LA MERCED Teresa Rocha, a migrant worker who picks coffee on the steamy, lush, green farms near La Merced in central Peru, might not understand the mechanics of climate change, but she knows its effects.
Rising temperatures and erratic weather patterns are changing historic trends in the coffee season, growers say in Peru, a country closely tied to the impact of climate change because of its rapidly melting tropical glaciers.
Rocha, 16, who moves with the seasons in search of ripe plants, says warmer temperatures are responsible for her early start this year -- about a month earlier than last.
Farmers are also reporting high-altitude plants are maturing at times more typical of their low-land counterparts.
"The seasons are changing tremendously. You can no longer say winter is in November, December or March. It falls in other months sometimes," said Cesar Rivas, president of the national growers' group.
"This is generating complete productive disorder," he said.
Traditionally, Peruvian coffee growers start picking their crop in April, some six months before the global arabica harvest. Its flip season has given Peru, the world's sixth largest exporter of coffee, a unique comparative advantage.
If the season continues to move earlier, farmers worry they could lose their privileged position.
"Producers can no longer make well-laid plans. Calculations are not the same," said Rivas. "The uncertainty is very difficult to deal with."
'A QUESTION WE CANNOT CONTROL'
Global temperatures are expected 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. Growers everywhere, and of all crops, will need to adapt.
In Costa Rica, rising temperatures are pushing coffee producers to higher and higher altitudes as areas previously too chilly are converted into prime agricultural real estate.
While climate change might make new land available to farm coffee, it could also expose the crop to unusual precipitation and atypical levels of humidity. Peruvian growers have said the scarcity of rains this year in some coffee-producing areas is the result of rising global temperatures.
Climate change has also been blamed for last year's drought in Brazil and winds in Guatemala. Both slashed coffee yields.
Pablo Vargas, director at La Florida, a coffee growers' cooperative in La Merced, says farmers in the group are aware of climate change and some are working to limit their environmental impact -- by planting shade-grown coffee, using natural fertilizers and not clear cutting farms.
But they are in a tight spot. By itself, Peru cannot stop the global march toward warmer temperatures, though it bears a disproportionate brunt of the impact.
Analysts say the Andean nation's melting tropical glaciers will run dry in some 25 years. That spells trouble for populations on the coast -- including the capital -- which rely on runoff and could threaten the country's energy security.
Some 70 percent of Peru's electricity is generated by hydropower. Alternative forms of power are more expensive.
An adamant advocate for the environment, even Vargas admits there are limits to what growers can do.
"Unfortunately, climate change is a question we cannot control," he said.
(Editing by Christian Wiessner)