Jan 26, 2023 - Science

More than one-third of the Amazon forest is degraded, study says

A deforested and burning area of the Amazon rainforest in the region of Labrea, state of Amazonas, northern Brazil, on Sept. 2, 2022. Photo: Douglas Magno/AFP via Getty Images

A deforested and burning area of the Amazon rainforest in the region of Labrea, state of Amazonas, northern Brazil, on Sept. 2, 2022. Photo: Douglas Magno/AFP via Getty Images

Two new analyses detail how land clearing and degradation are pushing the Amazon rainforest toward a tipping point of no longer being a forest that supports an abundance of life and buffers Earth from climate change.

Why it matters: The findings offer insights for policy paths and priorities aimed at trying to save the climate-crucial ecosystem.

Driving the news: Brazilian President Luiz Inácio Lula da Silva and Colombian President Gustavo Petro formed a "grand pact" earlier this month to try to save the Amazon "for humanity."

  • The first anti-deforestation raids on Lula's watch took place last week to stop illegal clearing of the forest.
  • Earlier this month, Lula signed a series of executive orders to address illegal deforestation in Brazil, which is home to 60% of the Amazon forest, and reactivated the Amazon Fund that invests in efforts to stop deforestation.

Where it stands: An estimated 13% to 17% of the original Amazon rainforest has been deforested over the last half century.

  • "Somewhere in the next 10% or 20%, there will be a phase shift," says James Albert, a biologist at the University of Louisiana at Lafayette. A recent analysis suggests about 31% of the eastern Amazon has been deforested — far above the estimated threshold of 20% to 25%.
  • "Forests exist within a range of factors that can keep them as forest," he says. But they can be pushed to a point where they turn from a forest to a savanna or degraded landscape, get too dry, and "simply burn."

What's new: In a paper published today in the journal Science, Albert and an international team of scientists report humans are causing changes to the Amazonian ecosystem in a matter of decades or centuries, as opposed to millions to tens of millions of years for natural processes.

  • "Organisms can't adapt in the period of decades or centuries," Albert says.

Another analysis published today looked at the lesser-known problem of land degradation in the Amazon due to logging, fires, extreme droughts and changes at the edges of the forest caused by the habitat being fragmented.

  • Deforestation changes the landcover and can be spotted by satellites. Degradation stems from changes in how the land is used and can be hidden by the forest canopy — a forest continues to be a forest but is degraded and weakened.
  • Using data from earlier studies and new satellite images, the authors estimate about 2.5 million square kilometers of the Amazon — about 38% of the remaining forest — is considered degraded by one or more the disturbances. That's in addition to the deforestation.
  • They also found the carbon lost from the forest due to degradation is on par with that due to deforestation — and degradation can lead to as much loss of the forest's biodiversity as deforestation.

Their projections suggest "degradation will continue to be a major source of emissions in the region, regardless of what happens with deforestation," says study co-author David Lapola, a research scientist at the University of Campinas (Unicamp) in Brazil.

  • "We need specific policies to handle degradation. It’s not using the same policies and actions for deforestation," he says.

Between the lines: Deforestation reduces the forest's ability to generate rainclouds, which, combined with climate change, significantly raises the odds of drought. And the more fragmented the forest is, the harder it is to bounce back after a drought ends.

  • Controlling fire, timber extraction and deforestation is "something Brazil and the other Amazonian countries can tackle and it's their responsibility," Lapola says.
  • But the extreme droughts are caused by "global climate change, which is not only for us to solve," he says.

The big picture: Passing the forest's tipping point would be devastating for the forest's biodiversity and for the Indigenous people that live there.

  • But the forests of the Amazon aren't just a reservoir for more than 3 million species of plants and animals: They store large amounts of carbon dioxide that, if the forests die, would be released back into the atmosphere.
  • Releasing that carbon dioxide would be "throwing away the goal" of the Paris Agreement to limit global warming to 1.5 degrees Celsius, Colombia's Minister of Environment and Sustainable Development Maria Susana Muhamad said last week at the World Economic Forum in Davos.

"But at the same time we know that could be the future prosperity for our countries," she added, referring to the economic benefits stemming from the Amazon's resources that are largely reaped by people in cities and other countries.

  • "We're not going to stop development and nor should we. Humans have the right to use their land and resources," Albert says.
  • "But the problem is how it's being done," he adds. He and his co-authors outline a "new Amazonian bioeconomy" based on sustainable use of the forest's resources that "extends beyond extractive and export-based economic activities."
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