Climate impact of a regional nuclear weapons exchange: An improved assessment based on detailed source calculations

Abstract

This study investigates the climate impact of a regional nuclear exchange between India and Pakistan, focusing on the production and atmospheric distribution of black carbon. Unlike previous models that predicted a significant global cooling effect, our simulations, which include detailed modeling of firestorm dynamics and black carbon production, show that the majority of black carbon remains trapped below weather systems, resulting in much lower global climate impacts. Our Earth system model simulations show limited and short-lived changes in global surface temperatures, primarily concentrated around the Arctic, and do not produce a “nuclear winter” scenario. These findings suggest that a regional nuclear exchange, while still catastrophic, is unlikely to cause the widespread global cooling and agricultural disruptions previously estimated. Our results are consistent with natural analogs like large forest fires and volcanic eruptions, which show limited long-term climate effects.