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1981 Paper's Predictions for Global Temperatures Spot-On

Layzej writes "The Register reports on a paper published in Science in 1981 projecting global mean temperatures up to the year 2100. 'When the 1981 paper was written, temperatures in the northern hemispheres were declining, and global mean temperatures were below their 1940 levels. Despite those facts, the paper's authors confidently predicted a rise in temperature due to increasing CO2 emissions.' The prediction turns out to be remarkably accurate — even a bit optimistic. The article concludes that the 1981 paper is 'a nice example of a statement based on theory that could be falsified and up to now has withstood the test.'"

26 of 371 comments (clear)

  1. monkeys throwing darts... by Anonymous Coward · · Score: 4, Insightful

    I'm not commenting on the climate one way or the other, but when you have dozens of different predictions over the years is it really surprising that a couple of them happened to hit the mark? Don't forget the Global Cooling sentiment which was around just a couple of years before this article came out...

    1. Re:monkeys throwing darts... by jIyajbe · · Score: 5, Insightful

      No, because the multiple predictions are not random, the way thrown darts are. This is Science 101. Multiple models are proposed to explain and/or predict an observable phenomenon. The model that makes the the most accurate predictions gains credence over the others.

      --
      "Don't blame the log for the fire." --Andrew Ratshin
    2. Re:monkeys throwing darts... by niftydude · · Score: 4, Interesting

      I'm not commenting on the climate one way or the other, but when you have dozens of different predictions over the years is it really surprising that a couple of them happened to hit the mark?

      Well that's pretty much how science works. Lots of different people with different theories make different predictions based on those theories.

      The guys that make accurate predictions the most are the ones whose theories scientists start to believe are true.

      --
      You can never know everything, and part of what you do know will always be wrong. Perhaps even the most important part.
    3. Re:monkeys throwing darts... by Elbereth · · Score: 5, Insightful

      There's a difference between a scientific theory that ends up correctly modeling reality for a long period of time and me just making wild guesses. However, a lot of people will conflate the two, saying that all those scientists were doing was making wild guesses that happened to pan out. This is the same kind of thing that creationists say, when they point out that evolution is "just a theory". It also allows them to create their own competing "theory", consisting of a bunch of mythological stories.

      Science is not just a bunch of old guys with wild hair who sit around, pulling shit out of their ass, and saying, "Hey, this sounds good. Let's go with this wild guess. The public will eat it up, and we'll get more grant money!"

    4. Re:monkeys throwing darts... by dkleinsc · · Score: 5, Informative

      I'm not commenting on the climate one way or the other

      Sure you are. You're argument in a nutshell, goes like this:
      1. Premise: There were hundreds of predictions about what would happen to the climate over a 30 year period.
      2. Premise: One prediction was demonstrably right.
      3. Inference: because 99.9% of the predictions were wrong, the one that was right must be due to pure chance.
      4. Final conclusion: I can safely ignore any other prediction about climate from anybody, because the only way it can be right is by pure chance.

      Well, that's not how science works. The logic of science works more like this:
      1. Premise: There were hundreds of predictions about what would happen to the climate over a 30 year period, each using different models and ideas to arrive at that prediction.
      2. Premise: One prediction was demonstrably closer to right than the others.
      3. Inference: The models and ideas that produced the correct prediction are closer to the truth than those that didn't correctly predict a result.
      4. Final conclusion: When making the next prediction, start from using those models and ideas and you'll get pretty close to the right answer.

      Here's a similar problem from physics:
      Model A: Acceleration due to Earth's gravity near the ground in a vacuum is ~10 m/s^2, so the ball should fall 100 meters in 4 seconds.
      Model B: Acceleration due to Earth's gravity near the ground in a vacuum is ~5 m/s^2, so the ball should fall 100 meters in ~5.8 seconds.
      Time for a ball to fall 100 is slightly over 4 seconds. Ergo, 10 m/s^2 is less wrong than 5 m/s^2.

      In the words of Isaac Asimov, Model A is wrong, Model B is wrong, but if you think that Model A is as wrong as Model B, then your view is wronger than both of them put together.

      --
      I am officially gone from /. Long live http://www.soylentnews.com/
    5. Re:monkeys throwing darts... by Anonymous Coward · · Score: 5, Insightful

      Exactly why the "controversy" is political and not scientific.

      If the arguments were scientific, the conclusions would not be divided among party lines - yet they are. That should tell you something.

    6. Re:monkeys throwing darts... by nedlohs · · Score: 5, Insightful

      No it gained credence over other models that didn't get things right.

      That in itself says nothing about whether it is actually correct in itself just whether it makes good predictions. A simpler model that makes exactly the same predictions would be prefered - that's what Occam's razor actually says after all. If the models make different predictions we don't need the razor we just see which one (if any) matches reality.

    7. Re:monkeys throwing darts... by Gadget_Guy · · Score: 5, Insightful

      I see no evidence that you even read this paper. All you are doing it spouting the standard denialist memes: it's cherry picked; it's not science; it's not falsifiable, etc. You say there is no error analysis, but does that mean that they gave a single temperature prediction? No, even just looking at the graph in the article you can see there is quite a wide range to their prediction with different areas based on what the human response to this problem was.

      You say some of the assumptions are false? Which ones? Why did you not include even a single example of how they got it wrong? And here is the my biggest problem:

      You can't simply say, "It will get warmer", be off by as much as 30% and get credit for good science.

      I did a search in the article for the text "It will get warmer" and could not find a match. It seems that the scientists behind the paper agreed with you, and so they didn't just make a single proclaimation without showing any supporting evidence.

      Climate change *could* be a serious thing but it gets washed up with politically driven junk from activists. They are doing more harm than good.

      Surely it is the skeptics that are doing the most harm. You know the ones. They have claimed over the past decade that global warming is false because it is actually getting cooler (although they have had to change this to claim that the temperature has remained steady once it became obvious that it was not getting cooler). They are the ones who make claims about climate changes without providing any supporting evidence, but will also deride scientists (who do actually show their working and their data) as doing the same.

    8. Re:monkeys throwing darts... by RightSaidFred99 · · Score: 5, Insightful

      I'm not a denier, but you're not really countering his point. If 500 scientists make 500 predictions, and one is right but 499 are wrong you can't really point to that one (possibly lucky) guy and say "see, we knew it!".

      What if I come up with some new crackpot theory tying the price of tea in china to the average incidence of Herpes amongst 19-22 year olds and then predict the price in 5 years based on that theory. I then get lucky, and the price matches my prediction. Have I totally kicked ass with my new theory of Herpes-driven tea prices?

      Like I said, I do believe in man-made GW, but the "other side" can easily find one loon who happened to be right and point to him as proving their point. We need broader theory and broader, more often repeatable tests.

    9. Re:monkeys throwing darts... by chill · · Score: 5, Informative

      I'm sorry, you're clueless.

      "Climate" means 30-year average in this context. Being able to predict next year's specific temperatures has nothing to do with climate.

      Think of the stock market. "Climate" is the 30-year graph and the ability to say "from 1982 to 2012 the trend is ever increasing". http://www.google.com/finance?chdnp=0&chdd=0&chds=0&chdv=1&chvs=maximized&chdeh=0&chfdeh=0&chdet=1333730258898&chddm=4050760&chls=IntervalBasedLine&q=INDEXDJX:.DJI&ntsp=0

      "Weather" is saying "last year was up and down". http://www.google.com/finance?chdnp=0&chdd=0&chds=0&chdv=1&chvs=maximized&chdeh=0&chfdeh=0&chdet=1333730383316&chddm=98923&chls=IntervalBasedLine&q=INDEXDJX:.DJI&ntsp=0

      You're confusing "long term trend" with "what will it be like this weekend". They are two distinctly different things.

      --
      Learning HOW to think is more important than learning WHAT to think.
    10. Re:monkeys throwing darts... by Gadget_Guy · · Score: 5, Informative

      If you can predict the climate, publish your predictions for each and every weather station so we can compare predicted values to actual values. (Oh, and yes, I do know the difference between weather and climate.) But no, we get some hazy predictions for something in 100 years, yet nothing for next year.

      It's funny. You claim that you know the difference between weather and climate, and yet you repeatedly mix up the concepts the rest of the time. If you know the difference, why do you want to be given a prediction for a specific location? If you know the difference, why do you want to be given a prediction for the coming year?

      The bizarre thing is that if you look at the graph you can see what they thought it would be next year, and indeed all years to the end of the graph. As it gets further into the future then the error range gets bigger because they can't know what the human response to this problem would be.

      Moronic arguments about weather vs. climate are not science.

      And moronic arguments that get weather vs climate wrong are also not science. This doesn't change merely because you keep mistakenly claiming that you do know the difference.

    11. Re:monkeys throwing darts... by b4dc0d3r · · Score: 4, Insightful

      You mean the way Einstein predicted things that "fit after the fact"? Just last year we found at least one more of his predictions was true. He's just like Nostradamus, right?

      A model gets proposed, then tested. The ones that are closest to reality are proven correct, the ones that don't are proven incorrect. You are saying that this person's credibility is strained because a lot of other people were wrong? If that is how we measure credibility, then how is anyone supposed to be credible?

      http://www.nytimes.com/2011/05/05/science/space/05gravity.html?_r=1&partner=rss&emc=rss

      There was a 2007 story about this, but from what I can tell the experiment didn't conclude until 2011.

    12. Re:monkeys throwing darts... by Mindcontrolled · · Score: 5, Funny

      Well, that is a nice example of "proof by anal extraction". Care to actually cite the thousands of not-useful ones? I mean, like, doing science and stuff? Or do you just create your reality by decree ex cathedra?

      --
      Ubi solitudinem faciunt, pacem appellant.
    13. Re:monkeys throwing darts... by phantomfive · · Score: 4, Interesting

      The problem is the exact same guy has made a lot of predictions. His 1988 prediction, which presumably should be more accurate since he made it with the benefit of more data, was much farther off.

      The idea here is, we have a rough idea of the major inputs and outputs, so scientists have to guess at the coefficients and constants. There are a number of them, positive and negative, so you can actually be wrong on every single one of them and still get the right answer. In this case, it appears he was off by 30%, which isn't a very good indication of predictive power. (Yes I know his prediction was under, but the goal here is accuracy, not who can predict the best disaster).

      When I get home from work I'll have a chance to read the paper in more depth, to get a better idea of how random his guesses were. It is definitely true that in 1988 he thought his prediction was better.

      --
      "First they came for the slanderers and i said nothing."
    14. Re:monkeys throwing darts... by ShanghaiBill · · Score: 4, Informative

      Bullshit. Ptolemaic system made accurate predictions, but based on completely wrong understanding of reality. Credence my ass.

      The Ptolemaic system was not discarded because it was wrong. It was discarded because the Newtonian System made more accurate predictions.

  2. Re:What about the rest? by AdmiralXyz · · Score: 5, Funny

    Care to cite one? Since it sounds like you're so well-informed.

    --
    Dislike the Electoral College? Lobby your state to join the National Popular Vote Interstate Compact.
  3. What? by niftydude · · Score: 4, Funny

    The eighties was 30 years ago?

    Shit I'm old.

    --
    You can never know everything, and part of what you do know will always be wrong. Perhaps even the most important part.
    1. Re:What? by gatfirls · · Score: 5, Funny

      Like people who used phones hooked to walls and paid 300$ for a walkman cd players would know anything about science or the climate.

  4. What that really means? by Extremus · · Score: 4, Interesting

    I am very far from being a specialist in this topic. The The Register article seems to imply that global warming must be true, given that there was ONE paper in 80s already anticipating it. That is not necessarily true. The prediction can be result of pure chance in a possibly erratic research study (I have no clue if that is the case or not). One could perhaps make an stronger statement in that direction if MANY papers anticipated global warming (possibly using different models).

  5. You asked for it! by jIyajbe · · Score: 5, Funny

    So, in yesterday's story about predicting the collapse of civilization, multiple posters snarked about how convenient it is to make predictions about what will happen 30 years from now, 'cause no one will remember you made those predictions--so you'll never be called to account for your oh-so-incorrect doomsday predictions.

    I now calmly await for yesterday's posters to issue "I can see now that I was wrong" statements.

    --
    "Don't blame the log for the fire." --Andrew Ratshin
  6. Re:30% off is spot-on by Trepidity · · Score: 4, Insightful

    I'm going to make a wild guess that you don't know very much about science in any field.

  7. Shift to a productive debate... by bdabautcb · · Score: 4, Interesting

    I wish coversation around this topic would shift from debate about whether or not the climate is changing and may in fact change dramatically over the course of several decades, and whether or not humans activities have an impact on the climate to a productive conversation about how to best react to changing climate and use it productively. It is obvious to me that where I live (Minnesota), the mean temperatures are rising and the growing seasons are getting longer. Shit, I had my vegetable seeds sprouting and even had them outdoors some days, early in March, in Minnesota! I am also growing a dwarf bananna tree that has made it through two winters here. I guess my point is, I think it would be great if people would quit arguing about empirical facts (such as there is more CO2 in the atmosphere than ever before during modern human civilization); and start wondering about how to react to the changes that might be brought about in this altered environment.

    --
    Koalas. They're telepathic. Plus, they control the weather. -Margaret
  8. Prescient by rrohbeck · · Score: 5, Interesting

    From the Hansen study:
    "Political and economic forces affecting energy use and fuel choice make it unlikely that the CO2 issue will have a major impact on energy policies until convincing observations of the global warming are in hand."

  9. Re:30% off is spot-on by rrohbeck · · Score: 4, Insightful

    Yeah, warming is 30% higher than they predicted, they were clearly wrong.

  10. Test of Time by Guppy · · Score: 5, Interesting

    "a nice example of a statement based on theory that could be falsified and up to now has withstood the test."

    Just wait till we finally reach a double of atmospheric CO2 values, at which point we'll get to see if the predictions Svante Arrhenius made in the late 19th / early 20th century pan out.

    If the quantity of carbonic acid in the air should sink to one-half its present percentage, the temperature would fall by about 4 degrees; a diminution to one-quarter would reduce the temperature by 8 degrees. On the other hand, any doubling of the percentage of carbon dioxide in the air would raise the temperature of the earth's surface by 4 degrees; and if the carbon dioxide were increased fourfold, the temperature would rise by 8 degrees.
    Although the sea, by absorbing carbonic acid, acts as a regulator of huge capacity, which takes up about five-sixths of the produced carbonic acid, we yet recognize that the slight percentage of carbonic acid in the atmosphere may by the advances of industry be changed to a noticeable degree in the course of a few centuries.

  11. A Pointless Anecdote by eldavojohn · · Score: 4, Interesting

    So about 8 years ago I moved from Minnesota to Northern Virginia for work. And one of the aspects of culture shock was that I was now living with, befriending and enjoying my time with folks from all over the country who had moved to the DC area for work. Many friends from Texas and Pennsylvania specifically. I even roomed with several of them and one thing really bothered me: they did not recycle. So I kept doing my own recycling and trying to help them out to no avail. This was quite different from Minnesota where it was stressed when we were young that it was important. You might call it common sense or indoctrination or nanny state or whatever your political views tell you to but that's just the way it was largely. And the reason was that the Earth is a precious resource.

    So, being an avid Slashdotter, I was fairly in tune with the Global Warming debate and would often talk to my new friends about it. Every single one of them either didn't want to hear it or thought I was an idiot. They seemed to only listen when I would bring up news items lending credibility to the absence of climate change. Then they asserted there was climate change but it is natural and so on and so forth. To this day, my friend from Texas does not recycle in his home. His Korean wife has asked me not to discuss global warming around her and continually asserts it was proven wrong years ago. My friend from Texas, being quite a bit smarter now likes to talk about what we can do about it without him having to alter his lifestyle at all. The reason for it is unimportant to him, now he just accepts that it's happening for some reason and how can we put something in space that can block the sun partially while maintaining a synchronous orbit around the sun between it and Earth. It's not that that is a simpler solution than reducing your personal carbon footprint but instead it's one that doesn't require government intervention (which he views as the ultimate evil) and doesn't require him to change.

    So what do you do when you read news about this, do you whip out your biggest "I told you so" font and e-mail it out to your friends until they get tired of it? I mean, I can't even politely offer to collect the cans and bottles from one of my friend's parties and take them to the local recycling center. He's almost proud of his freedom to be able to send it to the dump. So I have two options. One is silence and apathy and the other is not having any friends in this area. Silence and apathy it is.

    --
    My work here is dung.