Nuclear weapons represent one of the most severe existential threats to humanity, yet the specifics of how they might contribute to worst-case scenarios—such as large-scale attacks or future technological developments—remain poorly understood. Without a systematic evaluation of these risks, efforts to mitigate nuclear dangers may be based on incomplete or overly optimistic assumptions. One way to address this gap would be to conduct a rigorous assessment of how the most plausible worst-case nuclear scenarios could amplify existential risks, providing a clearer foundation for decision-making among longtermists and policymakers.

Understanding the Scope and Approach

This project would involve cataloging realistic worst-case nuclear scenarios, from near-term risks like large-scale urban attacks to long-term possibilities such as advanced weaponry. It would then assess how these scenarios could trigger existential risks, such as nuclear winter or societal collapse. To quantify the impact, the analysis could combine simplified Fermi estimates with expert surveys and sensitivity tests. The findings would be communicated with clear caveats to ensure they are neither overstated nor dismissed as too speculative.

• Scenario Identification: Defining plausible but severe nuclear threats based on historical context and expert consensus.
• Pathway Analysis: Evaluating how these threats might escalate into global catastrophes.
• Impact Modeling: Using probabilistic methods to estimate risk increases, incorporating uncertainty ranges.

Execution and Stakeholder Engagement

The project could be structured in phases, beginning with a literature review and expert interviews to refine the scenarios, followed by quantitative modeling and validation surveys. Potential beneficiaries include longtermist organizations, researchers, and policymakers, who would use these insights to prioritize interventions. A key challenge would be balancing expert biases, ensuring that the final assessment neither overestimates nor downplays risks.

This effort would differ from existing nuclear risk research by explicitly focusing on existential threats while integrating multiple danger pathways and newer weapon developments. By combining rigorous modeling with expert insights, it could offer a more comprehensive view of how nuclear risks could play out in worst-case scenarios.