What would the restoration of Earth's forests mean in the fight against climate change? Follow researchers around the globe as they race to understand how nature processes and responds to carbon on the largest scales and how microorganisms, plants, animals, and humans combine to sustain healthy ecosystems. NOVA's cameras travel to spectacular forest landscapes in Costa Rica, Canada, Brazil, Madagascar, and other places as a global team of scientists gather data on how forests work and try to figure out how they can help tackle the twin threats of climate change and the existential threat of species extinction.