Winter-Safe Deterrence

A new line of nuclear winter research shows that even small, regional nuclear wars could have catastrophic global consequences. However, major disarmament to avoid nuclear winter goes against the reasons nuclear weapon states have for keeping their weapons in the first place, in particular deterrence. To reconcile these conflicting aims, this paper develops the concept of winter-safe deterrence, defined as military force capable of meeting the deterrence goals of today’s nuclear weapon states without risking catastrophic nuclear winter. The article analyzes nuclear winter risk, finding a winter-safe limit of about 50 nuclear weapons total worldwide. The article then evaluates a variety of candidate weapons for winter-safe deterrence. Non-contagious biological weapons (such as anthrax or ricin), neutron bombs detonated at altitude, and nuclear electromagnetic weapons show the most promise. Each weapon has downsides, and the paper’s analysis is only tentative, but winter-safe deterrence does appear both feasible and desirable given the urgency of nuclear winter risk. Seth D. Baum, PhD in geography from Pennsylvania State University, is Executive Director of the Global Catastrophic Risk Institute (http://gcrinstitute.org), a nonprofit think tank he co-founded in 2011. His research focuses on risk, ethics, and policy questions for threats to human civilization including emerging technologies, global warming, and nuclear war. His research has appeared in many journals including Acta Astronautica, Ecological Economics, Science and Engineering Ethics, Science and Global Security, and Sustainability. Nuclear winter is back. Prominent in the 1980s, the topic faded from view following the end of the Cold War, only to re-emerge in recent years with a new, more advanced scientific study. The new results are in some ways more grim than the results of the original 1980s research, with catastrophic global consequences shown to follow from a war with as few as 100 nuclear weapons, or possibly even fewer. Meanwhile, global arsenals hold 16,000 total nuclear weapons and are not projected to go below 100 nuclear weapons any time soon. Despite calls for rapid disarmament and attempts to shift nuclear doctrine, nuclear weapons remain central to the security policies of nuclear weapon states, especially for deterrence. This paper evaluates prospects for winter-safe deterrence, defined here as a military force capable of meeting the deterrence goals of today’s nuclear weapon states without risking catastrophic nuclear winter. If feasible, this would be a win-win situation: Nuclear weapon states win because they continue to achieve their security goals, and all countries—including nuclear weapon states—win because they are no longer threatened by nuclear winter. Nuclear weapon states should pursue winter-safe deterrence both because it helps (or at least does not significantly hurt) their national security and because it is morally the right thing to do. This is