The Amazon rainforest is moving toward a “tipping point” past which trees will start to die off in large numbers, researchers have said.
The study, published in the Joumal of Natural Climate Change, was conducted by scholars from the University of Exeter, the Potsdam Institute for Climate Impact Research (PIK) and the Technical University of Munich. They used satellite data from 1991 to 2016 to examine trends in deforestation.
They calculated that 75 percent of the rainforest is now at risk of being unable to recover when experiencing droughts, which are also increasingly more common because of global warming.
“Deforestation and climate change are likely to be the main drivers of this decline,” Niklas Boers of PIK and the Technical University of Munich told the BBC. The study has predicted that it is only a matter of decades until a “significant chunk” of the Amazon is changed from rainforest into savannah (大草原).
What would the world be like without the Amazon rainforest?
The destruction of the Amazon rainforest, in some ways caused by global warming, will also speed up this process. “The Amazon stores lots of carbon and all of that would be released into the atmosphere, which would then further contribute to increasing temperatures and have future effects on global mean temperatures,” Professor Boulton of the University of Exeter told the BBC.
This worrying snowball effect means that the destruction of the Amazon will make the much larger battle against global warming more difficult.
The destruction of the Amazon would also have a huge influence on the ecology of the Earth. The Amazon rainforest is home to more than 30,000 species of plants, 2.5 million species of insects, 2,500 fish, over 1,500 bird species, 550 reptiles, and 500 mammals, according to the Wildlife Conservation Society. A savannah, a grassland environment that lacks a large variety of plant life, would be unable to host the large and varied ecosystems that currently exist in the rainforest. It is likely that many animals would become endangered or even die out, as they would be unable to adjust to this new ecosystem.
34. What does the underlined phrase “tipping point” mean in this passage?
A.return to zero | B.begin to become less |
C.remain unchanged | D.begin to become more |
35. How is the last paragraph developed?
A.By listing numbers. | B.By analyzing causes. |
C.By comparing ideas. | D.By describing details. |
36. What can we learn from the passage?
A.Researchers used satellite data to check trends in deforestation for more than 30 years. |
B.Deforestation and climate change are surely the main factors of the decline of the rainforest. |
C.The process of destruction of the rainforest will slow down because action has been taken. |
D.It is highly possible that the ecology of the Earth will become out of control. |
37. The writer wrote this passage ________.
A.to describe a lot of endangered species | B.to predict the special life in the future |
C.to explain the way to protect the environment | D.to make us pay attention to the rainforest |