Nuclear winter (also known as atomic winter) is a largely hypothetical global climatic effect of war and natural wildfires, that is most frequently suggested to follow after the combined combustion pollution from the burning of at least 100 city sized areas, at firestorm-intensity. With the term specifically being coined to refer to computer model results were this smoke remained for year-to-decade long intervals and caused massive planet-wide temperature drops/"winters" for as long as it remained.