The Amazonian rainforest in Brazil, it’s often said, serves as the Earth’s lungs, taking in huge amounts of carbon dioxide and breathing out oxygen. Now those lungs are ablaze.

Some 74,000 fires have raged this year in the world’s largest rainforest, about 80% more than at this time last year, according to the Brazilian research institute that monitors the Amazon. These are not natural wildfires, environmental experts warn. They are set by farmers, loggers and other inhabitants who are aggressively clearing forests for agricultural development.

Point much of the blame for this slow-burning catastrophe at Brazilian President Jair Bolsonaro, who sees rainforest protection as an impediment to economic growth. Since January, when Bolsonaro took office, the amount of deforestation climbed 39% over the previous year. He accused his own government’s scientists of exaggerating the pace of destruction and claimed, without evidence, that nongovernmental organizations are setting the fires in order to film them.

The Amazon is home to many indigenous people and at least 10% of the world’s known plant and animal species, representing the richest biodiversity of any ecosystem on the planet. Those forests also act as a critical defense against global warming because they absorb so much carbon dioxide — cumulatively they hold about a decade’s worth of the planet’s emissions, Paulo Moutinho of the Woods Hole Research Center told the Washington Post. “If you continue to deforest … you are releasing this huge amount of carbon to the atmosphere,” he said.

Over the years Brazil has tried to protect the environment and slow deforestation. Bolsonaro, who was elected last year, defiantly changed course. “The Amazon is ours, not yours,” he told a foreign journalist last month. Technically true, but with ownership comes a deep responsibility to the planet’s well-being. There’s a point in the deforestation process at which the Amazon would no longer be able to sustain its existence as a functioning rainforest. One bad result: more global warming.

Brazil’s president owes his own nation, and the world, a better fate.