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New scientific study describes severe consequences of a limited, regional nuclear war

October 3, 2019

New research on the consequences of a limited, regional nuclear war, published this week in the peer-reviewed journal Science Advances, concludes that casualty levels and long-term impacts on the global environment will be far more severe than previously believed. (Toon, Owen B., Charles G. Bardeen, Alan Robock, Lili Xia, Hans Kristensen, Matthew McKinzie, R. J. Peterson, Cheryl Harrison, Nicole S. Lovenduski, and Richard P. Turco, 2019: Rapid expansion of nuclear arsenals by Pakistan and India portends regional and global catastrophe.  Science Advances, 5, eaay5478, doi:10.1126/sciadv.aay5478.)

The authors of the paper, entitled “Rapid expansion of nuclear arsenals by Pakistan and India portends regional and global catastrophe,” look first at regional blast, thermal, and radiation effects, and conclude that “for the first time in human history, the fatalities in a regional war could double the yearly natural global death rate.

“Moreover, the environmental stresses related to climate changes caused by smoke produced from burning cities could lead to widespread starvation and ecosystem disruption far outside of the war zone itself.“

The authors, who include IPPNW science adviser Alan Robock of Rutgers University, other climate scientists, physicists, and nuclear weapons experts, describe the outcomes of a South Asian nuclear war between India and Pakistan. If India were to use 100 15-kiloton weapons and Pakistan were to use 150 in urban centers, about 50 million people—roughly the same number as in the Second World War— would die. If each country were to use 100-kt weapons, fatalities would increase to 125 million.

Beyond these immediate consequences, the new research shows that “nuclear-ignited fires could release 16 to 36 Tg [teragrams] of black carbon in smoke, depending on yield. The smoke will rise into the upper troposphere, be self-lofted into the stratosphere, and spread globally within weeks. Surface sunlight will decline by 20 to 35%, cooling the global surface by 2° to 5°C and reducing precipitation by 15 to 30%, with larger regional impacts. Recovery takes more than 10 years. Net primary productivity declines 15 to 30% on land and 5 to 15% in oceans threatening mass starvation and additional worldwide collateral fatalities.”

“Compounding the devastation brought upon their own countries,” the authors conclude, “decisions by Indian and Pakistani military leaders and politicians to use nuclear weapons could severely affect every other nation on Earth.”

IPPNW co-president Ira Helfand, the author of IPPNW’s report Nuclear Famine, said that the new study “once again shows that the risks of nuclear conflict are catastrophic and unacceptable. States that have or endorse nuclear weapons put the entire world at risk, and all responsible states must push back by joining the UN Treaty on the Prohibition of Nuclear Weapons.”

The full paper is open access on the Science Advances website.

Another description of the new findings, including animations, is at

IPPNW has prepared a two-page summary of the new study, including its implications for food security and nuclear famine, available in English, French, and Spanish.





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