The Renegades, Defenders of the Planet by Jeremy Brown (Paperback)

"Holed up on a ranch in Texas, the Renegades are recouping after their Arctic adventures. But a bout of mysterious fires soon sees them fly off to the Amazon, where deadly fire-breathing creatures called Flamejantes are destroying the rainforest. Katelyn, Mo, and Leon must team up with local indigenous activists to stop them. And it looks like something - or someone - sinister is behind the creatures' sudden appearance..."--Provided by publisher.