Scientists have made a groundbreaking discovery about the impact of bottom trawling on the environment. The practice of dragging massive nets along the seabed to catch fish has been found to release a staggering 370 million tonnes of carbon dioxide into the atmosphere annually. This revelation has prompted experts to label the issue as ‘too big to ignore’.

A recent study conducted over the period of 1996-2020 estimated that bottom trawling released 8.5 to 9.2 billion tonnes of carbon dioxide into the atmosphere. The study, titled ‘Atmospheric CO2 emissions and ocean acidification from bottom trawling’, was authored by a global team of climate and ocean experts. They likened the impact of bottom trawling to ‘marine deforestation’, citing its irreparable harm to the climate, society, and wildlife.

The research also revealed that 55-60% of the carbon dioxide released from the seabed by trawlers makes its way to the atmosphere within nine years. Trawling hotspots in the East China Sea, the Baltic, the North Sea, and the Greenland Sea were identified as the largest contributors to climate emissions.

Furthermore, the study highlighted that carbon released from the sea floor also leads to local acidification, diminishing the oceans’ capacity to absorb carbon. Dr. Trisha Atwood, an aquatic ecologist at Utah State University and National Geographic’s Pristine Seas, emphasized the destructive nature of bottom trawling, stating, ‘We have long known that dragging heavy fishing nets across the ocean floor destroys sea life and habitats. Only recently, we have discovered that bottom trawling also unleashes plumes of carbon, which otherwise would be safely stored for millennia in the ocean floor.’

The study’s findings were based on a vessel-tracking database processed by Global Fishing Watch, which provided insights into the locations of trawling activities from 1996-2020. By combining this data with information on sea-floor carbon, the researchers were able to quantify the significant impact of bottom trawling on carbon emissions and ocean acidification.