El Nino
http://www.cpc.ncep.noaa.gov/products/predictions/threats/threats.gif
Whens the last time you read about this?
Historical Review: Megadrought And Megadeath In 16th Century Mexico
"The epidemic of cocoliztli from 1545 to 1548 killed an estimated 5 million to 15 million people, or up to 80% of the native population of Mexico (Figure 1). In absolute and relative terms the 1545 epidemic was one of the worst demographic catastrophes in human history, approaching even the Black Death of bubonic plague"