Fishing nets churn up carbon from the sea floor, more than half of which will eventually be released into the atmosphere
Scientists have long known that bottom trawling – the practice of dragging massive nets along the seabed to catch fish – churns up carbon from the sea floor. Now, for the first time, researchers have calculated just how much trawling releases into the atmosphere: 370m tonnes of planet-heating carbon dioxide a year – an amount, they say, that is “too big to ignore”.
Over the study period, 1996-2020, they estimated the total carbon dioxide released from trawling to the atmosphere to be 8.5 to 9.2bn tonnes. The scientists described trawling as “marine deforestation” that causes “irreparable harm” to the climate, society and wildlife.
The study – Atmospheric CO2 emissions and ocean acidification from bottom trawling, written by a global team of climate and ocean experts – found that 55-60% of the carbon dioxide in the water released from the seabed by trawlers will make it to the atmosphere within nine years.
Bottom trawling is one of the most hideously destructive things we do to this planet. Imagine if you wanted to catch rabbits, so you hooked a giant nylon net to the back of two humvees. Put them 100 yards apart and drive through a forest, knocking down trees, shredding the underbrush, catching anything and everything in its path. At the other end of the forest you carefully step over all of the dying deer, moose, mice etc and pick out the 30-40 rabbits that you want. Then you leave the net and everything else you just happily killed lying at the edge of the forest so nothing can grow under it. That’s what bottom trawling is. People would be horrified by it, except that it literally happens under the surface.
This is a huge part of the reason that we’re missing a billion crab. This is a huge part of why the king salmon are dying, which is a huge part of why the orcas are starving.
Commercial fishing in general has massive, glaring environmental problems, from bycatch to emissions to illegal overfishing to everything else under the sun. But if I had to pick one issue to focus on it would be bottom trawling.