Southamerican glaciers on the retreat

South America accounts for about 65 percent of all Andean glaciers. The main areas in this region are the northern Patagonia Icefield with an area of 4,200 km2, the southern Patagonia Icefield with an area of 13,000 km2, and Cordillera Darwin with an area of 2,000 km2.

These icefields contain the largest glaciers in the southern hemisphere outside of Antarctica, and are a potentially invaluable source of present and past environmental information from the mid-latitudes, providing a link between the southern tropical and equatorial regions and Antarctica.

There are currently many examples of drastic glacier retreat within the southern South American icefields. O’Higgins Glacier has retreated 15 kilometers during the last century in what is probably the largest retreat in all of South America. A recent thinning of 14 meters a year has been measured at Upsala Glacier, and a record thinning of 28 meters a year has been detected at HPS 12 Glacier in Falcon fjord.

Glaciers of all the South American Andes, including the tropical and equatorial regions, cover a total area of 31,000 km2. Although they store an equivalent global sea level rise of only a few centimeters if they were to melt completely – which represents much less than ten percent of the total volume of mountan glaciers of the world – they are presently contributing more than ten percent of total global sea level rise from mountain glaciers. Glaciers have a critical importance for the water resources in the region, and are of great significance to mining, tourism and agriculture.

There have also been numerous incidents of catastrophic glacier floods and mudflows originating from glacier melt due to volcanic eruptions, which have affected human activities and settlements, causing several tens of thousands of casualties, such as in Nevado del Ruiz, Colombia, the Cordillera Blanca in Peru, east of Mendoza, Argentina, and at the Copiapó River, the Villarrica Volcano and the Paine National Park in Chile.

The Chacaltaya glacier in Bolivia, which provides water resources to the City of La Paz, is predicted to melt completely within the next 15 years if the present atmospheric warming trend continues into the future. The incidence and speed of glacial retreat has generally accelerated during the last decades, and hundreds of years old glaciers will collapse within our own lifetime.

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