The study, ... focuses primarily on Ethiopia, considered to be the birthplace of coffee. Temperatures there have been going up by an average of almost 0.3 degrees per decade since 1960....What’s at stake is Ethiopia’s wild Arabica, which Davis says is home to anywhere from 80 percent to 98.8 percent of the species’s gene pool. If Arabica’s genetic diversity is wiped out, there will be big consequences. ....“The Arabicas grown in the world’s coffee plantations are from very limited genetic stock,” says Davis. “If you look at the history of coffee cultivation since the 1700s, what’s happened is the industry repeatedly goes back to Ethiopia to sort out its problems, whether they’re productivity issues or simply taste—making a good cup of coffee—you have to have that genetic diversity, that gene pool, to go back to.” http://www.businessweek.com/articles/2012-11-15/the-coffee-beans-endangered-gene-pool
The problem is so serious tbat a collective, Coffee and Climate Change, has been formed. (OK, they call themselves a development iniative.) Find them at http://www.coffeeandclimate.org/initiative.html
Other studies have been done as well.
"Without question, all four pilot countries are still suffering from climate change impacts and are expected to experience more or less severe changes in the suitability of their current coffee cultivation areas. Surprisingly there are few practical adaptation and mitigation measuresbeing implemented to cope with climate change." http://www.nri.org/docs/promotional/D5930-11_NRI_Coffee_Climate_Change_WEB.pdf
Doesn't look good for your morning java - it is likely to be very expensive - and harsher tasting. Maybe this thought will galvanize climate deniers!