Plant-based diets offer potential ‘climate dividend’

By Joan Conrow

January 25, 2022

If people in rich nations reduce the amount of animal products they eat, they could help the world achieve a potential “climate dividend,” says a new study.

By transitioning to largely plant-based diets, rich countries would free up an area of land the size of the European Union for ecosystem restoration and carbon removal, found a study published Jan. 10 in Nature Food. The potential sequestration benefit could total more than a billion tonnes of carbon dioxide equivalent.

The reduced emissions and carbon sequestration achievable through changing to largely plant-based diets “could potentially fulfil high-income nations’ future sum of carbon dioxide removal (CDR) obligations under the principle of equal per capita CDR responsibilities,” write the seven authors, who represent universities in China, the Netherlands, the United States and Austria.

About half of this reduction would collectively occur in the US (29.9 percent), France (7.1 percent), Australia (6.5 percent) and Germany (4.4 percent), the authors report. Some large middle- and low-income countries, such as India and Brazil, would also see emissions reductions due to cutting their exports of agricultural products to high-income countries. The largest carbon benefits would be experienced by dietary changes in the US and Australia because they produce so much beef.

Since agriculture accounts for about 24 percent of global carbon emissions, shrinking its climate footprint will play a pivotal role in determining whether global warming can be kept to the 1.5C-degree increase targeted by the Paris agreement.

The authors warn that current agricultural emissions could preclude staying within even a 2-degree increase, noting that “radical land-use and agricultural management interventions may be crucial strategies for limiting climatic change. Dietary change, for one, has been found to be a practical and effective strategy in multiple studies.”

“Our results show that such dietary change could reduce annual agricultural production emissions of high-income nations’ diets by 61 percent while sequestering as much as 98.3 (55.6–143.7) GtCO2 equivalent, equal to approximately 14 years of current global agricultural emissions until natural vegetation matures,” the authors write.

To reach this conclusion, they simulated what would happen if 54 high-income nations (representing 68 percent of the global gross domestic product and 17 percent of the world’s population) adopted the EAT–Lancet planetary health diet, which emphasizes whole grains, fruits, vegetables, nuts and legumes over meat and dairy. The EAT-Lancet program also calls for reducing food waste and improving agricultural production.

It’s clear that high-income countries must take the lead, given that they consumed six times more meat per capita in 2013 than low-income countries, the study says. Additionally, animal products account for 70 percent of the food-system emissions in high-income countries, but only 22 percent in low–middle-income countries.

“Attribution of these emissions is complicated by agricultural globalization, whereby food consumption in high-income countries drives overseas GHG [greenhouse gas] emissions through international trade,” the authors write. “As such, dietary change in high-income countries may hold the potential to substantially reduce agricultural emissions around the world—a potential climate ‘dividend’.”

A second, additional carbon dividend could also result from wealthy nations eating few or no animal products if the bulk of the land now used for livestock is set aside for intentional ecosystem restoration. “In many regions, reverting cropland to its antecedent or ‘potential’ natural vegetation can substantially increase aboveground biomass carbon, belowground biomass carbon and soil organic carbon stocks, with additional co-benefits for biodiversity and other ecosystem services,” the authors write.

Transitioning to plant-based diets could free up an area of land slightly larger than the European Union. “Carbon sequestration would be achieved predominately in large countries with large amounts of agricultural production, especially feed crops and pasture,” the study finds, with more than half of the increase in global carbon sequestration occurring in just four nations: the US, Australia, Germany and France.

“Land spared by reducing the consumption of meat products, dairy products and eggs could capture and store 81 times the annual GHG emissions from annual agricultural production (1.22 GtCO2e yr−1) of food consumed in high-income countries in 2010,” the authors write.

While switching to a primarily plant-based diet would have the immediate effect of reducing agriculture’s carbon emissions, it could take decades or even centuries for sequestration to reach its full potential, the authors assert. “We conceptualize the latter effect as a one-time ‘committed’ mass of carbon that is sequestered over an unspecified period after restoration is initiated. However, such climate benefits will materialize only if land upstream in the supply chain is spared from agricultural activities.”

Additional carbon reduction could also be possible from downstream sectors, such as transportation, processing, packaging, retail and consumption.

Image: A plant-based diet offers a range of tasty, healthy options while also reducing climate change impacts. Photo: Shutterstock/marilyn barbone