As fire continue to burn in parts of the Amazon, false claims and misinformation continue to circle as well.
The fires are certainly occurring at a faster rate than in recent years and do pose serious risks to the climate and local ecosystems. There have also been other distressing reports of indigenous tribes losing their lands or homes due to the flames.
But not all of these claims are true. VERIFY previously broke down how the wrong photos have been used to represent the fires and how claims about political motives have been clouding the facts.
Now there’s another claim making the rounds: That the Amazon forest is responsible for 20 percent of the world’s free oxygen supply.
These claims are popping up frequently from celebrities and politicians with claims that the Amazon forest is the “lungs of the Earth.”
Here’s one by French President Emmanuel Macron.
And here’s a similar claim by former NASA Astronaut Scott Kelly.
Does the Amazon forest really produce 20 percent of the world’s oxygen supply?
While there could potentially be some confusion behind the claim going around, the scientific data and multiple experts say that the Amazon forest is actually responsible for around one to six percent of the world’s oxygen.
WHAT WE FOUND:
The claim that these fires risk about 20 percent of the world’s oxygen does sound frightening at first glance.
NASA data shows that the Earth’s atmosphere is about 21% oxygen and it’s a crucial part of many processes on Earth - including our own ability to breathe.
So wouldn’t the destruction of the place that makes 20% of that oxygen spell doom for us?
A study in the Journal of Ecology shows that while free oxygen in the air comes mostly from plants, most forests actually use almost all the oxygen they create.
Remember being taught Photosynthesis in school? Plants take Carbon Dioxide and sunlight and turn it into sugar and oxygen. But that’s only one part of the cycle. There’s also “respiration.”
That’s the process where plants and animals use oxygen and convert it to Carbon Dioxide.
Put another way: Plants create oxygen, but the plants and animals use that same oxygen and very little is left to go into the atmosphere.
And while fires do destroy plants, Environmental Scientist Dr. Jonathan Foley pointed out in a Tweet that most of the forests will be replaced by pastures or cropland that also use photosynthesis to produce oxygen.
Numerous studies show this. Here’s one from 2014 on the “Global Oxygen Cycle,” Here’s one called the “Human physiological impact of global deoxygenation,” and here’s one that breaks down the “Oxygenation of the atmosphere and oceans.”
These studies all cover different but related topics and have a lot of different data about their respective focuses.
One of the few things they all have in common? Their estimates of the amount of oxygen the Amazon Forest produces is all between one and six percent.
That’s significantly lower than 20 percent and multiple experts say it’s a sign that oxygen production isn’t a major concern as the fires continue burning in the Amazon.
Atmospheric Science Professor Scott Denning at Colorado State University also said in a tweet that the Oxygen in the atmosphere is mostly generated from sources in the ocean.
He agreed that the Oxygen levels aren’t of real concern in a system of fires that is causing other major damages.