Dispersal of marine plastic litter during tropical cyclones

Abstract

Many countries that are substantial contributors to global plastic pollution are also prone to tropical cyclones. Yet, the capacity for tropical cyclones to redistribute plastic waste has not been characterised. To address this, we simulate plastic transport from coasts in the Philippines archipelago during seven tropical cyclones, with a focus on the 2021 Super Typhoon Rai. To simulate plastic dispersal, a Lagrangian particle tracking model (OpenDrift) is forced with extreme typhoon wind conditions (parametric cyclone model) combined with ocean surface currents (comprising tidal currents, density-driven and wind-driven circulation, and Stokes drift). Compared to baseline simulations with quiescent wind conditions, we simulated plastics to be transported four times faster during Super Typhoon Rai (up to $\sim$ 40 km/day). Due to strong onshore typhoon winds, plastics were 10% more likely to become beached. Tropical cyclones create predictable patterns of plastic dispersal, exposing targeted regions to elevated plastic accumulation.