By Dana Ford

Reuters

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.