Massive Melting Of Andes Glaciers
The tropical glaciers in South America are melting at their fastest rate in 300 years. Glaciers in the tropical Andes have shrunk by 30-50% since the 1970s, according to a recent study.
The glaciers provide fresh water for tens of millions in South America.
The study included data on about half of all Andean glaciers and blamed the melting on an average temperature rise of 0.7C from 1950-1994.
Glaciers are retreating everywhere in the tropical Andes, but the melting is more pronounced for small glaciers at low altitudes.
Glaciers at altitudes below 5,400m have lost about 1.35m in ice thickness per year since the late 1970s, twice the rate of the larger, high-altitude glaciers.
Because the maximum thickness of these small, low-altitude glaciers rarely exceeds 40 metres, with such an annual loss they will probably completely disappear within the coming decades.
Water shortages: The researchers also say there was little change in the amount of rainfall in the region over the last few decades. Without changes in rainfall, the region would face water shortages in the future, the scientists say.
The Santa River valley in Peru would be most affected; its hundreds of thousands of inhabitants rely heavily on glacier water for agriculture, domestic consumption, and hydropower.
Large cities, such as La Paz in Bolivia, could also face problems. Glaciers provide about 15% of the La Paz water supply throughout the year, increasing to about 27% during the dry season.