Global veganism could undo 16 years’ of fossil fuel emissions

If land currently used to produce meat and dairy was returned to its native ecosystems, it could remove the same amount of carbon dioxide (CO₂) as was produced by burning fossil fuels over the last 16 years.

In a new study published in Nature Sustainability, researchers say that shifting global consumption away from animal products to a more plant-based diet would free up large areas of land. If native vegetation regrowth was encouraged, these areas could add to the fight against climate change by absorbing CO₂ in the atmosphere.

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"Restoring native forests could buy some much-needed time for countries to transition their energy grids to renewable, fossil-free infrastructure,” said Matthew Hayek, an assistant professor in New York University and the principal author of the new study.

Livestock produce large amounts of methane, a greenhouse gas that is 28 times more powerful than CO₂ at trapping heat. Many who call for meat consumption to be reduced cite their methane emissions, but this new study shows how going meat-free can hugely impact CO₂ emissions, too.

"We only mapped areas where seeds could disperse naturally, growing and multiplying into dense, biodiverse forests and other ecosystems that work to remove CO₂ for us," said Hayek. "Our results revealed over 7 million square kilometres where forests would be wet enough to regrow and thrive naturally, collectively an area the size of Russia."

In the study, the researchers saw three possible scenarios for 2050: business-as-usual, where meat consumption remains on its current course of increase; a healthier diet with 70 per cent meat reduction; and a vegan diet.

If meat consumption follows current economic trends, the business-as-usual diet would see further clearing of ecosystems to make more land space for animal agriculture.

Whereas the healthier, reduced-meat diet could remove 332 gigatonnes of CO₂ – equal to the amount of CO₂ produced over the last nine years by burning fossil fuels. The vegan diet would remove 16 years’ worth of CO₂ emissions from the atmosphere, a total of 547 gigatonnes. A gigatonne is equal to 1,000,000,000,000 kilograms.

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However, there are countries on an economic trajectory where it would be challenging to develop economies that weren’t based around livestock, said Hayek.

So, the team looked at the opportunities for a reduction in the consumption of animal products across different countries in order to identify which places should be targeted when thinking about restoring ecosystems.

“The greatest potential for forest regrowth, and the climate benefits it entails, exists in high- and upper-middle income countries, places where scaling back on land-hungry meat and dairy would have relatively minor impacts on food security," said Hayek.