If the United States and Russia waged an all-out nuclear war, much of the land in the Northern Hemisphere would be below freezing in the summertime, with the growing season slashed by nearly 90% in some areas, according to a new study.
Indeed, death by famine would threaten nearly all of the Earth’s 7.7 billion people, says professor Alan Robock.
The study in the Journal of Geophysical Research–Atmospheres provides more evidence to support the Treaty on the Prohibition of Nuclear Weapons the United Nations passed two years ago, Robock says.
Twenty-five nations have ratified the treaty so far, not including the United States, and it would take effect when the number hits 50.
Lead author Joshua Coupe, a doctoral student at Rutgers University, and other scientists used a modern climate model to simulate the climatic effects of an all-out nuclear war between the United States and Russia.
Such a war could send 150 million tons of black smoke from fires in cities and industrial areas into the lower and upper atmosphere, where it could linger for months to years and block sunlight.
The scientists used a new climate model from the National Center for Atmospheric Research with higher resolution and improved simulations compared with a NASA model used by a research team Robock led 12 years ago.
The new model represents the Earth at many more locations and includes simulations of the growth of the smoke particles and ozone destruction from the heating of the atmosphere.
Still, the climate response to a nuclear war from the new model was nearly identical to that from the NASA model.
“This means that we have much more confidence in the climate response to a large-scale nuclear war,” Coupe says. “There really would be a nuclear winter with catastrophic consequences.”
In both the new and old models, a nuclear winter occurs as soot (black carbon) in the upper atmosphere blocks sunlight and causes global average surface temperatures to plummet by more than 15 degrees Fahrenheit.
Because a major nuclear war could erupt by accident or as a result of hacking, computer failure, or an unstable world leader, the only safe action that the world can take is to eliminate nuclear weapons, says Robock.
Additional researchers from the National Center for Atmospheric Research and the University of Colorado, Boulder contributed to the study.
Written by Todd Bates.