February 5, 2016 — Fish is better than pork and beef—not just for your body, but for the planet. That’s long been the thinking, anyway. But a new study has uncovered a hidden climate impact of the fishing industry—one that, ironically, will get worse as boats switch to cleaner fuels. In some cases, the effect could make fishing for tuna as hard on the climate as raising pork, and trawling for shrimp about half as bad as raising beef.
Hogs and cattle get a bad rap because they—and their manure—emit a lot of methane, a powerful greenhouse gas. But the fishing industry also contributes to climate change: mostly from the carbon dioxide (CO2) from burned diesel fuel that persists in the atmosphere for hundreds of years. The boats produce other short-lived pollutants, such as sulfur oxides and black carbon, which have cooling and warming effects, respectively. But they have typically been neglected as unimportant in the grand scheme of things.
The new study may change that. Elliott Campbell and Brandi McKuin, environmental engineers at the University of California (UC), Merced, estimated fishing industry emissions by combining fisheries catch records with the amount of fuel typically needed to catch various species. Given the total burned fuel, they estimated the amounts of the pollutants, using information about engine types and fuel types. Black carbon, a form of soot that arises from incomplete combustion, has been underestimated by an order of magnitude in previous studies, the team reports in the Journal of Geophysical Research: Atmospheres.