ブラジル ベロ・モンテダム 今日の海外注目記事 19年6月30日

The price of ‘progress’ in the Amazon,The Washington Post,19.8.29

Proponents, including Brazil’s president, hail development as an irresistible opportunity. Scientists warn that the area is on the precipice of an environmental crisis.

ALTAMIRA, Brazil — Isolated indigenous tribes, three-toed sloths and stealthy jaguars still populate this corner of the Amazon rain forest. But now, it is also the home of something else.

The Whopper.

Burger King is just one of many new arrivals since an enormous dam project brought a population surge, shopping malls with food courts and U.S.-style subdivisions to civilization’s edge. As the Belo Monte dam complex — envisioned to be one of the world’s largest by power capacity — approaches completion, experts call the outcome here an example of the kind of massive development that could critically wound the world’s largest rain forest — even though Belo Monte is among the less environmentally damaging mega-projects of its kind.

Scientists believe the Amazonian ecosystem is far closer to an existential tipping point than previously thought, with potentially grievous results for the region and the planet. Yet under Brazil’s new far-right president, Jair Bolsonaro, the Belo Monte plant, which harnesses power through environment-altering dams, is a harbinger of the region’s future. Reversing a decision by the previous administration, Bolsonaro’s government has signaled its intention to put both large- and small-scale dams in the Amazon basin back on the table.

Dying trees where the Belo Monte dam was built
The Belo Monte dam utilizes a "run of the river" design that diverts part of the Xingu River into a secondary reservoir. (Jabin Botsford/The Washington Post)

The new dams could flood and destroy riverbanks, alter animal breeding cycles and provide the catalysts for large-scale urbanization, as happened here in Altamira. And even though they may generate renewable electricity, the huge projects will also spur greater deforestation because of the road networks and population surges that inevitably go with them. Many critics say the dams are not even needed to satisfy the nation’s power needs.

But for Bolsonaro’s Brazil, the dam network holds the irresistible potential of billions of dollars’ worth of investments in Latin America’s largest nation.--------

For years, scientists assumed that about 40 percent of the rain forest had to be lost before it would reach the dangerous point at which its ecosystem could no longer heal itself, creating drier, hotter weather cycles that could turn vast areas of the jungle into savanna.

But in recent years, scientists have delivered a more alarming verdict. Carlos Nobre, a senior researcher at the University of Sao Paulo, and Thomas Lovejoy, a noted ecologist at George Mason University, suggested that because of exacerbating factors such as climate change and worsening forest fires, such a red line could be crossed at a far lower threshold of 20 to 25 percent deforestation.

“If the rates increase — as one can see them increasing this year — it is likely that this tipping point will be reached between 20 and 30 years” from now, Nobre said.

The effect, scientists say, would be devastating. Vast areas of the rain forest would be indelibly altered by changing climate patterns, leading to higher temperatures in the immediate area and lower rainfall not only in Brazil but also in Uruguay, Paraguay and Argentina.

The global impacts could also be severe. Unless deforestation is stopped before reaching the tipping point, some 50 or 60 percent of the Amazon will be lost, meaning the forest will no longer be able to pull carbon out of the air at the same rate, allowing about 550 million tons of carbon dioxide to remain in the atmosphere each year, according to Nobre. This amount is comparable to the annual emissions of a major economy, such as Canada or South Korea, dealing a potentially critical setback to the global effort to cut greenhouse gas emissions.

“If that tipping point is crossed, it’s irreversible,” Nobre said. “It’s an ongoing dynamic process that will really lead to savanna-ization of 50, 60 percent of the Amazon.”------









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