http://www.envsci.rutgers.edu/%7Egera/nwinter/nw6accepted.pd...
In short, the conclusion was that a nuclear war using 1/3 of the world's arsenal would devastate agricultural production for years due to average global temperature drops on the order of the last ice age occurring in /less than one year/, with temperature drops over land five times as severe (~-20 C), reduction in precipitation by over 45%, and a reduction in freeze-free growing seasons across the northern hemisphere by 50-100 days.
Large scale nuclear wars: still a bad idea.
Any discussion beyond this is guesswork..as far as I know we have never really studied this stuff. It would be interesting if someone could point out that I'm wrong. The following article claims that the number of birth defects and cancer-related deaths from the Hiroshima/Nagasaki bombings are too small to be seen in the (admittedly sparse) data collected.
I think it's a good idea to study the traditional notion that nuclear war is so extremely destructive. The subject seems to be a voluntary intellectual wasteland - no one ever wants to find out how things really would work, only quote the canonical belief that any nuclear war would cause huge amounts of deaths from cancer, birth abnormalities, barren fields, genetic mutations and nuclear winter.
What such a war would do to society is an entirely different matter, but this is almost never discussed.
I love the word "traditional". As I was saying to my wife the other day, on the occasion of the passing of Les Paul, "it's amazing how many of the inventors of our ancient and venerable traditions were still walking around as of last week."
In this case, the "traditional notion" that nuclear war could destroy all of life of earth dates back only to the 1960s, was by no means universally accepted, and still is not universally accepted. Nuclear survivability has, for obvious reasons, always been of intense interest to our political leaders, and I assure you that the subject is not an "intellectual wasteland": There are reams and reams of research on it. Much of it is classified, of course.
And talk of "what will happen after the nuclear war" used to be popular -- witness all those movies and bomb shelters and plans made during the 1950s and early 1960s, when people held the then-quite-reasonable belief that nuclear war was inevitable. But then the popular notion of global nuclear annhilation took hold -- probably because, like quite a few "traditional notions", it contains a big grain of truth. Perhaps it is hard to kill the whole world in a nuclear war. But it's not so hard to kill my whole world. I can give you a target list of eight cities, all of which contain major US research universities, which (if bombed) would destroy, say, 95% of all the people I've ever known. In a full-scale nuclear exchange involving the United States, odds are that my world would be destroyed. (I, personally, am incredibly likely to die in the initial blast wave, as I live down the street from the Route 128 tech corridor, home to companies like Raytheon.)
So maybe a person who lives in the New Guinea highlands really can afford to laugh at the prospect of the post-apocalypse. (May we never know.) But those of us who live in Boston, San Franci, New York, or Washington can't. Because, for us, bombing all four of those cities would be an apocalypse.
I wouldn't call that livable.
I'm generally considered very pro-military in the crowd I run in, but I consider the nuking of Hiroshima and Nagasaki to both be in the top ten of WWII atrocities, and that's saying something.
There might still be people left, but it doesn't mean they'll have a good time.
For more about existential risks (and how to mitigate them), check out the work of the Lifeboat Foundation (http://www.lifeboat.com)
Am I the only one who heard the rumor that we have enough nukes to destroy humanity 8 times?