In a study published today, scientists have shown that bottom trawling is a previously undisclosed source of carbon emissions into the atmosphere. This study highlights the important role of bottom trawling – dragging heavy fishing nets across the ocean floor and restoring some of the carbon in seafloor sediments – as the world seeks to reduce emissions from fossil fuels, deforestation and other sources. It is the source of carbon pollution in the atmosphere.

The study was published on: Frontiers in Marine Sciences.

Previous research has shown that some of the carbon in sediments turns into carbon dioxide underwater. Today’s research shows that 55-60 percent of the carbon dioxide produced underwater by bottom trawling will be released into the atmosphere within nine years. According to estimates, the amount of carbon released into the atmosphere annually by bottom trawling doubles the annual emissions from burning fuel for the entire world’s fishing fleet (about 4 million ships).

Dr. from the University of Utah and National Geographic Pristine Seas. “We have known for a long time that dragging heavy fishing nets, some as large as ten 747 jet nets, across the ocean floor destroys marine life and habitats,” said Tricia Atwood. .

“We have only recently discovered that bottom trawling also releases columns of carbon on the ocean floor that would be safely stored for thousands of years. Our study is the first to show that more than half of the carbon released by bottom trawling enters the atmosphere as carbon dioxide within about a decade, contributing to global warming.” “Like deforestation, seafloor scraping causes irreparable damage to climate, society and wildlife.”

Research “CO2 emissions ₂ “Transition to atmospheric and ocean acidification by bottom trawling” was led by a global team of climate and ocean experts from the University of Utah, NASA Goddard Institute for Space Studies, UC Santa Barbara, Columbia University, James Cook University and National Geographic Pristine Seas. .

The researchers used data and advanced models on bottom trawling conducted worldwide between 1996 and 2020 to calculate the amount of carbon dioxide produced by bottom trawling ultimately entering the atmosphere. This study builds on a seminal study that found that the amount of carbon dioxide released into the ocean by bottom trawling exceeds the annual carbon emissions of most countries and is about the same magnitude as the annual carbon emissions of global aviation.

The new study identifies ocean regions where carbon emissions from bottom trawling are particularly high, including the East China Sea, the Baltic and North Seas, and the Greenland Sea. The researchers concluded that Southeast Asia, the Bay of Bengal, the Arabian Sea, parts of Europe and the Gulf of Mexico may also be major sources of carbon emissions from trawling, but we do not currently have sufficient data on the size and density of the bottom. trolling. in these areas.

Pristine Seas National Investigator and Executive Director Dr. “Countries are currently not including the significant carbon emissions from bottom trawling in their climate action plans,” said Enrique Sala. “Our research clearly shows that tackling these and other ocean emissions is critical to slowing global warming, as well as restoring marine life. The good news is that reducing carbon emissions from bottom trawling will have immediate benefits. The bad news is that delaying action , which will ensure that emissions from trawling will continue to leak into the atmosphere ten years from now.”

The new study also evaluates what happens to carbon trapped in ocean waters after bottom trawling. He concludes that 40% to 45% of the total carbon transported from the ocean floor by trawling remains in the water, leading to more localized ocean acidification. This increased acidity harms the plants and animals in the fishing area.

“There are many more issues with bottom trawling than carbon impacts, such as biodiversity and sustainability,” said Gavin A. Schmidt, director of NASA’s Goddard Institute for Space Studies. “But this ‘marine deforestation’ is large enough to attract attention and appreciation. “Hopefully this can lead to policy efforts that can try to maximize the benefits of all impacts.”