Agriculture is one of the hardest human activities to decarbonize, but researchers are evaluating a potential solution to the problem that eliminates farms altogether: synthesizing dietary fats.
In a study published in Nature Sustainability, a team of scientists assesses the potential for widescale synthetic production of dietary fats through chemical and biological processes. The raw materials for this method are the same as those used by plants: hydrogen in water and carbon dioxide in the air.
“Large-scale synthesis of edible molecules through chemical and biological means without agricultural feedstocks is a very real possibility,” says lead author Steven Davis, professor of earth system science at the University of California, Irvine. “Such ‘food without the farm‘ could avoid enormous quantities of climate-warming emissions while also safeguarding biodiverse lands that might otherwise be cleared for farms.”
Davis and his coauthors highlight other environmental and societal benefits of farm-free food in the paper, including a reduction in water use and watershed pollution, local control over food production, diminished risk of weather-related food shortages, and less need for low-paying and physically demanding agricultural labor. Another plus, according to Davis, would be the possibility of returning existing farmlands to a natural state, which could enhance biodiversity and build up natural carbon sinks.
“I like the idea of not depending on photosynthesis for everything we eat,” Davis says. “At whatever scale, synthesizing food will alleviate competition between natural ecosystems and agriculture, thereby avoiding the many environmental costs of farming.”
Davis highlights the practice of razing tropical rainforests to create space for palm oil plantations. Cookies, crackers, snack chips, and a lot of other middle-of-the-store products are made with dietary fats coming from this source. He asks if anybody would notice if the oil used to bake their cookies came from a food refinery up the road instead of a plantation in Indonesia.
The authors of the paper say they focused much of their attention on fats because they are the “simplest nutrients to synthesize thermochemically,” pointing to established large-scale soap-making and polymer chemistry techniques.
The researchers estimate that agriculturally derived fats correspond to roughly one to three grams of emitted carbon dioxide per thousand calories, whereas molecularly identical fats synthesized from natural gas feedstock using available electricity would produce less than a gram of CO2 equivalent emissions, and nearly zero emissions if using carbon capture from the air and non-emitting sources of electricity.
“The beauty of the fats is that you can synthesize them with processes that don’t involve biology. It’s all chemistry, and because of that, you can operate at higher pressures and temperatures that allow excellent efficiency,” Davis says. “You could therefore build big reactors to do this at large scales.”
A big remaining question is, will people accept food created this way?
“Food is a tougher problem than electricity; few people care where the electrons in our wall socket originate, but many people care a lot about where their food comes from,” Davis says. “Processed foods are thus a likely use for synthetic fats. Folks may be less concerned about what kind of fat is in a store-bought cookie or pie crust because they don’t know what’s in there right now.”
Davis’ collaborators on this research project, which received financial support from the National Science Foundation and the US Department of Agriculture, are from the Carnegie Institution for Science in Stanford, California and Breakthrough Energy in Kirkland, Washington; Orca Sciences, in Kirkland, Washington; the University of Waterloo in Ontario, Canada; and Tsinghua University in Shenzhen, China.
Source: UC Irvine
