The Congo rainforest makes its own spring rain

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The Congo basin is home to the world's second-largest rainforest, whose 500 million acres have been slowly drying out for the last four decades. To figure out why the dry season is getting longer, scientists have been asking: What makes it rain in the Congo rainforest?

The answer is the rainforest itself, according to a new study published in the AGU journal JGR: Biogeosciences, which publishes research on the interactions among biological, geological and chemical processes across Earth's ecosystems.

The new research found moisture leaving the dense forest canopy, or evapotranspiration, is the largest source of water vapor in the rainforest during the spring rainy season.