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Amazonia
The basin, the forest, and the flying rivers they make
The forest makes its own rain. Moisture rising from billions of trees is carried west by the trade winds, falls, rises again, and is recycled several times before it reaches the Andes — a flying river of vapor that waters much of South America. Amazonia is that machine: the drainage basin of the Amazon and the rainforest growing in it, some 6.7 million square kilometers across eight countries and one overseas territory. The distinction is worth keeping straight. The Amazon is the river; Amazonia is the basin, the forest, and the roughly thirty million people who live inside it. Cut enough of the forest and the machine falters, which is the fear hanging over every hectare cleared.
Water organizes the region. The Amazon gathers more than a thousand tributaries, several of them among the largest rivers on Earth, and discharges about a fifth of all the fresh water reaching the oceans. The basin is remarkably flat: Manaus, 1,500 kilometers inland, sits barely 30 meters above sea level, so rivers meander, braid, and flood vast tracts of forest each year. Its western rim is the Andes, whose glacier-fed headwaters include Yerupaja in Peru at 6,635 meters, the highest ground in the watershed. Brazil holds roughly 60 percent of the basin, with the rest in Peru, Colombia, Bolivia, Ecuador, Venezuela, Guyana and Suriname. Perhaps one in ten known species on Earth lives here.
People have shaped Amazonia far longer than the myth of untouched wilderness allows. Terra preta, the dark fertile soil that pre-Columbian societies built up over centuries, still turns up beneath the canopy, and lidar surveys keep revealing earthworks, causeways and roads. More than 400 Indigenous peoples live in the basin today, and the territories they hold show markedly lower deforestation than the land around them. Cattle ranching, soy, logging, gold mining and road-building drive the clearing, and Brazilian deforestation rates have swung sharply with politics. Scientists warn of a tipping point at which degraded forest flips to savanna. The basin stores tens of billions of tons of carbon, so the whole world has a stake in the outcome.