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Why could large-scale loss of the Amazon Rainforest increase drought risk?

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Edge of a dense forest in Romania where clear cutting has removed most trees, leaving a bare, brown slope beside standing green trees. — Deforestation A section of clear-cut forest in Romania.

Large-scale deforestation in the Amazon Rainforest significantly increases drought risk because the forest plays a vital role in the regional hydrologic cycle through a process known as "recycled rainfall."123

In the Amazon basin, vegetation acts as a critical moisture source. Through transpiration and evaporation, the forest releases water vapor into the atmosphere, which accounts for approximately half of the region's total rainfall. In areas far from the ocean, this local process is responsible for the majority of precipitation.12

When large areas of the forest are cleared, this moisture-recycling mechanism is disrupted, leading to a reduction in rainfall. Furthermore, deforestation alters the forest structure, converting closed, humid environments into more open, drier landscapes that are increasingly vulnerable to wildfires and the drying effects of natural climate fluctuations. If the rainforest were to disappear, the loss of this essential moisture source would likely result in widespread drought and could negatively impact the global energy balance.123