Lula and Petro have the chance of a lifetime to save the Amazon. Can they unite idealism and realpolitik to pull it off?

The South American leaders are in the spotlight as they prepare to host this week's Cop16 biodiversity summit, November's G20 meeting and next year's Cop30 climate summit

The rainforest nations of Brazil and Colombia have the best opportunity in a generation to drag the Amazon back from the abyss as they host three of the world's most important environmental negotiations in the space of little more than a year.

In the process, their leaders - pacesetting Colombian president, Gustavo Petro, and the more cautious and contradictory Brazilian president, Luiz Inacio Lula da Silva - will offer up overlapping visions for the future of the Amazon, and the world's path to net zero.