Forty world leaders will attend a virtual climate summit hosted by the United States on Thursday and Friday, but the majority of the focus may fall on just one: Jair Bolsonaro, the climate-change-denying president of Brazil.

Bolsonaro has become an international pariah as he has presided over record levels of deforestation in the Amazon rainforest since taking office in 2019, and his reputation has only worsened due to his disastrous response to the COVID-19 pandemic.

It may seem odd to focus on the one outlier at a conference intended to boost climate ambitions ahead of a larger United Nations climate summit in November. But instead of snubbing Bolsonaro, President Joe Biden has used his first few months in the White House to urge Bolsonaro to reclaim Brazils former mantle as a global leader in the fight against climate change.

Since February, the U.S. and Brazil have engaged in a series of diplomatic discussions about a potential agreement that could eventually resemble a plan Biden proposed during his campaign to create an international $20 billion fund to incentivize protecting the Amazon. (A similar program, the Amazon Fund, was established in 2008 to allow other countries to support projects that limit deforestation in Brazil, though its major European supporters halted donations in 2019 over Bolsonaros environmental policies.) And while that deal almost assuredly wont materialize this week, Bolsonaros approach to the summit could determine whether or not the two leaders reach an agreement both say they want.

Biden and former Secretary of State John Kerry, the U.S. special envoy for climate, really want to find a way to keep Brazil actively engaged in these climate talks, said Thomas Shannon, who served as the U.S. ambassador to Brazil from 2010 to 2013. So theyre making great efforts to make sure that the Brazilians come along with them. But at the same time theyre trying to make it very clear that this is not a moment for half-measures, and that what Brazil has been proposing is insufficient.