Officials here frequently claim that the huge hydroelectric dams that increasingly dot the Brazilian Amazon are a source of "clean energy.'
The dams often flood vast areas of rain forest, leading to a major loss of biodiversity and the devastating displacement of indigenous communities from their ancestral lands.
That is justified, President Dilma Rousseff claims, because they help fight climate change.
"[Hydroelectric power] does not emit greenhouse gases, and that means we have a renewable energy project,' she said when recently inaugurating one Amazonian dam.
Yet, according to independent scientists, that claim does not stand up to scrutiny.
In fact, the dams may even be causing Brazil's carbon footprint -- already the world's third largest, according to the International Energy Agency -- to expand significantly, dumping hundreds of millions of additional tons of the gases blamed for climate change into the atmosphere.
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