Meat and seafood production have a high environmental cost
Researchers have taken a comprehensive approach to evaluating the environmental impacts of different types of animal production. Overall, they found that the production of beef and farmed catfish have the greatest impacts, while wild-caught fish and the farming of mollusks have the least environmental impacts.
Study lead author Ray Hilborn is a professor in the School of Aquatic and Fishery Sciences at the University of Washington.
“From the consumer’s standpoint, choice matters,” said Professor Hilborn. “If you’re an environmentalist, what you eat makes a difference. We found there are obvious good choices, and really obvious bad choices.”
For their analysis, the experts reviewed hundreds of assessments focused on different types of animal protein production. Also known as a “cradle-to-grave” analysis, the assessments accounted for the environmental impacts generated by every stage of a product’s life.
The researchers used four metrics to compare the effects of various animal production methods including aquaculture, livestock farming, and seafood caught in the wild. The experts accounted for energy use, greenhouse gas emissions, the potential to release excess nutrients, and the potential to contribute to acid rain.
The results of the analysis clearly showed that the lowest environmental impacts across all measures were generated by farmed shellfish; capture fisheries such as sardines, mackerel, and herring; and mollusks, such as oysters and scallops.
The research also clearly identified the range of environmental consequences associated with various production practices, and the differences were striking.
Overall, catfish aquaculture and beef production result in 20 times more greenhouse gases than farmed mollusks, small capture fisheries, or farmed salmon and chicken.
Farmed catfish, shrimp, and tilapia used the most energy, primarily for the constant water circulation required for these systems.
Regarding excess nutrients, capture fisheries consistently scored the best because no fertilizer is used. Mollusk aquaculture actually absorbs excess nutrients that are harmful to ecosystems, while livestock and beef production rated poorly in this measure.
Livestock emit methane in their manure, giving them a poor score in the acid rain category. Farmed mollusks were rated the highest again, with small capture fisheries and salmon aquaculture scoring very high as well.
“I think this is one of the most important things I’ve ever done,” said Professor Hilborn said. “Policymakers need to be able to say, ‘There are certain food production types we need to encourage, and others we should discourage.’”
The researchers advise that consumers must decide what environmental impacts are the most important to them while making their food selections.
The research is published in the journal Frontiers in Ecology and the Environment.