Climate Change

My Puzzlement Over Climate Change Damage Estimates in New National Climate Assessment

Implausible worst-case scenarios do not further the debate over reasonable policies for addressing climate change.

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Korn Vitthayanukarun/Dreamstime

"Mass deaths and mayhem: National Climate Assessment's most shocking warnings," blares the headline at CBS News. The story, which discusses the government's Fourth National Climate Assessment (NCA4), says that the document predicts "an estimated loss of up to 10 percent gross domestic product by 2100." This same estimate was cited by many other news outlets. For example, the first paragraph of The New York Times' article on the NCA4 says that "if significant steps are not taken to rein in global warming, the damage will knock as much as 10 percent off the size of the American economy by century's end."

Puzzled by this reporting, I did a rough calculation in my initial reporting on the NCA4. Today's $20 trillion GDP, growing at a 3 percent rate, would rise to $226 trillion by 2100. With climate change, it would instead rise to only $203 trillion. Americans living at the end of this century would be about 10 times richer on average than we are now, albeit in a much warmer world.

So where did those estimates come from? Basically from a worst-case scenario of temperature increase called in climate-speak Representative Concentration Pathway 8.5 (RCP 8.5). RCPs are four different greenhouse gas concentration trajectories used by climate modelers and adopted by the Intergovernmental Panel on Climate Change for its fifth Assessment Report in 2014. Each makes different assumptions about population growth, economics, technological progress, and fossil fuel burning. RCP 8.5 implausibly assumes a global population of 12 billion by 2100, plus technological stagnation, slow economic growth, and consumption of fossil fuels at about 3 times current levels, with the result that atmospheric carbon dioxide concentrations reaches 950 ppm, up from 405 ppm now. In RCP 8.5, average global temperature could increase by as much as 10 degrees Fahrenheit.

Why choose to focus on the RCP 8.5? "Given this assessment's emphasis on using a risk-based framework, authors were asked to consider low-probability, high-consequence climate futures," explain the authors. Fair enough. But it did result in implausible doom-laden headlines.

In any case, this is the scenario that produced the NCA4 estimate of that 10 percent loss. But wait, it gets weirder. The total projected damages in this worst-case scenario add up to just over $500 billion per year in 2100 (see below). If that's 10 percent of GDP in 2100, that suggests that U.S. GDP will be only $5 trillion dollars (75 percent lower than now). I must be missing something.

NCA4Damages
NCA4

"Climate Change Is Affordable," opines Holman Jenkins over at The Wall Street Journal after parsing these figures. And he's not wrong, assuming these estimates are ballpark accurate.

Finally, the 10 percent GDP loss figure is apparently derived from an analysis by the Berkeley researcher Solomon Hsiang and his team published in Science in 2017. "Combined uncertainty in aggregate impacts grows with warming, so the very likely (5th to 95th percentile) range of losses at 1.5°C of warming is ?0.1 to 1.7% GDP, at 4°C of warming is 1.5 to 5.6% GDP, and at 8°C warming is 6.4 to 15.7% GDP annually," calculate the researchers. Note that the worst-case assumes an absurdly farfetched increase in average temperature of 8 degrees Celsius (14.4 degrees Fahrenheit) by the end of this century. Yet it is from this outlandish scenario that the scaremongering figure of a 10 percent lower GDP in 2100 is extracted.

Whatever the intentions of the NCA4 authors, highlighting a preposterously implausible worst-case scenario does not further the debate over reasonable policy responses to climate change.

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72 responses to “My Puzzlement Over Climate Change Damage Estimates in New National Climate Assessment

  1. Can I get a few copies of the report? I’m short TP.

    1. Forget paper.

      “reasonable policies for addressing climate change”

      Shit like that needs a shovel.

  2. Let me explain it – “things might get warmer, and weather related events/issues may have some minor impact on the economy, but overall, we’ll be fine, in fact, a lot more prosperous even in the worst case scenario” just doesn’t sell papers or bring in those sweet sweet grant dollars.

    1. Sweet sweet grant dollars!

      Yes, that is what I came here to say!

      “No, Chicken Little, the sky is not falling” doesn’t get you those sweet sweet grant dollars!!!

  3. nothing “furthers the debate” … “reasonable policies” to stop boogeyman are not reasonable.

  4. ” I must be missing something.”

    What you are missing is that this is bullshit.

    1. And Berkeley

      1. And CBS

        1. And the New York Times

          1. Well, of course. That’s the only legitimate newspaper of record in this miserable country.

            * sips kombucha, adjust fashionable wool stocking cap *

            1. So good.
              Perfect archetyping.

  5. What they fail to take into account even in their apocalyptic scenario, is the significant increase in plant growth due to more CO2, warmer temps, and a longer growing season. And, of course, fewer deaths from cold, less fuel usage for heating, and more rain in desert regions.

    But, of course, those things won’t be happening because the very premise of AGW is BS.

    1. I don’t get what you don’t get. The math/science behind global warming is simple – the resulting consequences are not. Denying it’s real doesn’t let the market address the problem. I’m confident that scientists and a free market can figure this out – but not if we fight about whether or not the effect is friggin real.

      1. re: “The math/science behind global warming is simple”

        No, it’s not. If it were simple, we would have so many, many examples of highly credentialed climate “scientists” making elementary mistakes in the statistical treatment of data. If it were simple, we wouldn’t have such expensive computer models which, for all their sophistication and processing power, still cannot correctly model the effects of the dominant greenhouse gas in the terrestrial atmosphere – water vapor.

        Whatever you think about global warming – it is anything but simple.

        1. You’re talking about the resulting consequences (which I noted) – Not the simple physics of adding greenhouse gasses to the atmosphere and the increased thermal load. The downstream impacts are incredibly complicated. The initial mechanism is ridiculously simple.

          1. Rick.. just stop. If you go by simple physics and ideal gas laws a doubling of carbon increases energy absorption to the tune of 0.7 degC. The models put the effect rates at 1.5 to 5ish based on climate feedbacks. The m.k odelrs themselves continue to admit they have no fucking clue the dynamic feedbacks in cloud creation which is actually the primary driver of heating, not carbon. Some models have rainfall as a net cooler while others have it is a positive feedback. Almost every model uses a random magic number for cooling effect of particles in the air.

            Don’t wade into a conversation you know jack shit about. If the math and science were easy we wouldn’t have such a wide range of possible outcomes.

          2. “Not the simple physics of adding greenhouse gasses to the atmosphere and the increased thermal load”

            I mean, yes, sort of.

            Except the simple physics is almost irrelevant, in practice, since simple physics doesn’t show the “forcing factor” needed to generate Scary Outcomes.

            Doubling CO2 alone with simple physics has such a minor effect that we can just ignore it, is the “problem”.

            (I am myself in this boat:

            “Yes, climate change happens, obviously.”
            “Yes, human beings have non-zero effect on it, and human action has warmed the planet more-than-zero degrees C/F”.
            “No, we cannot trust any of these claims of looming catastrophe, not based on models that keep not predicting and a lot of handwaving and cherry-picking of the Worst Possible Cases”.

            I think in practice we mostly agree.)

            1. That’s the boat I’m in too, Sigivald.

          3. Rick, as a chemical engineer, let me tell you something. It is physically impossible to model the temperature of a fluidized-bed reactor when you have a heater on it and a known reaction mechanics. You can quantify and model an approximation, but you cannot do it from theory because you cannot even partially know the particle size or density at any given point. The atmosphere is almost infinitely more complex than any reactor, and proportionally, we have almost no data of any quality, cannot do experimentation, and we are not even certain of the direction of some forcings.

            There is a reason that the temperature range that the IPCC quotes is 1.5C-4.5C per doubling of CO2. That +/-50% is optimistic. There are more assumptions than you can shake a stick at and enough free parameters to fit a herd of elephants.

            Almost no one questions the principle that adding CO2 will warm the planet somewhat. However, the key to the argument is that it will be huge, catastrophic warming. The data just does not support that conclusion if you keep proper skepticism of the data and methods used.

            1. Ben, you are 100% correct. I’m a PhD chemist, and we do a great deal of reactor modeling of systems much less complex than the atmosphere. We have the advantage of running dozens of experiments under various conditions with which to refine our models. And yet the models are not reliable beyond the range over which they were developed.

              John Christy ran 103 climate models starting from 1979 to today. ALL 103 were wrong beyond 2 sigma, and ALL were too hot. Thus all were wrong with 97% confidence. All were CO2 based.

              Oddly, the best model is an unconventional one that completely ignores CO2, and uses sunspots as the main determinant. I don’t believe that one either.

              1. “Oddly, the best model is an unconventional one that completely ignores CO2, and uses sunspots as the main determinant. I don’t believe that one either.”

                Do you have the name of this best model? I’m a curious, science literate person, but I have no real familiarity with this topic specifically, so I don’t even know what to search for.

                1. There’s a whole alternative set of scientists who have believed solar output levels, mostly driven by the sunspot cycle, is the main driver. Those people have done numerous models and calculations over the years… Their models from (IIRC) the late 90s/early 2000s have been the most accurate to date!

                  I’d say goggle sun spot climate change or something similar. That should get you down the rabbit hole.

        2. If it were simple, we wouldn’t have such expensive computer models which, for all their sophistication and processing power, still cannot correctly model the effects of the dominant greenhouse gas in the terrestrial atmosphere – water vapor.

          Yeah, nor can they model the effects of cloud cover shade. Go figure. Most morons have no clue that water itself is a major greenhouse gas, and oh yeah something like 80% of the surface of our planet is covered with it.

        3. The climate models are pretty much useless. Not because the people doing them are stupid, but rather because we don’t know enough to build accurate models.

          There are to many variables, many of which we have no idea how they truly behave, so the model is built and assumptions put in for the things they don’t know. The assumptions are then modified to be “reasonable”. The problem is that the “reasonable” result is warming, and the variables going in are adjusted so as to get than “reasonable” output from the model.

          In short, it is confirmation bias run wild.

      2. Except the Industrial Revolution wasn’t spearheaded by scientists and the market doesn’t intrinsically give two shits about 1-2 degrees of warming 8-10 centuries into the future.

        Fulton, Ford, Tesla, Wright, Edison… ‘engineer’ or ‘inventor’ were far more prodigious at lifting humanity out of the filth and easing the human condition. The scientists conceptualizing, discovering, and laying the ground work for global warming at the time, Fourier, Arrhenius, and Angstrom, were arguing that burning fossil fuels directly for the purpose of raising temperatures may be a good idea. The implications of using the heat produced from such reactions to produce food and do useful work doesn’t appear to have dawned on them.

        Self-proclaimed science and scientists can suck it. Einstein, Von Neumann, and more than half the scientists held up by modern Ph.D.s as people whom science strives to emulate were geniuses before doing any scientific work and were refuted by science and scientists when they did do it. It’s a paradoxical pseudo-religion that has cribbed an appreciable number of its saints from other fields in Texas-sharpshooter fashion.

        1. Wow, well said, great examples.

      3. Did you just call complex physics based on chaos theory simple? Holy shit you’re stupid. Go look up complex fluid dynamics sometime. It’s much less involved than climate modeling and takes hundreds of thousands of hours of computer time. Climate models are simplistic models based on assumptions that according to over 2 dozen peer reviewed papers overestimates a climate sensitivity to carbon by double at a minimum.

        1. No, idiot, he said the very basic fundamental idea that adding greenhouse gases warms the climate is simple.

          That’s got nothing to do with how big the effect is.

          Like Caf? Hayek likes to point out, it is fundamentally simple and undeniable to say that throwing a dime into a pool raises the water level. That has nothing to do with trying to actually measure the rise.

          1. Idoots running to the defense of idiots. Hilarious. See1 above dummy. There is no simplistic climate model. To get near one you have to use assumptions that make your model wrong. Stop defending ignorance.

            1. When you are looking for an idiot Jesse, may I suggest you start with your mirror.

      4. i.e.
        Our models for CO2 and temperature rise are simple. Just don’t complain about their predictions being hugely wrong for the last couple of decades. And don’t complain when major claims made in the most prestigious journals are shown to be *totally* false in a month’s time.

        The science is settled! OBEY!

    2. is the significant increase in plant growth due to more CO2, warmer temps, and a longer growing season

      Maybe you included it in ‘warmer temps’ but arable land mass is a critical point as well. The two largest nations by land mass are Canada and Russia. Permafrost covers 60% of Russia and 40-50% of the land in Canada. The amount of land covered in permafrost in Russia is greater than the *arable* land of the US and China combined and Russia’s oil reserves are largely untapped because of it.

      1. Next you’ll say the keep finding old trees lines under retreating glaciers!

        1. Jesse, we are really sorry that we keep dissing your religion. Why don’t you go off to your safe place for some meditation or something. Maybe this disturbing conversation will be other by then and you can avoid being offended.

          1. Sorry, missed the sarc

  6. ‘Whatever the intentions of the NCA4 authors, highlighting a preposterously implausible worst-case scenario does not further the debate over reasonable policy responses to climate change.’

    What does Ronny believe are ‘reasonable policy responses’ to a non-existent problem?

    1. He’s being diplomatic. His thesis is that even if you accept that it’s a major problem, you still should be upset about them focusing on the extreme exaggeration, and even in that exaggeration, their numbers don’t add up.

      1. Saying “nice doggy” while reaching for a big stick is diplomacy.

        Freely accepting the premise that, even if there is a problem, it requires governmental solution is not.

  7. How about every progressive takes one for mother earth and kills themselves?

    Why are they so selfish? They already ruined the planet by being white, here’s their chance to save it!

    1. I support common sense proggy control!

    2. Thanos would have it no other way.

      1. The finger snaps is 50%.

  8. there is no reason to believe that a warmer planet is a more violent planet, there is just as much chance that it will be calmer and with either scenario there is no reason why the economy should retract.

    1. So now you’re denying the violence in the middle east is from us causing warmer temps?

      1. OR is our violence in the middle east causing warming?

        1. Mind blown.

      2. I’m pretty sure it’s mostly Arabs and Semites in the middle east causing violence in the middle east… As it always has been!

        Granted Turks, Persians, and honkies add fuel to the fire from time to time just to keep things interesting!

  9. You know.

    I just had an epiphany.

    The government in my industry forced me into a product I don’t need and the ‘non profit co-op’ behind it gets to charge me!

    The epiphany?

    Everything is a scam. If you’re connected you get to use the government for profit if you’re shifty enough.

    Climate change is a scam. It’s a cottage industry. This should be evident to a sober, stoic, skeptical (perhaps cynical)
    observer.

    1. >>>Everything is a scam.

      only to the equal, not to the moreso.

  10. What the climate-change folks don’t seem to realize is that if China doubles their carbon emissions every 10 years (as they did between 2005 and 2014), it doesn’t really matter if the U.S. reduces emissions by 20% or 50% or 100%. China will make up for it.

  11. God help us, we’re in the hands of engineers.

    1. “God help us, we’re in the hands of engineers.”

      As opposed to imbeciles like you, scumbag.

    2. One of the times I worked for a company that actually manufactured things, a friend on the line had a sign in his office that read “there comes a time in the life of every product when it is necessary to shoot the engineers and start production”.

    3. Engineers>scientists!

      Also LOL about shooting engineers… Because it’s true.

      1. No, both have valuable strengths and some weaknesses.

        Scientists tend to think about things on a more fundamental level and can be creative thinking outside the box. But they (we) also tend to chase impractical, blue-sky ideas, like cold fusion.

        Engineers look at things from a more practical perspective, asking how can this be implemented. But they tend to believe their calculations at face value, reporting the distance from my house to the store as 7.28562107 miles.

        A good dose of common sense and experience is a great improvement for both. And I value having both on my teams.

      2. They aren’t talking about shooting engineers in favor of scientists. They were talking about shooting the engineers and getting the mechanics and operators on the thing to get something done.

        “Engineer” in industry is equivalent to “second lieutenant” in the army. You have to earn your respect from the men, because so many of our fellows have lost it already.

        And BigT, you must be in academia. Any engineer who gives that needs to be put into a plant and told quite frankly what is error margins are on each instrument (somewhere around +/- 5-10% or so so long as you are above half flow. Below that, the orifice plate starts reading negative, so don’t trust it. Paraphrased from one of my internship assignments all those years ago)

        1. One of the things that gives me perspective on the man-made climate change issue is that I am a control systems engineer. We build computer models and consider the real capabilities of measuring instruments … and the errors.

          I find the claims of the climate change set absurd in part because they make conclusions based on measurement changes within the error range of instruments. Sometimes WAY within the error range of the instruments.

  12. “Given this assessment’s emphasis on using a risk-based framework, authors were asked to consider low-probability, high-consequence climate futures,” explain the authors. Fair enough. But it did result in implausible doom-laden headlines.

    Media headlines are the fault of the assessment’s authors?

    The authors were required to assess the full range of RCP scenarios. Because the media plucks one of the worst scenarios, the assessment should have been different or considered less scenarios?

    twitter.com/KHayhoe/status/1067457724710076416

    twitter.com/KHayhoe/status/1067944390960631808

    Reason has been slow-walking any stories about the assessment. And what Bailey has put out has been very skimpy.

  13. The main hit to the 10% GDP decline is also based on deaths related to an improbable (IPCC estimates) so it would be decreased but so would the number of people, so a per capita GDP isn’t even effected really.

    The report was laughable. Yet all the usual idiots here read the headlines and declared themselves experts.

    1. Or – –
      All the dolts declared themselves experts and wrote the headline?

    2. Did they mention the economic costs of enacting whatever policies they desire to combat CC? I’m willing to bet it’s more than 10% of GDP.

  14. “Climate Change Is Affordable”

    In their absurd absolute worst case, it’s completely affordable.

    Worse, what they haven’t shown is an *alternate scenario* where we can *do* something to make the *net* GDP higher. Even if the costs were catastrophic, without a *cost effective* plan to possibly ameliorate those costs, what’s the point? It’s like showing the costs to the economy of friction. Yeah, I bet it’s plenty. So?

  15. Biatches look at data, Bailey!

  16. So where did those estimates come from?

    They came from inserting a set of futuristic assumptions based on faulty/incomplete models – about events that will almost certainly be extreme outliers with nothing ‘normal’ at all – through statistical analysis that assumes that outliers are rare and most events are ‘normal’ – into an economic model that can’t value any of that at all because none of it is even included – or priced – and outliers (or black swans) can’t be predicted anyway.

    It’s a complete waste of time and effort. Akin to having a dog dance Swan Lake on its tongue and using the outcome to determine the orbit of a space station.

    If I personally were to guess what will happen, it is that either:
    a)the changes will be significant and frequent enough to overwhelm our ability to do anything about them and we humans will revert to our worst bloody/violent instincts or
    b)the changes will be significant but not frequent enough to overwhelm and in 100 years, those generations will marvel at the progress THEY made compared to us blue-butt baboons.

    The probability of some Rip VanWinkle future where any of our predictions/assumptions are valid or events unfold linear/incrementally are zero.

    1. “It’s a complete waste of time and effort.”

      Worse that that. These cataclysmic predictions scare people into devoting resources to fake problems while real problems of pollution from mines, farm run-off, waste disposal, habitat loss, species endangerment, etc are left behind. Warmists are among the worst enemies of the environment.

      1. I agree. Even in dealing with the environment (difficult enough), it’s far more productive to address the stuff that is known – in smaller pieces – than some huge comprehensive chunk of distant unknown.

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  19. Government debt, regulations and mishandling of our resources has already diminished our GDP by more than 10%. Maybe global climate change is away to a healthier economy?

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