| SAN JOSE, Costa Rica
SAN JOSE, Costa Rica Costa Rican coffee farmers are facing threats from climate change but the rising temperatures are also expanding high-altitude regions where the country's most prized beans are grown.
Human emissions of greenhouse gases could cause the earth's surface temperature to rise anywhere between one and six degrees Celsius (1.8 and 10.8 degrees Fahrenheit) over the next 100 years, according to the United Nations, forcing growers of all crops to adapt to new weather conditions.
In Costa Rica, the temperature increases may help transform mountainous land that was once too chilly for delicate coffee trees into prime coffee-planting territory.
The strictly hard-bean Arabica coffee sought by specialty roasters is only found at high altitudes, so the shift could mean more opportunities for a country already known for its quality coffee.
"We can now plant at 2,000 meters (6,562 feet). We didn't plant there before," said Daniel Urena, an agronomist for the Coopedota coffee cooperative, which sells its high-altitude coffee to buyers such as Starbucks Corp.
Urena said the cooperative's coffee plants traditionally have not survived above 1,800 meters (5,906 feet).
DRY SPELLS, NEW PESTS
But while farmers in Costa Rica's highlands maybe able to develop into new areas, climate change could bring blight to the crop with unseasonable dry spells, unusual cold snaps and more difficulties growing coffee at lower elevations.
A recent U.N. study in Uganda found an increase of just two degrees Celsius (3.6 degrees Fahrenheit) would drastically cut back the land area suitable for coffee.
In the coffee-growing regions that survive, global warming could leave stressed coffee trees susceptible to new diseases and some coffee pests thriving in the warmer weather.
"Increases in the frequency of dry cycles that reduce the effect of cold on plants could favor the proliferation of fungus like the leaf rust coffee fungus," said Patricia Ramirez, a scientist working for inter-governmental Central American Integration System.
The rust infects mainly leaves, but also attacks young fruit and buds, and hit Brazil's coffee crop in 1970.
Strong winds that unexpectedly affected production in Guatemala and a severe drought in Brazil -- the world's leading coffee producer -- last year are examples of how global climate change can damage crops and reduce yields, said Jorge Ramirez, head of the Costa Rican Coffee Institute's research center.
He said growers can take measures to mitigate the effects of climate change by planting more shade trees in coffee fields to protect cherries from stronger-than-usual rains or creating protective windbreaks around farms with fast-growing trees.
"We have to educate farmers to use (these methods) more," he said.
(Additional reporting and writing by Mica Rosenberg; Editing by Christian Wiessner)