Rampant wildfires threaten Amazon rainforest collapse

This story was originally published by cabling and appears here as part of the Climatic desk collaboration.

The Amazon rainforest is on fire. Or at least a large part of it. On February 28, Brazil’s National Space Research Institute announced that 2,940 fires had broken out in the Brazilian Amazon over the course of that month, a record number for the month of February. Many of them are still burning.

Real time satellite monitoring shows that so far in 2024, more than 10,000 forest fires have devastated 11,000 square kilometers of the Amazon, in several countries. Never have so many fires burned so much forest so early in the year. Scientists fear this is pushing the region ever closer to a tipping point, where widespread degradation and repeated burning of the forest will become unstoppable.

“Fire is a contagious process,” says Bernando Flores, a researcher at Brazil’s Federal University of Santa Catarina who studies changes in the Amazon. “If nothing is done to prevent fire from penetrating remote areas of the Amazon, the system could eventually collapse due to megafires and become trapped in a state of persistently flammable open vegetation.”

The Amazon rainforest spans 6.7 million square kilometers, representing more than half of the remaining rainforest on the planet. It is home to 10 percent of the planet’s terrestrial biodiversity and plays a vital role in stabilizing both local and global climate. Amazon stores between 15 and 20 years of global CO2 emissions, and has a cooling effect of the world thanks to the humidity that its plants store and transpire into the atmosphere.

Since the 1980s, the Amazon basin has been warming at an average of 0.27 C per decade. Some parts, including the central and southeastern regions of the forest, have warmed even faster, at a rate of 0.6 C per decade. Today, dry season temperatures are, on average, two degrees higher than 40 years ago.

TO recent article published by Flores and colleagues in the journal Nature discovers that rain patterns have also changed. In the southern Bolivian Amazon, for example, annual rainfall has decreased by 20 millimeters per year since the 1980s. As a result, the Amazon has become “more flammable,” says Flores.

These trends have come to a head this year. A study published in late January by researchers at World Weather Attribution, a scientific collaboration that tracks the influence of climate change over the weather, found that the drought that has affected the Amazon basin since the middle of last year is mainly due to the change climate. This historic drought, the most serious ever recorded in the Amazon, has also been amplified by El Niño weather freak — a cyclical weather pattern defined by unusually warm temperatures in the central and eastern Pacific Ocean, typically lasting 9 to 12 months.

“When we have El Niño or drought, the forest is drier and more susceptible to forest fires,” says Dolors Armenteras Pascual, an ecologist and professor at the National University of Colombia. Record temperatures and this extreme drought have sapped moisture from Amazon trees, leaving the understory covered in wood remains that have dried out and are ready to burn. In the midst of this heat and dry air, Amazon trees also struggle to extract the water they need from the parched soil. As a result, they are “degraded.”

Rampant forest fires threaten the collapse of the Amazon rainforest. #Climate Change #Forest Fires #Amazon Rainforest

“Degradation means that there is still standing forest, but part of the structure, part of the functioning is being lost,” says Armenteras Pascual. “You might even look at it and think it’s really a beautiful forest, but it’s not that healthy.”

Degradation also makes a forest more prone to wildfires. And once part of the Amazon burns, it is more likely to catch fire again. “When a forest burns, the trees die, releasing organic matter onto the ground and opening up the canopy,” Flores says. “Therefore, more fuel is available and more sunlight and wind can dry out this fuel, making the ecosystem more flammable. The consequence is that burned forests are much more likely to burn again.”

When considering the impacts of human disturbance and extreme droughts in recent decades, up to 38 percent of what remains of the Amazon rainforest may already be degraded, Flores and his colleagues found.

By considering all the factors contributing to Amazon degradation (climate change, drought, deforestation, wildfires), the team also developed models that project heat, degradation and fire trends into the future. The results are grim. By 2050, their models show, temperatures in the Amazon basin are expected to be between 2 C and 4 C warmer than today, depending on greenhouse gas emissions over the next two and a half decades. By 2050, the Amazon dry season could last a month longer than now. Wildfires are expected to increase in frequency and severity.

As a result, they estimate that almost half of the Amazon could reach a “tipping point” by 2050, when it will cease to be forest and become savannah and grassland.

The impacts of this would be devastating locally and globally. TO 2021 report The Scientific Panel for the Amazon found that 10,000 of the rainforest’s plant and animal species are at risk of extinction due to climate change and habitat destruction. A widespread collapse like this could well push these species over the edge. Many of the Amazon’s 40 million people could be displaced by unbearable heat, with indigenous peoples in particular losing their livelihoods, ways of life and knowledge systems.

As alarmist as this may seem, Armenteras Pascual believes that the warnings from Flores and his colleagues are, if anything, underestimated. “It’s not like half the Amazon is going to collapse and the other half is going to be fine,” he says. “The whole system could collapse; the whole system in terms of hydrology, which is probably the most important role of the Amazon globally, its role in cooling the climate.”

If the Amazon were to suffer a “large-scale collapse” by 2050, as Flores and his colleagues warn, it could emit as much as 120 billion lots of carbon dioxide into the atmosphere, which is currently equivalent to about 3.5 years of global CO2 emissions. Global temperatures may rise 0.3 C as a result.

For now, the unusually high number of fires is expected to continue through the month of April, when the rainy season begins. “It’s fire season,” says Armenteras Pascual, who works with the Colombian government to monitor emissions from fires in the northern Amazon. “[Recently] We had 7,000 hectares burning that no one talks about, in one of the natural reserves that we have near the border with Venezuela.”

“Here in Colombia there are also some fires,” he adds. Satellite data shows that in the first week of March, just over 1,000 fires occurred in the Colombian Amazon. “The fires are burning,” says Armenteras Pascual, “and they are intensifying.”

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