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23. Urban fires
Urban fires from the first nuclear strike would cause sooty smoke, or black carbon, arising from a city’s ruins. Though smaller in magnitude, when black carbon was injected into the atmosphere 66 million years ago – when an asteroid impact caused much of the Earth’s surface to burn – it resulted in a mass extinction event.
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22. Forest wildfires
Wildfires ignited from a firestorm after a nuclear weapons exchange would contribute to a nuclear winter.
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21. Smoke from fallout
Smoke from fallout would block out sunlight for years, causing below-freezing temperatures.
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20. Soot in stratosphere
Black carbon would absorb radiation and heat up from sunlight. As a result, the surrounding air would become buoyant, lifting soot into the stratosphere.
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19. Winds carry soot
The buoyant aerosols would reach the higher levels of the stratosphere, encountering winds that would distribute the smoke over the Earth.