Brazil’s Amazon has burned this badly before. This year’s fires are still bad

The Amazon rainforest in Brazil is being ravaged by fire. More than 74,000 fires have burned in the country since January, according to the country’s National Institute for Space Research — with 9,500 new forest fires igniting since just last week, the result of the natural dry season and fires intentionally ignited to clear forest. Black smoke billows from treetops, spreading across parts of South America and even shrouding the coastal city of São Paulo in near darkness. 

The fires, along with concerns about biodiversity and climate change, have triggered global alarm. French President Emmanuel Macron and Canadian Prime Minister Justin Trudeau on August 23 urged other leaders in the Group of Seven major industrialized nations to discuss what Macron called an “international crisis” at their summit beginning August 24 in France. “Our house is burning. Literally. The Amazon rainforest — the lungs which produces 20% of our planet’s oxygen — is on fire,” Macron tweeted.

Brazil’s government complained in response that it was being targeted in a smear campaign against the country’s president, Jair Bolsonaro, who was elected last year amid controversy over what many see as anti-environment policies that support slash-and-burn deforestation practices in the Amazon.

To learn more about the fires and what’s at stake, Science News spoke with environmental scientist Jonathan Foley, who is based in San Francisco and leads Project Drawdown, a worldwide network of scientists, advocates and others proposing solutions to global warming. The following conversation has been edited for length and clarity.

SN: Are these fires in the Brazilian Amazon unprecedented?

Foley: The fires this year are unlike anything we’ve seen in quite a while. The preliminary data suggest that the number of fires burning now is about 80 percent higher from this time last year. That’s really alarming.

But if we look at the longer term, we actually used to see fires like this, and even worse, back in the 1990s and the early 2000s. That’s when the world mounted a really serious effort. With Brazil taking the lead, and with international nonprofits, science agencies and big corporations, we actually managed to get deforestation of the Amazon in Brazil down by about 80 percent. It, and the fires, dropped hugely from the early 2000s to about 2013–2015. And now after all that work and all that success, we’re starting to see a major backslide into the bad old days.

SN: Are claims that the Amazon contributes 20 percent of the world’s oxygen correct? 

Foley: It’s not really true. On land, all the tropical rainforests of the Earth — of which the Amazon is just a part, but a big part — does about 20 percent of all the photosynthesis. But [life in] the oceans does it too, and that’s about half. That means instead of 20 percent, it’s really more like 10 percent, and the Amazon is less than half of that. At most, 5 percent of the world’s oxygen comes from the Amazon.

SN: If not oxygen, what should we be worrying about with these fires?

Foley: All the other bad news about the Amazon does ring true. Tropical forests, as a whole, contain about half of the world’s land-based biodiversity, and the Amazon is a big chunk of that. So when we burn down the Amazon, we’re losing species; we’re losing habitats; and we’re losing the lands that belong to indigenous communities and have for millennia.

Globally, about 10 to 15 percent of our CO₂ emissions comes from deforestation. If this is going back up again in Brazil, that’s going to make climate change even worse. It’s erasing a decade or two worth of progress. It’s a big problem for the world in terms of climate change.

And it’s a huge problem for people locally and regionally who are dependent on the forest and have preserved them for millennia. It’s just a huge tragedy.

SN: What’s the worst-case scenario for the Amazon if these fires get worse?

Foley: Some computer models, but not all of them, show a hypothetical scenario that when we clear rainforest, it starts to almost immediately warm up and dry out the atmosphere nearby. When we stand in a forest, it feels cool and moist. But when you clear-cut large areas of the forest, the air right around you gets hotter and drier, and it affects even rainfall patterns. The worry is if you start clear-cutting more of the Amazon, in theory, a tipping point could be reached where the rest of the forest dries out, too.

If that happens, the idea is that the Amazon could flip suddenly from being a rainforest to being a dry savanna-like ecosystem. We’re not absolutely certain about it, but even that theoretical possibility is kind of terrifying.