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Earth Science Technology

Even 50-Year-Old Climate Models Correctly Predicted Global Warming (sciencemag.org) 407

sciencehabit writes: Climate change doubters have a favorite target: climate models. They claim that computer simulations conducted decades ago didn't accurately predict current warming, so the public should be wary of the predictive power of newer models. Now, the most sweeping evaluation of these older models -- some half a century old -- shows most of them were indeed accurate. "How much warming we are having today is pretty much right on where models have predicted," says the study's lead author, Zeke Hausfather, a graduate student at the University of California, Berkeley.

The researchers compared annual average surface temperatures across the globe to the surface temperatures predicted in 17 forecasts. Those predictions were drawn from 14 separate computer models released between 1970 and 2001. In some cases, the studies and their computer codes were so old that the team had to extract data published in papers, using special software to gauge the exact numbers represented by points on a printed graph. Most of the models accurately predicted recent global surface temperatures, which have risen approximately 0.9C since 1970. For 10 forecasts, there was no statistically significant difference between their output and historic observations, the team reports today in Geophysical Research Letters. Seven older models missed the mark by as much as 0.1C per decade. But the accuracy of five of those forecasts improved enough to match observations when the scientists adjusted a key input to the models: how much climate-changing pollution humans have emitted over the years.

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Even 50-Year-Old Climate Models Correctly Predicted Global Warming

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  • Geez (Score:5, Funny)

    by burtosis ( 1124179 ) on Thursday December 05, 2019 @06:15AM (#59486972)
    Just because someone turns 50 doesn’t mean they can’t do good work.
    • by XXongo ( 3986865 )

      Just because someone turns 50 doesn’t mean they can’t do good work.

      The fact that the models have held up pretty well isn't even new; Forbes looked back at the predictions of the 1967 Manabe and Wetherald model when it turned 50, and found it held up remarkably well: https://www.forbes.com/sites/s... [forbes.com]

      What's interesting here is that they look at a fourteen different climate models that have been published over the years, and they're all pretty good.

      This is not particularly unexpected; Manabe and Wetherald got the basic physics down on a global scale, and the later models ju

      • Re:Geez (Score:4, Insightful)

        by Spazmania ( 174582 ) on Thursday December 05, 2019 @03:35PM (#59488704) Homepage

        the accuracy of five of those forecasts improved enough to match observations when the scientists adjusted a key input to the models: how much climate-changing pollution humans have emitted over the years.

        This sentence sets of alarm bells for me. 17 models, 2 weren't predictive and 10 models predicted climate change accurately WITHOUT adjusting for the actual human inputs?

        That's a problem. The models can't just be positively predictive, they must be negatively predictive as well. If you change the inputs from the actual observations, the model should make the wrong prediction.

        • Perhaps.

          More likely, most of the predictions already spanned a range of emissions that included what we actually ended up emitting.

          Pretty much every forecast I've ever seen has had (at least) a "best case" and "worst case" predictions depending on how our emissions changed over time. Some researchers though intentionally underestimated the worst-case emissions to avoid generating predictions that would get them labeled as alarmists.

          However, since our actual emissions have actually been pretty much in-line

          • Falsifiability is the capacity for some proposition, statement, theory or hypothesis to be proven wrong. That capacity is an essential component of the scientific method and hypothesis testing.

            If they "spanned a range of emissions," how were they falsifiable?

  • Denial (Score:5, Insightful)

    by Joce640k ( 829181 ) on Thursday December 05, 2019 @06:17AM (#59486978) Homepage

    Climate change doubters have a favorite target: climate models.

    Not quite.

    Climate change doubt funders have a a favorite target: climate models.

    Most of the "doubters" are just parroting what the funders are posting online out of fear that they might have to drive a tiny car or become vegetarian or something (whatever evils the FUD spreaders are telling us will happen to us if we lift a finger to do something...)

    More info here: https://www.google.com/search?... [google.com]

    • Re: (Score:3, Funny)

      Let's put it this way:

      If an overwhelming amount of politicians are telling me A, I will inmediately turn to B, C or D.

      • Re:Denial (Score:5, Insightful)

        by Joce640k ( 829181 ) on Thursday December 05, 2019 @07:16AM (#59487042) Homepage

        Let's put it this way:

        If an overwhelming amount of politicians are telling me A, I will inmediately turn to B, C or D.

        Right... so if you own B, C and D then you go on social media pretending to be a politician telling people A.

        Geddit?

        What you need to do is stop listening to politicians and think:

        If 999 doctors tell you you have cancer and one doctor doesn't then what should you do, fixate on the one? Go around repeating that the 999 are liars?

        • Re: (Score:2, Insightful)

          by blindseer ( 891256 )

          If 999 doctors tell you you have cancer and one doctor doesn't then what should you do, fixate on the one? Go around repeating that the 999 are liars?

          You ask them what should be done to treat the cancer.

          I've been asking what should be done about global warming and it seems the people able to show their work all come to roughly the same conclusion, but they are all variations on a theme. We find energy sources to replace fossil fuels. Those energy sources will have to be affordable, safe, plentiful, low in CO2 emissions, high in energy return on investment, and be a technology we know how to reproduce at a meaningful scale. Those energy sources are ons

          • by Layzej ( 1976930 )

            I've been asking what should be done about global warming

            Put a price on carbon and let the market solve the problem. Make it revenue neutral so that income and sales tax can be reduced. Two birds with one stone.

            • by djinn6 ( 1868030 )

              How do you put the tax on third world countries? How do you get Russia, China, India, and Brazil to all agree on this? What do you do if they don't pay?

              Economic sanctions only work up until those countries combined has a larger market than US and EU, after which sanctions will hurt you a lot more than it hurts them, and your own people are going to vote against both the tax and the sanctions.

            • by rho ( 6063 )

              Put a price on carbon and let the market solve the problem.

              "When buying and selling is controlled by legislation, the first thing bought and sold is legislators."

              • Re:Denial (Score:4, Insightful)

                by Layzej ( 1976930 ) on Thursday December 05, 2019 @02:17PM (#59488296)
                That is largely why the USA doesn't already have a revenue neutral carbon tax. Economists agree that this is the most efficient approach. It also would allow us to reduce tax on things we ought to be encouraging like sales and income.
          • Solving it on paper is not sufficient. The problem comprises social and societal issues, as well.

          • by sjames ( 1099 )

            Claiming we have "solved" the problem of global warming is like connecting a hamster wheel to a motor out of your kid's toy car and claiming you fixed the blackout.

            We have to actually deploy the solutions at a scale that actually replaces the carbon emitting old tech before we get to say we've solved anything.

            Then we have to figure out how to deal with the remaining problems that are now inevitable thanks to the foot draggers.

        • Re:Denial (Score:4, Interesting)

          by phoenix321 ( 734987 ) on Thursday December 05, 2019 @08:49AM (#59487190)

          Science and medicine is not a democracy. It does not matter how many people agree on something to be true, it matters if it is true. And that can be proven beyond a doubt by simple experiments or it will forever be a contested subject that will never be settled unless that simple experiment or overwhelming evidence is produced.

          It is aggravating when people take the biggest, most complicated problem of geology and physics, "climate change", a problem on a planetary scale with billions of inputs and even more variables and observations, and compare it to topics that are absolutely trivial in comparison, like "is the Earth round" or in your case "does a cancerous mass exist in a human body". That doesn't mean cancer is easy to cure, sadly, that is still far away for most of the people who would fall ill to it, but in comparison to "climate change", it is easy to locate and detect with a high or absolute degree of certainty.

          Nothing regarding "climate change" is easy to detect, formulate and it's even harder to solve, even if we could agree on the tenets of its existence.

          Science is never settled and if you believe a problem on a planetary scale with billions of data points is easy to detect and easier to solve with one single input ("just emit less carbon, duh"), you have absolutely zero idea what constitutes science and what size and complexity the problem and its measurement actually have. That means you're not the tiniest bit qualified to decide about the solution, which like all problems is orders of magnitude harder than the detection, especially not if the proposed "solution" includes the initiation of force by the state towards untold millions of human beings.

          We have seen what happens when the government assumes power to initiate force upon individuals in the name of the greater good.

          • Re:Denial (Score:5, Insightful)

            by religionofpeas ( 4511805 ) on Thursday December 05, 2019 @09:03AM (#59487220)

            Science and medicine is not a democracy. It does not matter how many people agree on something to be true, it matters if it is true

            And in the case of climate change, how would you determine what is true, assuming for the moment that you are not a scientist yourself ?

            • Re: (Score:2, Interesting)

              by Anonymous Coward

              I live squarely in the land of "deniers", but funny thing. The overwhelming majority of them have not denied climate change for the better part of a decade. They deny the suggested causes (or the percentage of influence of those causes).

              But for whatever reason, the argument against them is always framed as 999 out of 1000 scientist agree in climate change, rather than 750 scientists out of 1000 (or whatever the actual number is) agree that man made pollutants are the primary cause of climate change.

              • The overwhelming majority of them have not denied climate change for the better part of a decade. They deny the suggested causes (or the percentage of influence of those causes).

                My question was broader than just the fact whether climate change is occurring. Suppose you want to know the answer to every reasonable question about climate change, including how much, where, the contribution of various factors, and the possible policies that we can implement. How would you find out these answers ?

                • by XXongo ( 3986865 ) on Thursday December 05, 2019 @10:39AM (#59487544) Homepage

                  The overwhelming majority of them have not denied climate change for the better part of a decade. They deny the suggested causes (or the percentage of influence of those causes).

                  Sorry, but I know a lot of them-- including posters on slashdot-- who do exactly that: they deny climate change, they say all the data showing it's real is faked, and all the scientists are either in a conspiracy to hide this, or are sheep that just parrot what one or two famous names say.

                  (I think that they don't have the slightest notion how many climate scientists, or how many different institutions are studying climate. Thousands of climate scientists would have to be in on the conspiracy, and tens of thousands of scientists would have to be working in fields close enough that they would notice. This is simply not credible.) But, for the most part, they don't care if what they are saying is credible. The purpose is to spread FUD (fear, uncertainty and doubt) on the science. A dumpster of garbage is as useful as a dumpster of credible arguments in the "argue by the dumpster load" approach.

                  But, basically, what you're saying is that some of the people who are defending fossil fuel usage have simply moved on to the next phase of defense, "ok, it's real, but we don't know humans cause it". And the line of defense beyond that: "ok, it's real, we're causing it, but it's not actually harmful." And they have more lines of defense behind those; you'll see these pretty soon.

                  My question was broader than just the fact whether climate change is occurring. Suppose you want to know the answer to every reasonable question about climate change, including how much, where, the contribution of various factors, and the possible policies that we can implement. How would you find out these answers ?

          • Re:Denial (Score:4, Interesting)

            by DavenH ( 1065780 ) on Thursday December 05, 2019 @09:55AM (#59487374)

            You're right that science is never "settled", as in it's always open to improvement no matter the current accuracy of measurements and predictions, but that does NOT imply that the current measurements are below a confidence threshold needed to be useful in evaluating risk. Frankly, that mark was passed in the 1970s. So in those terms, the science is settled on what is happening and why, and pretty settled on the degree (no pun intended) to which it will happen. What is not settled is the precise distribution of weather events, (how many conventionally 100-year storms will this particular region get in 2070?) which will keep getting more accurate as models run on finer and finer grids with more computation.

            And you draw attention to billions of data points, as if this crazy amount of samples is increasing the uncertainty. This is certainly a red herring. What you should be worried about is if global predictions are being made with mere hundreds of samples. You WANT the grid size of these simulations to be as small as possible. You WANT the terrain, albedo, temperature, wind, humidity measurements as fine as possible. In short, trillions of data should make you more confident in any projection.

            I believe what you may be trying to convey is that if a theory rests on a super complex hypothesis model, it's likely brittle and prone to misprediction. That is not the case with climate science. The formulae for radiative balance, humidity, etc are quite concise and as rigorously proven as any law of physics we have. Global Climate Models are not making any assumptions other than the first-principles laws of physics, with one exception: within grid simulation cells there are heuristics as to what happens. This is the area of research most debated, and accounts for differences in predictions of different models. Increasing the granularity of the grid cells requires enormous computation, but will continue to yield more dependable first-principles predictions as time passes.

            Science is never settled and if you believe a problem on a planetary scale with billions of data points is easy to detect and easier to solve with one single input ("just emit less carbon, duh"), you have absolutely zero idea what constitutes science and what size and complexity the problem and its measurement actually have.

            Now this is perfect nonsense. Note that you don't specify at all what is wrong with the prognosis "emit less carbon" because you cannot. Carbon dioxide (and to a lesser degree methane, sulfates) regulate the radiative equalibrium of the atmosphere. Water vapour too, but it's a closed cycle of condensation/evaporation and CO2 is the only long-lived substance being added en-mass to the atmosphere that has such radiative properties.

            We have seen what happens when the government assumes power to initiate force upon individuals in the name of the greater good.

            You mean like rule of law, mandatory education, zoning laws to keep us from pollution, air quality controls, you name it? Yeah I guess we have seen.

          • Science and medicine is not a democracy. It does not matter how many people agree on something to be true, it matters if it is true.

            That's certainly true for science but somewhat less true for medicine due to the placebo effect.

          • Nothing regarding "climate change" is easy to detect, formulate and it's even harder to solve, even if we could agree on the tenets of its existence.

            What a ridiculous strawman! Sure, you can move the goalposts of "easy", but the basic science and observations are easily articulated.

            For the cause, you do s simple experiment. Take sealable tubes, add air to both, then add a bit more CO2 to one of them. Put them in the sun for a while, then measure temperature. The one with added CO2 will be warmer. Cross-check these figures with the observable CO2 concentration in the atmosphere, compare with fossil fuel consumption, and voila.

            As for *detectin

          • Re: (Score:3, Insightful)

            by minogully ( 1855264 )
            You're failing to mention that the driver behind this complicated system is simple and has been proven in the lab quite easily - that CO2 absorbs UV this heats up the gas.
            With that basic nugget of truth, it's easy to extrapolate that the more CO2 there is in the atmosphere, the more the atmosphere will heat up.
            Next we have proof that there is more in the atmosphere from ice core samples and the sampling of the CO2 in our atmosphere.
            Lastly we can show without a doubt how much CO2 we as humans emit and sho
      • If an overwhelming amount of politicians are telling me A, I will inmediately turn to B, C or D.

        So you don't like to think for yourself ?

        • Re:Denial (Score:5, Insightful)

          by ElectronicSpider ( 6381110 ) on Thursday December 05, 2019 @07:30AM (#59487066)
          Ah yes, agreeing with politicians is how people think for themselves.

          If there's a big congregation of professional liars agreeing on something there's something very fishy going on there.

          • Ah yes, agreeing with politicians is how people think for themselves.

            Hint: thinking for yourself does not involve any politicians at all.

            • Politicianâ(TM)s do not exist in a vacuum. Their opinions translate to policies that affect your life. Policies in turn can change some of the parameters one uses to come to an opinion.

    • Re: (Score:2, Insightful)

      by Freischutz ( 4776131 )

      Climate change doubters have a favorite target: climate models.

      Not quite.

      Climate change doubt funders have a a favorite target: climate models.

      Most of the "doubters" are just parroting what the funders are posting online out of fear that they might have to drive a tiny car or become vegetarian or something (whatever evils the FUD spreaders are telling us will happen to us if we lift a finger to do something...)

      More info here: https://www.google.com/search?... [google.com]

      You are clearly a polite person with lots of people skills and I respect that, I however have none of those skills so I'm gong to call climate change doubters what they are: useful idiots. Given the amount of data supporting man made climate change these people might as well be 'gravity doubters'.

  • good to see at least one thing that is going according to schedule.

  • We need more data!
  • They had 14 different models, with 17 variations of forecast outputs.

    Seven of them were completely incorrect, and only returned the correct number after they "adjusted" the models by a large amount (they were off by 0.1 C per decade, so they were off by 0.5 C out of 0.9 C observed).

    So they were actually at 50% accuracy (using one forecast per model) from their cherry-picked "good" models (which were obviously the "lowball" models that were off by 0.1 C per decade, not the ones missing by 0.3 C or more per d

    • by religionofpeas ( 4511805 ) on Thursday December 05, 2019 @09:36AM (#59487306)

      Seven of them were completely incorrect, and only returned the correct number after they "adjusted" the models by a large amount (they were off by 0.1 C per decade, so they were off by 0.5 C out of 0.9 C observed).

      They didn't adjust the models. They adjusted the inputs to the models based on up-to-date information.

  • by ILongForDarkness ( 1134931 ) on Thursday December 05, 2019 @09:52AM (#59487362)

    What the hell does that mean? The error bars on the actual measurements are so wide that the models fall within them? The models have error bars so wide that the climate has fallen within it or the two? Meh, anyways "statistically significant" is in the eye of the beholder. 95% correlation might be good enough for you but not for me.

    That said imo if even the old models give good (TM) results when supplied with what the real variables were its a good sign. We still have the problem of people running off and applying models of what the inputs will be in the future to use the model to predict what the outputs will be. Ie we prodict a 10%/yr increase in CO2 to 2050 followed by a 0.5% per year reduction ... tada the world will be 5C hotter by 2060 or whatever. But I guess you use that to compare different policies to try to steer regulation. Just seems like a very complicated mess: policies have unintended consequences, you can guess at near term tech innovation but really no idea about future tech (we are supposed to have been ruled by robots and flying in cars 20 yrs ago).

  • As long as (Score:2, Funny)

    by sproketboy ( 608031 )

    As long as climate change kills environmentalists I'm fine with it.

  • The way I see this is like like two mountain climbers where one claims if you jump without a parachute or something you'll probably die while the second climber claiming that's false because your finger might not be broken on impact. Point is, this climate change has been predicted for years and it's only been getting more and more accurate with time.

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