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Thomas comments on [LINK] Nuclear winter: a reminder - Less Wrong
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AFAIK, they have popped about 1000 atom bombs so far. Do we see any really bad consequences?
But from 10 to 100 times more in a shorter time interval, there would be a Nuclear Winter?
I doubt it.
From the article:
I know. But how this compares to big wildfires, yearly coal and oil burnings and a volcano or two?
We are told, that the Giga tones of burnt coal and oil per year, warms the planet. About the same amount of plastics, wood and so on would trigger the so called Nuclear Winter?
I am a NW skeptic.
Also from the article:
The proximity of the bombs in time and place matters significantly. Even if you are skeptical of this, you'd have to be not updating enough based on expert opinions to view this as less than 10% likely.
Your comparison between the problems from greenhouse gasses and the particulate matter from a nuclear war is absurd.
2 Mt. 1.5% of the Tzar bomb, which exploded at Novaya Zemlya one day. Nothing much.
Enough to make as much fire as in Black Thursday bush fire? Which didn't caused a decade long "nuclear winter"?
Energy release by the bomb probably isn't the right metric here. A multimegaton bomb spends a lot of that energy heating plasma into hotter plasma. This has minimal climate impact.
The scenario the nuclear winter researchers had in mind was that those 100 bombs each start catastrophic fires that burn down major cities. Those fires can produce lots of soot and ash that have climactic effects, and then lift the particulates into the stratosphere.
I don't have enough of a background to comment on whether and why those fires would be worse than a large brushfire or forest fire, but I'm pretty sure it isn't about megajoules of energy.
If it isn't about MJ, then it is about the amount of dust and soot?
Pinatubo ejected about 10 cubic kilometers of dust into high altitudes. The potential energy of this dust was far greater than the energy of all atom bombs. Ignite them all and you will get just enough energy to get 1 cubic kilometer of rocks a few kilometers high.
It was no nuclear winter, again, from Pinatubo.
The atomic bombs are merely the ignition devices - their energy does not go into projecting particles upwards (or very little). The burning cities are the sources of smoke, the close proximity prevents easy dilution of the smoke, and solar heating gets the particles up the last few kilometers before the clouds have time to disperse (incidentally, smoke from forest fires isn't as black, thus the solar heating effect isn't prominent for them).
A volcano ash is often black. The mass of already mentioned Pinatubo's dust, exceeds the mass of all human artifacts on the planet. If everything we have, go in smoke, it has less mass than the said dust, airborne in 1991.
Now you're just making stuff up. According to this http://www.thefreelibrary.com/Mt.+Pinatubo's+cloud+shades+global+climate.-a012467057 , there were 20 million tons of SO2 ejected into the atmosphere. The number of cars in the world is about 800 million cars on the road http://en.wikipedia.org/wiki/Automobile, mass about 1.5 tons, so we're ahead on those alone. Even if we're generous, and include the "10 billion metric tonnes (10 cubic kilometres) of magma" in Pinatubo (most of which is not relevant for the current discussion), I haven't started counting the trucks and trains and the 300 000 tons super tankers, all the smaller ships, the roads and the railways, etc... We'll reach 10 billion tons long before we have to start counting the largest mass in human artifacts: the buildings.
The total energy released by the said Black Thursday Bush Fire was in the same range as the energy stored inside all world's nuclear bombs. 10^17 J.
Novaya Zemlya is tundra (ie, "lichen, sedge, sometimes grass, and if you're lucky, scattered dwarf shrubs sitting on permafrost") and glaciers. The Tsar Bomba went off in October. That's October in the Arctic Circle, by the way.
We shouldn't be surprised at this vast asymmetry between "models of nuclear warfare targeting cities in populated areas" and "one very large nuclear bomb, set off as a test, in the Arctic during the beginning of local winter."
The Parable of the Pawnbroker.
Take that one out of context a sec... ;)
Never take it out of context.
you doubt that 10 to 100 times more over a 1000..10000 times shorter interval - ~ 100 000 larger intensity than 'no really bad consequences' - can cause nuclear winter?
How so? If you doubt that kind of stuff because 5 orders of magnitude are never enough to get from 'not really bad consequences' to 'really bad consequences', then i don't know what you wouldn't doubt.
As I've said. All the atom bombs we have, have combined less energy than a big wildfire. So the energy is not a problem.
Then, the amount of "black smoke", which would those bombs emits, compared to a volcano is small. There is nowhere one ton of a black smoke emitting plastics per person alive, not to mention that everything will not be burned.
I don't see where they are getting their numbers. One of those scenarist was Carl Sagan. He made quite a panic when Saddam Hussein ignited those Kuwait oil pumps. He was wrong.
Look it now either from the energy point of view, either from the soot lifting point of view - it is not such a big event in the geological terms at all.
Billion of people may die, maybe more, maybe less. An unspeakable evil, it would be, yes.
But a nuclear winter from an event comparable with no such a big wildfire? One million square kilometers of the Australian bush burnt. One trillion square meters. One kilogram of grass and wood per square meter burnt. One million J of energy released. This is a very conservative calculation, but it gives you 10 times more energy than the combined nuclear stock pile would. And the biggest wild fire covered 5 times more land. So, maybe 50 times more energy released - caused no nuclear winter.
Every year we have enough wildfires to release more energy than there is in those bombs.
You have to put everything in a perspective.
I don't see the total arsenal yield figure, but i have total yield from testing:
http://en.wikipedia.org/wiki/Nuclear_weapon_yield
which is slightly above 500 megatons
For the wildfire:
10^12 m^2 * 10^6 j/m^2 = 10^18 j
1 megaton of TNT = 4 * 10^15 joules. Thousand megatons = 4 * 10^18 joules. 500 megatons = 2 * 10^18 joules , 2x your fire already. Multiply by your 10..100 (the arsenal vs testing quoted from yourself), you get 20 .. 200x the wildfire, that's just the yield, not the fires in cities.
And while we are on energy calculating, why not calculate how much solar energy Earth receives in a day and say how many zillion times its more than energy of bombs combined, lol.
Note: you just might by dumb luck be factually correct, but your argument is motivated cognition. Nukes are scary, and hence very motivational. Goes both ways.
You are saying, that the total energy amount of all the nuclear weapons is 4*10^18 J. Not 40 times less as I have said.
Even in that case, the wildfire which has covered 5 million square kilometers and consumed 1 kg of dry grass and wood was a bigger event. Especially since I gave 10 times smaller energy per kilogram of wood or dry grass as it is. It's 10^7 J/kg not 10^6 as I have calculated. Not to mention, 1 kg per square meter is a very low number.
But it matters only a little. This calculation is not very exact, but quite enough to see the main point.
I still don't see the main point. Wildfires don't put stuff into stratosphere very well, its not very concentrated, and it ignores burnable stuff in the cities.
For the calculations, just do them carefully one time ok? I don't know full yield, the 1000mt is just example. Your own estimate for yield of arsenal, vs yield of testing, was arsenal = 10..100x the testing. You need to pick your numbers, and stick to them all the way through without fitting them after you arrive at something you don't like. That is just math. If you can't do that why you think your opinion on nuke war results is at all coupled to the actual results in any way?
Very clear numbers:
5 million square kilometers of bush burnt. That's 5*10^12 m2. Every year you can expect at least 1 kg of wood growth per square meter. That's 10^7 J accumulated per year on every square meter. But let say, it is all that it's there.
This gives you 5*10^19 J released by the biggest Australian bush fire. Many times more than your estimation for the atom bombs aggregate energy release.
Pure and simple, do you object this numbers?
you picked one set of numbers, calculated something, then didn't like it, changed from 1 to 10 megajoules per square metre, that's not how you do it if you are thinking straight.
Regarding 'my estimate', once again: 500 megatons is total testing, 10 ... 100x the figure you picked, total 5000 .. 50 000 megaton , the 1 megaton of tnt is 4E15 j , times 5E3 = 2E19 , times 5E4 , 2E20 .
Top it off by the smoke not going into stratosphere from a bush fire because there's too little intensity, it doesn't even burn all at once, so there's nothing whatsoever even comparable about those numbers in the first place?
What part do you not understand about "you have been conclusively demonstrated that you are not thinking straight about existential risks" ? People have two reactions to existential risks: be sure that it exists, be sure that it does not, proceed to not thinking straight one way or another. Sagan demonstrably screwed up with oil well fires, yes. You are demonstrably screwing up right now. Nobody's safe from it. I'm only reasonably sure i'm not screwing up because i haven't been called on bad math, and haven't got very strong belief about nuke winter.
Americans have 10000 atomic weapons currently. Russians also. Others are negligible in this sense.
Say that the average bomb has 1 MT. This means 8*10^19 J of energy. What is a big overestimation, but for the sake of the discussion, would you accept this number first?
I don't accept the idea that the climate effect of the fire is in any way comparable to nukes in the first place, because fire doesn't get smoke high up in the atmosphere. I think its a very screwed up assumption. I've only been criticizing the numbers because the point is that people don't think straight about existential risks. Humans don't think about risks, they evaluate risks rapidly with some feeling & particular really simple strategy that they picked up, then rationalize verbosely.