"Arabicas are the ones at risk—they're very delicate trees," he says. "They depend on conditions that are not too warm, not too cold, not too wet, not too dry."
Besides needing near-perfect conditions to grow, Arabica is also highly vulnerable to a fungus known as coffee leaf rust, a disease that originated in Africa and Asia but has since spread to every coffee-growing region except for Hawaii and Australia. As its name implies, the fungus turns a coffee plant's leaves a dark brown, causing leaves to eventually fall off. An infected tree will have a lower coffee yield and may eventually die.
Left unchecked, coffee rust has the potential to completely destroy a country's crop. In the mid 1860s, the disease essentially wiped out all of Sri Lanka's coffee plantations. More than 100 years later, Sri Lanka still doesn't have any significant coffee production, according to the International Coffee Organization.
For decades, coffee farmers in South and Central America were insulated from the disease's effects because coffee plants in the Americas are grown in the cool mountains, where temperatures weren't warm enough to be suitable for the plant. But in the 1970s, the first cases of coffee rust reached Brazil, and increasing temperatures and rainfall caused by climate change have allowed the fungus to live at higher altitudes.
According to Galindo, "everything points to climate change being the main factor influencing this explosion in coffee leaf rust."
In February, Guatemalan President Otto Perez Molina declared a state of emergency in the country after an estimated 70 percent of its coffee plants had been infected with the disease. The country's estimated 2013-2014 coffee haul could be reduced by more than 40 percent, and the fungus has caused similar problems for Guatemala's neighbors.
While Arabica coffee around the world has been devastated by coffee rust, Robusta is doing just fine. Generally grown in southeast Asia, parts of Africa and Brazil, the variety can handle wide temperature and moisture changes, is naturally resistant to coffee rust, and is cheap to produce and easy to grow. It's generally used in instant coffee and flavored blends, where its acidic taste can be hidden.
Most coffee drinkers—at least those concerned with taste—don't like it.
"Robusta is much more tolerant of climate change, it has better heat tolerance, it's less dependent on orderly rainfall," Rhinehart says. "Unfortunately it doesn't taste as good in the cup."
That leaves few options for countries such as Colombia, which pride itself on its fine Arabicas.
Coffee is known as an "orphan crop," meaning that, internationally, little money is spent trying to understand how it is grown. There are countless organizations and companies dedicated to trying to grow better wheat, soybeans, corn and rice, an estimated $100 million annually is spent on learning how to grow a better coffee bean.
For decades, developing countries grew coffee and shipped it off to the developed world. The climate in coffee producing countries such as Costa Rica, Colombia, Ethiopia and Vietnam was relatively stable, and coffee hauls were generally predictable. That has changed recently as rust has spread and more variable temperatures have reduced coffee hauls.
"For most of the period we've been importing coffee, it's been grown in countries with emerging economies facing economic challenges," says Rhinehart, of the Specialty Coffee Association of America. "There was no significant coffee production in the industrialized north, so there was no investment from the consuming side into understanding coffee genetics and quality."
Most of those countries couldn't afford to put the resources into coffee research centers—with one notable exception: Colombia.
Since 1927, Colombia's Cenicafe research center, located in the country's main coffee hub of Manizales, has been one of the world's most important resources in combating diseases that plague coffee.
Corrected 03/28/13: An earlier version of this story misstated the total value of the worldwide coffee trade.