What Are the Risks of Fires in the Amazon?

What Are the Risks of Fires in the Amazon?

6.4分钟 1973 136wpm

亚马逊森林火灾存在什么风险?

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The fires in many parts of Brazil's Amazon area have brought an international outcry to save the world's largest rainforest.

Wealthy nations have offered Brazil at least $22 million to fight the fires. Actor Leonardo DiCaprio also offered $5 million for efforts to save the forest.

During the recent G-7 meeting in Biarritz, France, French President Emmanuel Macron commented on the fires. He told leaders meeting there that the world cannot permit Brazil to destroy what he called the "lungs of the planet."

What's in the Amazon?

The World Wildlife Foundation (WWF) says the world's largest rainforest contains millions of species of plants and animals. Many of them are still unknown. Among the best known animals are jaguars, eagles, pink river dolphins, parrots, large snakes and many butterflies.

The WWF says the forests contain over 40,000 kinds of plants and the 6,500 kilometers of rivers contain 3,000 kinds of freshwater fish.

The area drained by the Amazon River covers 40 percent of South America. The forest extends over seven other countries and a French territory.

More than 30 million people, including 350 indigenous and ethnic groups, live in the Amazon area and depend on the forests for food and shelter.

Is the Amazon the lungs of the planet?

The rainforest is often called the "lungs of the planet." But that might not be the best way to describe the area's importance to the world's ecosystem.

Carlos Nobre is a University of Sao Paulo climate scientist. He said a better way to think about the Amazon's role is as a sink, taking heat-trapping carbon dioxide, or CO2, from the atmosphere.

Currently, the world is releasing around 36 billion metric tons of CO2 into the atmosphere every year. And the Amazon absorbs about five percent of the CO2 making it important in preventing climate change.

Will the Amazon produce less oxygen for the planet?

While it is often said that the Amazon produces 20 percent of the world's oxygen, climate scientists say that is not the case.

They say forests, including the Amazon, absorb about the same amount of oxygen as they produce. Plants produce oxygen through a process called photosynthesis, but they also absorb it to grow, as do animals and microbes.

Scientists say the world's oxygen supply is not directly at risk from the fires. However, that does not mean the fires are not a problem. The Amazon forest also absorbs other heat-trapping gases produced by burning fossil fuels, like oil and coal.

What do the fires mean for the world's climate?

The fires not only destroy parts of the carbon-absorbing forests, but they release millions of metric tons of carbon into the air.

The Amazon rainforest also is important to rainfall in the area. Deforestation makes rains less frequent, extending the dry season.

Carlos Nobre estimates that if 20 to 25 percent of the forest were destroyed, the dry season would expand. That would mean the area would no longer be a rainforest, but a tropical savannah, or an area with grasslands and few trees.

Nobre added, "Unfortunately, we are already seeing signs of the Amazon turning into a savannah."

What is causing the fires?

The current fires in the Amazon are not wildfires. They are mostly set illegally by people who are clearing the forest to raise cattle and crops.

People clear the land by cutting down the trees during the rainy season, letting the trees dry out and burning them during the dry season. Fully clearing the thick forest for agricultural use can take several years of cutting and burning.

NASA researcher Doug Morton said researchers could see piles of trees months ago in satellite images. He said, "They're burning an enormous bonfire of Amazon logs that have been piled, drying in the sun for several months."

Nobre says Brazil's policy has changed under President Jair Bolsonaro. The new president has limited the power of forest protection agencies saying they get in the way of developing land.

Nobre added, "The number of fires increasing is because people think law enforcement won't punish them."
  • 时长:6.4分钟
  • 语速:136wpm
  • 来源:VOA 2019-09-02