Nuclear warfare is military conflict involving the deployment of nuclear weapons.

Nuclear war is potentially the primary near-term anthropogenic existential risk. Nuclear war would probably not cause human extinction through the direct damage of an exchange. Rather, researchers are concerned about the potential for a nuclear winter: firestorms caused by the explosions could release particulate matter into the stratosphere, causing significant global cooling which would last for several years. This cooling would disrupt global agriculture, which would likely kill many more people than the initial exchange (Robock 2010).

However, there is some disagreement about how climate systems would react to the particulate matter and how much soot would actually be created (modern cities are potentially less vulnerable to firestorms than those during the cold war). As a result, it is unclear whether nuclear war poses an existential risk or a non-existential global catastrophic risk.

Evaluation

80,000 Hours rates nuclear security a "second-highest priority area": an unusually pressing global problem ranked slightly below their four highest priority areas (80,000 Hours 2021).

Bibliography

80,000 Hours (2021) Our current list of the most important world problems, 80,000 Hours.

Baum, Seth D., Robert De Neufville & Anthony M. Barrett (2018) A model for the probability of nuclear war, working paper 18-1, Global Catastrophic Risk Institute.

Baum, Seth D. & Anthony M. Barrett (2018) A model for the impacts of nuclear war, working paper 18-2, Global Catastrophic Risk Institute.

Cirincione, Joseph (2008) The continuing threat of nuclear war, in Nick Bostrom & Milan M. Ćirković (eds.) Global Catastrophic Risks, Oxford: Oxford University Press.

Open Philanthropy (2015) Nuclear weapons policy, Open Philanthropy, September.
A report exploring possible interventions to address risks from nuclear war.

Robock, Alan (2010) Nuclear winter, WIREs Climate Change, vol. 1, pp. 418–427.

Related entries

North Korea