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Carl Sagan Warned the World About Nuclear Winter

• mcguire 9y ago
  I find it weird that scientists get crap from other scientists for speaking publicly. Simple jealousy doesn't explain the vehemence. As for the politics of the issue, mutual assured destruction has been the working theory since Eisenhower. Those who think strategic nuclear war is winnable, as well as the SDI nutters, are threats to that stability.
  • Xeoncross 9y ago
    > Simple jealousy doesn't explain the vehemence. In any industry, if you attack/speak-against my beliefs/views/plans/theories, then I don't like it. Even if you didn't mean too. Even if you didn't know I existed or had those views. It's not about science, it's about humans defending their worldview and beliefs. Even stamp collecting has this. Anything people put time/effort into has this. edit: ChuckMcM does a better job describing this.
    • ethbro 9y ago
      Aka https://en.m.wikipedia.org/wiki/Escalation_of_commitment https://en.m.wikipedia.org/wiki/Escalation_of_commitment https://en.m.wikipedia.org/wiki/Confirmation_bias https://en.m.wikipedia.org/wiki/Confirmation_bias https://en.m.wikipedia.org/wiki/Cognitive_dissonance https://en.m.wikipedia.org/wiki/Cognitive_dissonance
  • ChuckMcM 9y ago
    I think of it more in terms of the people. Someone doing research on a topic for any length of time probably sees themselves as dedicated (time commitment) and intelligent (PhD and post doc work). They really strongly believe what they believe. And someone else comes along with similar traits strongly believes a different thing. If a person can acknowledge that this other person is smart and qualified, and recognize that they hold a belief that, if true, implies the believe that the person holds is incorrect. Then they have to deal with being wrong on something they have invested a lot of time into and believed for possibly a very long time. Throw in a bit of imposter syndrome and I think it would be surprising is people just switched their point of view when presented with an alternative. Instead it sets up this conflict where each party tries really hard to prove the other wrong, and after one or more rounds of that one point of view or the other generally prevails (at least from the perspective of the audience). This is when really good science gets done because it does a great job of neutralizing implicit biases.
  • razakel 9y ago
    >I find it weird that scientists get crap from other scientists for speaking publicly. Simple jealousy doesn't explain the vehemence. I know a physicist who despises Brian Cox with a passion. It's jealousy.
  • mseebach 9y ago
    It's not about "speaking publicly", it's about claiming (implicitly, typically) that Science supports a particular side in a political debate. Science very rarely actually has the power to do that - it can advise on how (probably) best to achieve a given outcome under certain constraints. The political debate of Sagans time was unilateral nuclear disarmament and it fed eagerly on accounts of the horror of nuclear war. The unstated constraint was that it was perfectly happy to accept a significantly less restrained Soviet Union on the world stage. Science can't tell you if that's a good idea or not.
  • nabla9 9y ago
    Massive retaliation and Mutually assured destruction are different concepts. During the Eisenhower era U.S. doctrine was so called massive retaliation using a force disproportionate to the size of the attack. It was viable strategy only as long as Soviet Union did not have nuclear parity. Kennedy realized that massive retaliation was not credible anymore and asked other options. U.S. nuclear strategy changed into so called flexible response strategy. Soviet Union had always relied in the use of tactical nukes. First use of nuclear weapons does not automatically lead to all out nuclear holocaust. There was nuclear escalation ladders even against Soviet Union. Mutually assured destruction (MAD) is deterrence strategy only against massive decapitation attack. Today locally limited nuclear war is more likely than ever before. It's part of Russian doctrine if Russia is outmatched in local conflicts. US has nuclear weapons and strategies dedicated for limited nuclear war.
  • waterhouse 9y ago
    When a scientist speaks to the public, they represent (in much of the public's mind, anyway) all scientists in the field, and (arguably, to some extent) science and scientists in general. If they say anything wrong, then that harms the reputation of all of the above. From the perspective of a fellow scientist in the field, the speaker must (a) have made mistakes in his analysis, (b) have taken an approach to his analysis that was sloppy enough to allow such mistakes, and (c) have announced results despite having done an analysis that they should have known was sloppy. In other words, it demonstrates not just incompetence but negligence and a disregard for the truth. These are hateful qualities in a scientist. This is assuming the case of a scientist who confidently makes incorrect assertions. If they qualify what they're saying—"So far this is what the research says, but it's preliminary, there are a few other tests I'd like to see"—then that's a lot more defensible even if they're wrong. (There is a legendary tendency for reporters to remove all the qualifiers, but at least that's not the scientist's fault.) If they state everything confidently, more confidently than the evidence justifies, but they happen to be right on all their assertions so far, then that may be mildly irritating. If they're intellectually cautious and they're right, and if there are scientists that complain about these people, then that does sound like jealousy.
• augustocallejas 9y ago
  A great mini-doc overview of the same topic: https://www.retroreport.org/video/nuclear-winter/ https://www.retroreport.org/video/nuclear-winter/
  • rounce 9y ago
    Also, the 1984 BBC documentary 'On the 8th Day' is worth a look: https://www.youtube.com/watch?v=tCz9zqTTark https://www.youtube.com/watch?v=tCz9zqTTark
    • ghostcluster 9y ago
      How about this NYTimes story where even the scientist who coined the term disavowed it as a scenario. > the five scientists who introduced the term ''nuclear winter'' now acknowledge that they overestimated its severity, and their concession appears to have moderated the longstanding debate. > most discounted the extreme view that global chilling of the atmosphere would be severe enough to be described as ''winter.'' Scientists specializing in such studies also generally reject the suggestion that a ''nuclear winter,'' in itself, could bring about the extinction of the human race. Even Dr. Richard P. Turco, the physicist who coined the phrase ''nuclear winter,'' discounts the idea. http://www.nytimes.com/1990/01/23/science/nuclear-winter-theorists-pull-back.html?pagewanted=all http://www.nytimes.com/1990/01/23/science/nuclear-winter-the...
• dpflan 9y ago
  This article is interesting; I would say that it is crucial that such warnings and such "celebrity" scientists enter the public debate (expecting backlash and support and discussion - is this not similar to sharing research within one's academic community?). The public can have their existential dread soothed by the idea of nuclear weapons as defense, but it seems that their understanding of their usage is not sufficient. Sagan or someone needed to provide thoughtful discourse on the repercussions of using the weapon. It does seem great to think your nation can use this powerful tool to attack / ultimately defend its and your existence, but the power of and nature of the weapon requires understanding it. The scale of the weapon is not comprehensible, as much as say a simpler explosive device could be to layperson (voter?). The advocates of SDI and nuclear did not seem to discuss the repercussions of use, rather the fact that the power is a deterrent and useful against enemies. The repercussions are what limit the use of nuclear as a strategic weapon. Excerpt from the article: '“People didn’t want to change the way they were thinking of [nuclear] weapons,” he says. “I see an echo of that now. What nuclear winter shows is that they’re not really weapons in the sense that other things are weapons: that you can use them to harm your adversary without harming yourself. People are not really considering that if there really were to be a nuclear conflagration, in addition to how unthinkably horrible it would be in the direct theater of the use of those weapons—say in the Korean peninsula and surrounding areas—there would also be global effects.”' - Grinspoon
  • dpflan 9y ago
    '...there would also be global effects."' We can view the earth from orbit; we can be made aware of the fact that all nations are "in this together." So, to add some positivity to the comments thread, here is a video about the "Overview Effect" - maybe increased consumer space travel can help humanity's perspective; what if all major political leaders (G8 field trip!) had to go into space as "training/orientation" for their position... - https://vimeo.com/55073825 https://vimeo.com/55073825 - https://en.wikipedia.org/wiki/Overview_effect https://en.wikipedia.org/wiki/Overview_effect
  • ghostcluster 9y ago
    The absolutely incorrect thing to do is to lie to the public by using your credibility as a scientist to knowingly make up your own incorrect story about the hypothetical effects. You wonder why so many people don't trust "scientists" when you can see they are clearly lying to push a social cause?
• danielvf 9y ago
  Carl Sagan’s predictions were really dire. Here’s a three paragraph TLDR of his specific predictions from his 1983 article that brought "Nuclear Winter" into the vocabulary: — “Our baseline case, as in many other studies, was a 5000-megaton war with only a modest fraction of the yield (20 percent) expended on urban or industrial targets… In the baseline case, the amount of sunlight at the ground was reduced to… too dark for plants to make a living from photosynthesis. “Land temperatures, except for narrow strips of coastline, dropped to minus 25 Celsius (minus 13 degrees Fahrenheit) and stayed below freezing for months -- even for a summer war... virtually all crops and farm animals, at least in the Northern Hemisphere, would be destroyed, as would most varieties of uncultivated or domesticated food supplies. Most of the human survivors would starve. “But what if nuclear wars can be contained, and much less than 5000 megatons is detonated? Perhaps the greatest surprise in our work was that even small nuclear wars can have devastating climatic effects. We considered a war in which a mere 100 megatons were exploded, less than one percent of the world arsenals, and only in low-yield airbursts over cities. This scenario, we found, would ignite thousands of fires, and the smoke from these fires alone would be enough to generate an epoch of cold and dark almost as severe as in the 5000 megaton case. The threshold for what Richard Turco has called The Nuclear Winter is very low. — I think the reason the Carl Sagan was widely panned afterwords is that the science was just plain bad. The scale of the predictions he made were so off the charts from almost forty years of previous nuclear experience, that he was obviously was wrong. He predicted essentially the end of the humanity from a mere 100 megatons of nuclear explosions, and yet twenty years before article, the Soviet Union had tested a 50 megaton bomb with no more than the usual local effects. Using bad science to advance a public policy goal is exactly what got us to the current "distrust of science"
  • vilhelm_s 9y ago
    To be clear, the claim was not that 100 megatons themselves would cause climate change, but that 100 firestorms in cities would, and that a 1 Mt bomb would be enough to cause a firestorm (there was one in Hiroshima). It's not completely clear to me just how bad the science was; like the article says there is still a debate today, so it's not completely settled even now. Wikipedia has a lot of discussion. https://en.wikipedia.org/wiki/Nuclear_winter https://en.wikipedia.org/wiki/Nuclear_winter
• quotemstr 9y ago
  The concept of "nuclear winter" is a great example of science gone wrong. As it turns out, the original 1980s report vastly overestimated the amount of combustible fuel in cities and inaccurately estimated both modern nuclear weapon yield and blast size. Nuclear war would not create firestorms capable of injecting soot into the stratosphere and would not cause years-long crop failures. Nuclear war is, in fact, quite survivable. https://skeptoid.com/episodes/4244 https://skeptoid.com/episodes/4244 https://www.nature.com/articles/475037b https://www.nature.com/articles/475037b https://www.quora.com/How-many-nukes-would-it-take-to-cause-a-minor-nuclear-winter-What-about-a-moderate-one/answer/Allen-E-Hall-2 https://www.quora.com/How-many-nukes-would-it-take-to-cause-...
  • knz 9y ago
    > Nuclear war is, in fact, quite survivable. Nuclear winter may be less plausible than people believe but I'm not sure a nuclear war can be described as "quite survivable". The potential disruption to transportation networks that are essential for food distribution and delivery of medical supplies etc would be catastrophic in a nuclear war. I have no doubt that a nuclear exchange would be accompanied by electronic warfare - disruption/destruction of the power grid in the north could kill millions in the winter, especially if the petroleum supplies required to evacuate were also disrupted.
    • arethuza 9y ago
      I think my main worry is how well the economic system would hold up in even a fairly minor attack - given how worried politicians were at the time of the banking crisis (e.g. here in the UK having to put troops on the streets to control public order was considered likely if any of the major banks had gone under) I suspect the answer is "not very well".
      • otempomores 9y ago
        I think the church would develop a nasty luddistic strain of belief
    • mseebach 9y ago
• nihil75 9y ago
  Isn't he the father of Psychohistory and The Foundation?
• wallflower 9y ago
  "I do not know with what weapons World War III will be fought, but World War IV will be fought with sticks and stones!" ~Albert Einstein
• marcoperaza 9y ago
  Worries about nuclear fallout are vastly overstated. If you detonate the weapons at the right altitude, they retain most of their destructive effect without creating long term catastrophic fallout.
  • fokinsean 9y ago
    > If you detonate the weapons at the right altitude Yeah and if you detonate the at ground level there is going to be a lot of fallout. Worries are very valid.
    • ghostcluster 9y ago
      Crying wolf by making up deliberately exaggerated scenarios in order to push a social agenda is not valid, and damages the reputation of scientists.
      • fokinsean 9y ago
        lol nuclear fallout isn't a hoax https://en.wikipedia.org/wiki/Downwinders https://en.wikipedia.org/wiki/Downwinders
        • ghostcluster 9y ago
          'Nuclear Winter' is. That is the topic of this post. http://www.nytimes.com/1990/01/23/science/nuclear-winter-theorists-pull-back.html?pagewanted=all http://www.nytimes.com/1990/01/23/science/nuclear-winter-the...
  • knowaveragejoe 9y ago
    Surely that will be considered when employing these weapons in a war.
    • bcoates 9y ago
      The "right altitude" maximizes damage and mostly reduces fallout as a side-effect, so yeah
• Robotbeat 9y ago
  I think it's worth pointing out that the global nuclear arsenal today is about a fifth the size it was when Carl Sagan made this warning. We've made significant progress toward reducing existential risk. https://en.wikipedia.org/wiki/List_of_states_with_nuclear_weapons#/media/File:US_and_USSR_nuclear_stockpiles.svg https://en.wikipedia.org/wiki/List_of_states_with_nuclear_we...
  • thrillgore 9y ago
    It's a fifth of what it was, but yet the ordinance (and "migratory" patterns of civilization to cities/shrinking factory towns, globalized economy) is enough to decimate the population dozens of times over; and suspend modern civilization.
• Lendal 9y ago
  Was Carl Sagan aware of just how many nuclear weapons had already been detonated in testing by both countries, as well as by India and China? I don't know the exact number but I do know it's over a hundred. If his models were correct, we'd have already been experiencing a nuclear winter by the 1980's.
  • toss1 9y ago
    Um, no. The tests were rather deliberately located away from cities and avoided creating the firestorms required to raise the massive dust clouds and create the effect. They were also not near-simultaneous.
• downrightmike 9y ago
  You probably don't need a high yield if you just nuke a volcano or super volcano https://en.wikipedia.org/wiki/Volcanic_winter https://en.wikipedia.org/wiki/Volcanic_winter
• bayesian_horse 9y ago
  Winter is coming! Sorry, couldn't resist.