. This is in direct contravention of all of the thermodynamic conventions, laws, predominant thermal gradients, and observations. In addition, the IPCC does not specify whether the flux is radiative (Rdown) or sensible heat (-Hs). Neither do they, after 25 years of investigation, have any observational evidence or thermodynamic calculations that equate the observed ocean heat accumulation to their “expected’ (that’s all it is) air => sea energy flow (see Part 2 of my series)

      I find this entire notion (Otto(?)/Nuccitelli/Rahmstorf/Schmittner/IPCC) highly problematic. If I have to make Hobson’s choice, I’m on the side of Rob Painting even though his SkS faction is off-side with the IPCC and the Nuccitelli SkS faction (although they present a united front). I have a lot of respect for Rob Painting, his knowledge of ocean processes is extensive (better than mine, and most sceptics I venture) but it’s just unfortunate that he’s latched on to one small AO interface action that although it exists it is negligible and hence his miss-attribution.

      Are the CS guys making a similar miss-attribution (as I contend) Andy?

    • Richard C (NZ) on 25/05/2013 at 2:02 pm said:

      I also note that Otto et al and Lewis appear to be making the same error as Balmaseda et al (and Thomas) in that they assume global aggregate data (e,g, 0-700m) is typical of all 3 ocean basins when in fact the 2002–11/12 (Lewis) “differences in the heat-uptake” have been due to the skew in the global aggregate data from the Indian Ocean (upper Indian warming spectacularly, upper Pacific and Atlantic cooling).

      If Lewis carried out the same CS analysis but separated into 3 ocean basin sets, he would get 3 totally different CS figures. The Indian set would return a figure close to his estimate because that data predominates the global aggregate dataset but I don’t even know how CS methodology deals with cooling for him to arrive at a figure for the Pacific and Atlantic.

      Similarly, if atmospheric AND ocean cooling occur post May 2013 (already indicators over the last decade in GMAST and SST) how will CS methodology deal with that?

    • Richard C (NZ) on 25/05/2013 at 2:08 pm said:

      >”Are the CS guys making a similar miss-attribution (as I contend) Andy?”

      Just spotted this:-

      “The 0.16 W/m2 estimate – half natural, half anthropogenic – seemed reasonable to me”

      Definitely NOT reasonable to me.

    • Richard C (NZ) on 25/05/2013 at 2:14 pm said:

      Does CS methodology account for the thermal lag in the sun-ocean-atmosphere system Andy?

      Trenberth 6 and 10 – 100 years, Abdussamatov 14 +/- 6 years, Scafetta 1 and 12 years.

    • Andy on 25/05/2013 at 5:24 pm said:

      The lay-person’s summary by Bishop Hill in comments is useful

      It was surprising that the Otto paper came up with very low TCR but only low-ish ECS. This turns out to be due to the choice of dataset for top-of-ocean heat content. For ocean heat, Otto et al used the Levitus dataset, but for the top of the ocean they replaced Levitus’s data with an alternative – Domingues et al.

      Nic has reworked Otto et al’s calculations using the original Levitus top-of-ocean data and also with a variety of alternatives (he also updates to slightly more recent data) and found that in every case the estimate for ECS value obtained is lower than the one reported by Otto.

      He finds a value of around 1.6-1.7C, close to his own paper and also those of Aldrin et al, Forster and Gregory etc. Otto et al reported 2.0C.

  10. Magoo on 25/05/2013 at 11:24 am said:

    An article in the Herald about a lowering of climate sensitivity. A few comments for Renwick thrown in as well:

    • Andy on 25/05/2013 at 12:03 pm said:

      Just for clarification, the link you post is what the blog post is about, I.e Herald coverage of Otto et al

    • Magoo on 25/05/2013 at 12:56 pm said:


    • Mike Jowsey on 25/05/2013 at 1:50 pm said:

      Professor Reto Knutti of ETH Zurich said even at the low end of the range warming would be well over the two-degree goal that countries had agreed to.

      It seems so silly that countries can agree to a certain level of warming. Too silly for words.

    • Andy on 25/05/2013 at 6:07 pm said:

      Mike – I think this agreement of 2 degrees came from one of the COPs (Copenhagen?). This was a side-effect of the other agreement that 2 degrees was “dangerous”.

      These arbitrary agreement levels are then dependent on the climate sensitivity models and calculations, and also the emissions pathways models, of which there is some agreement

      A veritable bureaucrats dream, I think we are in agreement on that.

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