Re:How a small nuclear war would transform the entire planet...
by jcranmer on Tuesday March 08, 2022 @10:12AM
(#30600730)
The usual explanation boils down to the fuel load of cities. Another possible explanation is... the potential impact of nuclear weapons are greatly overestimated to make nuclear war too unbearable to countenance.
There's a very big unknown here, which is how much soot a nuclear-induced conflagration of a city pumps into the stratosphere. We know that stratospheric soot would induce global cooling, for a time period of at least a few years, based on the observed effects of existing natural stratospheric soot pumps known as volcanoes. And we also know that without stratospheric pumping of soot, climatic effects are at best localized in both space and time (see, e.g., Kuwaiti oil well fires).
Personally, I am very unconvinced by the assertion that nuclear weapons causes severe global cooling. The most powerful volcanic eruptions in recorded history are VEI 6 or VEI 7, which means they erupted up to around 100 cubic kilometers of stuff. If you assume a city has an average height of 100 meters (for the sake of round numbers), you'd need a firestorm to completely consume 1000 square kilometers of city to produce the same volume of material. Furthermore, a volcano's eruptive column is a relatively narrow plume of ejection as opposed to a broadly dispersed firestorm base, so it seems that you'd have a far lower conversion rate of material into stratospheric soot--and correspondingly you'd need to burn even more area to achieve the same effect.
And at the end of the day, even the most severe volcanic winter in recorded history (1815) happening today would be roughly equivalent to rolling back global warming to 1850. For less than a decade.
There's a very big unknown here, which is how much soot a nuclear-induced conflagration of a city pumps into the stratosphere. We know that stratospheric soot would induce global cooling, for a time period of at least a few years, based on the observed effects of existing natural stratospheric soot pumps known as volcanoes. And we also know that without stratospheric pumping of soot, climatic effects are at best localized in both space and time (see, e.g., Kuwaiti oil well fires).
Personally, I am very unconvinced by the assertion that nuclear weapons causes severe global cooling. The most powerful volcanic eruptions in recorded history are VEI 6 or VEI 7, which means they erupted up to around 100 cubic kilometers of stuff. If you assume a city has an average height of 100 meters (for the sake of round numbers), you'd need a firestorm to completely consume 1000 square kilometers of city to produce the same volume of material. Furthermore, a volcano's eruptive column is a relatively narrow plume of ejection as opposed to a broadly dispersed firestorm base, so it seems that you'd have a far lower conversion rate of material into stratospheric soot--and correspondingly you'd need to burn even more area to achieve the same effect.
And at the end of the day, even the most severe volcanic winter in recorded history (1815) happening today would be roughly equivalent to rolling back global warming to 1850. For less than a decade.