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Carl Sagan Warned the World About Nuclear Winter (smithsonianmag.com)
160 points by anarbadalov on Nov 16, 2017 | hide | past | favorite | 119 comments



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://www.nature.com/articles/475037b

https://www.quora.com/How-many-nukes-would-it-take-to-cause-...


> 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.


It depends on what exactly is meant by "quite survivable."

Does that mean you'll have a 99% chance to survive even if you do any special preparation? If so, nuclear war definitely does not qualify.

Does it mean you'll have a greater than 50% chance to survive with good preparation? Nuclear war probably qualifies.

Or does it just mean that nuclear war won't result in human extinction? Nuclear war definitely qualifies.

An all-out nuclear war would definitely kill tens of millions immediately, and tens if not hundreds of millions with the after-effects. You may not see years-long crop failures due to nuclear winter, but you'll get the same ultimate effect from lack of fertilizer, machinery, and distribution infrastructure. And fallout. A good chunk of the US's productive agricultural land is downwind from ICBM sites which would be targeted for extremely dirty ground burst attacks.


There's no reasonable interpretation of a 50%-ish survival rate that can be described as 'quite survivable'. Toxicologists say LD50, for instance, not QS50.


On an individual scale? Sure. On a civilization or species scale? Survival of the larger group is almost certain if each individual has "only" a 50% chance of death.


The Black Death, after all, killed about half of Europe's population. European civilization survived.


Was it really half? I have seen figures around 30%. Are there any accurate records in every country at the time?


Well, a subset of the population persisted. The order of society changed radically, as it became impossible to enforce enserfment.


You have a quibble with that one but not with defining it as "humanity doesn't go extinct"?


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".


I think "survivable" is to be understood on a civilization scale, not for individuals. It would definitely be a calamitous event with massive loss of life - but if you survive the attack itself and can feed yourself and otherwise survive for a few months perhaps, you would have decent odds. I think.


Mad Max survival is still survival.


The Quora link you put says the reason the 1980s report is no longer relevant is the drawdown from Cold War nuke levels.

The Nature letter was written by Russell Seitz, who is also skeptical against the harm cigarette smoking can do, that climate change has, and so on. I don't know of any scientific views not aligning with profits of military contractors and big business that he is not skeptical of. He is associated with the Marshall Insitute, founded by his cousin Fred Seitz, who himself was skeptical of cigarette's harm, global warming, deterioration of the ozone layer etc.

The Skeptoid link references the same thing as the Quora link - that nuclear stockpiles have decreased to where a full-scale war would be less than in the 1980s, when the stockpiles were much higher.

For political reasons, it was necessary from the 1940s to 1980s to minimize fears of the impact of a full-scale nuclear war. I used to have an old Stanford Research Institute report which said that if the US and USSR had a full nuclear exchange, the US would get back to current GNP levels - in five years!

I don't know how this is science gone wrong - two of the links you put say this is no longer applicable due to post-Cold War drawdowns, and the other one is by someone who is skeptical not only of this, but that cigarettes are harmful, that climate change is happening and on and on.


The simplistic 1D climate model and the incorrect fuel loading assumptions are also relevant. And I think we owe it to ourselves to evaluate scientific arguments on their merits instead of trying to imply guilt through association.

Nuclear war certainly isn't desirable, but it doesn't do any good to exaggerate its likely effects.


>evaluate scientific arguments on their merits

Provided such merits exist and arguments are indeed scientific.


Thank you for the links. I'll have to read your articles very closely later, but recent climate simulations by Alan Robock at Rutgers and analysis by Ira Helfand at IPPNW and others show that a nuclear autumn, created by 100 15-kT (Hiroshima sized) nukes could cause a famine that affects up to 2B people.

I wrote to Dr. Robock and asked him about his model (explicitly on the record, so I'm not disclosing a private conversation). I asked specifically why did the Iraq oil well fires from the Gulf War not inject soot into the stratosphere and cause climatic effects. He wrote back that the difference lies in the formation of firestorms. I draw from this by implication that he believes there remains enough combustable material to start a firestorm in enough places to matter. It's worth noting that while cities have changed a lot, a firestorm did develop in one of the two Japanese cities bombed. I'll have more to say about this in a month or so once I do more research and review your materials.

Here's a link to some of their work: http://ippnw.org/nuclear-famine.html


These estimates look only cities and their fuel loading.

It would be interesting to see how California would manage during dry 'fire season' if nuclear bombardment caused massive forest fires all over the place. If large fires create massive combined updraft it could be a global catastrophe.

We already know that large-area wildfires sometimes cause firestorms that throw soot into the stratosphere.


> affects up to 2B people

"Affects." Saying it affects 2B people without saying how much means very little. The tailpipe emissions from my single car family affect 7B+ people, just very slightly.

I think we should start with lives lost as an easy to understand measure.

Thanks for linking the source.


I dug up the correspondence. Here's what Dr. Robock said. Again, I explicitly asked permission to quote him. Here's the relevant excerpt.

Me: "I understand that you've conducted 100 Hiroshima simulations that describe a nuclear autumn that could lead to mass starvation. Is it known where the crossover point is located between deaths due to direct effects and incidental effects of nuclear war? Furthermore, is this even a useful question to ask?"

Dr. Robock: "We simulated one case of an India-Pakistan nuclear war. We estimated 20,000,000 direct casualties, and Ira estimated 1,000,000,000 to 2,000,000,000 indirect deaths. We have a new project to do much better jobs of investigating more credible scenarios and quantifying the impacts on agriculture and food availability."

I'd recommend digging into the paper for more info. Probably in a month or two, I'll have an article that explores this question based on available credible sources in more depth.

He has a TEDx talk here: http://www.youtube.com/watch?v=qsrEk1oZ-54

EDIT: added TEDx link


Thanks!


I agree with your criticism. We'll have to read the paper to find out what that means. ;)


> I draw from this by implication that he believes there remains enough combustable material to start a firestorm in enough places to matter

Well recently the world has learned just how combustible many buildings are (Grenfell Towers) because they are covered in flammable cladding. We might not have a lot of wood construction anymore, but we've moved on from the concrete jungle as well.


Science is a process, not a single event or fact. The fact that the nuclear winter research was inaccurate was exposed by the scientific process as much as it was put forward by it.

Additionally, the absence of nuclear winter does not imply that "nuclear war is quite survivable". Nuclear war is almost certainly survivable, with or without nuclear winter. The question is though: what survives? Even without nuclear winter, crop yields are going to plummet drastically immediately, due to the collapse of world trade, industry, and commerce. And that's a positive feedback loop due to population effects. Our current state of industry and agriculture results in nuclear war causing an initial death-toll followed by a delayed death toll as things settle into a drastically different economic/industrial/agricultural equilibrium. Or, to make things clearer: the sustainable population level of a post-nuclear war scenario is vastly lower than the initial surviving population. What happens after that is still, somewhat thankfully, an open question. The human race may survive, but how long it takes civilization to recover to the same level of technology is unknown. It might take years, decades, centuries, or millenia. Indeed it might never happen, for various reasons. Nuclear war is more than likely going to result in everyone currently alive never seeing this level of technological sophistication, affluence, comfort, etc. in their lifetimes.


This is a very strong claim, and based on what I've read I do not believe it is accurate to say nuclear winter research was so off the mark as to be "inaccurate". Please see my comments further up the thread. Please cite the arguments you are basing this claim on.

My understanding is that the major source of confusion was the headline of a 1990 NYT article that made it look like nuclear winter was wrong, but the actual contents were much more moderate.

http://www.nytimes.com/1990/01/23/science/nuclear-winter-the...


> Nuclear war is, in fact, quite survivable.

That's highly debatable. I'm 1/2 way through Command and Control (the book) and one criticism I have throughout for both history (the military and politicos), as well as the author, is no mention of the massive refugee crisis that would emerge as a result of a nuclear war. It makes Mad Max look more realistic, not so much the widespread wasteland, as much as the total breakdown of civil society.

If "civil" society, modern governments, do this thing, they forfeit moral high ground. They've failed. So why wouldn't they be immediately dismantled? Why trust anyone? I think it would be such high order betrayal people would take up a new religion that commands them murder is a gift from god, do it as often as possible in order to survive.


John McClane: Come on. Government's gonna have dozens of departments dedicated to that shit!

Matt Farrell: It took FEMA five days to get water to the Superdome.


>Nuclear war is, in fact, quite survivable.

Short term, or long term? In the long term, that's a lot of hungry people with no org chart above them. Short term, a lot of people will die, be gravely injured, and probably haunted.

Your definition of survival is pretty opaque.


I don't know the science enough to judge which side of this argument is more likely to be correct. But I do know I felt more comfortable about the approach our leaders took towards nuclear war when everyone was terrified of it vs. the attitude of "Hmm, maybe it isn't so bad... maybe we could win a nuclear war?"


I understand the sentiment, but in the long run, I don't think it does us good to promote fiction over the truth, even in instances where we think the fiction will do more immediate good. We can't make sense of the world unless we understand it, and it's hard to predict what new insights we can gain from truth.


Nuclear Winter won’t matter when spent nuclear fuel pools in those nations undergo meltdowns following sustained losses of offsite power caused by catastrophic damage to the national electrical distribution system. The fuel in a nuclear reactor is marginal relative to SFP loading.


A nuclear meltdown is a localized concern. It's small potatoes compared to an all out nuclear exchange.


An SFP fire is not a reactor meltdown, and the distribution of fission products from a SFP and a weapon are also very dissimilar. SFP fires will result in long-lived contamination over plumes of >100km that would result in exclusion zones.

For example, failure to restore cooling to the Fukushima pools could have necessitated the evacuation of 35MM people.

http://scienceandglobalsecurity.org/archive/sgs24vonhippel.p...

Even in a pure-counterforce exchange that avoided targeting population centers, the resulting damage to infrastructure could result in the denial of current urban centers to habitation for many decades.


Freeman Dyson wrote about this and his feeling was that it would be similar to the London smog after the war. Which was warm - so his conclusion was it wouldn't be a nuclear winter.



Those are both just repeating the Sagan scare scenario and rhetoric, handwaving about levels of smoke and tar generation that we know is wrong given previous nuclear test explosions, and smoke generating events like the 1991 Kuwaiti oil fires.


“Handwaving”

No that’s pretty much your game I think, unless you just didn’t read the paper.


> 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-the...


Ignoring modern Studies in favor of a 27-year-old New York Times article? Right, something smells here.


> The concept of "nuclear winter" is a great example of science gone wrong.

It's not science gone wrong. It's an example of politics co-opting and exploiting science because science has the credibility that politics doesn't. The elites wanted to scale back nuclear spending and needed a cover to convince the masses and the soviets to support "denuclearization".

History is full of "science" being exploited to advance a political agenda. One of the most poignant examples is nazi germany using social darwinism to justify their political agenda. Modern global warming scaremongering industry is the newest example of "science" being co-opted for a political agenda.

Certainly, human activity is affecting the environment, but the doomsday nonsense peddled by al gore, dicaprio and the media isn't science, it's a politically driven scaremongering tactic to get the world under one "system" ( carbon tax, trade, etc ).


It's a shame that you're being down voted. You're right about the political cooptioon of science. In my original message, I was trying to be minimally divisive.

I think you're wrong on climate change, but for understandable reasons. We're been peddling lies under the name of science for so long now (see the role of sugar in nutrition) that science has lost much of the credibility it needs to drive the changes we need to address climate change. I don't blame people for distrusting counter-intuitive science generally these days.

Maybe that's why we keep talking about ineffective emissions regulations instead of prototyping effective geoengineering remedies for the carbon forcing and ocean acidification.


This comment is probably being downvoted for good reason. It has a valid core idea. Politicians often cherrypick science that agrees with their ideology to further their agenda. But this statement smacks of conspiracy, crankery and sloppy thinking.

"It's not science gone wrong. It's an example of politics co-opting and exploiting science because science has the credibility that politics doesn't. The elites wanted to scale back nuclear spending and needed a cover to convince the masses and the soviets to support "denuclearization"."

Who are 'the elites.' The Illuminati? Carl Sagan and company? Ronald Reagan who began the START treaty process? So Carl Sagan and other scientists entered into a conspiracy with Ronald Reagan to defraud the public with a poorly crafted scientific paper to boilster nuclear disarmament.


I don't think the OP was talking about the kind of conspiracy you describe. Or maybe he was: it doesn't matter, because there's a subtler point. Scientists are not somehow exempt from confirmation bias and motivated reasoning, and political biases can creep into research without anyone cackling in a smoke-filled room.

Look, for example, at the current sorry state of social science research, much of which does not reproduce. Ego depletion, stereotype threat, the IAT: all "scientific" ideas that are politically convenient but fiction, and which went unquestioned for a long time because, deep down, most researchers didn't want these ideas to be wrong. That doesn't make these researchers conspirators.


And I completely agree. That's why I said the post"...has a valid core idea. Politicians often cherrypick science that agrees with their ideology to further their agenda."

But I'm sorry the sentence I quoted isn't blatant crankery but it is loaded with conspiracy innuendo.


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"


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


My problem with these predictions is that volcanic eruptions at these energy scales and with plenty of ash output occur with some frequency, and the effects are still not human extinction.


5,000 megatons would be enough to destroy every major and semi-major city on the planet, literally.

There are 4,416 cities on the planet with 150k+ population. 10 100kt bombs are more than enough to destroy most cities on the planet, at least when you define "destroy" as "most everything is broken and/or on fire and most people are dead within 1 year's time".

After your 10-nukes-per-city campaign, you've still got another 5,840 100kt bombs left in your 5,000 megaton budget to divide among the largest cities (NYC, Tokyo, Hong Kong, Tehran, etc.).

I'm stating this because I don't think it's too useful to predict the secondary effects (nuclear winter, etc.) of a war so terrible that basically everyone on the planet would already be dead (from blast, fire, etc.) or dying within a year's time (radiation, starvation from infrastructure collapse, etc.).


I'm certainly not saying nuclear war wouldn't be awful - it would be!

But in judging Carl Sagan's claims, we look at what he actually wrote to the public, and it's the specific climate claims that Carl Sagan made that appear to be wildly incorrect.


The people not near the cities targeted wouldn't die from environmental results. That's the point. They might die from serious economic disruption if they can't get access to food. But there would be people who would survive it. There's quite a lot of land in flyover states and what not. A lot of that is farmland.


A lot of that farmland you're referring to houses ICBM silos, command and control facilities, or airbases.


I'm guessing that's less than 0.01% of the actual land area. Anyway, there's mountains, forests, arctic wilderness, islands, etc. where some people live in various concentrations. Human civilization would take a massive blow from an all-out nuclear war, but human beings wouldn't go extinct, and some elements of civilization would remain. It's not like all technological capability or knowledge would be lost.


The interdependency of technology between cities, states and nation-states shouldn't be underestimated. How many books are available today that can describe how to make a semiconductor? Will these books survive? How about the process to create pure silicon? Or the lithography necessary to create CPUs? And with multiple nuclear detonations, the likelihood of EMP effects is high; this will cripple civilization as much as any explosions or fallout.

Sure, technology can survive; witness the gunsmiths in the Hindu Kush who can recreate a functioning Enfield rifle (or ak-47) from scrap metal. But the world would be set back at least 100 years or more, and much knowledge would be lost because of poor archiving, poor dissemination, and the death of experts who are invaluable.


> A lot of that farmland you're referring to houses ICBM silo

Certainly NOT a lot. Even if you have tens of thousands of ICBM silos that's still not much density compared to whole land at your disposal.


That sounds like a city-dweller's perspective.

Sure, I would almost certainly be dead, but life on Earth would continue, our species would continue, and our civilisation would continue (albeit with some major setbacks).

Besides, I don't think anyone's nuclear war plan is actually to destroy every major to semi-major city on Earth. In a realistic 1980s nuclear war, a lot of nukes would be targeted at military bases and the like. Plenty of others would destroy every major city in the US and USSR, plus each country's nuclear-armed allies. Maybe we here in Australia would get a nuke or two out of spite. But is anyone going to bother to nuke South America?


> In a realistic 1980s nuclear war, a lot of nukes would be targeted at military bases and the like

i think it's mentioned in Command and Control (book) but if I recall correctly the plan from the US perspective was not only to nuke military targets, but also all major population centers, with several thermonuclear bombs for each target, for good measure. And that was not only the USSR, but basically every ally of the USSR as well.

You can imagine that the other side was also going to do about the same thing.

Sure, some countries may have been relatively spared, but all in all the whole of Europe, US, Russia, China, would have been annihilated.


> ... is anyone going to bother to nuke South America?

Yes.

There is this tendency to assume that, because you're ("you're" in the general sense) not thinking about a place, then that place necessarily isn't important from a geopolitical point of view.

Not taking into account the geopolitical value of maintaining military bases on the US's southern flanks, it's worth noting that Brazil is the 12th largest oil producer, among its many other important economic attributes. Argentina is one of the go-to places for China to buy farm land[1]. Take those two and you're left with basically 10% of South America.

1. https://www.wsj.com/articles/SB10001424052702303823104576391...


"Soviet Union had tested a 50 megaton bomb with no more than the usual local effects"

The Tsar Bomba was tested over artic wildereness in Novaya Zemlya, not over a city.


Do the effects on the climate change depending on whether it's over a city or the wilderness?


The contention was yes: cities are built primarily of loose-frame wood structures that burn easily with rapidly-spreading fires (unlike forests, which are much harder to light and sustain). So the idea is that one bomb causes the inner city and all the urban expanse surrounding it to burn within a few hours as a "firestorm" that would lift the soot into the stratosphere.

Now, that's been debunked apparently. But the hypothesis as stated is sound enough. It's not the blast itself, it's the fire.


I believe the idea is that if you explode an H-bomb over a large city an awful lot of stuff is going to catch fire resulting in huge firestorms that would (along with the effects of the explosions themselves) raise a lot of stuff into the atmosphere.

Of course, thankfully, we don't really know what would happen when a large city receives a realistic attack from multiple H-bombs.


Except we know what happens when major cities are fire bombed from World War II, and we know the effects of the much worse 1991 Kuwait oil fires which caused no such effects.


I think it's not quite so easy. There were many cities bombed in World War II (maybe 60 in Japan and additional ones in Germany), but there were only 5 or 6 firestorms. Similarly, the Kuwait oil fires created a lot of soot, but the plume is isolated to a given point, which causes it to disperse before reaching the stratosphere.

The claim is that firestorms in particular would create climate change, because a single city-sized plume could carry the soot much higher than if the city burned and released the same amount of soot in an ordinary fire.

https://en.wikipedia.org/wiki/Firestorm#City_firestorms https://en.wikipedia.org/wiki/Nuclear_winter


700 oil wells along with several lakes of oil burned for months in 1991. Many of the same people who projected 'nuclear winter', advanced the same environmental winter projections for the hypothetical fires before the conflict.

https://en.wikipedia.org/wiki/Nuclear_winter#Kuwait_wells_in...


I don't think we had either climate models or remote sensing capabilities during World War II adequate to assess what climate effects may have resulted from the several firestorms that occurred. The 1991 Kuwait oil fires were apparently projected by some to cause a "petroleum winter", but these models were disputed and many simulations apparently suggested that the particles would not reach the stratosphere (and evidently they did not)[0]. However, it seems that since 1998[1] it has been known that smoke from naturally occurring firestorms (resulting from wildfires) can reach the stratosphere and cause regional climate effects significant enough to alter hemispheric temperature patterns.

[0] https://link.springer.com/chapter/10.1007%2F978-94-011-1685-...

[1] http://adsabs.harvard.edu/abs/2006AGUFM.U14A..04F


Except Carl Sagan himself was one of the scientists advancing the "petroleum winter effect" in 1991 in the lead up to the gulf conflict, just as he advanced his nuclear winter scenario earlier.


If your point is that Carl Sagan may not be the foremost authority on nuclear winter, I think it's already been made (though, that is an interesting catch). I have no ability to speak on that subject, I was merely pointing out that I find it misleading to suggest that firestorms have been shown not to cause climate effects when the opposite is also true in some instances.


I think celebrity scientists propounding disaster scenarios that have actual poor scientific backing, is one of the reasons why there is still so much skepticism about global warming. It is kind of like the story of the "boy that cried wolf". Scientists have been warning about impending doom so many times in the past, and in general things have never been better for humans on a global scale now. People learned to disregard dire predictions. Now, when there is a real danger, people are skeptical.


What are these "so many times" that scientists have incorrectly been warning about impending doom?

Nuclear winter might qualify, but given that it's merely the difference between "everyone dies" and "humanity survives, but civilization is wrecked and we really must ensure that this never happens," it doesn't seem huge.

What else is there?


Ehrlich and the whole overpopulation predictions, DDT would wipe out songbirds, the prediction we would run out of oil, a new ice age, ozone hole, the whole concept of the doomsday clock, and now the whole AI will wipe out humanity fear.

Part of this blame falls on the media. It amplifies the "gloom and doom" voices because that is what sells.


How common was Ehrlich's prediction? A doomsday scenario proposed by one guy, no matter how popular his book is, doesn't seem like it should count.

The problems with DDT and the ozone hole were averted because people took action in response to them, not because the warnings were incorrect.

The "new ice age" thing was never a mainstream prediction. The idea that scientists were warning about global cooling in the 70s is a myth.

Peak oil and the doomsday clock are both absolutely correct, they just haven't happened yet. Oil reserves are finite on human timescales, and global thermonuclear war would devastate human civilization and the chance of it happening is still disturbingly large.

AI is too early to say, but already pegging it as an incorrect warning now, when nothing even close to human-level AI exists, seems a bit premature. (One could also argue that the warning is premature, but that's different from being wrong.)


> The idea that scientists were warning about global cooling in the 70s is a myth.

The Scientific American articles from the 80s still exist. Myth, is not the appropriate term.


The key word in the quoted text is "scientists." The media hype was real. Unlike the current climate change hype, it wasn't based on scientific consensus.


Indeed: The Myth of the 1970s Global Cooling Scientific Consensus, Peterson, Connolley, Fleck (http://journals.ametsoc.org/doi/abs/10.1175/2008BAMS2370.1)


"consensus" is the new goalpost? SMH


What would you suggest here? It wasn’t even close to a majority.


In the context of the 70's, everything was a disaster or crisis waiting to happen. From movies that made you worry about earthquakes, burning skyscrapers, killer bees, to books Ehrlich's book, Rachel Carson's overhyped "Silent Spring" and magazines like Newsweek that touted a coming ice age. If that wasn't enough, the overwhelming sense of fear of a war with the USSR, or running out of oil due to an OPEC embargo was a real thing.


> magazines like Newsweek that touted a coming ice age

Please be a little more careful there: you are very close to shifting goalposts from "bad science" to "bad journalism"— those two are very separate things yet you don't bother to make a clear distinction.


I'm not shifting goalposts in anyway. The zeitgeist at the time was very much centered on the crisis du jour. This was in a wide array of media sources.


The ozone hole was absolutely real. We took action and fixed it. We are running low on cheaply extractable oil, but we're making progress towards replacing it with renewable sources. This is not fearmongering, this is responding to the evidence and taking action.

And the Doomsday Clock is a strange example of a false prediction, since it doesn't actually make strong predictions, just estimates the level of nuclear tension at any given time. You can hardly argue that we haven't been close to nuclear war several times in the past 50 years.


What whas wrong about the ozone hole?

About the coming Ice Age, https://arstechnica.com/science/2016/06/that-70s-myth-did-cl...


Y2K, ozone hole.

I know that those "don't count", because they actually got addressed, but they still feed into an unfortunate perceptual pattern.


That seems unfair... but since we're talking about how people perceive it, that doesn't make it wrong.


> What are these "so many times" that scientists have incorrectly been warning about impending doom?

Oh, like every time there's a bird flu epidemic? The WHO cries Wolf about every couple of years.


The "Spanish" flu epidemic of 1918 resulted in the deaths of 50 to 100 million. The fact that we haven't had a similar epidemic since is in large part due to the work of groups like WHO and CDC. But this preventive work is not unlike IT departments making backups -- nobody thinks it is that important until the system fails.


thaTs a pretty impressive claim to make in a pre antibiotics and pre modern medecine world when tuberculosis and rabbies were still killing a lot of people every year. we did not wait for the WHO to have better standards.


It reminds me of Bill Nye, an ME who is presented as a scientist, but isn't much more a scientist than an amateur scientist.

He's good for kids, but not someone adults should look to for science, given it's scriptwriters and producers putting forth the "science" with him as frontman.


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.


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.


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.


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.


> 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.



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.


>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.


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_we...


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.


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


'...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://en.wikipedia.org/wiki/Overview_effect


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?


I agree. That is a true failure that has effects on all future scientists going public. Presenting hypothetical effects as a possibility and open to discussion / discourse is still important.


A great mini-doc overview of the same topic:

https://www.retroreport.org/video/nuclear-winter/


Also, the 1984 BBC documentary 'On the 8th Day' is worth a look: https://www.youtube.com/watch?v=tCz9zqTTark


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-the...


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.


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.


You probably don't need a high yield if you just nuke a volcano or super volcano https://en.wikipedia.org/wiki/Volcanic_winter


"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


Winter is coming!

Sorry, couldn't resist.


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.


> 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.


Crying wolf by making up deliberately exaggerated scenarios in order to push a social agenda is not valid, and damages the reputation of scientists.


lol nuclear fallout isn't a hoax

https://en.wikipedia.org/wiki/Downwinders


'Nuclear Winter' is. That is the topic of this post.

http://www.nytimes.com/1990/01/23/science/nuclear-winter-the...


Surely that will be considered when employing these weapons in a war.


Surely the "when" was meant to be an "if"? Is the default assumption that this level of violence will happen again? The presence of that mindset is what allows escalation, rather then it being considered at most a crazy edge case scenario.

My coworkers were discussing what would happen if California voted to declare independence from the United States. The hypothetical scenario instantly moved to "occupation by US Military forces", which hadn't even come up in my mind. Its not like the EU states moved to occupy Britain or anything. It seems like the obvious solution is to try to sit down, think about it, debate it, and work out the problems of the involved parties. Why turn directly to violence?


>The hypothetical scenario instantly moved to "occupation by US Military forces", which hadn't even come up in my mind. Its not like the EU states moved to occupy Britain or anything.

We had a war about this. US states are not allowed to secede. The Union is perpetual.


And in contrast, the EU explicitly allows exit. So it’s not a very good comparison.


So was the Roman Empire.


The "right altitude" maximizes damage and mostly reduces fallout as a side-effect, so yeah




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