One day in 2014, Belém, a member of Brazil’s Kayapo tribe, went deep into the forest to hunt macaws and parrots. He was helping to prepare for a coming-of-age ceremony, in which young men are given adult names and have their lips pierced. By custom, initiates wear headdresses adorned with tail feathers. Belém, whose Kayapo name is Takaktyx, an honorific form of the word “strong,” was a designated bird hunter.

Far from his home village of Turedjam, Belém ran across a group of white outsiders. They were garimpeiros, gold prospectors, who were working inside the Kayapo reserve—a twenty-six-million-acre Amazonian wilderness, demarcated for indigenous people. Gold mining is illegal there, but the prospectors were accompanied by a Kayapo man, so Belém assumed that some arrangement had been made. About nine thousand Kayapo lived in the forest, split into several groups; each had its own chief, and the chiefs tended to do as they pleased.

Ever since the Kayapo had come into regular contact with the outside world, in the nineteen-fifties, whites had been trying to extract resources from their forests, beginning with animal skins and expanding to mahogany and gold. In the eighties, some chiefs made easy profits by granting logging and mining rights to outsiders, but after a decade the mahogany was depleted and the price of gold had dropped. After environmental advocates in the Brazilian government brought a lawsuit against miners, the Kayapo closed the reserve to extraction. Since then, though, international gold prices have tripled, to fourteen hundred dollars an ounce, and an influx of new miners have come to try their luck.

The prospectors whom Belém met told him that they wanted to build a road linking Turedjam with their mine, about forty miles away through the forest. Belém understood why they wanted such a road. Turedjam was situated on the Rio Branco, which formed the northeastern boundary of the Kayapo reserve. The area was rich in gold—and Turedjam had a recently built bridge that could support heavy vehicles. The proposed road would also allow prospectors to sneak machinery through the reserve under tree cover, without being spotted from the air by federal police, who periodically raided their operations.

“All of us here realize we’re fucking the environment,” Jorge Silva, a forty-eight-year-old miner, said. “It’s not like we want to—it’s that we haven’t found any alternative means to survive.” Photograph by Mauricio Lima for The New Yorker

Back in Turedjam, Belém told his chief, Mro’ô, about the proposal. A young chief, Mro’ô had founded Turedjam four years earlier, leading a group of Kayapo from his home village after a dispute with a senior chief, who wished to allow outsiders to mine and to log mahogany. Mro’ô had established Turedjam as a “sentinel village,” keeping watch over the vulnerable edge of the reserve. He told Belém to let the prospectors know that he wasn’t interested.

A year later, Mro’ô died, apparently from diabetes. His brother, a heavy drinker known as Juan Piranha, quickly made a deal with the prospectors, and before long their road was cut—a track through the forest wide enough for excavators capable of moving hundreds of tons of rock and earth a day. Then Mro’ô’s successor began allowing prospectors to work the surrounding land in exchange for ten per cent of their findings. Hundreds, perhaps thousands, of miners poured in.

Wildcat mining is less pervasive than logging, but it can be more insidious. Loggers usually harvest valuable trees and leave the rest; miners cut everything. Mercury, used in the refining process, leaves rivers poisoned, and the pollution can spread hundreds of miles downstream. The allure of gold attracts fortune-seekers, who bring prostitution, alcohol, drugs, and violence. “Letting prospectors into the Kayapo reserve is like leaving your children in the protection of a drug gang,” Barbara Zimmerman, a Canadian ecologist who has worked with the Kayapo for three decades, told me. In the past few years, according to environmentalists, several hundred thousand acres of the reserve have been destroyed or degraded by illegal mining and logging.

The destruction of Kayapo land is just part of what Zimmerman calls the “sacking” of the Amazon. In addition to the mining and logging, soy farmers and cattle ranchers have cleared huge tracts of forest, mostly by fire. Brazil’s National Institute of Space Research, which tracks the damage, calculates that one-fifth of Brazil’s Amazonian rain forest—the world’s largest remaining “green lung,” which absorbs billions of tons of carbon dioxide—has been destroyed since the nineteen-seventies. Indigenous reserves serve as a bulwark against destruction, green islands amid industrial soy fields and clear-cut ranchlands. But the closer indigenous people live to whites the more vulnerable they are. In these places, all that stands in the way of the destruction of the Amazon is the ability of a few thousand indigenous leaders to resist the enticements of consumer culture. In Turedjam, that battle is being lost. “It’s like the Four Horsemen of the Apocalypse have been let loose,” Zimmerman said.

There are eighty-two Kayapo settlements, scattered across the green expanse of the reserve. In riverside communities, small boats are the primary means of transportation; prospectors haul away ore on barges, or in trucks where there are roads. In the forest, indigenous people traditionally walked from village to village, on journeys that could take days. During the past few decades, airstrips have been hacked out, so that bush planes can ferry people and goods.

In the course of a two-week visit, I took several flights over the forest. On one, as the plane cleared the treetops, I saw smoke rising in a huge, menacing column, like a cloud of volcanic ash. For hours, the fire burned, unattended, and a dense blanket of smoke settled on the horizon. Fires like this one are an increasingly regular feature of life in the Amazon, where settlers regard them as an essential part of progress.

Kupato, the forty-five-year-old chief of Turedjam, stands outside his home. Photograph by Mauricio Lima for The New Yorker

Thomas Lovejoy, an American biologist who for decades has been a preëminent authority on the Amazon, told me that the burning of forests, along with climate change, was disrupting the Amazon’s ability to produce rain for itself. “We’re now seeing historic droughts every four or five years,” he said. “The problem with droughts is that they dry up rivers and cause more fires, leading to more deforestation.” The Amazon, he noted, produces twenty per cent of the world’s rainwater. If the system is pushed too far out of balance, the forest will cease to be able to regenerate itself and turn into a savanna; a carbon sink nearly the size of the continental United States will become a carbon producer. “We’re really close to the tipping point right now,” Lovejoy said.

The conquest of the forest began in earnest in the seventies, after Brazil’s government, which was then a military dictatorship, carved a highway into the Amazon and encouraged people to move in. Since then, millions of settlers have founded towns and cities, built roads, dammed rivers, and burned forests, ultimately clearing an area larger than France.

Much of their land sits uneasily alongside indigenous reserves, which constitute about thirteen per cent of the national territory—more than four hundred thousand square miles, in which approximately nine hundred thousand people live. (They are what remain of an estimated eleven million indigenous people who lived there when the Portuguese arrived, in 1500.) For decades, FUNAI, the country’s indigenous-affairs agency, has delineated reserves and helped guard them from developers. But Brazil’s leaders have been lax about enforcing the strictures, and in the Amazon conservationists and indigenous-rights activists have struggled to contain a scramble for land and fortune. While the leftist President Inácio Lula da Silva was in office, from 2003 to 2010, deforestation decreased for a time. But since last January, when Jair Bolsonaro became President, the destruction has become a kind of perverse political goal.