What are Amazon’s “flying rivers”?

Scientists have warned that the Amazon’s “flying rivers” — invisible streams of moisture that carry rain across South America — are weakening due to deforestation and climate change. The decline threatens to disrupt forests, agriculture, and hydropower, with far-reaching effects across the continent.

What Are “Flying Rivers”?

“Flying rivers” are vast airborne streams of moisture that transport rainfall from the Atlantic Ocean westward across the Amazon Basin.

• Origin: Most Amazon rainfall begins as moisture over the Atlantic Ocean.
• Mechanism: Trade winds carry this moist air inland. The Amazon rainforest acts as a biological pump, with trees absorbing water through roots and releasing it as water vapor through transpiration — recycling moisture across thousands of kilometers.

This continuous process sustains rainfall across southern Peru, northern Bolivia, and other interior regions of South America.

Growing Threats and Regional Impacts

New research shows that southern Peru and northern Bolivia are becoming increasingly vulnerable to droughts, as deforestation and global warming weaken the forest’s ability to recycle moisture.

Scientists warn that if these moisture corridors collapse, it could:

• Destabilize regional climate patterns,
• Reduce rainfall essential for farming and hydropower, and
• Push the Amazon rainforest toward a “tipping point” — transforming it into a drier savanna ecosystem.

Origin of the Term and Scientific Background

The term “flying rivers” was coined in 2006 by Brazilian climate scientist Carlos Nobre and colleagues, who calculated how water vapor from the Atlantic moves through and exits the Amazon Basin. Their work emphasized the Amazon’s crucial role in regulating South America’s hydrological cycle.