Decades of destruction in the Amazon rainforest might be the reason that Brazil’s taps are running dry, Brazilian scientists say. Deforestation is crippling the jungle’s ability to pump moisture into the air, which could be causing drought across broad swaths of the South American country, the Associated Press reported Thursday.

“With each tree that falls, you lose a little bit more of that water that’s being transported to São Paulo and the rest of Brazil,” Philip Fearnside, a professor at the Brazilian government’s National Institute for Research in the Amazon, told AP. “If you just let that continue, you’re going to have a major impact on big population centers in Brazil that are feeling the pinch now.”

Over the years, loggers, farmers and ranchers have razed hundreds of millions of jungle acres to expand agricultural production or make big money off precious timber. As a result, fewer trees are left to perform the critical function of pulling up water through their roots and spreading it into the atmosphere. This in turn is drying up the massive “sky rivers” that deliver rains to most of southeastern Brazil, according to scientists.

In São Paulo, the nation’s financial hub and home to 23 million people, rainfall is at one-third the normal level, and the megacity is suffering its worst drought in over 80 years. Experts warn that unless the region sees intense and enduring rains, São Paulo could run out of water in a matter of months or even weeks. In other regions, drought is hampering production of coffee and sugar, two of Brazil’s largest exports.

Antonio Nobre, of Brazil’s Center for Earth System Science, told AP that the drought is magnifying the need to halt the cutting of trees in the Amazon. Despite government efforts to slow deforestation and enforce environmental laws, huge tracts of the rainforest are still bare. In an October report, Nobre warned that one-fifth of denuded areas need to be replanted to restore the atmosphere's withering sky rivers.

“We’re like the Titanic moving straight toward the iceberg,” he told AP.