How Amazon Can Weather a Long-Term Drought: Key Strategies and High Costs Ahead

The Amazon rainforest faces significant challenges from climate change, including the threat of long-term drought. A recent study highlights how this shift could have severe consequences for the forest and its vital role in our ecosystem.

As the climate warms, some areas of the Amazon are expected to become drier. This transformation could lead to the loss of many large trees, which store a tremendous amount of carbon. When these trees die, they release carbon into the atmosphere, reducing the rainforest’s ability to absorb carbon emissions from human activities.

Covering over 2 million square miles, the Amazon’s long-term response to these changing conditions isn’t well understood. Past studies have raised alarms about the possibility of the rainforest transforming into a less dense forest or even a savanna if temperatures continue to rise and deforestation persists.

One study, which is the longest of its kind on drought in tropical rainforests, reveals what the future might hold for the Amazon. Researchers conducted an experiment over 22 years on a one-hectare area in northeastern Brazil. They began this project in 2002 by installing panels to redirect about half of the rainfall from the trees, simulating long-term drought conditions.

Researchers from the University of Edinburgh and the Federal University of Pará found that most of the biggest trees in the study area died during the first 15 years. After that, the forest stabilized, allowing the remaining trees to access more water. Interestingly, these survivors experienced little drought stress compared to trees in nearby areas that were not part of the study.

Despite the survival of some trees, the area suffered a loss of over one-third of its biomass, which includes all the trunks and roots where carbon is stored. This massive decline would translate to major emissions of carbon dioxide into the atmosphere, diminishing the Amazon’s role as a carbon sink.

While the surviving trees now show slight gains in carbon storage, the overall biomass is still lower than that of typical rainforests. This indicates some resilience to the drier conditions, but the cost is high, with enormous losses initially.

Experts stress the need for further research to understand how other factors—like changes in air moisture, temperature swings, and increased occurrences of storms or wildfires—might impact the rainforest. Dr. Pablo Sanchez Martinez from the University of Edinburgh emphasizes that even if some rainforests can withstand drought, their ability to store and absorb carbon is likely to be significantly weakened.

Understanding the ecological responses to climate change is crucial for predicting its impacts, both locally and globally. Continued research, such as this, is vital for grasping how these changes will unfold over time.

This study was published in Nature Ecology and Evolution and involved collaboration among researchers from multiple institutions, supported by organizations such as the Natural Environment Research Council (NERC) and the UK Met Office Newton Fund. The findings are a reminder of how interlinked human actions and environmental health can profoundly affect our planet’s future.

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