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Even modest dietary shifts could free up enough land to offset global coal emissions

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Even modest dietary shifts could free up enough land to offset global coal emissions

Researchers imagined what would happen if bioenergy crops grew where livestock once roamed. Their findings are striking.
February 16, 2024

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Researchers have made a novel case for consuming less dairy and meat: it could free up land to grow bioenergy crops—enough, in fact, to replace the fuel currently generated by polluting coal plants worldwide. 

Typically, biofuels haven’t been seen as a clearcut win for the environment, because the crops may compete with agriculture or wild habitat for space, heaping pressure on food security and biodiversity in the process. 

But in the new One Earth study, the researchers imagined what would happen if bioenergy crops were confined only to land that could be freed up by livestock as we switch to other forms of protein instead, a transition that’s already underway.

The new work looked at a process called bioenergy with carbon capture and storage (BECCS), whereby quick-growing crops like miscanthus and switchgrass are not only turned into clean electricity and hydrogen, but the carbon they suck out of the atmosphere and store in their plant fibers can also be permanently locked away. 

As for where to grow this biofuel? To figure that out, the researchers took all the land required to rear and feed livestock globally, then calculated how much of it would be released, if diets changed to substitute anywhere between 10% and 100% of animal protein with alternatives. They looked at how much biofuel biomass could be produced on the available land at those different levels, and how much fuel and carbon we could go on to capture from that. 

 

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The model also locked in a baseline calorie and protein supply, to ensure that whatever share of land bioenergy took up, enough food could always be grown on the remaining land. 

The study looked at replacing up to 100% of animal protein—but showed that impressive benefits could actually be achieved with far less. If we substituted 50% of animal-derived protein with alternatives, the available land could grow enough green fuel to match, and even slightly exceed, global coal power production each year. Effectively, biofuel could replace coal. What’s more, the BECCS process could lock away up to 9.3 gigatons of CO2-equivalent annually, roughly the equivalent of what coal emits each year. 

That wouldn’t only remove coal-associated emissions, but also permanently suck away an equivalent amount of greenhouse gas, a positive double-whammy for the planet and its changing climate. 

“Even modest adoption levels of alternative proteins could free up large agricultural areas,” the study authors write. In fact, further dropping that substitution target to 30% could produce an amount of fuel and reduced emissions that fall just shy of those linked to global coal production each year.

That 30% target may be a relatively realistic one, too. The study cites market research which shows that alternative proteins sourced from plants, microorganisms, and cell cultures could feasibly replace up to 30% of animal-based products by 2030, rising as high as 70% by 2050. (Though, some studies reveal that when consumers buy meat alternatives, it’s not always a clean switch.) 

Until now, most research exploring the benefits of dietary shifts has shown the immense carbon-sequestering potential of rewilding the newly-reclaimed land. But the researchers on the new work also show that biofuel crops would actually be able to sequester more carbon, overall, than forest, grassland, or other rewilded land. 

With that said, the paper is careful to highlight the multiple other benefits that rewilding brings, beyond locking carbon away. Clean air, water, and greater biodiversity are all linked to rich natural ecosystems, for which biofuel croplands simply cannot be a substitute. With this in mind, the researchers estimate that after a period where biofuel farming has sequestered enough carbon to make a real dent—about 700 gigatons—the land could be turned over to the wild again. As they put it, “the adoption of BECCS or other land-based CO2 removal methods does not exclude natural succession altogether.”

Whether that freed land were to become forest or fuel, ultimately, this new research provides a compelling new reason to change the way we eat. The opportunities it could bring for climate and planet seem too good to pass up. 

Rueda et. al. “A protein transition can free up land to tap vast energy and negative emission potentials.One Earth. 2024.

Image: ©Anthropocene Magazine

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