Joe Biden and Jair Bolsonaro square off over the Amazon

BRAZILIAN BUSINESSES rarely preach greenery. Yet last July, 20 months after Jair Bolsonaro was elected president, rampant deforestation in the Amazon roused 38 CEOs to speak up. Foreign investment was falling and trade talks were stalled. “This negative perception has an enormous potential for harm,” they wrote in a letter to the government, urging Mr Bolsonaro to do something. He ignored them. The pace of deforestation, as reported in November, was 10% faster in 2020 than in 2019. Yet the president merrily slashed the budget for environmental enforcement for the third year in a row.

Now those Brazilian bosses are placing their hope in another president—one who lacks Mr Bolsonaro’s populist disregard for science. Joe Biden has signalled that both his foreign and domestic policies will aim to arrest climate change. More than 60% of the remaining tree cover in the Amazon is in Brazil. Not only is the rainforest brimming with irreplaceable biodiversity; it is also a carbon sink. Burning or chopping it down turns it into a source of carbon emissions instead. American diplomacy under Mr Biden will seek to persuade Mr Bolsonaro not to let that happen. This is perhaps the first time that a major bilateral relationship has focused on trees.