What if the Amazon dried out? A decades-long study reveals clues

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🗞️ Driving the news: A groundbreaking 24-year experiment in Brazil’s Caxiuanã National Forest has revealed how the Amazon rainforest might respond to long-term drought
• Researchers from Brazil and the UK simulated severe rainfall reduction over a hectare of forest, observing that after eight years, large trees began dying, resulting in a 40% decline in biomass and a temporary shift from carbon absorption to carbon emission
• The findings, published in Nature Ecology & Evolution, offer crucial insights into the Amazon’s vulnerability to climate change

🔭 The context: The Amazon rainforest, spanning multiple South American nations, stores carbon equivalent to two years of global emissions and plays a vital role in climate regulation
• Past climate models suggested drought could push the forest toward savannization, but the experiment showed resilience in vegetation type — though not in carbon storage
• The research offers a rare controlled glimpse into long-term ecological impacts of reduced rainfall, contrasting with short-term droughts driven by recent El Niño events

🌍 Why it matters for the planet: This study underscores the risk of the Amazon shifting from a carbon sink to a carbon source under prolonged drought, intensifying global warming
• Although the forest retained its biome characteristics, the loss of mature trees and stored carbon could accelerate climate tipping points
• The project also highlights how even without complete biome conversion, ecosystem functions crucial to climate stability can degrade significantly

⏭️ What's next: With drought conditions lifted, scientists are now observing whether and how the forest regenerates
• The next research phase will assess root development, sap flow, soil processes, and carbon recovery
• These insights are particularly timely as Brazil prepares to host the upcoming UN climate summit in Belém, near the study site — placing Amazon conservation and restoration high on the global agenda

💬 One quote: “We’re seeing a loss of the forest’s ability to absorb carbon… instead, carbon is being released back into the atmosphere,” — Lucy Rowland, University of Exeter ecologist and study co-author

📈 One stat: The experimental plot lost 40% of its biomass, transforming from a carbon sink into a temporary carbon emitter

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