Signal Trawling may release 160 to 400 million tonnes of carbon a year

Summary

Continental shelf sediments hold vast stocks of organic carbon, and bottom trawling is a leading human pressure that stirs them up again and again. When resuspended sediment meets oxygen-rich water, the stored carbon can decompose and escape as carbon dioxide. Global modelling indicates that trawling could release 160 to 400 million tonnes of carbon each year, some of which may reach the atmosphere. The report admits that these figures remain uncertain. Even so, it argues that they show how activities disturbing seabed sediments can weaken a natural store that would otherwise lock carbon away over geological time. It therefore calls for marine spatial planning to account not only for biodiversity but also for carbon storage and nutrient cycling.