The term “flying rivers” was coined by José Marengo, a scientist from Brazil’s National Space Research Institute (INPE). It describes the air currents that carry water vapor from the Amazon forest to the eastern Andes and up to northern Argentina. The Amazon’s trees play an essential role in the creation of this vapor, acting as a massive water pump by absorbing and releasing billions of liters of water in the form of humidity.
Satellite images from INPE reveal an absence of flying rivers in January and February of this year, a marked contrast from the previous five years. INPE also reveals that deforestation in the Amazon has risen by 10 percent in the past year, following a successful period between 2004 and 2013 when the country implemented stricter controls on its forest clearing practices.
Climate Central claims that deforestation has reduced 22 percent of the Amazon rainforest, 47 percent of the Cerrado in central Brazil and 91.5 percent of the Atlantic forest.
But this is not a new problem. In 2009, Brazilian climate scientist Antonio Nobre warned of the disappearance of the flying rivers.
“Destroying the Amazon to advance the agricultural frontier is like shooting yourself in the foot,” he told the journal Valor Economico.
“The Amazon is a gigantic hydrological pump that brings the humidity of the Atlantic Ocean into the continent and guarantees the irrigation of the region. Of course, we need agriculture. But without trees there would be no water, and without water there is no food.”
“Water is the main agricultural input,” he added. “If it weren’t, the Sahara would be green, because it has extremely fertile soil.”
According to Nobre, the flying rivers transport more water through the region than even the Amazon river. “A big tree with a crown 20 meters across evaporates up to 300 liters a day, whereas one square meter of ocean evaporates exactly one square meter,” he said. “One square meter of forest can contain eight or 10 meters of leaves, so it evaporates eight or 10 times more than the ocean. This flying river, which rises into the atmosphere in the form of vapor, is bigger than the biggest river on the Earth.”
Farmers often use fires to clear forest areas for agriculture or livestock. Burning the forest “introduces too many particles into the atmosphere, dries the clouds, and they don’t rain,” says Nobre. The longer this continues, the drier conditions get, not only drying up the flying rivers but also leaving the trees – which have no natural resistance to fire – more vulnerable to wildfires.
With the disappearance of the flying rivers, São Paulo’s 9 million residents are suffering from an unprecedented drought. Brazil’s Public Ministry warns that, without rain, the city will run dry in the next 100 days.