Climate Central: Athletes and tourists converging on Brazil this week are crowding into a country where rapid environmental change and natural weather fluctuations nurtured a viral epidemic that has gone global.
The Zika virus has exploded throughout South America, up through Mexico and Puerto Rico and into Florida, but the conditions it needed to fester in northern Brazil were rooted in urbanization and poverty. The initial Brazilian outbreak appears to have been aided by a drought driven by El Nio, and by higher...