New analysis shows that forest loss in the Brazilian Amazon could drop by 89% if incumbent president Jair Bolsonaro is voted out of office in this Sunday’s general election.

An area of 75,960 square kilometres of the Amazon, roughly the size of Panama, could be saved from destruction by 2030 if Bolsonaro’s left-wing challenger and two-term former president—Luiz Inácio Lula da Silva, known as Lula—emerges victorious, reports Carbon Brief.

Voting out Bolsonaro would also significantly curb Brazil’s emissions when accompanied by a new focus on forest restoration, the climate news website adds, citing University of Oxford analysis that models Brazil’s implementation of its Forest Code.

Though many factors affect the Amazon’s future, “the results highlight the impact that enforcing environmental legislation could have after years of neglect under Brazil’s current right-wing leader,” Carbon Brief says.

Deforestation is the main driver of Brazil’s emissions, the sixth highest of any country in the world, and it has accelerated under Bolsonaro’s weak environmental governance. In contrast, between 2003 and 2010 when Lula was president, the rate of forest loss dropped by three-quarters from peak levels in 2004. Deforestation rates remained low during the term of Lula’s successor Dilma Rouseff, until her impeachment in 2016.

Polls show Lula with roughly 50% of the votes—with some indicating as much as 52%—putting him roughly 10 points ahead of Bolsonaro and within reach of a first-round election win on Sunday. The campaign will continue into a runoff October 30 if neither candidate receives a clear majority.

The Oxford analysis compares projected deforestation rates following each candidate’s potential presidency and assumes that the differing deforestation trends will continue until 2050. A central difference is how each president will enforce the Forest Code, Brazil’s main law against deforestation. While the code requires landowners to preserve a certain portion of forest on their property and to restore illegally deforested land, it has been poorly enforced during Bolsonaro’s presidency and has been changed over the past decade to benefit landowners.

The projections assume that Lula, if elected, would follow through on pledges to reduce deforestation rates, while Bolsonaro would continue his track record of environmental deregulation.

“If he remains in power in 2023, no one should expect that Bolsonaro’s war against the Amazon, Indigenous people, environmental legislation, including the Forest Code, and science to monitor forests and land use to change,” said Carlos Rittl, a senior policy advisor at Rainforest Foundation Norway.

In a baseline scenario that projects continued deforestation unchecked by the Forest Code, annual losses stay above an average of 10,000 square kilometres this decade. Under a Lula presidency that reprises his past track record, levels would drop by 89%, say the researchers, from 13,038 to 1,480 kilometres from 2021 to the end of the decade.

Complete enforcement of deforestation regulation could be difficult, but the 89% drop is comparable to Lula’s earlier presidency, say experts, and they are optimistic about his adherence to the Forest Code.

“Lula has a track record of conservation and control policies from past mandates Code,” said Dr Grace Iara Souza, a fellow of the King’s College Brazil Institute. “There is hope that Lula’s government will be mindful of the global climate change and the Amazonian tipping point concerns and will restore the forest.”

Still, many regions most vulnerable to farmland conversion aren’t located within the Amazon, and experts say 330,000 square kilometres of native vegetation would disappear by 2050 even in a best-case scenario.

And meanwhile, Lula’s current lead may not be enough to avoid a second-round vote in a controversial election marred by a rise in political violence, and which Bolsonaro is already preparing to contest if he loses. He is likely to employ the “Big Lie” strategy that failed U.S. presidential candidate Donald Trump used to undermine the 2020 U.S. election results, reports NPR.