On the afternoon of Aug. 19, the sky over São Paulo, Brazil’s largest city, went dark. A cold front combined with ash from forest fires in the Amazon rainforest and formed ominous clouds that blocked out the sun. Photos of the blackened sky began to pop on Twitter, and soon the world was paying attention to the blazes rampaging across the forest called “the lungs of the world.” Many blame President Jair Bolsonaro’s rhetoric as the central factor in the crisis.