Tipping the AMOC: Impacts of Tropical Cyclones in a Changing Climate

The Atlantic Meridional Overturning Circulation (AMOC) is one of the most critical tipping elements in Earth’s climate system, with its collapse posing far-reaching implications for weather dynamics and extremes, sea level rise, and Northern Hemisphere cooling. Although it is considered a low-probability but high-impact scenario, recent studies suggest that the AMOC may already be on a trajectory towards collapse. Moreover, current climate models struggle to fully capture the complex interactions between Greenland ice sheet melting and the AMOC slowdown, adding further uncertainty to climate projections. Artificial hosing experiments in the North Atlantic, project the weakening of the AMOC to increase sea surface temperature in the Southern Hemisphere and the tropics, particularly in ocean basins where tropical cyclones form. This warming, combined with rising sea levels and changes in vertical wind shear, could create conditions that promote the development of tropical cyclones and amplify their impacts. Although several studies have explored the relationship between tropical cyclone activity and AMOC weakening, the associated socioeconomic impacts remain uncertain. The goal is to investigate the direct and indirect socioeconomic impacts of tropical cyclones under future climate scenarios characterized by a weakened and fully collapsed AMOC. Will tropical cyclones affect areas that were previously unaffected? Will tropical cyclones' activity intensify, leading to greater societal impacts? To answer these questions, two sets of five-member ensemble simulations were performed for a 2°C stabilization emission scenario using the GFDL ESM2M, with and without induced AMOC collapse. These simulations were then coupled with the MIT coupled statistical-dynamical tropical cyclone model to simulate tropical cyclone activity under these conditions, and the probabilistic climate risk modeling platform CLIMADA was used to analyze the socioeconomic impacts. We anticipate this study to be a stepping stone in a broader ongoing effort to assess the socioeconomic impacts of extreme weather events triggered by tipping points.