Africa: Carbon Emissions From Trawler Fishing On a Par With Aviation, Say Ocean Researchers

Barcelona — Protecting just 3.6% of the ocean would cut risk of carbon disturbance due to bottom trawling by 90%, study finds

Trawling of the ocean floor by fishing fleets releases roughly the same amount of carbon emissions into the water as aviation puts into the atmosphere each year, researchers said on Wednesday, calling for greater protection of the planet’s seas.

In a study published in the journal Nature, a team of 26 scientists and conservationists said marine protected areas (MPAs) are an effective tool for restoring biodiversity, expanding seafood supplies and storing climate-heating carbon.

But at present, only 7% of the ocean has been designated or proposed as an MPA, with less than 3% under full or high protection from fishing, mining and other habitat destruction.

The study explored the benefits of boosting that share to at least 30%, a goal governments are being urged to adopt this year when they agree new global targets to stop and reverse the damage humans are causing to nature.

Lead author Enric Sala, who is an “explorer-in-residence” at the National Geographic Society, said ocean life has declined worldwide because of overfishing, climate change and damage to marine habitats.

“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,” he said in a statement.

Researchers calculated for the first time the climate impacts of bottom trawling, a fishing method that involves dragging heavy nets across the ocean floor, and found it produces one gigatonne of carbon emissions on average each year.

That exceeds the annual emissions of all countries except China, the United States, India, Russia and Japan, they said.

Paper co-author Trisha Atwood of Utah State University said the “destructive” practice of trawling disturbs the seabed, releasing some of the carbon it contains, which is then broken down by microbes and turned into carbon dioxide (CO2).

It is still unclear how much of that CO2 finds its way from the sea into the air, where it contributes to warming the planet, she told the Thomson Reuters Foundation.

But if it stays in the water, it contributes to the acidification that is harming coral reefs and means the ocean can absorb less CO2 from the atmosphere, she added.