Environmentalists and scientists fear that Brazil’s newly elected president, the far-right politician Jair Bolsonaro, will accelerate the destruction of the nation’s Amazon rainforest and Cerrado savanna, which rank among the world’s largest storehouses of carbon.

Both absorb massive amounts of greenhouse gas from the air, stocking it away in trees, grasses, roots, and soil. Bolsonaro’s campaign rhetoric and ties to agribusiness have led observers to fear he’ll push to loosen environmental rules and monitoring, says Tica Minami, coordinator of Greenpeace Brazil’s Amazon campaign. That could embolden farmers to burn down or otherwise clear more land for soybeans, sugarcane, and cattle, releasing vast quantities of carbon dioxide back into the atmosphere.

Already, as much as 15% of global climate emissions come from “deforestation and degradation of tropical forests,” studies have found.

The Amazon

Deforestation rates in the Amazon have declined significantly since early in the last decade, in part thanks to the “Save the Rainforest” movement and stronger land-use regulations. But figures seem to be creeping back up, and the election of Bolsonaro could send them soaring.

The Amazon is the world’s largest rainforest, spanning nine nations and accounting for around 17% of global carbon trapped in vegetation on land.

A 2011 study led by NASA scientists found that carbon biomass in the Amazon generally ranged from 125 to more than 200 metric tons per hectare. If deforestation rates in the Brazilian Amazon were to return to the 2004 peak, a likely scenario under Bolsonaro’s rule, it could boost annual emissions to almost 3 billion metric tons over his term, at the top end of that range. That’s nearly half the United States’ total annual greenhouse-gas emissions, which stood at 6.5 billion metric tons in 2016.

A study by scientists at Brazil’s National Institute for Space Research found that additional emissions could be even higher. They estimated that Amazon deforestation rates could triple, reaching 25,600 square kilometers a year, if Brazil exited the Paris climate deal, authorized mining on indigenous lands, and enacted other policies Bolsonaro has floated.

That would add up to an additional 1.3 billion metric tons of carbon dioxide and equivalent greenhouse gases annually, or more than 13 billion from 2021 to 2030, the researchers found, according to the Estadão newspaper in São Paulo.