NUCLEAR WARPotential Environmental Effects of Nuclear War

Published 3 July 2025

In the 1980s, in response to the buildup of U.S. and Russian nuclear arsenals during the Cold War, scientists issued warnings about the potential for a “nuclear winter” scenario which would follow a nuclear war between the United States and the Soviet Union. Since then, military, political, and technological changes have reshaped the nuclear weapons landscape, while scientific advances have deepened the understanding of and ability to model Earth system processes.

A new congressionally mandated report from the National Academies of Sciences, Engineering, and Medicine examines the potential environmental, social, and economic effects that could unfold over the weeks to decades after a nuclear war and includes research recommendations. 

A series of major scientific studies conducted in the 1980s in response to the buildup of U.S. and Russian nuclear arsenals during the Cold War issued warnings about the potential for a “nuclear winter” scenario — the possibility that a large-scale exchange of nuclear weapons could inject massive amounts of soot and particulates into the upper atmosphere that would block incoming solar radiation and cause major ecosystem and societal disruptions. Since then, military, political, and technological changes have reshaped the nuclear weapons landscape, while scientific advances have deepened the understanding of and ability to model Earth system processes.

The effects of any nuclear exchange would depend on key processes and interactions along a causal pathway with six stages: weapon employment scenarios and effects; fire dynamics and emissions; plume rise, fate, and transport; physical Earth system impacts; ecosystem impacts; and socioeconomic impacts. The report identifies major uncertainties and data gaps that currently limit researchers’ ability to understand and model the effects of a nuclear war at each stage of the causal pathway that would connect nuclear detonations to their eventual environmental and societal impacts.

The report recommends that relevant U.S. agencies coordinate the development of and support for a suite of model intercomparison projects (MIPs) to organize and assess models to reduce uncertainties in projections of the climatic and environment effects of nuclear war.

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