From The Guardian by Karen McVeigh
Dragging heavy nets across seabed disturbs marine sediments, world’s largest carbon sink, scientists report
Fishing boats that trawl the ocean floor release as much carbon dioxide as the entire aviation industry, according to a groundbreaking study.
Bottom trawling, a widespread practice in which heavy nets are dragged along the seabed, pumps out 1 gigaton of carbon every year, says the study written by 26 marine biologists, climate experts and economists and published in Nature on Wednesday.
Only 7% of the ocean is under some kind of protection.
Humanity and the economy benefit from a healthier oceanDr Enric Sala, scientist
“It’s clear that humanity and the economy will benefit from a healthier ocean. And we can realise those benefits quickly if countries work together to protect at least 30% of the ocean by 2030.”
The scientists identified marine areas where species and ecosystems face the greatest threats from human activities.
The top 10 countries with the most carbon emissions from bottom trawling, and therefore the most to gain, were China, Russia, Italy, UK, Denmark, France, the Netherlands, Norway, Croatia and Spain.
The analysis shows that the world must protect a minimum of 30% of the ocean in order to provide multiple benefits.
“There is no single best solution to save marine life and obtain these other benefits. The solution depends on what society – or a given country – cares about, and our study provides a new way to integrate these preferences and find effective conservation strategies,” said Dr Juan S Mayorga, a report co-author and a marine data scientist with the Environmental Market Solutions Lab at the University of California, Santa Barbara and Pristine Seas at the National Geographic Society.
One notable priority for conservation is Antarctica, which has little protectionDr David Mouillot, co-author
The study calculates that eliminating 90% of the present risk of carbon disturbance due to bottom trawling would require protecting only about 4% of the ocean, mostly within national waters.
The study estimated the emissions at between 0.6 and 1.5 gigatons of carbon dioxide a year, or an average of 1 gigaton annually. Aviation emissions of carbon dioxide in 2019 were 918m tons.
The UN’s biodiversity conference, Cop15, which is to be held in Kunming, China, this year, is expected to produce a global agreement for nature, building on the targets already set by some nations to protect at least 30% of the ocean by 2030.