Andes glaciers in rapid retreat

Glaciers in the tropical Andes shrank 30 percent to 50 percent in 30 years, a dramatic retreat at the highest rate in three centuries, French researchers say. Scientists from the Institut de Recherche pour le Developpement in Marseille recently published a summary of the history of these glaciers since their maximum extension, reached between 1650 and 1730 in the middle of the Little Ice Age. The current faster melting is due to rapid climate change in the tropics since the 1950s, and in particular since the end of the 1970s, the researchers said, leading to an average temperature rise of 1.2 degrees F in this part of the Andes, an IRD release reported Monday. At the current pace of their retreat, small glaciers could disappear within the next 10 to 15 years, affecting water supply for the populations. Based on a study of rock deposits along the glacier sides revealing their previous positions, scientists were able to map and date the extent of glaciers throughout their retreat from the 1730s, combining that with aerial photographs and satellite images revealing changes in glacial surfaces after 1950. At the current rate of retreat, some smaller glaciers could disappear within the next 10 to 15 years, the researchers said, affecting water supply for the populations living in the area.