Drought Bites as Amazon's 'Flying Rivers' Dry Up

The unprecedented drought now affecting Sao Paulo, South America's giant metropolis, is believed to be caused by the absence of the "flying rivers" - the vapour clouds from the Amazon that normally bring rain to the centre and south of Brazil.

Some Brazilian scientists say the absence of rain that has dried up rivers and reservoirs in central and southeast Brazil is not just a quirk of nature, but a change brought about by a combination of the continuing deforestation of the Amazon and global warming.

This combination, they say, is reducing the role of the Amazon rainforest as a giant "water pump", releasing billions of litres of humidity from the trees into the air in the form of vapour.

Meteorologist Jose Marengo, a member of the Intergovernmental Panel on Climate Change, first coined the phrase "flying rivers" to describe these massive volumes of vapour that rise from the rainforest, travel west, and then - blocked by the Andes - turn south.

Satellite images from the Centre for Weather Forecasts and Climate Research of Brazil's National Space Research Institute (INPE) clearly show that, during January and February this year, the flying rivers failed to arrive, unlike the previous five years.

Drought Bites as Amazon's 'Flying Rivers' Dry Up