Those looking for a healthy, climate-friendly diet may want to consider eating more oysters and herring.
When it comes to greenhouse gas emissions, plant-based foods are usually touted as a low-impact alternative to lean meat. However, new research has shown that certain types of seafood, such as farmed shellfish and small oily fish such as herring, are more climate-friendly than some vegetables, given their nutritional value. However, other seafood, including farmed shrimp, scored worse than beef.
The lead author of the study, Zachary Kane, said: “I wanted to see how seafood stacks with all of the various land production systems.”
Kane, an early career fellow at the Stanford Ocean Solution Center, now considers the greenhouse gas emissions generated by the life cycle of various foods and how those foods meet specific dietary requirements. I compared it when. He completed his dissertation published in an environmental research letter on Tuesday while earning his PhD. With co-authors Edward H. Allison and Ray Hillborn of the University of Washington. Christopher Golden of Harvard University was also the author.
According to Kane, each food received a value based on the greenhouse gas emissions needed to meet nutritional requirements measured as an average of 12 nutrients essential for health and child development. The highest scorers in all food groups were carrots, parsnips, root vegetables such as turnips, pelagic fish such as sardines and anchovies, farmed mussels, lajonkairia lajonii and oysters. According to the paper, they can all be produced or harvested in a relatively unaffected way while providing nutrient density.
The worst scorers were farmed catfish, tilapia and shrimp due to their relatively low nutritional value and high emissions. Even beef was defeated because beef is nutritious despite its high production.
In the analysis, Koehn aggregated previous studies to compare global commodities such as feedlot beef rather than farmed seafood and grass-fed beef imported from Asia.
Cultured mussels such as oysters and mussels absorb carbon dioxide and do not need to be fed, resulting in a very small footprint. Small pelagic fish are harvested in purse seine, a type of net that uses less fuel because it does not drag the bottom. Farmed shrimp, on the other hand, are often harvested on trawlers that use a lot of fuel.
This paper is one of the new areas of research that should be admired for investigating the effects of food on the climate by examining its relative nutritional value rather than comparing a pound of apples with a pound of chicken. The department is the Faculty of Resources and Environment, Dalhousie University in Halifax, Nova Scotia.
“They are contributing to this important next area of food system analysis, looking beyond individual foods to food and dietary combinations,” said Monterey, creating his own seafood carbon emission tool. Tidemars, who has been an advisor to Bay, said. Aquarium seafood watch program.
However, Tyedmers has several data on food life cycle assessments, a method of measuring environmental impacts that may take into account everything involved in the production of a pound of potatoes, lettuce heads, or salmon fillets. Withdrawing from research raises issues because the methods are different.
Kane said he re-run the study figures to make sure the life cycle assessment was in line with what he knew.
“I recognize that future research needs to investigate it much deeper,” he said.
Both Koehn and Tyedmers state that seafood is so complex that it is often rejected in food policy debates due to the varying sustainability of farmed and wild fish, imported and domestic fish and shellfish. But it overlooks the fact that many types of seafood have less climate impact than other foods and promise to feed a growing world population.
“There is growing awareness that many types of seafood are very nutritious,” says Koehn. Still, “they are often excluded from food system policies,” such as federal agricultural bills, food stamping systems, and school lunch programs. Kane said he believes this is because wild-caught seafood is regulated by the Department of Commerce, not the Department of Agriculture, which oversees these programs.
Other studies comparing the environmental impacts of seafood and land foods have focused on their protein content, but Kane thought it important to consider a wider range of nutrients, so He performed nutritional analyzes based on omega-3 fatty acids, vitamin B12, iron, zinc and other micronutrients.
Although canned anchovy and anchovy have revived during the pandemic, many are willing to eat herring and oysters, at least for most of their diet. Koehn said more culinary work is needed to make these types of foods acceptable to the general public.
“It’s very important when thinking about a more sustainable and nutritious food system,” he said. “We really need to think about all the options on the table.”
Tara Duggan is a staff writer for the San Francisco Chronicle. Email: tduggan@sfchronicle.com Twitter: @taraduggan
