The Amazon rainforest now emits more carbon than it absorbs
Fires burned in the forest tipped the balance, decade-long study has found.
The Amazon rainforest is now emitting more carbon than it is able to absorb, a study by a team of international researchers has found.
For generations, the vast area of forest, often referred to as the ‘lungs of the Earth’, naturally absorbed carbon dioxide in the air. But now, the researchers say it is putting out around one billion tonnes of carbon dioxide more a year than it can absorb.
The whole Amazon basin comprises about half of the planet’s tropical rainforests, though the study only covered the forests found in Brazil, which make up about 60 per cent of that figure.
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The emissions are largely driven by fires set by developers deliberately burning down the trees to clear agricultural land for the grazing of cattle or the growing of soy beans, the researchers say.
Over the last 40 years, the conversion of the natural landscape to agricultural land has caused a 17 per cent decrease in rainforest in the Amazon. This has caused the forests to dry out, which can reduce their capacity to store carbon and increase their vulnerability to fires.
“An important message is that essentially it shows that these forests are starting to suffer,” one of the study’s authors Prof Emanuel Gloor, from the University of Leeds, told BBC Science Focus.
“And that’s not good because these forests are not only important because of the carbon cycle, but they are important also because of this enormous biodiversity that is there.
“We have already destroyed so much on the Earth, and in a way, this shows that we could say that the Amazon is starting to become sick. It’s not a good sign.
"We know that there is deforestation, so it’s not really a surprise, but one could say it is large-scale proof that things are not going in a good direction.”
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The team used an aircraft to fly above the Amazon to measure the carbon dioxide and carbon monoxide over several areas of the Brazilian rainforest from 2010 to 2018.
They found that fires produced around 1.5 billion tonnes of carbon dioxide per year on average, while new growth could only account for removing around 0.5 billion tonnes.
While breaching the carbon emission tipping point may seem dire, there is still time to reverse the trend, they say.
“I would say with the foremost urgency do not support any products or agricultural products that originate from newly destroyed forests,” said Gloor.
“But my hunch would be that it is possible to halt this. But I do think in places where large-scale deforestation has happened, the forests might not return very rapidly.”
Emanuel Gloor is a professor in Biogeochemical Cycling at School of Geography and Priestley International Climate Centre at the University of Leeds. He studies the global carbon cycle, the Amazonian climate and tropical forest ecology.
Jason is the commissioning editor for BBC Science Focus. He holds an MSc in physics and was named Section Editor of the Year by the British Society of Magazine Editors in 2019. He has been reporting on science and technology for more than a decade. During this time, he's walked the tunnels of the Large Hadron Collider, watched Stephen Hawking deliver his Reith Lecture on Black Holes and reported on everything from simulation universes to dancing cockatoos. He looks after the magazine’s and website’s news sections and makes regular appearances on the Instant Genius Podcast.
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