- A recent study found that the western and southern Amazon will struggle to survive against increasingly extended periods of drought brought on by climate change, which will reduce the areas’ ability to store carbon.
- Researchers sampled more than 540 trees across 129 species at 11 separate sites in the western, central-eastern and southern Amazon, covering Brazil, Peru and Bolivia.
- Trees in the southern part of the Amazon show the greatest degree of adaption to cope with drought but will also face harsher conditions than other areas, which will lead to higher mortality rates.
MEXICO CITY — As climate change continues to choke off rainfall, many parts of the Amazon are facing a higher probability of dying off from drought than previously thought.
A recent study found that the western and southern Amazon will struggle to survive against increasingly extended periods of drought brought on by climate change, which will reduce the areas’ ability to store carbon — a necessary function for keeping global temperatures below 1.5°C (2.7°F).
“The Amazon is threatened by multiple stressors, including deforestation and climate,” said David Galbraith, co-author and professor at the University of Leeds. “Understanding the stress limits that these forests can withstand is a major scientific challenge.”
The study, which was published in Nature last month, suggests that previous research may have underestimated the impacts of drought on the Amazon because it focused on central-eastern areas that are less vulnerable to drier climates.
Researchers sampled more than 540 trees across 129 species at 11 separate sites in the western, central-eastern and southern Amazon, covering Brazil, Peru and Bolivia. They wanted to know which tree species and forest conditions could withstand future drought, and whether they would be able to store carbon. It involved measuring tree hydration during periods of high- and low-water stress.
Previous studies and Mongabay reporting have found that the Amazon is already seeing a reduction in rainfall, causing the dry season to stretch weeks longer than normal. Nowhere is this truer than in the southern Amazon, the study said, partially as a result of deforestation.
Trees in the southern part of the Amazon show the greatest degree of adaption to cope with drought, the study explained, but will also face harsher conditions than other areas, which will lead to higher mortality rates.
Meanwhile, trees in wetter parts of the Amazon show lower levels of adaptation to drought but will also likely be insulated from the worst of climate change impacts.
As trees face a higher risk of mortality from drought, their ability to store carbon goes down significantly, the study said. Even today, the most water-stressed parts of the Amazon in the southeast no longer act as a large-scale carbon sink.
That could be the case for more and more of the Amazon as drought worsens.
“Forests that are ‘safer’ from drought-induced mortality are accumulating more carbon than those that face greater risk of drought-induced mortality,” Galbraith explained.
Banner image: The Amazon Rainforest in Peru. Photo courtesy of Rhett A. Butler.
Citation:
Tavares, J.V., Oliveira, R.S., Mencuccini, M. et al. Basin-wide variation in tree hydraulic safety margins predicts the carbon balance of Amazon forests. Nature 617, 111–117 (2023). https://doi.org/10.1038/s41586-023-05971-3
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