Peru's Cordillera Blanca, a snow-topped northern mountain range sometimes called the "Peruvian Switzerland," is slowly disappearing because of climate change, a key issue on the table of a Latin America-EU summit being held in Lima this week.

The glaciers making up the range -- declared a natural world heritage site by UNESCO -- have steadily been shrinking, said Marco Zapata, the head of the glaciology unit of Peru's National Institute for Natural Resources.

He explained that between 1948 and 1976, the Cordillera Blanca has diminished by nine meters, and between 1977 and now by around 20 meters.

The time left for tourists to see the spectacular zone is limited, and depends on temperature variations, he said.

Zapata added: "It is known that the shrinking process of the glaciers is irreversible and nothing can be done."

A 1989 evaluation found that Peru had more than 3,000 glaciers in an area of 2,041 square kilometers. Just eight years later, the area had been cut by a quarter, to 1,595 square kilometers.

A clear example of what is happening can be seen on the Pastoruri mountain, a 5,240-meter-high peak that each year attracts 60,000 tourists. "It is turning into an ice-capped mountain, because the snow is rapidly shrinking," Zapata said.

In 1995, the perimeter at the snowline was 1.8 square kilometers. By last year, that had eroded to just 1.1 square kilometers.

Huascaran National Park, where the Cordillera Blanca is situated, contains 663 glaciers including the 6,768-meter-high Huascaran summit itself, along with 296 lakes and 41 rivers.

But Jean Ortiz, who heads the running of the park, said global warming was seriously changing the face of the reserve, where many high-altitude plants and animals were becoming rarer or had disappeared entirely.

"It's unusual to see with your own eyes deer, mountain cats, Andean cats, vicunas (a llama-like animal), Andean condors, partridges," he said.