Over the last three decades, many Latin American coffee farmers have abandoned traditional shade-growing techniques, in which the plants are grown beneath a diverse canopy of trees. In an effort to increase production, much of the acreage has been converted to "sun coffee," which involves thinning or removing the canopy.
Shade-grown farms boost biodiversity by providing a haven for birds and other animals. They also require far less synthetic fertilizer, pesticides and herbicides than sun-coffee plantations.
...So... the lesson seems to be: if you are going to drink coffee, make sure that it is shade-grown if you want to mitigate the impacts of climate change upon coffee-growing regions. You could argue then that shade-grown coffee 'trumps' fair-trade coffee, since it insures the presence of plantations in the long run, as opposed to the destruction of sun-grown plantations under conditions of climate change. Of course, currently, shade-grown and fair-trade are co-related; many shade-grown operations seem to be fair-trade.
"This is a warning against the continuation of this trend toward more intensive systems," said Ivette Perfecto of the U-M School of Natural Resources and Environment, one of the authors. "Shaded coffee is ideal because it will buffer the system from climate change while protecting biodiversity."
The livelihoods of more than 100 million people worldwide are tied to coffee production. In Latin America, most coffee farms lack irrigation---relying solely on rainwater---which makes them especially vulnerable to drought and heat waves.
Shade trees help dampen the effects of drought and heat waves by maintaining a cool, moist microclimate beneath the canopy. The optimal temperature range for growing common Arabica coffee is 64 to 70 degrees Fahrenheit.
Shade trees also act as windbreaks during storms and help reduce runoff and erosion.
"These two trends---increasing agricultural intensification and the trend toward more frequent extreme-weather events---will work in concert to increase farmer vulnerability," Lin said. "We should take advantage of the services the ecosystems naturally provide, and use them to protect farmers' livelihoods."