Amazon deforestation threatens São Paulo’s water supply

Since October 2020, the Cantareira System, one of the country’s largest water reservoirs and the main responsible for supplying the metropolitan region of the State of São Paulo, has presented a storage rate of 35.6%, the lowest volume recorded since December 2013, a period that preceded one of the high points of the chronic Brazilian water crisis. According to scientists, the deforestation in the Amazon is linked to the lack of rainfall throughout the year.

This cause-and-effect relationship had already been explained by the National Institute of Space Research (Inpe) with the report “The climatic future of the Amazon” (2014). The study shows that the removal of vegetation can cause the decline of humidity-laden winds that come from the ocean to the continent. Geologist Pedro Côrtes explained the phenomenon. “You destroy trees with long roots and exchange them for grass, with short roots, which does not have the drainage capacity to reach the deep aquifers of the [Amazon region]. The result is a reduction in the atmosphere’s humidity, while the winds continue to blow [to the south], but increasingly dry”.

Côrtes also pointed out that other important reservoirs in the country face the same problem and emphasize that this is a historical problem. “This model of deforestation in the Amazon is 50 years old. It began in the 70s, with the Transamazon highway, and there is no longer justification for its maintenance. There are scientific works from the late 1980s that already warned that it could generate environmental impacts, including a reduction in the volume of rainfall. Today, we are reaping the consequences”, he said.