No, Amazon rainforest does not produce 20% of earth’s oxygen

A post shared on Facebook in Nigeria claims that “20% of the Earth’s oxygen is produced by the Amazon rainforest”.

Does the Amazon, the world’s largest tropical rainforest, produce a fifth of the world’s oxygen? We checked.

Amazon fires and fake news

The Amazon covers much of northwestern Brazil and extends to Colombia, Peru and other South American countries. It received a lot of media attention in 2019 because of the fires that spread throughout the forest. 

Because of the media coverage, celebrities and environmentalists started making claims about the Amazon, many of them untrue, according to Forbes magazine. One of these was that 20% of the world’s oxygen is produced by the Amazon.

Gordon Bonan, a senior scientist at the National Center for Atmospheric Research in Colorado, US, told fact-checking organisation Fact Check that he’s been hearing the 20% claim for at least a decade. 

“People want to talk about the impact of deforestation,” he said. “Somehow they’ve latched on to this idea that forests create oxygen. That’s not what deforestation is doing.”

The Amazon isn’t critical because it makes oxygen for humans to breathe, according to Fact Check, it’s crucial because of the area’s rich biodiversity.

‘Based on a misunderstanding’

Scott Denning, professor of atmospheric science at Colorado State University in the US, also said the claim was based on a misunderstanding, in an article published by the US’s Public Broadcasting Service

Denning said: “In fact nearly all of Earth’s breathable oxygen originated in the oceans, and there is enough of it to last for millions of years. There are many reasons to be appalled by this year’s Amazon fires, but depleting Earth’s oxygen supply is not one of them.” 

Michael Coe, who directs the Amazon program at the Woods Hole Research Center in Massachusetts, told National Geographic that the claim “just doesn’t make any physical sense” because there “simply isn’t enough carbon dioxide in the atmosphere for trees to photosynthesize into an entire fifth of the planet’s oxygen”. 

“The fact that they’re throwing up this 20 percent number, to me, implies that they’re trying to say that our oxygen supply is in danger,” Neal Blair, professor of environmental engineering and earth and planetary sciences at Northwestern University, told the US county newspaper the Daily Republic.

“And our oxygen supply is in no way in any danger,” Blair said. “You can burn down the whole Amazon forest, and you would see a tiny, tiny, tiny drop in our oxygen levels, but we wouldn’t notice it.”Taryn Willows


 

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