Agence France-Presse: Drought is killing off trees in Brazil’s fragile Amazon rain forest and depleting the region’s carbon reservoirs — an ecological double-whammy with devastating implications, according to a study published Thursday. The Amazon’s lush vegetation in a typical year absorbs nearly two billion tonnes of carbon dioxide, one of the chief culprits causing climate change. But a 30-year study published by the journal Science found that the world’s largest tropical rain forest is …