Ocean trawling, condemned by green groups for destroying marine habitats and depleting fish populations, generates a similar volume of carbon emissions to the global aviation industry, driven by activity in Chinese national waters, according to a paper published in the journal Nature. Bottom trawling, a fishing method that involves dragging heavy nets across the seafloor, is responsible for between 0.6 and 1.5 gigatonnes of carbon emissions a year, compared with the aviation industry’s emissions of close to IGt, the researchers found. The global aviation industry produces about 2 percent of all human-induced carbon emissions.
The majority of this pollution occurs in less than 4 percent of the ocean, in the sovereign fishing waters of coastal nations known as “exclusive economic zones”, said the paper. Trawling by boats in Chinese waters generates by far the greatest volume of emissions, or about 770m metric tonnes of C02, while trawlers in the economic zones of Russia, then Italy followed by the UK caused the next most pollution, the researchers said. The UK emits roughly 370m metric tonnes of carbon a year.
“The ocean floor is the world’s largest carbon storehouse. If we’re to succeed in stopping global warming, we must leave the carbon-rich seabed undisturbed,” said Trisha Atwood of Utah State University, a co-author of the paper. Oceans cover roughly 70 percent of the earth’s surface and play a critical role in absorbing heat and C02. The study said governments could achieve the triple benefits of carbon savings, increased marine biodiversity and greater fishing yields by protecting larger areas of the ocean.
It also endorsed an international initiative — which is likely to be a feature of this year’s China-hosted biodiversity conference, known as COP 15 — to safeguard at least 30 per cent of the world’s oceans by 2030.