A new paper published in Ecological Modelling finds climate sensitivity to doubled CO2 concentrations is significantly lower than estimates from the IPCC and climate models which “utilize uncertain historical data and make various assumptions about forcings.” The author instead uses a ‘minimal model’ with the fewest possible assumptions and least data uncertainty to derive a transient climate sensitivity of only 1.093C:
“A minimal model was used that has the fewest possible assumptions and the least data uncertainty. Using only the historical surface temperature record, the periodic temperature oscillations often associated with the Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation were estimated and subtracted from the surface temperature data, leaving a linear warming trend identified as an anthropogenic signal. This estimated rate of warming was related to the fraction of a log CO2 doubling from 1959 to 2013 to give an estimated transient sensitivity of 1.093 °C (0.96–1.23 °C 95% confidence limits) and equilibrium climate sensitivity of 1.99 °C (1.75–2.23 °C). It is argued that higher estimates derived from climate models are incorrect because they disagree with empirical estimates.”
Otto et al find equilibrium climate sensitivity [over the next several centuries] is only ~1.3 times greater than transient climate sensitivity, thus the estimate of 1.093C transient sensitivity could be associated with as little as 1.4C equilibrium sensitivity, less than half of the implied IPCC central estimate in AR5 of ~3.3C.
Moreover, this paper does not assume any solar forcing or solar amplification mechanisms. The integral of solar activity plus ocean oscillations explain ~95% of global temperature change over the past 400 years. Including potential solar forcing into the ‘minimal model’ could substantially reduce estimated climate sensitivity to CO2 to a much greater extent.
- Empirical estimates of climate sensitivity are highly uncertain.
- Anthropogenic warming was estimated by signal decomposition.
- Warming and forcing were equated in the time domain to obtain sensitivity.
- Estimated sensitivity is 1.093 °C (transient) and 1.99 °C (equilibrium).
- Empirical study sensitivity estimates fall below those based on GCMs [Global Circulation Models].
Abstract
Climate sensitivity summarizes the net effect of a change in forcing on Earth’s surface temperature. Estimates based on energy balance calculations give generally lower values for sensitivity (< 2 °C per doubling of forcing) than those based on general circulation models, but utilize uncertain historical data and make various assumptions about forcings. A minimal model was used that has the fewest possible assumptions and the least data uncertainty. Using only the historical surface temperature record, the periodic temperature oscillations often associated with the Pacific Decadal Oscillation and Atlantic Multidecadal Oscillation were estimated and subtracted from the surface temperature data, leaving a linear warming trend identified as an anthropogenic signal. This estimated rate of warming was related to the fraction of a log CO2 doubling from 1959 to 2013 to give an estimated transient sensitivity of 1.093 °C (0.96–1.23 °C 95% confidence limits) and equilibrium climate sensitivity of 1.99 °C (1.75–2.23 °C). It is argued that higher estimates derived from climate models are incorrect because they disagree with empirical estimates.
Well at least the lousy paper has triggered an entertaining dialogue.
“If you want to join the debate. Publish your work . posting on the internet doesnt count.“.
This blog comment was, of course, part of the debate, and it was posted on the internet.
Now, about the paper: some here like the paper because it counterbalances the AGW rubbish. That’s understandable, but it’s a political view not science-based. Some here like the paper because they think it gets the right result. That’s not science-based either. Wrong result = bad science. Right result for wrong reason = bad science. It’s a dreadful paper that should never have reached an editor let alone get past an editor and reviewers.
If you want to understand just how bad the paper is, just read rgbatduke’s comments.
There are thus four free parameters in this curve fitting exercise.
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I have no problem with curve fitting, so long as it has predictive ability. That is how a whole lot of science was discovered. A whole lot.
Curve fitting isn’t automatically wrong. It is almost always wrong, but not automatically. Sometimes someone hits upon the right combination, and the formula for the curve then becomes science.
I’m not saying this author is correct. Most likely not. However, we cannot simply dismiss curve fitting unless and until it has been tested outside the range of known data.
Just a note that the PDO was never integrated into the models because it wants discovered when the models were first formulated in the early 1990s. It changes everything.
It’s incredible that scientists cannot agree on the climate sensitivity to the doubling of the atmospheric concentration of carbon dioxide.
Perhaps everyone needs to get back to basics by referring to “The Infrared Handbook” published by the Office of Naval Research, a department of the US Navy.
You are being far too kind even with these questions. One of the reasons that they cannot get climate models to work — one of many — is that they cannot specify initial conditions in the model sufficiently precisely, in part because nobody knows what the current “state” of the Earth is, in part because they would have to specify it to sub-centimeter resolution (the Kolmogorov scale for the dynamics is a few millimeters). Then, they know perfectly well that they are getting cloud dynamics wrong, in part because at their best grid resolution things like thunderstorms are literally invisible. And we could go on for hours simply tabulating our ignorance or the unverified approximations that are supposedly bandaids concealing it.
Then, as you note, there is “forcing”. We could speak for a while about lat/long gridding schemes mapped onto a sphere. Kriging and other means of data infilling might be worthy of volumes of specification and speculation, given the paltry number of observations we have to reconstruct a temperature record of the entire planet, to depth in both atmosphere and ocean, over hundreds of years (before taking over with proxies that commit logical and statistical fallacies almost from the start). And the beauty of it all is — it is impossible to be falsified! You can build any model you want, get any result you want, and nobody can prove you wrong! As long as you toe the party line, you can get published. If not, well, we’ve seen how the in-crowd applies pressure to get you fired (tenure or not) or marginalized. Build a model find something it gets right, declare success!
Of course, we can’t even measure a lot of the things the models are supposed to predict particularly accurately, and there are thumbs on all scales (in every sense of the word). Inconvenient facts are “re-examined” and shown to be false. MWP? Never happened. LIA? Sorry, the temperature then was actually rather flat. Never mind historical evidence, geological evidence, and the prevailing beliefs — bristlecone pines have the final word, by the time a hand-coded PCA scheme gets done with the data.
Climate science — with halfway decent data — is only around 30, maybe 40, years old. With less than halfway decent (but still global and electronically gathered) data perhaps another 30. Before that is the dark ages, open for exegesis and hermeneutics galore. Miracles abound. Thermometers aren’t to be trusted, and some of the trees have a lean and hungry look about them as well.
rgb
rgbatduke says:
July 23, 2014 at 6:47 pm
Of course, we can’t even measure a lot of the things the models are supposed to predict particularly accurately…………..
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Sunday, July 20, 2014
New paper unexpectedly finds diverging trends in global temperature & radiative imbalance from greenhouse gases
Unsettled science:
A new paper published in Geophysical Research Letters finds that the radiative imbalance from greenhouse gases at the top of the atmosphere has increased over the past 27 years while the rate of global warming has unexpectedly decreased or ‘paused’ over the past 15+ years.
This finding contradicts expectations from AGW theory of increased ‘heat trapping’ from increased greenhouse gases. However, the finding is consistent with radiosonde observations showing that outgoing longwave radiation to space from greenhouse gases has unexpectedly increased rather than decreased over the past 62 years, inconsistent with more heat being “trapped” in the mid-upper troposphere.
http://hockeyschtick.blogspot.ca/2014/07/new-paper-unexpectedly-finds-diverging.html
I think they found Trenberth’s missing heat………..
Leif Svalgaard says:
July 23, 2014 at 9:46 am
Greg Goodman says:
July 23, 2014 at 4:04 am
firstly the world has been warming for several 100 years, clearly there is a long term process independent of AGW.
If it has, it is not due to solar activity which does not show any trend the past 300 years:
http://www.leif.org/research/New-Group-Numbers.png
What about 400 years?
Richard M says:
July 23, 2014 at 7:33 pm
“If it has, it is not due to solar activity which does not show any trend the past 300 years:
http://www.leif.org/research/New-Group-Numbers.png”
What about 400 years?
Good question. There is a puzzle here. We know that cosmic rays were still modulated during the Maunder Minimum, we know that there was significant solar magnetism even during the deepest part of the MM, we do not know why there were no visible sunspots, so there is, at this time, no good answer. If there was a change, it must have been rather abrupt, rather than a ‘trend’ over centuries. In addition, there are good arguments that the MM was not significantly different from what happens at every solar minimum, in particular the recent one: http://www.leif.org/EOS/2011GL046658.pdf
My understanding is that the Maunder spots were ‘large, sparse, and primarily Southern Hemispheric.’ I think that Livingston and Penn explain ‘large’ and ‘sparse’ but not ‘primarily Southern Hemispheric’. I also suspect that ‘primarily Southern Hemispheric’ is a large clue to the climate effects of the sun on the earth.
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swifty says
(proposes experiment)
Guess I will have to do it myself?
henry says
it is not as easy as you think.
CO2 absorbs and traps some LW IR
but it also absorbs and deflects some SW IR and even some UV [this is how we can detect it nowadays on other planets]
This is why I said that the closed box experiments [alone/only] are no good.
I explained this here
http://blogs.24.com/henryp/2011/08/11/the-greenhouse-effect-and-the-principle-of-re-radiation-11-aug-2011/
and you should try and understand all the basics first, before you design an experiment.
Anyway, my best guess is that the LW IR entrapment balances out against the cooling due to deflection to space since I could not detect any non-natural descend in the speed of minimum temps.
http://wattsupwiththat.com/2014/07/23/new-paper-finds-transient-climate-sensitivity-to-doubled-co2-levels-is-only-about-1c/#comment-1692933
Leif Svalgaard says:
July 23, 2014 at 7:55 pm
There is a puzzle here. We know that cosmic rays were still modulated during the Maunder Minimum,…
It might be that the Earth’s magnetic field was responsible for GCR modulation during the Maunder minimum,
The earth has number of spectral components, strongest at 21 and somewhat weaker at 16,34 and 46 years, see comment:
http://wattsupwiththat.com/2014/07/23/new-paper-finds-transient-climate-sensitivity-to-doubled-co2-levels-is-only-about-1c/#comment-1692579
the above numbers would give an average modulating signal at about 29 years. Hiroko Miyahara found that the MM’s GCR data show modulation magnetic cycle of about 28 years, as you can see here
, also interesting comments about climate influence too.
Leif Svalgaard says:
July 23, 2014 at 7:55 pm
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Whilst not entirely germane to your point, but the interection between solar and earth, is not limited solely to how active the sun may or may not be, but rather how much much solar energy gets through to the surface of the earth, and changes in patterns of the receipt of that energy (eg., more being received over the ocean). Indeed, subtle changes in the patterns of the wavelength received could even be significant since the absorption of solar by the oceans is wavelength dependent in the sense that whilst the total energy absorbed may be the same (irrespective of wavelength), there could be subtle changes to the depth at which that energy is being absorbed (eg., at 50 cm, at 1m, at 5m, at 10 m, etc and so on), and this could impact on SST on a multi decadal time scale.
We also know that the Earth’s magnetic field has been weakening for some time, and not uniformally at that. There is the South Atlantic anomaly, which is weakening at a substantially faster rate (may be 5 to 10 times as quickly).
See generally the section on secular variation http://en.wikipedia.org/wiki/Earth%27s_magnetic_field,
and the recent data coming in from the swarm satellites. http://news.msn.com/science-technology/earths-magnetic-field-is-weakening-10-times-faster-now
and the South Atlantic anomaly: http://en.wikipedia.org/wiki/South_Atlantic_Anomaly
Now I am sorry to post, without knowing the detailed data on this, but has there been subtle changes in the amount of solar being received in the area of the South Atlantic anomaly? It coincides with an important part of the global conveyor belt and hence the heat transportation system, http://en.wikipedia.org/wiki/File:Corrientes-oceanicas.gif so changes here could have wider impact.
I do not know whether there are studies on it, and without data the point I raise is speculative, but I consider that one problem that arises whenever there is a discussion regarding solar, is that we do not know precisely what we are meant to be looking for, since we do not know whether there are some subtles, which presently we do not know about, in the planet’s relationship, and therefore do not understand what is going on, and why that is the case.
And so time marches on, and relentlesslessly, study by study, we come closer to that seemingly inevitable point when CS will be concocted as being zero +- something. No-one seems to mention the dreadful inconvenient ultimate conclusion that if CS == 0, AGE, at least as far as CO2 is concerned, is nonexistent? If that were to be concluded, does that mean the unthinkable, i.e. that all the lukewarmers here will have to become Sla***s or start arguing for higher CS? What a prospect! What entertainment awaits! Meanwhile we watch all the dancing with angels on pinheads pretending to not notice the looming shadow of the elephant…
They actually do agree on the mean global temperature response to a doubling of CO2 (all other factors remaining the same). It’s about 1 deg C. This figure, based on multiple lines of evidence, was cited in the 1979 Charney Report. Garth Paltridge and Richard Lindzen both contributed to this report and both accept the ~1 deg C per 2xCO2 sensitivity figure.
The major disagreement relates to feedback – mainly from increased water vapour. “Sceptical” scientists such as Lindzen, Paltridge, Roy Spencer and Jack Barrett believe that any feedback effect is small and may even be negative. The AGW mainstream scientists believe that there is a strong feed back effect. To be fair, evidence from the LGM does offer them some support. However, recent observations (i.e. the temperature records) tend to suggest that the ‘baseline’ CO2 sensitivity figure is not far off the mark.
I haven’t read Craig’s paper yet, but it seems to confirm that the mean temperature is indeed increasing at a rate which is consistent with the base sensitivity.
John Finn says:
“Sceptical” scientists such as Lindzen, Paltridge, Roy Spencer and Jack Barrett believe that any feedback effect is small and may even be negative.
Why the quote marks around ‘skeptical’, John?
The only honest scientist is a skeptic, first and foremost. Alarmist scientists like Mann are not skeptics.
Furthermore: Lindzen is right, based on how the real world has responded. The small warming effect of rising CO2 is swamped by negative forcings. Thus, there has been no global warming for many years.
I believe what Planet Earth is telling us. What do you believe?
The perception of “scepticism” or “skepticism” tends to be a bit varied on this blog. Lindzen et al are not necessarily sceptical of AGW but they are sceptical of CAGW (i.e. Catastrophic AGW).
My opinion now is the same as it has been for the past 10 years, i.e. that doubling the concentration of CO2 in the atmosphere will result in a mean global temperature rise of a shade over 1 deg C. This, very roughly, equates to an average trend of less than 0.1 deg per decade so I fully expect periods when the temperature increase due to CO2 is offset by natural variability.
Further to the point made by GabrielHBay says: at July 24, 2014 at 12:25 am, whenever the issue of Climate Sensitivity is raised, one should not over look the fact that the only proper observational assessment of Climate Sensitivity is the one performed by Miskolczi (see his paper http://ruby.fgcu.edu/courses/twimberley/EnviroPhilo/SemiTransparentAtmospheres.pdf and http://www.friendsofscience.org/assets/documents/E&E_21_4_2010_08-miskolczi.pdf)
Miskolczi found Climate Senistivty (at current rates of CO2 of say 340ppm+) to be approximately ZERO.
As far as I know, it has never been established that this finding is wrong. It has been pointed out (by many) that some of the data on which his study and finding was based has issues . But heck, we are dealing with Climate Science, and there is not a single data set that does not have issues. You have to work with the data warts and all, but be aware that because it has warts and all, there are always uncertainties, and possibly wide error margins.
It is because all the data sets have issues, that no significant advancement in our understanding has taken place these past 35, or so years.
John Finn says:
July 24, 2014 at 2:35 am
My opinion now is the same as it has been for the past 10 years, i.e. that doubling the concentration of CO2 in the atmosphere will result in a mean global temperature rise of a shade over 1 deg C. This, very roughly, equates to an average trend of less than 0.1 deg per decade so I fully expect periods when the temperature increase due to CO2 is offset by natural variability.
Such is the power and idiocy of a Belief system. Pretty awesome.
Ah, climate science!
Cherry-pick a chunk of an obviously harmonic function, extrapolate the linear regression to death, and pluck a number out of a hat – not forgetting to incorporate a nice chunk of False Precision Syndrome. 1.093 °C ? FFS!
I’m just glad these people don’t design airplanes, or even hamster exercise wheels come to that.
But I’m only an engineer, so what would I know?
Some good stuff above. Leif says there is a puzzle here which perks up my ears and Latitude links Geophysical Research Letters findings about radiative imbalance at the top of the atmosphere. Good way to start the day.
I hope to hear more about GRL findings since it appears to be very significant. Am I interpreting it right?
When I first began reading into the science behind AGW I was firmly convinced that the effect of CO2 was negligible. It’s clear to me now that this cannot possibly be the case. CO2 determines the altitude at which outgoing LW radiation is emitted to space. It, therefore, must influence the energy balance at TOA.
This is nothing to do with a “belief system” but an acceptance of basic physics. Richard Lindzen, Roy Spencer, Jack Barrett, Garth Paltridge et al also accept this same basic physics. If you’re going to start labelling those who “believe” the realities of the “greenhouse” effect as idiots. I’d suggest you become considerably more informed than you currently are.
John Finn says:
I have no issue with this, but would suggest you find an IR Thermometer and point it straight up on a clear day.
John Finn says:
July 24, 2014 at 5:39 am
This is nothing to do with a “belief system” but an acceptance of basic physics. Richard Lindzen, Roy Spencer, Jack Barrett, Garth Paltridge et al also accept this same basic physics. If you’re going to start labelling those who “believe” the realities of the “greenhouse” effect as idiots. I’d suggest you become considerably more informed than you currently are.
Right, we’ve seen your type of arguments here many times before. True to form, you mouth “basic physics” and “the realities of the greenhouse effects” in kneejerk fashion, as if they had anything to do with what is actually happening with our climate. I suggest you read up yourself. There are many resources available right here, as well as books. But I know you you won’t, because that would challenge your idiotic Warmist Belief system.
If only the climate system would get on board with what it “must” do. Seems it has a mind of its own, more’s the pity.
Here are my opinions on this topic.
Well informed skeptics cannot deny the existence of atmospheric CO2’s ability to absorb and reemit longwave infrared radiation which is then transformed into heat not readily absorbed and used by land and ocean surface material as heat energy. However, to get our knickers in a twist over CO2 as the boogie man of warming is laughable. Water vapor is King, Queen, Rook, Bishop, Knight, and even the lowly pawn of greenhouse gasses. CO2 is nothing more than the dust that often collects on an unused chess board. Anthropogenic CO2 is the germ in the dust planted there by an opponent’s occasional sneeze.
Further, to say that greenhouse gasses are the end all be all of this chess game we call global warming is also laughable. The giant drivers on this Earth directly responsible for warming/cooling trends has little to do with greenhouse gas (in fact greenhouse gas POINTS to the drivers). Oceans absorb massive amounts of shortwave infrared, store it as heat, and emit longwave infrared. Land surfaces do too but land quickly uses SW IR instead of storing it. Oceanic and atmospheric teleconnections are the two players and sources of the temperature trends, plain and simple, either coughing up longwave infrared radiation heat into the atmosphere or absorbing shortwave infrared radiation which is then stored as heat. When the oceans cough up more warmth we warm up (and cloud up). When they spend more time absorbing solar SW infrared we cool off (and dry out).
Henry says
I have to agree with Bruce here.
John Finn, you are only denying what you know to be true, probably because your life [‘s work] depends on it.
Pam is right. There is no way that a change of 0.01% in the atmosphere (water vapor:0.5%) can do anything much to nature (i.e the sun). That is what made me investigate all of this for myself.
http://wattsupwiththat.com/2014/07/23/new-paper-finds-transient-climate-sensitivity-to-doubled-co2-levels-is-only-about-1c/#comment-1693283
We [sceptics] know that even WUWT is trying to keep mainstream by [just] claiming there is a pause [in warming].They are only being able to keep up with this so-called “pause” by lengthening the time period which cancels the time when we still had warming.
Truth is there is no pause. Truth is that it has been cooling.
Most datasets show it is cooling from 2002.
http://www.woodfortrees.org/plot/hadcrut4gl/from:1987/to:2015/plot/hadcrut4gl/from:2002/to:2015/trend/plot/hadcrut3gl/from:1987/to:2015/plot/hadcrut3gl/from:2002/to:2015/trend/plot/rss/from:1987/to:2015/plot/rss/from:2002/to:2015/trend/plot/hadsst2gl/from:1987/to:2015/plot/hadsst2gl/from:2002/to:2015/trend/plot/hadcrut4gl/from:1987/to:2002/trend/plot/hadcrut3gl/from:1987/to:2002/trend/plot/hadsst2gl/from:1987/to:2002/trend/plot/rss/from:1987/to:2002/trend
My own 3 data sets show it it is cooling from at least 2000. Note the last graph on the bottom of the minima table.
http://blogs.24.com/henryp/2013/02/21/henrys-pool-tables-on-global-warmingcooling/
If there were any warming due to more GHG it should show up [as a factor in Rsquared on a random sample] especially on minima.
There is no AGW. It is cooling naturally. Just go or live with it.
Hopefully the wheel will turn up again
some time ahead
Chances are / history shows that somehow we could miss the actual [electrical?] switch
I have it that it should come around 2016, otherwise I donot know where we will end up
Keep praying that it will switch back to warming again.