VOA慢速英语--天气因素可能是巴西潘塔纳尔火灾的原因（在线收听）

Weather Event May Be Cause of Brazil’s Pantanal Fires

Since the middle of July, a fire has been burning in the wetlands of west-central Brazil. It has left a burned area that is larger than New York City.

The wetlands, known as the Pantanal, are smaller and less-known than the Amazon jungle. But the area attracts many different animals because of where it is in South America. It is between the rainforest, Brazil's grasslands and Paraguay's dry forests.

The fires are now threatening one of the most diverse environments on the planet, biologists say. The Pantanal is about 150,000 square kilometers in size. The wetland is home to 1,200 vertebrate animal species. Thirty-six of those species are close to dying off completely.

Fire is not new there, but the current fires are historic. The biggest ones in the Pantanal this year are four times the size of the largest fire in Brazil's Amazon rainforest, NASA satellites show.

A record 23,490 square kilometers have burned through September 6. A study by the Federal University of Rio de Janeiro said that represents nearly 16 percent of the Brazilian Pantanal.

Warming in the Atlantic Ocean

The Pantanal is known for being wet, not dry. The world's largest floodplain normally fills with water during the rainy season, which lasts from November to April.

This year, the floods never came. The Paraguay River, which crosses the Pantanal, fell to its lowest level since 1973. That estimate comes from Julia Arieira, a climate researcher at Brazil's Federal University of Espirito Santo.

Scientists blame the dry weather on warming in the Atlantic Ocean. That warming takes moisture away from South America and sends it north where it can form hurricanes.

Doug Morton is a scientist with the U.S. space agency NASA. He said this process is caused by changes in ocean temperatures. These changes are known as the Atlantic Multidecadal Oscillation.

This weather event is to the Atlantic Ocean what El Niño is to the Pacific Ocean. Unlike El Niño, however, which usually happens every two to seven years, the oscillation changes between hot and cold every 30 to 40 years.

Changing ocean temperatures are "a likely driver of the dry conditions we've seen so far this year in the Pantanal," said NASA's Morton.

Morton is concerned global warming could change the Oscillation and leave it permanently warm – possibly leading to more fires.

Even if that does not happen, scientists fear global temperature increases could make large fires more common.

Philip Fearnside is an ecologist at Brazil's National Institute of Amazonian Research. He said destruction of the Amazon rainforest is worsening dry conditions in the Pantanal over the long-term. He said jungle trees take rain and push the moisture back into the air. This moisture is then carried by winds to nearby areas.

Amazon deforestation – the act of cutting down forests - has increased 34.5 percent in the 12 months through July, compared to the same period a year earlier. That increase comes from early estimates released by the government space research agency Inpe.

Humans and animals

Mato Grosso state firefighting Lieutenant Colonel Jean Oliveira said no humans have died in the Pantanal fires. The victims, he said, are wildlife - reptiles, mammals, and more.

Oliveira has been leading the government response to the fires.

Biologist Rogério Rossi at the Federal University of Mato Grosso estimated that thousands of animals have died.

Local guide Eduarda Fernandes is working with the rescue team in the area. She picked up a snake that had been burned in the fire. It had bitten itself. A biologist said the snake likely had an uncontrolled reaction as it tried to escape the heat.

Asked what she thought happened, Fernandes responded, "Pain. Despair."

Words in This Story

diverse – adj. made up of people or things that are different from each other

vertebrate – adj. biology: describes an animal that has a backbone

species – n. biology : a group of animals or plants that are similar and can produce young animals or plants : a group of related animals or plants that is smaller than a genus

floodplain – n. an area of low, flat land along a stream or river that may flood; an area of land built up from soil left by floods

moisture – n. a small amount of a liquid (such as water) that makes something wet or moist