http://www.nytimes.com/2011/03/10/science/earth/10coffee.html?hp

Timbío, Colombia — Like most of the small landowners in Colombia’s
lush mountainous
Cauca region, Luis Garzón, 80, and his family have thrived for decades by
supplying shade-grown,
rainforest-friendly Arabica
coffee for top foreign brands like Nespresso and Green Mountain. A sign in
the center of a nearby town proclaims, “The coffee of Cauca is No.1!”

But in the last few years, coffee yields have plummeted here and in many of
Latin America’s other premier coffee regions as a result of rising temperatures
and more intense and unpredictable rains, phenomena that many scientists link
partly to global warming.

Coffee plants require the right mix of temperature, rainfall and spells of
dryness for beans to ripen properly and maintain their taste. Coffee pests
thrive in the warmer, wetter weather.