Collapse-scale nuclear winter

[aubergine]

Back in the '90s, when Warzone was developed, scientific models for predicting what a nuclear winter would be like were basic, to say the least. There simply wasn't enough computing power or data to build accurate models. As such, the general consensus is that a nuclear winter would last for maybe a couple of years, and then start to subside.

Current day models suggest a very different story -- the effects would last for at least a decade.

As soon as the nuclear strikes start, vast amounts of smoke, dust and other chemicals start to be injected in to the atmosphere from vast fires all over the world.

If there were only one or two nukes, the smoke would "only" reach the upper troposphere, about 6-8km above the surface. The troposphere is home to all the clouds you are familiar with, and precipitation and virga from those clouds would help wash the smoke particles back down to earth within a relatively short amount of time (most of it gone in less than a year). The adverse effects would be fairly localised and life would start returning to normal in a relatively short amount of time.

If there were about 50-100 nukes, the effects would be much worse, with the smog reaching the troposphere ~20km above the surface. That's like a war between India and Pakistan - where the nukes are being detonated over a single continent. Here, the nuclear winter would last for longer, and the overall climate effects would still be felt a decade later: worldwide!

However, in the collapse, with many thousands of nukes being detonated in short succession, all over the world, a very different scenario would unfold. The smoke would easily reach the upper stratosphere, and possibly even go as far as the mesosphere. The smog cloud would be 30-40km thick within a few weeks, the sky would be almost pitch black at midday, and the air practically unbreathable.

Shortly after the first nukes, strike, the skies start to turn dark as a result of local smoke pollution in the atmosphere. For example, regions such as Arizona would become unrecognisable: At midday, the sky would be dark, with 90% of the sunlight blocked out, and temperatures would struggle to reach 4ºC even in the height of summer.

As the fires continue to pump more pollution in to the skies, and the veil of smog makes its way up to the stratosphere and beyond, temperatures start to plummet and nuclear winter would start. Vast quantities of snow would fall, covering most of the land in several metres of snow, which would start to turn to ice as the temperatures continue to drop.

Temperatures would drop by up to 50ºC, basically plunging the world in to an ice age. It would take years for the temperatures to start rising again, and decades or maybe even longer for the nuclear winter to end....

[Rman Virgil]

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Would depend on the type of nuke warheads used.

If enhanced radiation reduced blast (ERRB) warheads were used (and neutron based) the post collapse sceanario would be more like in WZ, I think. Perhaps with all the present concerns over climate change and precipitating a new ice age, this could be concieved as a "saner" way to conduct a nuclear war in an extrapolated future like the late 21st century. Just some alternate possibilities.

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[Shadow Wolf TJC]

Back in the '90s, when Warzone was developed, scientific models for predicting what a nuclear winter would be like were basic, to say the least. There simply wasn't enough computing power or data to build accurate models. As such, the general consensus is that a nuclear winter would last for maybe a couple of years, and then start to subside.

Current day models suggest a very different story -- the effects would last for at least a decade.

As soon as the nuclear strikes start, vast amounts of smoke, dust and other chemicals start to be injected in to the atmosphere from vast fires all over the world.

That may be so... if buildings throughout the world were still as flammable as the ones at Hiroshima and Nagasaki were back during the end of WWII, which I believe isn't the case with regards to buildings in a developed country such as the United States. Even then, they would only catch on fire if the situation was right, such as if there were a lot of ovens in use when the nukes come falling, since nuclear weapons do damage in much the same way as thermobaric weapons such as a fuel-air bomb, by creating a longer-lasting explosive shockwave to destroy structures. With that in mind, we could probably take most of the fires out of the equation (though we would keep the dust that is thrown into the air from the force of the explosions themselves).

Also, nukes aren't just capable of leveling miles of land. They could also be used to wipe out whole continents full of electronics through the effects of a high-altitude nuclear EMP. While it is possible to protect electronics from them, the sheer number of them failing would lead to millions of indirect deaths.

Assuming that people during 2086 still depended on fossil fuels (which I believe would be true even then, albeit on a possibly smaller scale than now), then the billions of deaths, both direct and indirect, would likely cause a massive reduction of greenhouse gases. Given how our planet has been getting warmer since we started pumping greenhouse gases into the atmosphere over a century or 2 ago, and assuming that global warming would continue at (hopefully) a slower pace than it is now (where agriculture would migrate closer to the poles), this would definitely play a role in causing a nuclear winter, as temperatures would likely stabilize at no cooler than what was the normal temperature before the Industrial Revolution came along (though the nuclear winter "could" possibly be as cool as when Mount Tambora erupted in 1815, leading to what is known as the "Year Without a Summer").

In short, if anything's going to cause a "nuclear winter" as described in Warzone 2100's backstory, then I believe that it would be the loss of greenhouse gases.

[aubergine]

All sorts of things would still catch fire - things like oil refineries, chemical plants, lots of industrial sites, cars, planes, trains, farms, etc., and if a fire storm starts the fires would spread rapidly.

Even today, there are cases where smoke from large forest fires has made it in to the stratosphere.

From my readings, it seems that the nuclear winter is when large amounts of smoke/pollution get very high up in the atmosphere - at that height, which is also subject to -70ºC or colder temperatures, the resulting pollution acts like a mirror bouncing sunlight back out in to space, thus causing the cooling effect. At the same time, the suns radiation actually causes the pollution to gain altitude (I've not yet looked in to the science behind that).

[Rommel]

INteresting read. It seems doubtful humanity would survive, unless some well prepared people had bunkers they could live in for like 50 years or so.

[aubergine]

They exist: Preppers

I imagine the initial members of The Project were Preppers, or were camped out in a bunker owned by a Prepper.

[Rman Virgil]

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All these scenarios remain hypothetical, especially the worst case presented as inevitable.

This article covers all the reasons for that statement:

http://skeptoid.com/episode.php?id=4244&no_mobile=true

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[bendib]

I doubt such a scenario could come to pass, since there is a relatively wide understanding nowadays that massive nuclear strikes harm a lot more than the target. If it was an accident, well, that's a different story, but it's unlikely that any such event could occur. As far as I recall, there are no nuclear capable satellites in orbit of Earth, and controls for nuclear warheads are very well designed and secure nowadays.