Over the weekend, the ultra-conservative candidate Jair Bolsonaro handily beat his opponent, Fernando Haddad of the Workers’ Party (PT), in the second round of the Brazilian presidential elections.  For a campaign season characterized more by rhetoric than policy proposals, both candidates did set out clear agendas for the environment. Bolsonaro, for his part, condemned the country’s existing environmental regulations and agencies as bad for development and has promised to roll them back. (He has pledged to continue supporting renewable energy, though.) Haddad, by contrast, put forward a suite of policies meant to reduce pollution and control deforestation.

On their own, Bolsonaro’s proposals might not have amounted to much. After all, his party will still control fewer seats than the PT in the National Congress. But a shift toward the right in Congress and in some lesser-noticed state elections means that he’ll likely get his way: Whatever happens at the top of government, Bolsonaro’s agenda will be advanced at the state level. In turn, deforestation and greenhouse gas emissions could skyrocket, undoing what has been one of Brazil’s signature achievements on the world stage.

On the campaign trail, one of Bolsonaro’s most eye-catching environmental promises was to follow U.S. President Donald Trump’s lead and abandon the Paris Agreement on climate change. He has since recanted, but even if his country stays in the agreement, his policies will surely undermine it.  Since 2014, greenhouse gas emissions have steadily crept back up.

Historically, most of Brazil’s greenhouse gas emissions have come not from industrialization but from massive deforestation. Under PT President Luiz Inácio Lula da Silva, who led the country from 2003 to 2011, deforestation in the Amazon dropped by nearly 80 percent. That alone put Brazil on track to make one of the most substantial contributions of any country to meeting the Paris Agreement’s goals by its first deadline in 2020. Since 2014, though, after the narrow re-election of Lula’s successor, Dilma Rousseff, emissions have steadily crept back up, reflecting both loosened restrictions on the timber industry and increased emissions from other sectors.