
When Carl Sagan Warned the World About Nuclear Winter (2017) - bryanrasmussen
https://www.smithsonianmag.com/science-nature/when-carl-sagan-warned-world-about-nuclear-winter-180967198/
======
pmoriarty
By far the most terrifying movie I've seen on nuclear war has been _Threads_.

If you can find a good copy of it, watch it.

Also, many people these days act like the threat of nuclear war went away with
the end of the Cold War. But the threat is still very real, and there are
still thousands of nuclear weapons that the US and Russia continue to aim at
each other, not to mention the rest of the world's nuclear powers, some of
which have been at war with each other before and stand a good chance of going
to war again.

~~~
Trasmatta
> Also, many people these days act like the threat of nuclear war went away
> with the end of the Cold War

Lots of people seem to be convinced that MAD is a sufficient deterrent for
nuclear war. Which may be true if your safeguards are perfect and your actors
are always rational. But in reality, all it takes is a mistake or a madman to
set off nuclear armageddon.

~~~
simonh
That was certainly true during the Cold War, with two implacably opposes
factions that have no dependencies on each other and no real understanding of
each other either. It was terrifying, and mistakes were made that brought us
extremely close to catastrophe.

I think that less of an existential threat now. The works us a lot more
interconnected and interdependent. What would Russia be without the west to
export its oil and gas to? What would China be without foreign markets? We all
need each other. Proliferation means the risk of nuclear terrorise or limited
conflict us still significant, but not at the globe killing level we had 40
years ago. A limited or regional nuclear exchange would be catastrophic, but
not species killing.

~~~
acqq
>> But in reality, all it takes is a mistake or a madman to set off nuclear
armageddon.

> The works us a lot more interconnected and interdependent. What would Russia
> be without the west to export its oil and gas to? What would China be
> without foreign markets? We all need each other.

The argument was "all it takes is a mistake or a madman." Neither cares about
the fact that "we all need each other."

If you worked anywhere in tech long enough, you should be aware how much
unexpected errors are indeed possible even in "old and tested" workflows.

And some madman is always somewhere where "everybody thought he's so nice."

> A limited or regional nuclear exchange would be catastrophic, but not
> species killing.

Note: "species" and "civilization" aren't the same.

~~~
simonh
OK, what is the scenario where a single madman causes a complete simultaneous
nuclear conflagration by the USA and USSR, the only countries with enough
bombs to cause a global nuclear holocaust?

Russia and the USA have no interest in destroying each other. All the other
nuclear powers are too small fry to cause more than regional damage.

~~~
acqq
> what is the scenario where a single madman causes a complete simultaneous
> nuclear conflagration

An actual nuclear war planner wrote a whole book about that:

"The Doomsday Machine Confessions of a Nuclear War Planner"

[https://www.bloomsbury.com/us/the-doomsday-
machine-978160819...](https://www.bloomsbury.com/us/the-doomsday-
machine-9781608196746/)

P.S. USSR doesn't exist anymore.

------
gxqoz
Another take on the same incident:
[https://www.newyorker.com/magazine/2017/01/30/the-atomic-
ori...](https://www.newyorker.com/magazine/2017/01/30/the-atomic-origins-of-
climate-science)

"The biggest consequence of the nuclear-winter debate, though, has had to do
not with nuclear-weapons policy but with the environmental movement. In the
short term, the idea of a nuclear winter defeated the idea of deterrence. In
the long term, Sagan’s haste and exuberance undermined environmental science.
More important, the political campaign waged against nuclear winter—against
science, and against the press—included erecting a set of structures,
arguments, and institutions that have since been repurposed to challenge the
science of global warming."

~~~
hypertexthero
Ann Druyan, Sagan’s wife, responded to this article with the following:

> Lepore has done history and science, your readers, and my late husband, Carl
> Sagan, a great disservice. Her article’s central thesis demeans Carl’s
> scientific acumen and his character, wrongly asserting that, in his
> “grandiosity,” he harmed the environmental movement by advancing an
> exaggerated theory of the long-term consequences of nuclear war.

> From Lepore’s account, readers would conclude that Carl’s interest in the
> greenhouse effect on Venus was something that he picked up from a bright
> grad student. In fact, five years earlier, Carl had published his own
> dissertation, viewed as the beginning of our modern understanding of Venus,
> which included his groundbreaking greenhouse model.

> Lepore also gives the impression that the theory of nuclear winter has been
> debunked. If anything, more recent scientific research indicates that Carl
> and his colleagues were conservative in their estimates. Tellingly, she
> makes no reference to the findings—in peer-reviewed, refereed
> publications—that fully support, and expand on, the models created by Carl
> and the other nuclear-winter scientists.

> Carl is also faulted for “partisanship,” in part for declining an invitation
> to dine with the Reagans in the White House—a choice that I made, in
> response to the El Mozote massacre and other crimes in Central America for
> which I believed Reagan bore some responsibility. Does Lepore find those
> public figures and celebrities who refuse to be co-opted by the Trump White
> House to be partisan? Or is that an unwillingness to lend your cachet to
> policies that you abhor?

> According to Lepore, Sagan “made some poor decisions” and “undermined
> environmental science.” She leaves the reader to wonder what those bad
> decisions were. Fighting for the reduction of tens of thousands of nuclear
> weapons? Sounding the alarm on global warming decades before others started
> paying attention to it? Mounting the world’s most successful campaign for
> public scientific literacy? Attracting multitudes to science and reason?
> Turning the camera on Voyager 1, which was out by Neptune, to point
> homeward, to make us see our true circumstances in the vastness? What better
> decisions have other people made?

> Ann Druyan

> Ithaca, N.Y.

—[https://www.newyorker.com/magazine/2017/02/27/letters-
from-t...](https://www.newyorker.com/magazine/2017/02/27/letters-from-the-
february-27-2017-issue)

~~~
TaylorAlexander
Wild that Ann Druyan’s words would be downvoted here.

------
gojomo
This article should mention that the original conception of, & strongest
warnings about, a global 'nuclear winter' effect haven't really held up with
better models & better understanding of how ground fires/explosions might
affect the upper atmosphere.

The answers here include a fair summary of the updated case _against_ :

[https://www.quora.com/Is-the-nuclear-winter-a-hoax](https://www.quora.com/Is-
the-nuclear-winter-a-hoax)

------
Trasmatta
The threat of nuclear war doesn't seem to occupy people's minds the way it
used to. It tends to still scare me and keep me awake more than the threat of
climate change (although both give me pretty regular existential crises).

There was even an earthquake where I live a few months ago (first I've
experienced). It woke me up, and the first thing my mind thought was "nukes"
for some reason (despite not living somewhere that would be a likely target).
It only took a split second to realize what was really happening, but it was
interesting that it was the first thing my mind went to.

------
makerofspoons
I went to several of Professor Brian Toon's presentations when I was a student
at CU Boulder. The article briefly mentions his current research but if anyone
is interested in the effect a nuclear exchange between India and Pakistan
would have on the world, this is a sobering read:
[https://www.sciencedaily.com/releases/2019/10/191002144251.h...](https://www.sciencedaily.com/releases/2019/10/191002144251.htm)

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jpm_sd
As a kid in the 80s, I was terrified of nuclear winter. Had nightmares about
it.

~~~
njharman
Same, well not winter, I assumed I'd die in initial strike living near major
targets.

I, and many people of similar age I've talked with since, did not believe they
would live into adulthood. Believing nuclear war was imminent and inevitable.

~~~
gojomo
I as a teen in the 80s, I never believed nuclear war was _inevitable_ , but it
was a constant background fear. In the suburbs of Houston, any nighttime
lightning-strike waking me up would trigger the thought: "was that a nuclear
detonation over the city?"

Those seeking to learn more about the mindset could check out ABC's 'The Day
After' miniseries (1983) or the movie 'Miracle Mile' (1988) – which I'd
suggest viewing with no other pre-reading other than this recommendation.

------
ardy42
> This article marked the public’s introduction to a concept that would
> drastically change the debate over nuclear war: “nuclear winter.” The story
> detailed the previously unexpected consequences of nuclear war: prolonged
> dust and smoke, a precipitous drop in Earth's temperatures and widespread
> failure of crops, leading to deadly famine. "In a nuclear 'exchange,' more
> than a billion people would instantly be killed,” read the cover. “But the
> long-term consequences could be much worse..."

> According to the article, it wouldn’t take both major nuclear powers firing
> all their weapons to create a nuclear winter. Even a smaller-scale war could
> destroy humanity as we know it.

What's the current consensus on the idea of a nuclear winter? I vaguely recall
reading that the early papers like these overestimated the effects, and it
would take a far larger nuclear exchange than has ever been possible to cause
that kind of effect on the climate.

~~~
catalogia
> _According to the article, it wouldn’t take both major nuclear powers firing
> all their weapons to create a nuclear winter. Even a smaller-scale war could
> destroy humanity as we know it._

I'm skeptical of this; in the 20th century there were more than 500
atmospheric nuclear tests. Given that, it seems unlikely that a ""small""
nuclear war would necessarily cause such dramatic effects as humanity-
destroying nuclear winter. This said, cities getting nuked would probably
launch more soot into the atmosphere than the desert or ocean getting nuked,
so... maybe?

But I think we should try to avoid finding out for sure. ;)

~~~
simonh
The theory is that the incineration of so many cities, and the subsequent
firestorms would put vast amounts of smoke and particulates into the upper
atmosphere. It’s this rather than the bombs themselves that has the main
climatic effect. The fact that all these particulates would be radioactive is
an extra dimension to it all.

~~~
ardy42
> The theory is that the incineration of so many cities, and the subsequent
> firestorms would put vast amounts of smoke and particulates into the upper
> atmosphere. It’s this rather than the bombs themselves that has the main
> climatic effect. The fact that all these particulates would be radioactive
> is an extra dimension to it all.

Some later Googling of mine found some stuff about how the nuclear winter
theorists's models made predictions that oil well fires would result in a
small scale global winter, but the Kuwaiti oil files did not confirm that
prediction.

[https://en.wikipedia.org/wiki/Nuclear_winter#Kuwait_wells_in...](https://en.wikipedia.org/wiki/Nuclear_winter#Kuwait_wells_in_the_first_Gulf_War):

> One of the major results of TTAPS' 1990 paper was the re-iteration of the
> team's 1983 model that 100 oil refinery fires would be sufficient to bring
> about a small scale, but still globally deleterious nuclear winter.[109]...

> In articles printed in the Wilmington Morning Star and the Baltimore Sun
> newspapers in January 1991, prominent authors of nuclear winter papers –
> Richard P. Turco, John W. Birks, Carl Sagan, Alan Robock and Paul Crutzen –
> collectively stated that they expected catastrophic nuclear winter like
> effects with continental-sized effects of sub-freezing temperatures as a
> result of the Iraqis going through with their threats of igniting 300 to 500
> pressurized oil wells that could subsequently burn for several
> months.[110][111][112]

> As threatened, the wells were set on fire by the retreating Iraqis in March
> 1991, and the 600 or so burning oil wells were not fully extinguished until
> November 6, 1991, eight months after the end of the war,[113] and they
> consumed an estimated six million barrels of oil per day at their peak
> intensity....

> The atmospheric scientist tasked with studying the atmospheric effect of the
> Kuwaiti fires by the National Science Foundation, Peter Hobbs, stated that
> the fires' modest impact suggested that "some numbers [used to support the
> Nuclear Winter hypothesis]... were probably a little overblown."[119]

> Hobbs found that at the peak of the fires, the smoke absorbed 75 to 80% of
> the sun's radiation. The particles rose to a maximum of 20,000 feet (6,100
> m), and when combined with scavenging by clouds the smoke had a short
> residency time of a maximum of a few days in the atmosphere.[120][121]

> Pre-war claims of wide scale, long-lasting, and significant global
> environmental effects were thus not borne out, and found to be significantly
> exaggerated by the media and speculators,[122] with climate models by those
> not supporting the nuclear winter hypothesis at the time of the fires
> predicting only more localized effects such as a daytime temperature drop of
> ~10 °C within 200 km of the source.[123]

------
KorfmannArno
I'm often amazed that the world didn't encounter a nuclear war yet.

What is so effective preventing it?

~~~
thansz
Luck.

In the short period of time we have had access to nuclear weapons, we have
come very close to nuclear war between superpowers:

* Cuban Missile Crisis - Vasili Arkhipov Prevents launching of nuclear torpedo while his Soviet submarine flotilla is being bombarded by depth charges (happened to be signaling depth charges). Turns out the US warships above them just wanted the submarines to surface so they could communicate the end of hostilities.

* Computer Malfunction - Stanislav Petrov Holds off alerting officials of multiple incoming nuclear ICBMs because he "suspected" they were a glitch, preventing a likely nuclear counter-attack.

* Science experiment looks like nuclear attack - Boris Yeltsin correctly decides to wait launching a counter-attack based on an incoming rocket. All the while sitting in front of an activated nuclear briefcase and being pressured by aids to launch within the 12 minute response window. The rocket was meant for atmospheric testing.

There are many, many more.

Proliferation means more and more nation states have access to nuclear
weapons. Balancing peace amongst all those nations can be difficult (look at
India and Pakistan). Countries with existing nuclear stockpiles can undergo
dramatic shifts in leadership and policy (US politics anyone?).

We also have 7.5+ billion people on the planet, consuming more resources than
ever, on a planet with a finite amount of things.

Now throw in the further ramifications of climate change like political
instability, infrastructure strain, resource scarcity, and refugee migrations
into the mix. Or a truly mad guy with a nuke.

There are way too many people out there that are crazy optimistic that we
aren't going to have a nuclear war...ever. We have always had warfare, and
when the shit hits the fan, armies have always used the biggest weapons they
have had.

Nuclear weapons may very well be our great filter.

~~~
KorfmannArno
Like, I'm very inclined to think it might happen soon.

But what is making me less inclined is the fact it didn't happen within the
last ca. 70 years.

~~~
thansz
We haven't had a global pandemic in over 100 years and yet here we are.

Countries have nuclear weapons and the global community has to get it right
every single day to avoid nuclear war.

I'm hoping it doesn't happen, but the lack of precedent doesn't mean nuclear
war cannot happen. If we needed precedent for something to occur, we never
would have a "first" of anything, and history is littered with firsts.

But here's hoping. Did I mention I'm great at parties?

------
atemerev
Except that the current consensus on nuclear winter hypothesis is that it was
largely politically (as opposed to scientifically) motivated. So comparing it
to climate change is rather controversial in its own regard.

------
hchz
The valid criticisms of the accuracy of these studies are missing the forest
for the trees. A major exchange would utterly cripple the global economy,
destroy much of our electrical generation and distribution infrastructure,
along with our information storage and processing systems, and our
manufacturing capability to rebuild it.

------
staycoolboy
I remember the ham-fisted "The Day After" miniseries when I was in highschool.
It was the biggest TV event since the miniseries "Roots" in the late 70's
(watch that and you'll never look at "Reading Rainbow" or Geordi La Forge the
same way again). It was a super cheesy depiction of nuclear war and the days
that follow.

I was too young for the "duck and cover" drills of the 50's, but my generation
(X) knew that global thermonuclear war (heh) had no chance of survival.

Toward the end of the 80's and early 90's, fear of nuclear war tapered off
after The Wall came down. In fact, Sagan was harassed by the GOP and Right-
wing pundits for claiming that if Saddam burned the oil fields, we would
experience a nuclear-winter around the equator.

The 80's were nuts tho: Reagan & Gorby's nuclear standoff was pretty fucking
insane in hindsight: mutually assured destruction is in the DNA of the modern
right-wing movement.

Jeez, even Sting wrote a #1 hit about it in 1985 using a melodic theme by
Prokofiev.

Those were the days?

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umc0der
talk about synchronicity... sam harris recently released a podcast entailing
the ever-present threat of nuclear war:
[https://open.spotify.com/episode/7DbMBiOYCCr7LRObkqfffe](https://open.spotify.com/episode/7DbMBiOYCCr7LRObkqfffe)

