Bishop Hill Von Storch on the models again
Aug 23, 2013 Climate: MWP Climate: Models Climate: Zorita Climate: von Storch In a post at Klimazwiebel, Von Storch and Zorita have expanded onf the views they put forward in the discusion paper I mentioned the other day.
We want here to set straight some misinterpretations that may have arisen in the blogosphere, e.g. Bishophill, and may also have been present in the review processes by Nature as well.
The main result is that climate models run under realistic scenarios (for the recent past) have some difficulty in simulating the observed trends of the last 15 years, and that are not able to simulate a continuing trend of the observed magnitude for a total of 20 years or more. This main result does not imply that the anthropogenic greenhouse gases have not been the most important cause for the warming observed during the second half of the 20th century. That greenhouse gases have been responsible for, at least, part or even most of the observed warming, is not only based on the results of climate simulations, but can be derived from basic physical principles, and thus it is not really debated. It is important to stress that there is to date no realistic alternative explanation for the warming observed in the last 50 years. The effect of greenhouse gases is not only in the trend in global mean near-surface temperature, but has been also identified in the spatial pattern of the observed warming and in other variables, such as stratospheric temperature, sea-level pressure and others.
Although von Storch and Zorita talk of misinterpretations, I'm not sure there is any great difference between what they say here and what I concluded last week. At the time I said that the models are falsified - they run too hot. A model that had a slower rate of warming would not be. So a claim that part of the observed warming is anthropogenic is still scientifically tenable. How big a part is manmade is, given the failure of the models, anyone's guess.
I'm not, however, convinced that the only plausible explanation for the warming of the last 50 years is greenhouse gases. As I mentioned the other day, the IPCC looks set to conclude that there was a Medieval Warm Period. Last time I heard Rob Wilson discuss the matter, he said that the climate models couldn't even get the MWP in the right historical position, let alone explain its apparently large magnitude.
So once again I find myself returning to the point I make so often. The unknown unknowns are a big problem. Scientists would do themselves a favour if they recognised it.
[Comments will be tightly edited for relevance and tone]
Reader Comments (89)
It is scientifically untenable to proclaim 2010 warmer than 2005 or 1998. That's not debated.
The basic physical principles are just that, and can be taken to be fairly well established at this stage. It is how they relate to the Earth's climate system which is clearly not well understood and subject to debate. That's when we start to run into non existent hotspots and missing heat which suggests that knowledge is seriously incomplete.
omnologos
Did you notice that the table showed 95% confidence limits for Hadcrut3 and Hadcrut4?
Both are ~ +/- 0.1C for recent data.
NCDC, GISS and Berkeley are similar, though you'll have to go to their own websites for confirmation.
Entropic
A trend line through the peaks? Whatever floats your boat.
omnologos
Good. Now we're getting to the point of my reply to ssat. The 15 year period he quotes is too short to generate statistically useful trend data.
To get a 95% statistically significant difference between two sets of temperature data, whether for individual years or for longer periods, you need to see a difference exceeding 0.2C between the means.
At latter 20th century warming rates this usually took about 25 years for the trend to significantly emerge from the noise.
Thus we can say with 95% confidence that the 21st century years are significantly warmer than the early 1990s. What we cannot say is that the warming trend continues, that it has slowed, that it has stopped, or even that it is cooling.
This is why the scientists are reluctant to discuss what the 21st century data is doing. They can observe the temperature data, but are reluctant to draw conclusions until they can substantiate them statistically.
The spin-sceptics, on the other hand, have no such compunction. They make claims like " no warming for 15 years", with no statistical support whatever.
My own preference is to follow the 5-year running mean, which minimises any tendency to focus on particular years. It also helps damp out the year-on-year variations.
http://data.giss.nasa.gov/gistemp/graphs_v3/Fig.A2.gif
GISS shows this well. The 5-year average showed on inspection a continuing increase to 2002, then a flattening. The 95% confidence limits shown are +/- 0.05C,
All we can deduce with confidence from this is that in the last decade actual temperatures have risen by no more than 0.1C, dropped by no more than 0.1C or done something in between.
Yes. A much under-discussed point.
As is often pointed out, a computer can be relied upon to come up with the wrong answer much more quickly than experimentation. It is thus also cheaper, and easier, to ignore/dismiss calculated results that may, apparently, be considered 'clearly wrong'. But the false-positives and the false-negatives need to be counted. Yet real climate experiments take an awfully long time, and concurrent control-experiments are generally close to impossible.
In the chemical world, such as drug design, the tension between computational and experimental approaches has many times been described as a sine wave: The two move in and out of fashion asynchronously. I have, on occasions, been seduced by one or the other. And the more I did it, the more I believed in it.
But selected 'hits' from the computational approach still have to pass the test of reality. Far fewer people (close to none, maybe) will take the trouble to computationally model all the compounds which have already failed in the laboratory.
1 ... The Physics does not support C02 as a driver, that is conclusively falsified. The Sagan science is just plain wrong, the models don't work either hind or forecast.
2 ... The whole meme assumes expensive, scarce hydrocarbons, false shale.
3 ... The religion and money thing
It is all a great fraud. MFG, omb
One wonders and one worries whether atmospheric climate scientists and climate modelers would in the same vein as Sir Paul Nurse to Delingpole, accept the level of 'evidence' they seem happy with in climate science, in the evidence based oncological care of one of their children who hypothetically had cancer?
Entropic Man
'The 15 year period he quotes is too short to generate statistically useful trend data.'
and yet one extreme but normally occurring weather event is more than enough to 'prove 'climate doom , odd how that works . You need to get up to date because 'weather is not climate ' line has been dropped as climate continues to fail to match the models so any weather event can that can is jumped on as 'proof ' of the cause.
KnR
Read the science. One "event" is not evidence of climate change. A long term change in event frequency is. Once again, such evidence depends on a sufficiently long time period for the trend to show significantly above the short term variation.
Again, it is revealing that scientists are reluctant to speculate ahead of the data, but sceptics like yourself are quite happy to reject the possibility of trends without any statistical justification.
Manfred
The treatment for cancer does almost as much damage as the disease. You do not start it lightly.
Of course an oncologist can get more reliable evidence. The patient is avaliable and can be examined in detail and at once. It is relatively easy to get good data. Even so, there is still some uncertainty.
The climate scientist works with a patient 8000 miles across, with a slowly changing complex condition. The two examples are not comparable.
Now I've taken a quick read at the site, I have to say that some of it seems self-contradictory. To whit,
It then goes on to offer four possible excuses for why the models perform so poorly. (Others have already been commented on up-thread.)
But in my version of the English language,
means "there is a realistic alternative explanation that we have not thought of."
"...there is to date no realistic alternative explanation for the warming observed in the last 50 years".
The last 60 years have seen about 20 years of slight cooling, 20 years of warming and 20 years of plateau. The warming phase was a little more intense, so the overall mean shows some warming.
The amplitude of the warming phase is about the same as that of 1920-40 and 1860-80 and "there is to date no realistic explanation" for those either. If those two were caused by unexplained (and largely unexamined) natural variance, then Occam would suggest that the third is the same.
It is not really debated that basic physical principles show that GHGs give rise to part of the observed warming. But use the word "most" is heavily debated. In the leaked 5AR draft this open-ended word is replaced by "more than half", suggesting a value in the 50-60% region. How do von Storch and Zorita contend this "can be derived from basic physical principles".
Key question: Which physical principles make it 95% certain that greenhouse gases contribute 50%+ to the observed warming trend rather than 50%-.
HadCRUT4 and NOAA say the observed mean warming trend since 1962 has been 0.143°/decade. The von Storch argument seems to be that non-AGW causation could not exceed about 0.7°/decade without "a realistic explanation".
It was pointed out by Arrhenius as far back as 1900 that infrared absorption by CO2 was 'saturated'...meaning adding more will not make any difference...there is an alternate explanation of warming and cooling which i put forward 3 years ago...there seems to be a natural 30 year cycle...warming from 1920-1950...cooling from 1950-1980...warming from 1980-2010...cooling since then...the most likely explanation lies beneath the oceans...which have more than 1000 times the heat capacity of the atmosphere.
Gobal, indeed. The oceans (and solar magnetic influences) on cloud cover are the drivers, and CO2 has feck all to do with it, once levels are above 250ppmv. Arrhenius also considered the warming to be of net benefit, Arrhenius and Global warming.
Chris / Phillip -
This is all I can find on Youtube:
Prof. Bob Watson and Prof. Singer on BBC Newsnight, Nov 2009) but Bob Watson was also interviewed on Channel 4 News at that time, and it was his response to a viewer's question (mine) that he came up with the we can't think of anything else statement. I don't think C4 publicly archive their news items and I can't find the interview on Youtube. This was my question, which I thought was going to be put to Millband, but Jon Snow put to Watson:
"If the Minister for climate change is so sure that the science is settled, could he please produce convincing OBSERVATIONAL EVIDENCE (i.e. not from computer models) that proves that climate change has been caused by human activity, and provide this evidence before he commits the UK government to any legally binding treaty at Copenhagen?"
michael hart responds to Theo Goodwin:
Reminding me of a response made to Steve McIntyre this time last month:
The key phrases there being 'to remove such suspicions' and 'all generalisations thereof'.
We have a long way to go. But Feynman would be cheering you on Michael.
I note that EM inverts the usually accepted role of evidence and proof. It is not correct to pronounce a theory and then require those who do not instantly accept it to produce the proof that they are correct.
I say I don't know and that I am not impressed by the evidence. EM thinks I ought to be able to prove that. I suspect pedagogy.
Von Storch should read this article about another recent and thorough examination of the climate models discussed by Lawrence Solomon in the Financial Post.
http://opinion.financialpost.com/2013/08/22/lawrence-solomon-model-mockery/
Apart from the two satellite datasets, that is.
The earth only modestly warmed up from one of the coldest cycles in the past 10,000 years due to the most active sun in the past 1000 years. Since 1998 our sun is cycling back to its 200 low sunspot cycles and the coming cycle 25 will be very low indeed. Millions die from crop failure during previous low cycles like the Dalton and Maunder Minimum. Vast amounts of Farm Herbs have been buried alive by snow this past winter. My fear is the AGW crowd kills cheap energy just when will really will need it.
I agree.
However I believe there is conscious and unconscious stretching of credibility. Without being silly, it happens in every belief driven cult. Extreme statements are made and the crowd supports it. Individuals stay within their own group and turn their backs on other versions of reality.
I will not discuss things I am not qualified to discuss. However I quote things I fully understand. Like this. Note that Professor Jones uses 1995 . Please also note that while scientists are constrained to a 95% statistical significance reality test, the rest of as aren't. The projected 0.12C per decade is not enough to trigger any CO2 reduction policy.
The BBC's environment analyst Roger Harrabin put questions to Professor Jones, including several gathered from climate sceptics. The questions were put to Professor Jones with the co-operation of UEA's press office.
Do you agree that from 1995 to the present there has been no statistically-significant global warming
Yes, but only just. I also calculated the trend for the period 1995 to 2009. This trend (0.12C per decade) is positive, but not significant at the 95% significance level. The positive trend is quite close to the significance level. Achieving statistical significance in scientific terms is much more likely for longer periods, and much less likely for shorter periods.
C - Do you agree that from January 2002 to the present there has been statistically significant global cooling?
No. This period is even shorter than 1995-2009. The trend this time is negative (-0.12C per decade), but this trend is not statistically significant.
Do you agree that according to the global temperature record used by the IPCC, the rates of global warming from 1860-1880, 1910-1940 and 1975-1998 were identical?
An initial point to make is that in the responses to these questions I've assumed that when you talk about the global temperature record, you mean the record that combines the estimates from land regions with those from the marine regions of the world. CRU produces the land component, with the Met Office Hadley Centre producing the marine component.
Temperature data for the period 1860-1880 are more uncertain, because of sparser coverage, than for later periods in the 20th Century. The 1860-1880 period is also only 21 years in length. As for the two periods 1910-40 and 1975-1998 the warming rates are not statistically significantly different (see numbers below).
I have also included the trend over the period 1975 to 2009, which has a very similar trend to the period 1975-1998.
So, in answer to the question, the warming rates for all 4 periods are similar and not statistically significantly different from each other.
http://news.bbc.co.uk/1/hi/sci/tech/8511670.stm
I don't think you understand.
Let's change what Jones said to the situation in the next year as you have stated.
'This trend (0.12C per decade) is positive and IS significant at the 95% significance level.'
Do you agree with that ?
I think we can all agree that there has been roughly no warming in the last 15 years.
Even the big business sponsored, Wall Street front NYT agrees..
The rise in the surface temperature of earth has been markedly slower over the last 15 years than in the 20 years before that.
http://www.nytimes.com/2013/06/11/science/earth/what-to-make-of-a-climate-change-plateau.html?_r=0
I am still waiting to find out exactly what has to pass before AGW is a disproved theory in Climate Scientists minds, its been asked many times but the silence is deafening. Moving goalposts comes to mind, well invisible ones actually ;) .
Aug 24, 2013 at 12:18 AM | Unregistered CommenterManfred
Cue Delingpole: Your argument is circular. Whether climate science is a genuine science is the question at issue. We cannot assume that climate scientists have established a record of success comparable to that of cancer surgeons. Or would you like to present that record of success?
Pardon me for repeating myself, but it is very important to note that Von Storch and most climate scientists offer a circular argument that, additionally, ignores the evidence of their own record of achievement. Von Storch recognizes the failures of the models but then asserts that he will not surrender the CO2 theory because there is no realistic alternative explanation of rising temperatures. In effect, Von Storch is asking that we accept his claim that he has a scientific explanation of observed warming even though his particular formulation of that explanation, via models, has met with failure upon failure. He seems to demand that his critics have faith in him despite his failures.
Rhoda at Aug 23, 2013 at 9:43 PM...
Rarely have I agreed with a comment more.
We do not know that the solar changes will govern the climate. Anymore than we know the change in CO2 will dominate all other feedbacks.
Ignorance is not a virtue, But awareness of ones ignorance is a virtue.
And we are all ignorant of the workings of the climate.
If we weren't we could model the climate accurately.
I agree that we will never be able to model the climate accurately. But I am not sure that solar magnetic fluxes changes (and cosmic galactic ray fluxes) don't govern the climate, at least over millennial timescales.
The Milky Way Galaxy's Spiral Arms and Ice-Age Epochs and the Cosmic Ray Connection
am still waiting to find out exactly what has to pass before AGW is a disproved theory in Climate Scientists minds, its been asked many times but the silence is deafening. Moving goalposts comes to mind, well invisible ones actually ;) .
Aug 24, 2013 at 8:26 PM | Breath of Fresh Air
An easy question to anawer, and a point I have been trying to knock into some of the thicker skulls here.
In science all theories are approximate descriprtions of reality.
You use them, improve them and, when a better theory comes along, replace them.
The current theories of climate are approximate, but work well enough for weather forecasting an approximate long term forecasts.
If you want the climate scientists to change paradigm , pointing out the flaws is not enough. They already know about the flaws.
You need to supply a theory which works better than the current one!
Again EM inverts the scientific method. If somebody's theory doesn't hold up, or has no falsifiability criteria, NOBODY has any responsibility to provide a better theory.
Aug 25, 2013 at 8:13 PM | Unregistered Commenterrhoda
Well said, as history has demonstrated. Copernicus criticized Ptolemy's theory of the heavens because it contained huge problems. Copernicus did not wait until he had an alternative theory ready to go. He criticized Ptolemy's theory, changed it fundamentally, and proceeded with a vastly improved theory that directly contradicted Ptolemy.
Remember this is post normal Science, EM has just confirmed I am correct with his reply.
rhoda, Theo Goodwin, Breath of fresh air.
Your Copernicus example rather makes my point. He criticised Ptolemy's theory and then put forward a better one.
The Ptolomeic system was not abandoned because it had been criticised, but because a better one displaced it.
Tyco Brahe had been taking accurate measurements which fitted Copernicus' view better than Ptolemy's. The final nails were when Kepler's calculations showed that the orbits were elliptical and Newton's Law of Gravitation explained why.
Despite what the spin-sceptic blogs tell you, attempts to falsify the current climate science paradigm have made no progress at all.
To continue the analogy, you are Ptolomeics, clinging to an outmoded view while ignoring the evidence. Climate science is in the post Kepler stage, with Newton developing the inverse square law.
Entropic: That's truly exciting. And Isaac Newton is Michael Mann, I assume?
Entropic Man (5:46 PM) -
An interesting analogy. So what would you say was the epistemic state of Ptolemy's theory, before Kepler's work? While it was certainly viewed differently in hindsight (after Kepler/Copernicus/Newton), the Ptolemaic view before them was just as kludgey, and agreed just as well (or poorly) with Brahe's observations. Yet one could have said at the time that it was "the best science we have". Does that make its inaccurate predictions any better?
HaroldW
I do not think that Ptolemy's view could be described as science, especially as the Medieval scholars involved made no attempt to test his theory.
Brahe, Kepler and Newton used something recognisable as an early form of the scientific method, as articulated in Newton's principles of inquiry.
(1) We are to admit no more causes of natural things such as are both true and sufficient to explain their appearances.
(2) The same natural effects must be assigned to the same causes.
(3) Qualities of bodies are to be esteemed as universal.
(4) Propositions deduced from observation of phenomena should be viewed as accurate until other phenomena contradict them.
Brief descriptions of changes and initial shake-down calculations of a couple of GCMs. Note almost complete focus on parameterizations, including those that are associated with and affect the "basic first principles" radiative energy transport.
The Met Office Unified Model Global Atmosphere 4.0 and JULES Global Land 4.0 configurations
Abstract
We describe Global Atmosphere 4.0 (GA4.0) and Global Land 4.0 (GL4.0): configurations of the Met Office Unified Model and JULES community land surface model developed for use in global and regional climate research and weather prediction activities. GA4.0 and GL4.0 are based on the previous GA3.0 and GL3.0 configurations, with the inclusion of developments made by the Met Office and its collaborators during its annual development cycle.
This paper provides a comprehensive technical and scientific description of GA4.0 and GL4.0 as well as details of how these differ from their predecessors. We also present the results of some initial evaluations of their performance. These show that, overall, performance is comparable with that of GA3.0/GL3.0; the updated configurations do, however, include improvements to the science of several parametrization schemes and will form a baseline for further ongoing development.
A reviewer's comments: http://www.geosci-model-dev-discuss.net/6/C943/2013/gmdd-6-C943-2013.pdf
Another Model System
The Norwegian Earth System Model, NorESM1-M – Part 1: Description and basic evaluation of the physical climate
Abstract
The core version of the Norwegian Climate Center’s Earth System Model, named NorESM1-M, is presented. The NorESM family of models are based on the Community Climate System Model version 4 (CCSM4) of the University Corporation for Atmospheric Research, but differs from the latter by, in particular, an isopycnic coordinate ocean model and advanced chemistry–aerosol–cloud–radiation interaction schemes. NorESM1-M has a horizontal resolution of approximately 2(deg) for the atmosphere and land components and 1(deg) for the ocean and ice components. NorESM is also available in a lower resolution version (NorESM1-L) and a version that includes prognostic biogeochemical cycling (NorESM1-ME). The latter two model configurations are not part of this paper. Here, a first-order assessment of the model stability, the mean model state and the internal variability based on the model experiments made available to CMIP5 are presented. Further analysis of the model performance is provided in an accompanying paper (Iversen et al., 2013), presenting the corresponding climate response and scenario projections made with NorESM1-M.
Here's an interesting comment in one of the reviews. Reviewer # 1
Page 31, discussion on the results on the AMO: a recent paper (Booth et al., 2012) claims that the AMO is actually a forced variability due to the indirect effect of anthropogenic aerosols during the industrial period. This reference can put some additional value to discuss your results on the AMO.
Booth, B. B. B., Dunstone, N. J., Halloran, P. R., Andrews, T., & Bellouin, N. (2012).
Aerosols implicated as a prime driver of twentieth-century North Atlantic climate variability. Nature, 484(7393), 228-32. Nature Publishing Group. doi:10.1038/nature10946