By Darin Graham

Reporter, The Climate Question

picture copyrightBoston Globe/Getty Images

picture captionCod is a species of fish generally caught utilizing backside trawling

Eating fish could possibly be worse for the local weather than beforehand thought, in keeping with a current scientific examine.

Previous analysis indicated that seafood has a smaller carbon footprint than different animal proteins, as a result of fishing does not require farmland or the care of livestock.

But a brand new examine printed in Nature and led by Dr Enric Sala, claims that catching fish utilizing heavy nets that drag throughout the seabed – referred to as backside trawling – emits about the identical quantity of carbon dioxide (CO2) globally because the aviation trade.

Seabed sediments that act as large carbon sinks are churned up throughout this sort of trawling – and this ends in CO2 being launched.

picture copyrightGetty Images

picture captionEnric Salla says backside trawling emits about the identical quantity of CO2 yearly as aviation

“The ocean is full of little creatures that we call the plankton, microscopic algae and microscopic shrimp and so forth,” says Dr Sala, explorer-in-residence at National Geographic.

Speaking to the BBC World Service’s, The Climate Question, he says “most of these creatures, when they die, will sink to the bottom of the ocean. And over thousands and millions of years, those little organisms will accumulate first forming mud”.

His paper calculates that on common, about 1Gt (gigaton) of carbon dioxide is created due to bottom-trawling actions. “That’s about 2% of the global CO2 emissions,” he says.

By comparability, it’s estimated that aviation emits about 1.04Gt or 2.5% of worldwide emissions every year.

Bottom trawling is among the most typical strategies of fishing on the earth and the federal government says it accounts for half of the UK’s annual fish catch.

picture copyrightRowan Coe / 500px

picture captionMarine sediments are the world’s largest carbon sink

However, The Climate Question spoke to fishing specialists who dispute the outcomes of the paper and are involved that Dr Sala has overestimated the CO2 emissions ensuing from backside trawling.

The South African Deep-Sea Trawling Industry Association says that it isn’t but identified how a lot carbon within the ocean will get into the environment.

Dr Sala believes, nevertheless, that this info shouldn’t be as essential because it may appear. His argument is that if an excessive amount of CO2 is absorbed into the water from the seabed, then the oceans will be capable of take in much less carbon from the air.

“The ocean absorbs a quarter or more a third of our CO2 emissions every year. So if we increase the CO2 in the water, that will diminish the ability of that part of the ocean to absorb more CO2 from the atmosphere, ” he says.

Safeguarding the ocean

Protecting components of the ocean could possibly be one option to cease these emissions, he argues, and plenty of international locations have created marine protected areas, or MPAs.

Nearly 1 / 4 of the UK’s waters are coated by MPAs, nevertheless, the marketing campaign group Oceana, says that the majority of these areas nonetheless enable bottom-trawling.

picture copyrightIUCN

picture captionMinna Epps of the IUCN says backside trawling can nonetheless happen in marine protected areas

Minna Epps, the worldwide director of the marine and polar programme on the International Union for Conservation of Nature (IUCN), says it is because some MPAs enable these sorts of actions to happen.

“There are six different categories which the IUCN sets, basically ranging from the absolute strict, no interference to the lowest category where you are allowed to have bottom-trawling activities within that.”

The UK authorities says it recognises “the important role of marine habitats” and the way carbon saved within the seabed helps within the battle in opposition to the local weather disaster. It says it’s dedicated to decreasing the impression of the fishing trade on marine life.

“While trawling can cause carbon to be released from sediments, the processes are complex and the overall impact remains unclear,” a spokesperson from the Department for Environment, Food & Rural Affairs (Defra) mentioned.

picture copyrightYuri Smityuk

picture captionPulling a Danish seine or backside internet aboard a trawler within the Peter the Great Gulf, Russia

Defra says the UK desires to extend the variety of MPAs, and is main calls “for a new global target to protect at least 30% of the ocean by 2030”.

But some within the fishing trade warn in opposition to organising too many marine protected areas – as backside trawling may simply be displaced elsewhere.

“What are the impacts of where the vessels have been moved to? Not only that, it’s likely that somebody else will be fishing there, what are the knock on consequences there?” says Barrie Deas, chief government of the National Federation of Fishermen’s Organisations.

“Like the rest of the citizens of the world, we as an industry take climate change very seriously. And obviously we have to play our part in in addressing it,” he says.

“We as a planet need to be able to fish for food and bottom trawling has an important role to play.”

Listen to The Climate Question on Is backside trawling for fish unhealthy for the local weather? on Monday 23 May 2021 on BBC World Service radio, or meet up with the newest podcasts right here.