system
Given the following post, respond as if you're commenting on Reddit:
human
How many nukes would it take to cause a nuclear winter?

I'm confused about nuclear weapons. A Ted talk I watched, along with several other sources, all say "a hundred or so nukes will be enough to cause a nuclear winter and wipeout humanity". But, according to google, there have been over 1000 nuclear detonations. Why such a discrepancy between these numbers?
gpt
A nuclear winter would be caused, primarily, by the fires that followed a comprehensive thermonuclear exchange between the nuclear powers.  China, US, Russia, France, Great Britain, Israel, India, Pakistan and a few others.  Many of these fires would be swept up to actual fire storms and the smoke and ash that would be fed into the upper atmosphere.  Blocking the sunlight and creating the conditions for a nuclear winter.  You can not create the conditions for a nuclear winter by simply detonating even a single huge nuclear weapon.  It has to be a large number of weapons spread over a large geographic area.