Wind speed and direction influence beach plastic accumulation patterns on remote Christmas Island

Plastic pollution is accumulating rapidly in the global oceans, including in remote areas. On beaches, debris is not uniformly distributed with the type, source, and quantity of items influenced by oceanic conditions. Using monitoring data collected by community scientists during 2023-2025, we describe the annual and seasonal patterns in debris accumulation on Christmas Island in the remote Indian Ocean. Most debris originated overseas, with only 1.8 % of items originating on-island or from the Australian mainland. Debris densities varied significantly across the four monitored beaches, with windward-facing sites having the highest rates of debris deposition (range (dry season): 62.0-1618.2 g/m²). Despite being located only 2 km apart, debris deposition was up to 50× higher on Greta Beach (1618.3 ± 2393.4 g/m²) than Dolly Beach (62.0 ± 26.6 g/m²), potentially due to the shape of the surrounding cliffs which may alter the prevailing winds and currents and funnel debris onto Greta Beach. These findings highlight the key role citizen science programs can play in delivering multi-site, multi-year debris monitoring programs, especially in remote areas. These data are essential to identifying patterns in debris deposition that may impact upon local communities, inform logistics and planning for removal teams, and play a critical role in generating the data necessary to assess the effectiveness of waste policy, including the Global Plastics Treaty.