English: Percent of the world's population dead from a nuclear war: summarizing climate simulations by an international team of 10 scientists who specialize in mathematical and statistical modelling of climate, food production, and economics (Xia et al. 2022; see esp. their Table 1) with models fit thereto. The vertical axis is the percent of the world's population expected to die within a few years after a one-week-long nuclear war that injects between 1.5 and 150 Tg (teragrams = million metric tons) of smoke (soot) into the stratosphere, shown on the top axis.
[1] The bottom axis is the total megatonnage (number of nuclear weapons used times average yield in kilotons of TNT divided by 1,000 to convert from kilotons to megatons) simulated to produce the quantity of soot plotted on the top axis. The nuclear explosions would produce firestorms that loft soot into the stratosphere, where it covers the earth and lingers for years. That soot would block sunlight and reduce growth of living things. Substantial portions of the earth's population would likely starve to death if they did not die from something else sooner. The points plotted mark simulations performed by Xia et al. "IND-PAK" marks a range of hypothetical nuclear wars between
India (IND) and
Pakistan (PAK). "USA-RUS" marks a simulated nuclear war between
the US (USA) and
Russia (RUS). "PRK" = a simulated nuclear war in which
North Korea (the People's Republic of Korea, PRK) used their existing nuclear arsenal estimated at 30 weapons with an average yield of 17 kt
[2] without nuclear retaliation by an adversary, as recommended in this article. In the simulated scenarios, between 90 and 95 percent of the deaths were in countries not officially involved in the nuclear exchange.