Substituting meat from cattle and other ruminants with microbial protein grown in bioreactors could greatly reduce deforestation and emissions from global meat consumption by mid-century, according to a study in the journal Nature.
The study projects a business-as-usual scenario for 2050 that includes population growth, deforestation for livestock grazing and feed, and growing meat consumption linked with increased affluence. If just 20% of projected future meat consumption is shifted to microbial protein, the study calculates, deforestation and related emissions drop by more than half.
Described by the New Scientist as “a meat-like product often made from a fungus, fed with sugar and fermented in heated vessels,” if this microbial protein is substituted for a larger percentage of meat—up to 80%—emissions from nitrous oxide and methane, along with agricultural water use, are all reduced proportionally. Land use and related carbon emission benefits increase, as well, but not as much.
Past assessments found that microbial proteins have 80% lower emissions than meat from cattle, sheep, and other ruminants. They can also consume 90% less land and water, a big benefit as increased land use for livestock feed and grazing is a primary driver for global deforestation. The study does include the land required to grow sugar, but not the energy required for factories producing the microbial protein. And projected emissions reductions are contingent on a decarbonized electricity source.
A shift to microbial protein would also reduce dependence on crop-based agriculture, which is vulnerable to climate-related extreme weather events such as droughts, floods, and heat waves. Sugar production, if required, would still be vulnerable, but in future may be replaced in the microbial protein process with carbon dioxide or methane from the air. Start-ups are also exploring algae and bacteria as alternatives to fungus.
Microbial protein is distinct from cultured meat grown in petri dishes from animal cells. According to lead author Florian Humpenoder of the Potsdam Institute for Climate Impact Research, which conducted the Nature study, the biotechnology used for cultured meat is still in development, with unknown costs and a long lead time. By contrast, microbial protein is commercially available today, being sold as ‘Quorn’ across Europe. It can be made to “mimic the look, smell, texture and taste of meat,” making it a palatable alternative for meat consumers.
But microbial proteins “might not have as bioavailable forms of zinc, iron, or protein as the ruminant meat it is modelled to replace,” said Rachel Mazac of the University of Helsinki. Another concern is the impact on farmers and the risk of accelerating the shift from local ownership to corporate agribusiness.
Study co-author Alexander Popp also acknowledged the need for decarbonized electricity. “Yet if we do this properly, microbial protein can help meat lovers embrace the change. It can really make a difference.”
After making himself a pancake from microbial protein, European author and activist George Monbiot predicted “the beginning of the end of most agriculture.”
