Nuclear Niño response observed in simulations of nuclear war scenarios

The climate impacts of smoke from fires ignited by nuclear war would include global cooling and crop failure. Facing increased reliance on ocean-based food sources, it is critical to understand the physical and biological state of the post-war oceans. Here we use an Earth system model to simulate six nuclear war scenarios. We show that global cooling can generate a large, sustained response in the equatorial Pacific, resembling an El Nino but persisting for up to seven years. The El Nino following nuclear war, or Nuclear Nino, would be characterized by westerly trade wind anomalies and a shutdown of equatorial Pacific upwelling, caused primarily by cooling of the Maritime Continent and tropical Africa. Reduced incident sunlight and ocean circulation changes would cause a 40% reduction in equatorial Pacific phytoplankton productivity. These results indicate nuclear war could trigger extreme climate change and compromise food security beyond the impacts of crop failure. A nuclear conflict could lead to global cooling followed by a large and sustained El Nino-like response in the tropical Pacific region, according to an evaluation of six scenarios for nuclear conflict with an Earth system model.