They call Brazil's President Bolsonaro the "Trump of the Tropics". He says hurtful things about women, minorities and immigrants.

Opinion polls predict he will lose to former president Luiz Inacio "Lula" da Silva on Sunday.

Experts say Brazil's election may decide the fate of the Amazon and the future of climate changeLong-term shifts in temperatures and weather patterns. Human action is a major cause of climate change..

The Amazon is the world's largest rainforest. It has 390 billion trees. Over Bolsonaro's four years, an area the size of Belgium has been cut down to farm cattle.

Lula promises, "there will be no Amazon deforestation" if he wins. Bolsonaro plans new laws to give ranchers more power.

Rainforests take carbon dioxide out of the atmosphere. This helps slow global warmingThe Earth is getting hotter due to climate change..

But deforestation means the Amazon is "releasing more carbon into the atmosphere," says researcher Luciana Gatti. Bolsonaro's critics say he is burning the "lungs of the world".

However, some say the Amazon is not the Earth's lungs. Climate scientists say activists exaggerate the amount of oxygen it produces.¹

Deforestation shrank 65% when Lula was president. But political experts warn a change of president will not be enough. New laws must punish land grabbers and support people who live in the forest.

And Lula has not won yet. His right-wing rival Bolsonaro is using scare tactics, comparing Lula to the authoritarian leaders of Venezuela and Nicaragua. Latin American expert Steven Levitsky says there is "zero evidence" that Lula threatens democracy.

But experts worry Bolsonaro may not accept defeat. He has said "something abnormal" will have happened if he receives less than 60% of the vote. "Only God will oustDrive someone out me", he told supporters.

Turbulent days may lie ahead for the world's seventh largest economy. What happens next in Brazil will be felt across the world.

Yes: Bolsonaro does not believe in the science behind climate change. He wants to develop the Amazon. If his policies continue, the rainforest will disappear.

No: The rainforest is important, but life in the oceans plays a much greater role in preventing climate change.

Or... One vote may not change the Amazon's fate, but it could deal a blow to democracy.