Nuclear winter is a hypothetical environmental disaster which could occur in the aftermath of a full-scale nuclear war. The firestorm resulting from nuclear explosions would incinerate cities and forests; the resulting smoke would create a massive cloud of ash, which would ascend to the stratosphere and form a sun-shield around the planet. Consequently the global temperature would plummet, and permanent night would descend. The constant darkness would prevent plant life from photosynthesising and growing, and the loss of all food sources could lead to the complete extinction of life on earth.
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