Brazil builds ‘rings of carbon dioxide’ to simulate climate change in the Amazon

In the depths of the Amazon, Brazil is building an otherworldly structure — a complex of towers arrayed in six rings, poised to spray mists of carbon dioxide into the rainforest. But the reason is utterly terrestrial: to understand how the world’s largest tropical forest responds to climate change.

Dubbed AmazonFACE, the project will probe the forest’s remarkable ability to sequester carbon dioxide — an essential piece in the puzzle of world…