Risk of Nuclear War

Extracted Attributes

• Category

  Global Catastrophic Risk

• Primary Concern

  Potential for escalation of regional conflicts into a major multinational conflict involving nuclear powers

• Key Threat Actors

  Senior Russian politicians (e.g., Vladimir Putin, Dmitry Medvedev, Sergey Lavrov)

• Infrastructure Risk

  Occupation of Zaporizhzhia Nuclear Power Plant

• Exacerbating Factors

  Abandonment of nuclear arms control treaties, development of new nuclear weapons, expanded circumstances for nuclear weapon use, inadvertent escalation, nuclear 'near misses'

• Specific Russian Actions

  Statements widely interpreted as nuclear blackmail, crossing numerous 'red lines' without nuclear retaliation

• Specific Ukrainian Actions

  Coordinated drone attack on Russia's strategic bomber force (Operation Spiderweb)

• Potential Consequences (General)

  Billions of deaths, unfathomable suffering, civilization setback, radioactive fallout, global cooling, nuclear winter, 'Nuclear Little Ice Age'

• Simulated Casualties (US-Russia War)

  91.5 million (34.1 million dead, 57.4 million injured) in first few hours

• Simulated Casualties (Regional War with 250 warheads)

  >1.4 billion deaths globally due to nuclear winter

Timeline

• Princeton researchers release a new study on US-Russia nuclear war simulation, forecasting 91.5 million casualties in the first few hours. (Source: web_search_results)

  2019-09-18

• LSU publishes an article discussing how nuclear war would affect Earth today, including the potential for a 'Nuclear Little Ice Age'. (Source: web_search_results)

  2022-07-07

• Many of Russia's 'red lines' were crossed during the invasion of Ukraine without nuclear weapons being used in response. (Source: summary)

  2024

• Ukraine conducts a coordinated drone attack on Russia's strategic bomber force during Operation Spiderweb. (Source: summary)

  2025-06-01

Nuclear risk during the Russian invasion of Ukraine

During the Russian invasion of Ukraine, several senior Russian politicians, including president Vladimir Putin, former president and prime minister Dmitry Medvedev, and foreign minister Sergey Lavrov, have made a number of statements widely seen as nuclear blackmail. The possibility of Russia using tactical nuclear weapons, and the risk of broader nuclear escalation, has been widely discussed by commentators and in the media. By 2024, many of the Russian government's "red lines" had been crossed without nuclear weapons being used in response. As well as nuclear weapons threats, the Russian occupation of the Zaporizhzhia Nuclear Power Plant has led to a crisis over the safety of the plant and the risk of a nuclear disaster. On 1 June 2025, one leg of Russia's nuclear triad, its strategic bomber force that has been used for conventional attacks against Ukraine, was subjected to a coordinated drone attack by Ukraine during Operation Spiderweb.

Web Search Results

• [PDF] Nuclear War as a Global Catastrophic Risk

  ............................................................................7 Nuclear War as a Global Catastrophic Risk  vii Summary Nuclear war is clearly a global catastrophic risk, but it is not an existential risk as is sometimes carelessly claimed. Unfortunately, the consequence and likelihood components of the risk of nuclear war are both highly uncertain. In particular, for nuclear wars that include targeting of multiple cities, nuclear winter may result in more fatalities across the [...] threaten extinction, rather than merely the horrific cataclysm that it would be in reality.12 To summarize, nuclear war is a global catastrophic risk. Such wars may cause billions of deaths and unfathomable suffering, as well as set civilization back centuries. Smaller nuclear wars pose regional catastrophic risks and also national risks in that the continued functioning of, for example, the United States as a constitutional republic is highly dubious after even a relatively limited nuclear [...] Figure 1. Images of Devastation Caused by Nuclear War Nuclear War as a Global Catastrophic Risk  3 the nuclear threshold into uncharted territory is so dangerous.2 While it is clear that nuclear war is a global catastrophic risk, it is also clear that it is not an existential risk. Yet over the course of the nuclear age, a series of mechanisms have been proposed that, it has been erroneously argued, could lead to human extinction. The first concern3 arose among physicists on the Manhattan

• New Study on US-Russia nuclear war: 91.5 million casualties in first ...

  Equally alarming as the casualty toll of this nuclear war simulation is the growing probability that it becomes a reality. “The risk of nuclear war has increased dramatically in the past two years as the United States and Russia have abandoned long-standing nuclear arms control treaties, started to develop new kinds of nuclear weapons and expanded the circumstances in which they might use nuclear weapons,” wrote the Princeton researchers on the project website. [...] But that’s not all. The overall death toll would be even higher due to long-term consequences of a nuclear war, including radioactive fallout and global cooling of the Earth’s atmosphere, researchers add. Even a limited nuclear exchange between India and Pakistan could put one billion people at risk of starvation and another 1.3 billion at risk of severe food insecurity due to global cooling, according to a 2013 study by International Physicians for the Prevention of Nuclear War. [...] ICAN - International Campaign to Abolish Nuclear Weapons ## New Study on US-Russia nuclear war: 91.5 million casualties in first few hours ###### SHARE September 18, 2019 34.1 million people could die, and another 57.4 million could be injured, within the first few hours of the start of a nuclear war between Russia and the United States triggered by one low-yield nuclear weapon, according to a new simulation by researcher’s at Princeton‘s Science and Global Security programme.

• Nuclear Risk | XLab - The University of Chicago

  ### Even a relatively small, regional war using as few as 250 warheads could cause a nuclear winter effect leading to the deaths of more than 1.4 billion people globally. [...] # 5. ### Accidental nuclear war as a result of inadvertent escalation has nearly occurred numerous times—these events are called nuclear “near misses.” [...] unintentionally make an adversary feel that their arsenal is threatened if it introduces communication gaps and information shortages in their nuclear chains of command. Ambiguity over whether an incoming missile is nuclear-armed may force a state to make hasty and escalatory decisions. Even in the absence of an active conflict, an adversary’s build up of dual-use weapons systems may make a state uncertain about the other’s intentions.

• Forecasting Nuclear Escalation Risks: Cloudy With a Chance of ...

  The values of p(m,n) supplied by each participant for each scenario can be used to calculate PTn, the probability that the crisis reaches threshold n and then terminates at that threshold. Thus PT3+PT4+PT5 is the probability of a nuclear war, and PT5 is the probability of an “all-out” nuclear war (or at least what counts as all-out in our simplified, six-threshold escalation model). [...] The size of this discrepancy can be quantified. On average, participants assessed that, in the event of an all-out nuclear war, there was a probability of about 0.70–0.75 that it would result from escalation along the principal pathway (see table 4, which, because all estimates were of the same order of magnitude, presents their arithmetic mean, rather than their median).18 To put this finding in context, with sixteen available pathways, this probability could be as low as 0.0625 (which would [...] to a somewhat lesser extent, the controllability of escalation after first use. Forecasting is also useful for guiding the development of risk-mitigation policies. Our results suggested that efforts to reduce the likelihood of nuclear alerting (preparing nuclear forces so they are ready to launch) and to mitigate escalation pressures after nuclear first use—two generally neglected areas of risk reduction—could play important roles in minimizing the danger of an “all-out” nuclear war.

• How Nuclear War Would Affect Earth Today

  Skip to main content # How Nuclear War Would Affect Earth Today July 07, 2022 The new ocean state after nuclear war, AGU Advances Today's nuclear war capabilities would have devastating impacts on Earth. If detonated, the smoke and soot from nulcear explosions would block out the Sun resulting in worldwide crop failure, plunging global temperatures and sea ice expansion that would throw the planet into a "Nuclear Little Ice Age" that could last up to thousands of years.