Thomas comments on [LINK] Nuclear winter: a reminder - Less Wrong

4 Post author: Stuart_Armstrong 19 March 2012 11:48AM

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Comment author: Thomas 20 March 2012 09:14:35AM *  -2 points [-]

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.

Comment author: Dmytry 20 March 2012 09:23:20AM *  -2 points [-]

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?

Comment author: Thomas 20 March 2012 09:35:52AM -2 points [-]

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?

Comment author: Dmytry 20 March 2012 12:01:26PM *  -2 points [-]

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.

Comment author: Thomas 20 March 2012 12:36:55PM -2 points [-]

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?

Comment author: Dmytry 20 March 2012 12:44:26PM *  -2 points [-]

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.

Comment author: Thomas 20 March 2012 12:59:23PM -2 points [-]

I don't accept the idea that the climate effect of the fire is in any way comparable to nukes

But you admit, that the energy stored in the nuclear arsenal is hardly as big as the energy released by a really big forest fire?

Comment author: Dmytry 20 March 2012 06:05:44PM *  0 points [-]

I don't have a good estimate of energy stored in the nuclear aresnal, and I care about this assertion just about as much as I care about comparison between energy of nuclear arsenal and energy of sunlight that hits the earth in a day.

But yes, I would say it is somewhere within similar order of magnitude, for the yield vs forest fire, ignoring the combustion of items in the cities.

BTW, nukes are incendiary weapons, there's not enough appreciation of this basic fact by public. Don't imagine your house being blown away, imagine all interior catching on fire first, then being blown off. Ditto for all asphalt.

Comment author: Thomas 20 March 2012 06:24:10PM -1 points [-]

But yes, I would say it is somewhere within similar order of magnitude

I am glad. It is important to understand this fact. I haven't seen it mentioned yet, anywhere.

People should update, not follow Carl Sagan blindly. He had "good intentions" when (probably) misinformed the world.

Comment author: Dmytry 20 March 2012 06:28:27PM *  -1 points [-]

Important for what exactly? Why is it more important than 'total yield << sunlight in a day' fact? edit: Because forest fires and nukes are both nasty?