World

The Amazon is burning

Ueslei Marcelino/Reuters

The Amazon region of South America, soaked in hundreds of inches of rainfall each year, is home to some of the wettest land on Earth. So how can it burn? And why are wildfires — blazes that spewed so much smoke this week they turned the Sao Paulo day into night — growing?

Ueslei Marcelino/Reuters

Ueslei Marcelino/Reuters

Ueslei Marcelino/Reuters

Scientists point to three main causes — each the result of human activity. First is deforestation, much of it illegal. The Amazon is shedding an astonishing amount of forest canopy — and the rate is growing. An area half the size of Rhode Island was lost in July alone. The easiest way to dispose of the felled trees and foliage is to let it dry in the sun for months — and then burn it.

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“This is prevailing,” said Carlos Nobre, one of Brazil’s leading scientists studying the Amazon.

Ueslei Marcelino/Reuters

Ueslei Marcelino/Reuters

Ueslei Marcelino/Reuters

Another spark is farming. More than three-quarters of deforestation in the Amazon is the result of cattle ranching or soy production, according to the nongovernmental organization Amazon Watch. For farmers, fire is a standard tool to clear out brush and help maintain an area for agricultural use.

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“This technique has increased a lot in that last 10 years,” said Ricardo Mello, head of the Amazon program of the World Wide Fund for Nature. “The farmers use it to clear the land when it’s too difficult for machines.”

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The final main cause is droughts. These occur naturally, but scientists say climate change and deforestation are making them more frequent — and more severe. This creates a self-reinforcing loop: Less water dries or even kills trees, providing more fuel for more fires.

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All of these factors — deforestation, agricultural practices and droughts — feed into one another. “The result: normally fire-proof rainforests become flammable,” researchers wrote this year in the Conversation.

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RAPHAEL ALVES/AFP/Getty Images

RAPHAEL ALVES/AFP/Getty Images

What’s most troubling, however, isn’t what’s happening now. It’s what will happen next. Researchers already say they’ve seen more fires this year than ever before — and the driest part of the year is still ahead.

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“I cannot remember any other big fire episode like this one,” said Vitor Gomes, an environmental scientist at the Federal University of Para. “Attributing the whole episode to natural causes only is practically impossible. We are not even in the middle of the drying season.”

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The implications are global. The Amazon is one of the best defenses against climate change: It accounts for a quarter of the carbon dioxide absorbed by the world’s forests. The mutually reinforcing cycle of deforestation and fire, researchers warn, will make it very difficult, if not impossible, to hold global warming below destabilizing levels.

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Ueslei Marcelino/Reuters