This gallery is part of a special National Geographic News series on global water issues.
The Negro River, a major tributary of the Amazon River, dropped to a depth of about 46 feet (14 meters)—the lowest point since record-keeping began in 1902.
About 60,000 people in the Amazon have gone hungry as falling river levels paralyzed transport and fishing. Millions of dead fish have also contaminated rivers, leading to a shortage of clean drinking water, the Reuters news agency reported. (How much do you know about drinking water? Test your knowledge with a quiz.)
Caused by El Niño—a cyclical warming of tropical waters in the central and eastern Pacific Ocean—such a severe drought usually occurs once in a century. But the 2010 disaster comes just five years after the latest Amazon "megadrought," according to Reuters.
The drought also fits within predictions of climatic extremes this century due to global warming, Reuters reported. (Explore an interactive map of global warming's effects.)