A new paper from Hausfather and colleagues (incl. me) has just been published with the most comprehensive assessment of climate model projections since the 1970s. Bottom line? Once you correct for small errors in the projected forcings, they did remarkably well.
Climate models are a core part of our understanding of our future climate. They also have been frequently attacked by those dismissive of climate change, who argue that since climate models are inevitably approximations they have no predictive power, or indeed, that they aren’t even scientific.
In an upcoming paper in Geophysical Research Letters, Zeke Hausfather, Henri Drake, Tristan Abbott and I took a look at how well climate models have actually been able to accurately project warming in the years after they were published. This is an extension of the comparisons we have been making on RealClimate for many years, but with a broader scope and a deeper analysis. We gathered all the climate models published between 1970 and the mid-2000s that gave projections of both future warming and future concentrations of CO2 and other climate forcings – from Manabe (1970) and Mitchell (1970) through to CMIP3 in IPCC 2007.
We found that climate models – even those published back in the 1970s – did remarkably well, with 14 out of the 17 projections statistically indistinguishable from what actually occurred.
We evaluated these models both on how well modeled warming compared with observed warming after models were published, and how well the relationship between warming and CO2 (and other climate forcings) in models compares to observations (the implied transient climate response) (see Figure). The second approach is important because even if an old model had gotten all the physics right, the future projected warming would be off if they assumed we would have 450 ppm CO2 in 2020 (which some did!). Future emissions depend on human societal behavior, not physical systems, and we can usefully distinguish evaluation of climate models physics from paths of future concentrations.
However, it is not totally obvious how one should correct for the forcing assumptions because of subtle issues related to the different efficacy of different forcings and, of course, the remaining uncertainty in the real value of the actual forcings (driven predominantly by the aerosol component). For forcing projections that were close to linear, this didn’t make that much difference, but for scenarios that weren’t (notably scenario C in Hansen et al (1988)), the correction does not work well.
There are a few other results that stand out, notably the (infamous?) low sensitivity result in Rasool and Schneider (1971), which was mainly due to a lack of stratospheric adjustment and water vapor short wave absorption in their formulation. This was noted by Schneider (1975) and the calculation redone by Schneider and Thompson (1981) which turned out to be far more accurate. On the other hand, only Mitchell (1970) appears to have substantially overestimated the TCR – even while he predicted the temperature rise quite accurately (due to a compensation between a too large sensitivity and an underestimate of the forcings). [Amusing aside, both Manabe’s and Mitchell’s 1970 projections appeared in a special volume on the Global Effects of Environmental Pollution, reporting on an 1968 AAAS workshop and edited by (the now-notorious) S. Fred Singer before he went off the deep end].
It’s worth noting that this comparison includes two kinds of climate model – those published prior to 1988 which are energy balance models of varying complexity, and those published afterwards which are true GCMs and include atmospheric (and eventually, ocean) dynamics. Of the early models, the work of Sawyer (1972) stands out as being the most accurate in terms of both temperature trends and forcings, though this must be considered somewhat fortuitous.
The fact that both classes of climate model did so well in projecting future warming should increase our confidence that current climate models are getting things right for mostly the right reasons. While there are still real uncertainties in future warming associated with climate sensitivity, we can confidently state that the rate of surface warming we are experiencing today is pretty much what past climate models projected it would be.
Gosh, maybe we know something about climate after all!
Note: all the data and code for this study are available here.
References
- Z. Hausfather, H.F. Drake, T. Abbott, and G.A. Schmidt, "Evaluating the Performance of Past Climate Model Projections", Geophysical Research Letters, vol. 47, 2020. http://dx.doi.org/10.1029/2019GL085378
- S.I. Rasool, and S.H. Schneider, "Atmospheric Carbon Dioxide and Aerosols: Effects of Large Increases on Global Climate", Science, vol. 173, pp. 138-141, 1971. http://dx.doi.org/10.1126/science.173.3992.138
- S.H. Schneider, "On the Carbon Dioxide–Climate Confusion", Journal of the Atmospheric Sciences, vol. 32, pp. 2060-2066, 1975. http://dx.doi.org/10.1175/1520-0469(1975)032<2060:OTCDC>2.0.CO;2
- S.H. Schneider, and S.L. Thompson, "Atmospheric CO2 and climate: Importance of the transient response", Journal of Geophysical Research: Oceans, vol. 86, pp. 3135-3147, 1981. http://dx.doi.org/10.1029/JC086iC04p03135
- "Global Effects of Environmental Pollution", 1970. http://dx.doi.org/10.1007/978-94-010-3290-2
- J.S. SAWYER, "Man-made Carbon Dioxide and the “Greenhouse” Effect", Nature, vol. 239, pp. 23-26, 1972. http://dx.doi.org/10.1038/239023a0
#47 David Young,
I found the Palmer and Stevens piece perfectly reasonable (although some of the language on page 4 was a bit florid), but it sounded very much like what the Denialists are always talking about…a quest for funding.
Nothing wrong with that; they accept that the science is sufficiently settled to make the case for reducing CO2 production, but they think they have approaches to increasing precision and regional constraints that should be explored.
But the problem, as I referenced at #32, is that it has the same vagueness as the endlessly-moving-goalpost games of the Denialists.
Can you give any specifics about the utility that we gain at some specific level of precision or specific regional scope?
It’s kind of absurdist to argue for precision without being precise, no?
J Doug Swallow @50, please provide at least 20 years of NOAA climate model predictions for Americas winters, and 20 years of Farmers Almanac winter predictions over the same period, together with historical data on that weather, and we shall see which has done best.
42
The truth that sets Barton free is not always the one he likes to hear — one Science senior writer wrote in that decidedly partisan journal, The New Republic:
“The main technical challenge to nuclear winter comes from Stephen Schneider and Starley Thompson, researchers at the National Center for Atmospheric Research in Boulder, Colorado. They agree with Sagan that the number of nuclear weapons should be reduced, but they say the integrity of atmospheric science should not be sacrificed to make that point.
Schneider claims that it has been clear for perhaps two years that Sagan’s original description of nuclear winter is not the most accurate. But coaxing has not brought any acknowledgment that this is so. Sagan said recently that he found “nothing new” in a state-of-the-art computer analysis by Schneider and Thompson to change his view of Armageddon. Schneider and Thompson laid out their doubts in a Foreign Affairs article last summer, reporting that the chance of human extinction after a nuclear war is “vanishingly low,” They find no risk of a new ice age…
The more apocalyptic version of nuclear winter has become a part of the anti-weapons
dogma of the 1980s, As a result, some people may be reluctant to let it go…At a private gathering of experts at the National Academy of Sciences in January. It became clear that this new mild version of “nuclear autumn” is credible and may even overstate the temperature drop. This does not mean the climatic impacts of war would be mild… But there would be no ice in the tropics; that is certain. Schneider says: “Carl’s idea was brilliant. He proposed an invasion from Mars,” It just didn’t hold up under scrutiny.
The freeze movement may have gained a tactical victory through the promotion of nuclear winter. It helped get attention. But the advantage appears to have been short-lived. Now, as the computer termites gnaw at the data, the structure creaks and totters. Soon it may be gone. Perhaps if we are lucky, 1987 will bring the final debunking of two great science fictions of the Reagan era: nuclear winter and Star Wars.”
— Elliot Marshall, The Little Chill
Zebra, It is a transparent plea for funding but it is honest about the math and science, which is a big step forward. It’s a tremendously complex subject. Just Navier-Stokes for dramatically simplified engineering calculations is very complex and progress has slowed dramatically in the last 20 years. Climate is orders of magnitude more complex. The first step in improving is to admit there is a big problem. So good for them. Gavin’s post here shows lots of results that don’t add anything to our understanding. You can get any answer you want out of an EBM model depending on the inputs, some of which were very uncertain in the past. They are still uncertain.
NASA’s CFD vision 2030 is an almost exact mirror of this proposal by Palmer and Stevens. And both share serious technical and cultural difficulties.
1. The seemingly constantly escalating hype and biased papers (selection bias and positive results bias infects at least half of all papers in CFD) and the even more blatant dishonesty of the press releases gives the strong impression to laymen that the science is vastly better than it really is. Their natural reaction is well, its a solved problem, so you don’t need any more funding. I have about 40 links I’ve saved to top flight journals discussing these problems of bias.
2. Academic and even government agencies have come to rely more and more on soft money. The constant search for soft money causes escalating dishonest marketing. Academics’ pay and promotions depend strongly on getting lots of soft money and having a hoard of students and post docs. This army of low paid workers generate hundreds of papers which in turn generate more soft money and high pay for the CEO (the academic). Academia needs serious reforms. Perhaps the only way is to sack a lot of administrators and start o
3. Now on the science, it is indeed possible to make incremental progress. Steady Navier-Stokes saw steady progress up to about 2000 with improvements in virtually all aspects of the science and math. Turbulence models have advanced tremendously with algebraic models being replaced by PDE models. Grids are at least 10000 times bigger and solution adaptivity is being used more even though its still fixed grid codes that constitute the vast majority of runs. Numerical methods have gotten vastly better with finite element methods starting to be recognized as superior. Newton’s method has proven its superiority.
4. Climate models are where NS was in the 1970’s. Algebraic subgrid models seem to predominate. Numerical methods are often the best from the 1960’s. Grids are completely inadequate. Climate models boil down to tuning parameters to get large errors to cancel for outputs used in turning. So yes, there is 30 years of hard work which will require thousands of people working on all the details for incremental improvements already developed for NS. Will the funding be available? Not if the scientific salesmanship continues.
5. However, the analogy breaks down here to some extent. Weather models are time accurate eddy resolving simulation much like LES simulation. Solution adaptivity for example is impossible using classical methods (this a mathematical theorem). There is no knowledge of the nature of the attractor(s), neither their dimension nor their Lyopanov constants. What is really needed is a crash program in mathematics. Computations can play a role too. We have really little real science even for LES with uniform onset flows and low pressure gradients. People should start with the easier problems first. Is this possible in the current structure of science? Scientists need to stop denying the problems and try to come up with improvements.
6. What this really shows is how scientifically weak Hanson’s original thoughts on climate models were. There is still little scientific support for their skill (beyond what simple EBM models can skillfully predict). Some of these things are quite important such as forcing efficiencies and we need models to estimate them.
7. So Palmer and Stevens is a small step forward. But until the scientific establishment reforms itself and makes the scientific literature more representative of negative and uncertainty results, their attempts will probably not bear fruit. There is still a defensive posture of most climate scientists about these models. This posture will result in further retarding funding and progress on a topic that is vital to human well being.
Just my opinions. These haven’t changed much since I first commented here at Real Climate even though I have dramatically improved my knowledge of the details. I have a long dissertation on these subjects with references, but haven’t bothered to get it out yet. It’s s very complex field and only those with decades of experience have the understanding needed. Palmer and Stevens seem to be among those who understand some of the basics.
I’m sure that Gavin A. Schmidt will not agree with this below and moderate it into a faraway land to never be seen by his loyal followers.
Uncertainty
Climate models at their limit?
“Estimates of climate-change impacts will get less, rather than more, certain. But this should not excuse inaction, say Mark Maslin and Patrick Austin.
For the fifth major assessment of climate science by the Intergovernmental Panel on Climate Change (IPCC), due to be released next year, climate scientists face a serious public-image problem. The climate models they are now working with, which make use of significant improvements in our understanding of complex climate processes, are likely to produce wider rather than smaller ranges of uncertainty in their predictions. To the public and to policymakers, this will look as though the scientific understanding of climate change is becoming less, rather than more, clear.
Scientists need to decide how to explain this effect. Above all, the public and policymakers need to be made to understand that climate models may have reached their limit. They must stop waiting for further certainty or persuasion, and simply act.
[…]This leads to a large range of potential futures, some of which contradict others. For example, detailed hydrological modelling of the Mekong River Basin using climate model input from the UK Met Office’s HadCM3 model projects changes in annual river discharge that range from a decrease of 5.4% to an increase of 4.5% (ref. 2). Changes in predicted monthly discharge are even more dramatic, ranging from a fall of 16% to a rise of 55%. Advising policymakers becomes extremely difficult when models cannot predict even whether a river catchment system will have more or less water.”
https://www.nature.com/articles/486183a?WT.ec_id=NATURE-20120614
Nigelj @52 wants at least 20 years of NOAA climate model predictions for Americas winters, and 20 years of Farmers Almanac winter predictions over the same period, together with historical data on that weather. That would be a good project; but, one must be aware of certain limitations due to the fact that the Old Farmer’s Almanac was founded in 1792 and NOAA was formed in 1970. Since you seem to be so interested in the questions that your brought up, I suggest that you research it and report back on what you have found to be true.
I’m not too sure where National Geographic derives the information from that made them issue this report below.
You must remember that the environmentalist had been telling the Californians that they were heading into a 1,000 year drought & it would never rain again or snow in the Sierra Nevada Mountains again either.
“They’ve Seen Lots of Droughts, But This One’s Different
This time, crispy lawns, short showers, and unflushed toilets may be the new normal. If that fails? “Beat everyone to Oregon,” one Californian says.”
By Cheryl Katz,
National Geographic
PUBLISHED JULY 6, 2015
http://news.nationalgeographic.com/2015/07/150706-drought-california-water-conservation-environment/
Nigelj @52 Needs to explain how a 1,000 year drought could have ended in such a short time. Where was National Geographic getting their erroneous information from to make these kind of ludicrous predictions? A century went by real fast, in a matter of 2 years water was about to wash out the spillway on Oroville Dam.
National Geographic needs to make sure that they understand how nature works before waving the red flags of the anthropogenic global warming crowd whose cult they seem to have joined.
OROVILLE Note the date.
February 11, 2017 05:24 AM
Water began pouring over the emergency spillway at Oroville Dam early Saturday for the first time in its 48-year history. State officials continued to say they don’t expect the situation to result in flooding in Oroville or other communities downstream.
http://www.sacbee.com/news/local/article132154774.html
“California and Nevada Pummeled By Flooding Rain, Mudslides and Rockslides; Rain Heads South Until Tuesday”
Jan 8 2017
“Another multi-day siege of heavy rain and Sierra snow is pounding California and adjacent parts of Nevada which has resulted in flooding, mudslides and rockslides. The heaviest rain will slide south into Southern California early Monday, while another blast of heavy rain will arrive in northern California Tuesday.
This very potent atmospheric river event will continue to aim a fire hose of moisture at the West Coast into Monday. The rain combined with snowmelt due to high snow levels is leading to rises on rivers and other waterways. The National Weather Service says that flooding with this event may be the greatest since December 2005 for some locations.”
https://weather.com/forecast/regional/news/california-atmospheric-river-sierra-snow-flood-forecast-jan2017
“There is something fascinating about science. One gets such wholesale returns of conjecture out of such trifling investment of facts.” Mark Twain
“Climate is what we expect, weather is what we get.”
Mark Twain
Sorry, Russell, but you’re the one who doesn’t want to face reality. Your whole take on nuclear winter is to attribute motive, to accuse Sagan and the other TTAPS authors of being hippie freezeniks who lied for political reasons. The fact is, you still can’t rule out nuclear winter, and you can babble about “nuclear autumn” all you want, and you still can’t prove you’re right, which is why it keeps getting modeled. Maybe if you shut up about politics and concentrated solely on the science more people would listen to you, but as it is you come off like a right-wing jerk with an agenda.
Nuclear Winter. 1.
For those too young to remember nuclear winter or the freeze movement, here’s a quick precis.
In 1983, Turco, Toon, Ackerman, Pollack, and Sagan published a paper in Science detailing the effects of a nuclear exchange between the United States and the Soviet Union. They concluded that detonations in cities would create a tremendous amount of soot which, lofted into the stratosphere, would blanket the Earth for some time (especially between 30 and 60 degrees north latitude), blocking sunlight and effectively ruining agriculture for some years. This was called “nuclear winter.” The authors had previously done atmosphere modeling studies of Venus, Mars, and asteroid impacts on the Earth.
At the time, US-Soviet tensions were still high, arsenals were high (60,000 nuclear warheads existed), and in the US a political movement sought to “freeze” warhead levels before they got any higher. Some of the TTAPS authors (the acronym came from the first letter of their last names) signed onto freeze petitions.
In 1985, Schneider and Thompson published their own modeling study which concluded that a nuclear exchange would only cause a much milder “nuclear autumn.”
Nuclear Winter. 2.
Since then, many more nuclear-war studies have been done. The main discrepancy between the two types of study (nuclear winter versus nuclear autumn) is in plume heights. If plume heights are high, the soot makes it into the stratosphere, spreads out, and stays for a while. If they are low, the soot rains out quickly, and climate consequences are much less severe.
There are other factors as well, such as the optical properties of the soot particles. There are five major factors of interest here: absorption coefficient ka, scattering coefficient ks, extinction coefficient ke, single scattering coefficient ω, and scattering asymmetry coefficient g. There are simple relations among some of these; e.g. ke = ka + ks and ω = ks / ke = ks / (ka + ks). But plume height is the main problem.
Nuclear Winter. 3.
In 1982, I was working for Energy Impact Associates, a firm which modeled the atmosphere effects of factories for various industrial customers, with a view to meeting EPA requirements. Our simulation for plumes had long had a problem: plume heights invariable came out too low by a factor of three.
I did a unit analysis of the equations which went into the problem, and I eventually found a point at which we had feet on one side of the equation and meters on the other. That neatly solved that problem.
It would be incredibly unlikely that Schneider and Thompson made the same mistake; that would be asking too much of coincidence. But until I have it demonstrated to me that the abnormally low plume heights characteristic of nuclear autumn studies are justified, I have no reason to accept those studies as reasonable.
Nuclear Winter. 4.
One problem with this issue, as with so many scientific issues in America, is that it became embroiled in politics. Liberals favored nuclear winter studies, conservatives favored nuclear autumn studies. In 2010, one of the nuclear winter modelers–Alan Robock–traveled to Cuba to talk about nuclear winter. In the view of conservatives, of course, this was a clear sign that Robock and all his colleagues were Marxists seeking to destroy our republic from within. It makes it all the more ironic that present-day Republicans are bending over backwards to hand the Putin government everything it wants on a silver platter.
DY 54,
Perhaps climate modelers defend the models because they have been right so many times:
http://BartonLevenson.com/ModelsReliable.html
JDS 57: Needs to explain how a 1,000 year drought could have ended in such a short time.
BPL: A 1,000 year drought does not mean “a drought that lasts for 1,000 years.” It means “a drought the severity of which only happens once every 1,000 years.”
The please for 20 years of comparisons between Farmer’s Almanac and NOAA are because a sample size of one year is inadequate.
In short, you don’t seem to understand what you’re criticizing. Given that, the rest of your posts are irrelevant.
Barton, What your post does is transparently invalid and a blatant example of selection bias. There are at least 17 things models get quantitatively wrong, including cloud fraction as a function of lattitude, the pattern of SST warming, even the temperature anomaly unless forced with measured SST’s. But wait, we don’t know what SST patterns will be in the future since models fail to predict them. The tropospheric hot spot is over predicted by models as this site’s post on data vs. models clearly shows.
In addition, your list includes mostly things like “polar amplification.” Well that’s not even really a quantitative prediction. We need to know the size of polar amplification. And I believe models seem to be unskillful concerning Antartica slightly cooling.
Your post is just noise and has no scientific value.
#54 David Young,
I guess my language was too plain there when I used the term “utility” and “precision” and “specific”. I’m all for science for the sake of science, but what we are talking about here is a kind of “reverse engineering” of a complex system; we’re not looking to solve profound questions about the nature of the universe.
So, what I’m asking for is along the lines of how useful is any of this going to be, and what the parameters and variables are that you intend to predict. How big is a “region”…the USA, or Texas, or Rhode Island? Are we talking about yearly average rainfall, or the intensity of rainfall over any 72-hour period? How narrow are your error-bars going to be? I could go on, but I’m sure you get the point.
So, in terms of utility, it’s hard to see where it leads, and why taxpayer dollars should go to it. I look at the posts just after yours from JD Swallow and I see exactly the No True Scotsman arguments that would follow from this path.
If you can give an example of real-world numbers and how they would be used, that would help.
Before Barton lets his political imagination carry him any farther afield, he should read what I said in the Spring 1984 issue of Foreign Affairs in reply to what Carl Sagan wrote in the Winter 1983-4 issue.
David Young said:
It would be nice if you would actually show some real work instead of just yapping about your experiences with testing airplane wings.
For one, geophysical fluid dynamics never uses the full Navier-Stokes but instead simplified versions appropriate to the reduced dimensionality, e.g. see Laplace Tidal Equations. These of course can be used to model tides quite effectively, but they also appear to work well for the reduced gravity of the ocean thermocline interface, showing much promise for describing the dynamics of ENSO/El Nino. I presented work on this at the last 3 AGU Fall meetings but skipped the conference this year as I finally have the model published in long form.
It’s never a safe move to say something is impossible to do in science because you will eventually be proven wrong.
Barton Paul Levenson #64 is the one that the onus to explain how the 1,000 year drought could have ended in such a short time falls upon Levenson, since he asked the question. The explanation that Levenson presents about what the true meaning of what National Geographic was fear-mongering over is far from what message these publications that I will provide links for were attempting to convey. It will be interesting to see how this true believer in anthropogenic climate change is able to interpret these headlines that various ‘scientific’ organizations were trying to make people believe.
“California’s drought is the worst in 1,200 years, evidence suggests”
“Worst Drought in 1,000 Years Predicted for American West”
“California’s drought is the worst in 1,200 years, evidence suggests”
Date: December 5, 2014
Source: Woods Hole Oceanographic Institution
Summary: As California finally experiences the arrival of a rain-bearing Pineapple Express this week, two climate scientists have shown that the drought of 2012-2014 has been the worst in 1,200 years. https://www.sciencedaily.com/releases/2014/12/141205124357.htm
We can now go to the consistently wrong National Geographic Magazine, since they threw in with the Anthropogenic Global warming crowd, & see what they have predicted.
“Worst Drought in 1,000 Years Predicted for American West”
Global warming to cause historic “megadrought” by century’s end. FEBRUARY 12, 2015
“Large parts of the U.S. are in for a drought of epic proportions in the second half of this century, scientists warn in a new study that provides the highest degree of certainty yet on the impact of global warming on water supplies in the region.
The chances of a 35-year or longer “megadrought” striking the Southwest and central Great Plains by 2100 are above 80 percent if the world stays on its current trajectory of greenhouse gas emissions, scientists from NASA, Columbia University, and Cornell University report in a study published Thursday in the new open-access journal Science Advances.
[…]In their study, Cook’s team used 17 computer models of droughts and three models of soil moisture to predict the likelihood of dryness over the next century. After they found a high degree of agreement among the models, they applied them to data gathered from tree rings going back to about the year 1000.
http://news.nationalgeographic.com/news/2015/02/150212-megadrought-southwest-water-climate-environment/
My, aren’t those computer models wonderful tools to analyze the climate?
“In short, you don’t seem to understand what you’re criticizing. Given that, the rest of your posts are irrelevant.” In the words of Barton Paul Levenson.
64 Barton Paul Levenson feels the need to lecture me on what is ‘relevant’ regarding this discussion. One can legitimately wonder how relevant a diatribe about a “nuclear autumn” or a “nuclear winter” is to the topic of climate models? He offers up this information that is irrelevant to the main topic of climate models;
“In 1985, Schneider and Thompson published their own modeling study which concluded that a nuclear exchange would only cause a much milder “nuclear autumn.” ”
This I’m sure is the same ‘Schneider’ that this quote is attributed to;
“We need to get some broad based support, to capture the public’s imagination… So we have to offer up scary scenarios, make simplified, dramatic statements and make little mention of any doubts… Each of us has to decide what the right balance is between being effective and being honest.” – Stephen Schneider, Stanford Professor of Climatology, lead author of many IPCC reports
This link below will take you to information about the much touted, “1,000 drought”, in California that the climate models were predicting.
Palmer Drought Severity Index
December 2012 – November 2019
https://www.ncdc.noaa.gov/temp-and-precip/drought/historical-palmers/psi/201212-201911
#55, JDS–
Nice reference from 2012. But much less “damning” than you think; difficulties with improving regional forecasting are well-known and much lamented. It’s a hard problem.
However, that does not bear on the reliability of the big-picture problem. The more geographically precise the forecast needs to be, the more difficult. It’s much easier to project global mean surface temperature, given the relevant forcings, than the change in drainage in the Mekong. (It would be even harder to forecast what will happen to Beaver Creek, SC, 2 miles up the road from me.)
(On a ‘meta’ note, you will be aware that your comment was not boreholed. In, effect it asked a sensible question–even if you didn’t think that was what you were doing. Will you have enough integrity to consider the answer?)
#69 & 70, JDS–
Sigh.
The “explanation” offered is not Barton’s; it’s a well-known bit of terminology, albeit one more usually applied to flooding than drought. But the principle applies.
https://www.usgs.gov/faqs/what-a-1000-year-flood?qt-news_science_products=0#qt-news_science_products
The same is true of the California drought.
Note that this is not the same as claiming, as in your link about the tree-ring drought study, that the drought is the worst in 1,000 years–although it’s true that if climate were static you’d expect to see 1,000-year droughts at a *mean* interval of 1,000 years. (Actually–to be exact!–the number in the study linked was 1,200 years. It’s true that journalists and especially headline writers don’t always keep that difference in mind, but that is not the fault of climate science.)
[Bolding by KDM.]
Do I really need to point out that in 2019 it’s just a tad early to declare projections of megadrought by 2100 incorrect? Let alone ones “in the second half of this century?”
The loaded (and IMO inapplicable) word “diatribe” aside, 1) nuclear winter/autumn studies arguably *are* climate studies themselves (they are at least examples of “extended weather”), 2) they are about modeling the effects of atmospheric aerosols, which is a critical piece of the more general problem of climate modeling, and 3) he wasn’t talking to you, he and Russell were carrying on a separate discussion, to which you’ve added nothing.
Sigh, again.
Apparently I *do* need to point out that PDSI data from 2012-2019 have nothing to say about whether a megadrought will, or will not, occur by 2100.
Evidently Barton was right:
“In short, you don’t seem to understand what you’re criticizing.”
@65
Some confirmed model-based predictions:
1) Post-1950s tropospheric warming + stratospheric cooling + mesospheric cooling + thermospheric cooling, with a rising tropopause.
2) Mitigation of lower stratospheric cooling upon the Montreal Protocol limiting the release of ozone-depletion CFCs, while cooling continues higher in the stratosphere where the impact of increased CO2 is larger.
3) Post-1970s increase in radiation absorption at a wavenumber of ~666 cycles per cm.
4) More warming of air above land than air above ocean.
5) Polar amplification, where the Arctic warms more than much of the rest of the world (including warming more than Antarctica).
6) Arctic ice loss (both land ice and sea ice).
7) Antarctic ice loss (land ice, and total ice levels).
8) Tropical hot spot, where the tropical troposphere warms more than the tropical ocean surface.
9) Ocean acidification, due to ocean uptake of anthropogenic CO2.
10) Ocean de-oxygenation with warming.
11) Decreased atmospheric ratios of C14 and C13 isotopes of CO2.
12) Decreased ratio of O2/N2 from fossil fuel combustion.
13) Specific changes in precipitation patterns, with intensification of the hydrological cycle. [ex: “Observed heavy precipitation increase confirms theory and early models”]
14) Sea level rise and its acceleration with warming.
15) Increased hurricane intensity with warming.
16) Increased water vapor levels in response to warming; also, water vapor acting as a positive feedback on warming.
17) Clouds acting as a net positive feedback on warming.
18) Positive ice-albedo feedback.
19) Near-continuous increase in ocean heat content, with the ocean warming from above downwards, with most of the warming in the first 200 meters of depth.
20) Shorter-term climate sensitivity, as represented by the ratio of global surface warming vs. increases in radiative forcing.
And don’t commit the nirvana fallacy when discussing the accuracy of climate model predictions. Also, your claim on the “tropospheric hot spot” is just a tired contrarian talking point. No, it’s not a matter of models over-estimating tropospheric warming due to something like over-estimating climate sensitivity (or under-estimating climate sensitivity, as per the negative lapse rate feedback). It’s instead primarily due to errors in inputted forcings; hence models correctly representing the ratio of bulk tropospheric warming vs. surface warming, and models accurately representing bulk tropospheric warming when forced with observed surface warming. If you’re not aware of the published literature on this, then I can cite it for you. But seriously, don’t dodge the decades-long history of climate models making accurate predictions.
I’ll conclude with Dr. Ray Pierrehumbert being great again, back in 2012:
“Tyndall Lecture: GC43I. Successful Predictions – 2012 AGU Fall Meeting”
https://www.youtube.com/watch?v=RICBu_P8JWI
Well Zebra, It is difficult to predict in advance how much progress will be made and how fast it will be. We need this to find effective forcings for energy balance methods. We also really need it to prepare adaptation measures. This latter is huge and is a matter of trillions of dollars.
Naiver-Stokes improvements from 1970 – 2000 have saved billions of dollars and have produced skillful predictions over a broad range of engineering flows. Perhaps half of engineering flows are still problematic however. So going from 0% usefulness to 50% is perhaps a rough estimate for climate models. Reducing error by 50% is significant I think.
In reality, I don’t care personally. There may be other better uses of this money including fundamental theoretical research or development of simpler models or better data from the real world. If they go with Stevens and Palmer, they really really need to focus on the simplest possible setups first, meaning that climate models won’t be impacted right away.
J Doug Swallow: My, aren’t those computer models wonderful tools to analyze the climate?
“In short, you don’t seem to understand what you’re criticizing. Given that, the rest of your posts are irrelevant.” In the words of Barton Paul Levenson.
AB: Yeah. I’ve had beefs with BPL in the distant past (mostly my fault) but the dude provides value. He proved that by noting that you have no clue about what a “1000 year event” means EVEN AFTER YOU’VE BEEN TOLD!!!
Grasping desperately onto errors (a 1000 year drought means little rain for 1000 years?!?) after you’ve been schooled about the meaning of the phrase (a drought like this is expected once every 1000 years) shows that you really have no business commenting here…
…until you comment with humility and the intent to learn.
#71 Kevin McKinney says: “Nice reference from 2012. But much less “damning” than you think; difficulties with improving regional forecasting are well-known and much lamented. It’s a hard problem.” I do not really understand what your point is when you say; “Nice reference from 2012. But much less “damning” than you think….” If you want more information about droughts you can go to this link and see what the occurrence of droughts were from December 1900 to November 2019. Make sure that, in the remote case that you do open the link, observe how much of the nation was suffering from extremely dry conditions in the 1930’s. This is off of the topic of models; but, could the current models have predicted what occurred in the Dakotas in 1936.
I would certainly hope that you are able to notice the year that these records were set.
South Dakota Maximum Temperature 120°F July 5, 1936 GANN VALLEY
South Dakota Minimum Temperature -58°F February 17, 1936 MC INTOSH
In Steele, North Dakota on July 6, 1936 the record HIGH Temperature for the state was 121⁰F.
In Parshall, N. Dakota on Feb. 15, 1936 the record LOW Temperature for the state was -60⁰ F.
http://www.ncdc.noaa.gov/extremes/scec/records
It appears that G.A. Schmidt does not want to have the views of a very respected atmospheric scientist, Dr Roy Spencer, that seem to be 180⁰ different from the views that he upholds, to be seen by others on his blog. Science is all about seeking the truth and that cannot happen if the truth is covered up for political purposes.
#63 Barton Paul Levenson says: “DY 54, Perhaps climate modelers defend the models because they have been right so many times” I must inform Barton Paul Levenson that his high regard for the performance of climate models is not universally agreed upon by folks who have a high degree of knowledge about the Earth’s temperatures from actual observations, such as Dr Roy Spencer. “Spencer received a B.S. in atmospheric sciences from the University of Michigan in 1978 and his M.S. and Ph.D. in meteorology from the University of Wisconsin–Madison in 1980 and 1982. […]As well as his position at UHA, Spencer is currently the U.S. Science Team leader for the Advanced Microwave Scanning Radiometer (AMSR-E) on NASA’s Aqua satellite, a position he has held since 1994. In 2001, he designed an algorithm to detect tropical cyclones and estimate their maximum sustained wind speed using the Advanced Microwave Sounding Unit (AMSU).”
This is what Dr Roy Spencer had to say about 95% of Climate Models.
“95% of Climate Models Agree: The Observations Must be Wrong
These are all interesting exercises, but they miss the most important point: the climate models that governments base policy decisions on have failed miserably.
I’ve updated our comparison of 90 climate models versus observations for global average surface temperatures through 2013, and we still see that >95% of the models have over-forecast the warming trend since 1979, whether we use their own surface temperature dataset (HadCRUT4), or our satellite dataset of lower tropospheric temperatures (UAH)”
https://www.drroyspencer.com/2014/02/95-of-climate-models-agree-the-observations-must-be-wrong/
This is directed at the sighing and I imagine confused about just what the point was in his dissertation about just what a 1,000 year flood or drought is/was, Kevin McKinney.
“Monthly maps of drought conditions in the contiguous U.S. as measured by the Palmer Drought Severity Index, Palmer Hydrological Drought Index, Palmer Modified Drought Index, and Palmer Z-Index (Palmer, 1965) are provided for January 1900—November 2019. Animations of any set of monthly maps for any period desired can be viewed by selecting the beginning and ending dates of interest.
Palmer:
Start Year: Start Month:
End Year: End Month:
Palmer Drought Severity Index
December 1900 – November 2019”
https://www.ncdc.noaa.gov/temp-and-precip/drought/historical-palmers/psi/190012-201911
What is your view on droughts, Kevin McKinney?
It really was very cold in 1940’s….The Dust Bowl drought 1932-1939 was one of the worst environmental disasters of the Twentieth Century anywhere in the world. Three million people left their farms on the Great Plains during the drought and half a million migrated to other states, almost all to the West.http://www.ldeo.columbia.edu/res/div/ocp/drought/dust_storms.shtml
“In June, 1934 the entire country had triple digit heat. We didn’t come anywhere close to that this summer.”
http://docs.lib.noaa.gov/rescue/mwr/062/mwr-062-06-0212.pdf
”Over the 11-year span from 1930-1940, a large part of the region saw 15% to 25% less precipitation than normal. This is very significant to see such a large deficit over such a long period of time. This translates to 50 to 60 inches of much needed moisture which never arrived that decade. For an area which only averages less than 20 inches of precipitation a year, deficits like this can make the region resemble a desert. Deficits like this are the equivalent of missing three entire years of expected precipitation in one decade. Figure 2 is a map of the precipitation departures from normal in terms of a percentage of normal (total precipitation divided by normal precipitation) for the Dust Bowl region for 1930 to 1940.”
http://www.srh.noaa.gov/ama/?n=dust_bowl_verses_today
D 65: Your post is just noise and has no scientific value.
BPL: It illustrates that the frequent denier meme of “the models got everything wrong” is bullshit.
JDS 69: Barton Paul Levenson #64 is the one that the onus to explain how the 1,000 year drought could have ended in such a short time falls upon Levenson, since he asked the question.
BPL: For the second time, a 1,000 year drought does not mean, never has meant, and never will mean, “a drought that lasts 1,000 years.” It means a drought that only comes along once every 1,000 years. Get the definition right, or you will continue to embarrass yourself.
R 67: Before Barton lets his political imagination carry him any farther afield, he should read what I said in the Spring 1984 issue of Foreign Affairs in reply to what Carl Sagan wrote in the Winter 1983-4 issue.
BPL: I couldn’t care less what either you or Carl Sagan had to say in Foreign Affairs. I care what TTAPS, and Schneider and Thompson, and Robock et al., etc. had to say in peer-reviewed science journals. Do you understand the distinction I’m drawing here? For you, this thing is inextricably bound up in politics. For me, it’s a science issue.
JDS #69 Could you explain how a major drought by 2100 has been disproved in 2019? This makes no sense to me, is a time machine involved?
#73: A comment with less scientific value is hard to imagine. Most of your points are just yes/no answers, i.e., qualitative. What we really need to know and what models are supposed to tell us are the magnitude of the changes, i.e., quantitative information.
You would do well to stop the selection bias and try to look at the bigger picture. Do you deny the information in the Palmer and Stevens paper I cited earlier? They are vastly more honest than you are.
Barton, What a silly straw man argument. No one who’s serious says “the models get everything wrong.” They usually get right those outputs used in tuning like TOA radiation balance. Things like regional climate they get wrong. Patterns of SST warming are another huge issue. That they get this wrong seems to have emerged as the reason they disagree with observational estimates of TCR and ECS.
JDS @ 77: “a very respected atmospheric scientist, Dr Roy Spencer
Bwaaa haaa ha ha……
That was priceless. Simply priceless. It will save me from ever wasting time reading anything JDS writes in future.
Al Bundy #75 says that I have no business commenting here. It appears that Al Bundy was unable to understand where the information about the “1000 year event” came from; such as;
“They’ve Seen Lots of Droughts, But This One’s Different” JULY 6, 2015
“Like Baker, Vender is more worried today than she was during the last big drought in the late ‘80s and early ‘90s. “We didn’t have global warming then,” she said. “Now it could be permanent.”
https://www.nationalgeographic.com/news/2015/07/150706-drought-california-water-conservation-environment/
“5 Things You Should Know About California’s Water Crisis” APRIL 6, 2015
Drought, and the resulting shortage of melting snow, is driving the historic water shortages across much of the American West.” National Geographic
http://news.nationalgeographic.com/2015/04/150406-california-drought-snowpack-map-water-science/
“These 4 Things Need to Happen to End California’s Drought” JANUARY 7, 2016
The Golden State is being drenched this week by heavy rains and snow driven by a powerful El Niño. But quenching a years-long thirst takes more than a few storms.”
http://news.nationalgeographic.com/2016/01/160107-california-drought-snowpack-el-nino-rains/
U.S. Droughts Will Be the Worst in 1,000 Years
The Southwest and central Great Plains will dry out even more than previously thought
https://www.scientificamerican.com/article/u-s-droughts-will-be-the-worst-in-1-000-years1/
Worst Drought in 1,000 Years Predicted for American West
Global warming to cause historic “megadrought” by century’s end. FEBRUARY 12, 2015
LARGE PARTS OF the U.S. are in for a drought of epic proportions in the second half of this century, scientists warn in a new study that provides the highest degree of certainty yet on the impact of global warming on water supplies in the region. https://www.nationalgeographic.com/news/2015/2/150212-megadrought-southwest-water-climate-environment/
Study: Current Environmental Conditions Mirror Factors Leading To 1,000-Year Drought September 15, 2016
LOS ANGELES (CBSLA.com) — Greenhouse gases trapped in the upper atmosphere mirror the natural climatic forces of some ancient droughts that lasted for 1,000 years, UCLA researchers say in a Scientific Reports study released Thursday.
Global warming created by these gases could be making a more arid climate “the new normal,” like what California has seen in its current five-year drought, according to UCLA geography professor Glen MacDonald.
https://losangeles.cbslocal.com/2016/09/15/1000-year-drought/
Scientists: Worst Drought in 1,000 Years Threatens U.S. Food Supply December 13, 2014
America’s food supply is under threat because California is experiencing its worst drought in more than 1,000 years, scientists say.
Scientists who study tree rings say California is facing its worst drought in 1,200 years, The San Jose Mercury News reported. They can determine when droughts occurred because trees grow faster in wet years and slower in dry spells.
https://www.offthegridnews.com/current-events/scientists-worst-drought-in-1000-years-threatens-u-s-food-supply/
I wonder if Al Bundy #75 is able to notice how often the term ,1,000 years, is used. I hope that Al Bundy #75 is able to get beyond the semantics involved in the use of “1,000 years” and come to understand how this impending catastrophic drought that was being predicted by, who knows what models, never materialized and is just another failed prediction that the anthropogenic climate change crowd used to try to fear monger the population with.
People like Al Bundy #75 did not publicize these facts that I present below;
NASA Study Finds 1934 Had Worst Drought of Last Thousand Years
October 14, 2014
A new study using a reconstruction of North American drought history over the last 1,000 years found that the drought of 1934 was the driest and most widespread of the last millennium.
https://www.nasa.gov/content/goddard/1934-had-worst-drought-of-last-thousand-years/
OROVILLE Note the date.
February 11, 2017 05:24 AM
Water began pouring over the emergency spillway at Oroville Dam early Saturday for the first time in its 48-year history. State officials continued to say they don’t expect the situation to result in flooding in Oroville or other communities downstream.
http://www.sacbee.com/news/local/article132154774.html
Historic Flooding Continues in Midwest (PHOTOS) March 19 2019
“Evacuation orders were in effect in Craig, Missouri, after a levee breach on Wednesday. Residents were given the option to remain in their homes if they registered with the city in case they needed to be rescued as conditions deteriorate.
At least three people have died as a result of the devastating floods that struck parts of the Midwest. The National Weather Service called the event a “major and historical river flooding” along parts of the Missouri and Mississippi River basins.”
https://weather.com/safety/floods/news/2019-03-15-midwest-flooding-photos
Jim Eager #85, who I’m sure has better credentials and a better record while developing the Advanced Microwave Scanning Radiometer (AMSR-E) on NASA’s Aqua satellite than what either Drs Christy or Spencer have been credited with. This is your chance, Jim Eager, to show me your work. Can you somehow show evidence of your NASA’s Exceptional Scientific Achievement Medal? Dr. Spencer suggests that global warming is mostly due to natural internal variability, and that the climate system is quite insensitive to humanity’s greenhouse gas emissions. I assume that due to your superior education and knowledge regarding the Earth’s climate, that you cannot agree with that assessment.
I am a realistic skeptic and therefore I know that what you alarmist ignore is these truths. The sun makes up 99.86% of the mass of the solar system. Do you agree with that summation? Carbon dioxide is around .03%-.04% of the earth’s atmosphere. Do you agree with that summation? Of the two, the sun or CO₂, which do you believe has the most influence on the earth’s climate? The people associated with the essential for the survival of modern civilization, the fossil fuel industries, also know the correct answer and will continue to supply the resources that are in demand while ignorant goons who share your views supply nothing of value to anyone, not even yourselves.
This site shows how the models faired when compared to observed temperatures, just like the link to Dr Spencer’s site showed.
“Christy notes that in science, the test of whether we understand a natural system is whether we are able to predict its behavior. Thus, “If we are unable to make accurate predictions, then at least some of the factors in the system are not well defined or perhaps even missing.” Hind-casting is no substitute for prediction, because complex hypotheses such as climate models can be adjusted to produce results similar to what has already occurred. Yet Figure 1 shows that the models do not “even reproduce the past climate.” ”
http://www.globalwarming.org/2016/02/05/satellites-and-global-warming-dr-christy-sets-the-record-straight/
JDS 77 lauds Roy Spencer to the skies, apparently unaware of his famous failure with the satellite observations. I wonder if he also agrees with Spencer’s creationism?
JDS,
Looks like you’ve collected some news articles. OK. BPL’s point is that weather extremes happen periodically and said periodicity is changing. Your handful of clippings had at least one that spoke of extreme flooding. Note that GIVEN that a warmer world WILL have more rain, if drought increases then wouldn’t flooding be expected to increase even more?
These unusual weather events are going from rare as hens’ teeth to relatively commonplace. Nothing like having one or two 1000-year floods per decade. Of course, that means the definition of a 1000-year flood gets to change. With one per decade in the new normal the same event is a 10-year flood. (Of course, this is just a transient definition. By the time you read this it will be a 9.99-year flood. Gotta keep up with the GHGs!)
By the way, the Dust Bowl was both an unusual natural weather event and a man-made weather event. By ripping up the prairie and using inferior farming techniques farmers increased the resulting aridity and temperature. Kind of the Rural Heat Ocean effect.
In contrast, nowadays all those center-pivots mining the Ogallala give us the Rural Evaporative Cooling effect. I wonder how big an effect irrigation has on global temperature? Shut them down, farm Old School, and I’m thinking that the Dust Bowl would return on a regular basis.
I would like to know what global surface temperature predictions have been made by Very Respected Atmospheric Scientist Dr Roy Spencer that are superior to those made by mainstream scientists using models. To interest me, they need to be global, and cover at the very least a decade, more likely 2 or 3.
How did the models do on predicting loss of Greenland ice?
here’s the context for that question.
https://phys.org/news/2019-12-greenland-ice-losses-faster.html
headline: Greenland ice losses rising faster than expected
OK moderators, BPL @88 has gone too far. BPL believes in magical creatures but ridicules someone who believes in a slightly different interpretation of what this particular magical creature has done.
#76 & 78, JDS–
Hmm. You’re an unmannerly fellow, aren’t you?
You said:
Presuming what someone else will or won’t do is foolish and rude, especially when you are the newbie. And, as it happens, I’m very well aware of what happened in the Dust Bowl years, thank you very much.
You also said:
Dude, you’re the confused one. I told you, quoting from the USGS:
Barton told you:
AB told you:
Now William Jackson ‘told’ you (in the form of a question):
You ask “my view” on droughts. I’ll be glad to tell you if you start reading for comprehension and engaging in good faith. Otherwise, you’re just trolling for response. I decline to waste my time much further if that’s the case. And so far, you’re displaying exactly zero capacity to learn.
JDS. When confronted with conflicting information, do you check sources, logic or do you choose the answer that you like? This question is important because here is some contrary information for you.
Firstly, if you think Spencer and Christie are so trustworthy, have a look at this. A few problems there? Dont take the sites word for it, check the references.
And Christie’s testimony is misleading to put it politely. Try this post here for a rather more careful look. Again, check the references.
I assume you are not challenging conservation of energy, so which “natural” source is producing the warming and where is your evidence for it?
“The sun makes up 99.86% of the mass of the solar system. Do you agree with that summation? Carbon dioxide is around .03%-.04% of the earth’s atmosphere. Do you agree with that summation? Of the two, the sun or CO₂, which do you believe has the most influence on the earth’s climate?”
This is the most bizarre bit of sophistry I have seen in while. Mass affects climate how??
Try this one: The earth’s surface is heated from two sources: 161Wm2 comes directly from the sun (short wave), 342Wm2 comes as longwave from atmosphere thanks to greenhouse gases. Measured directly by instruments. Numerous references for this, but try this one.. And for direct measurement of effect of CO2, try this paper here.
You can take two approaches to this. You could try for motivated reasoning which is what humans usually do. Try frantically to find information to support your point of view. You have obviously found the sewers in disinformation to help with this. Or you could try critical thinking which is a whole lot harder. This starts with evaluating in your mind what data would cause you to change your mind. This is examples of what would change scientists minds.
JDS:
“Of the two, the sun or CO₂, which do you believe has the most influence on the earth’s climate? ”
As climate scientists point out, the sun. That is all that stands between us and a planet fairly close to absolute zero, of course. This says nothing about CO2s ability to modulate climate by slowing the release of long-wave infrared radiation. A drop in global temps of 5C or so is enough to trigger an ice age, and ice ages aren’t caused primarily by fluctuations in solar energy output.
Regarding the fact that CO2 is a tiny percentage of the atmosphere, go drop 300 micrograms of LSD – an extremely small percentage of your body weight – and report back regarding the inability of “trace amounts” of something not able to cause very noticeable effects …
@JDS #87
“I assume that due to your superior education and knowledge regarding the Earth’s climate, that you cannot agree with that assessment.”
I assume you are aware that the vast majority of climate scientists do not agree with that assessment? That includes a lot of scientists with far superior credentials to Roy Spencer or John Christy, so if this is your way of assessing scientific credibility, you must now defer to these others, and ignore Spencer & Christy.
“Yet Figure 1 shows that the models do not “even reproduce the past climate.”
Ahem, this Figure 1 was discussed already on this site by someone with far superior credentials to John Christy – one Gavin Schmidt:
https://www.realclimate.org/index.php/archives/2016/05/comparing-models-to-the-satellite-datasets/
Christy’s graph was a good lesson of how NOT to compare models to satellite datasets.
JDS 87. You think that big things must have a greater effect than small things. How about distance? After all almost every living organism of the planet is within 3.34 × 10^−10 metres of a molecule of CO2 – while the sun is about 1.5 x 10^10 metres away. Do you agree that small things close can be more influential than big things a long way away? Of course if it is just about size, I presume you would accept that the 99.5% of scientists who accept that ACC is a crisis outweigh the .5% who don’t?
JDS 87: Dr. Spencer suggests that global warming is mostly due to natural internal variability
BPL: He’s wrong, as anyone can show with a simple analysis of variance. CO2 accounts for 82% of the warming for the past 168 years.
JDS: and that the climate system is quite insensitive to humanity’s greenhouse gas emissions.
BPL: See above.
JDS: The sun makes up 99.86% of the mass of the solar system. Do you agree with that summation? Carbon dioxide is around .03%-.04% of the earth’s atmosphere.
BPL: And 0.0001% of fluorine in the air can kill you. You clearly have no idea what the relevant physics are and think that citing relative masses is somehow impressive. It would be impressive only to someone who, like you, never studied the relevant physics and (apparently) doesn’t want to learn.
signin