Abstract Geopolitical tensions in Eastern Europe underscore the urgency of addressing the climatic and radiological consequences of a regional nuclear conflict. Using an Earth System Model, we simulate a hypothetical nuclear conflict at the Ukraine-Russia border that releases 5 Teragram (Tg; 5 million tons) of black carbon (BC), the dominant driver of the post-detonation climate response, into the stratosphere. We adopt the 5 Tg BC post-detonation emission scenario because it is a widely modelled scenario for a “limited” regional nuclear conflict (typically India–Pakistan), enabling a direct comparison with prior studies. The extended stratospheric lifetime of BC induces hemispheric climate disruption: the Northern Hemisphere cools by ~1 °C in year-1, with anomalies of −5 °C in Russia and −4 °C in the United States; surface solar radiation declines by ~30 W m −2 over the US; and precipitation decreases by ~40% across mid-latitude croplands. Stratospheric warming alters subtropical and polar jets, displacing the Intertropical Convergence Zone ~2–6° southward, delaying climate recovery by ~6 years. Long-lived radionuclides transported with BC disperse globally, with ~40% depositing in the Southern Hemisphere. These findings underscore the importance of nuclear-risk reduction and provide a robust benchmark for food-security and humanitarian-impact assessments.
Ranjithkumar et al. (Wed,) studied this question.