MEASUREMENT OF THE RETREAT OF QORI KALIS GLACIER IN THE TROPICAL ANDES OF PERU BY TERRESTRIAL PHOTOGRAMMETRY

Although the consequences of global warming in the last century may be most pronounced on glaciers of the tropics and subtropics, documentat ion of their recent retreat is extremely limited. The extent and volum e of the largest outlet glacier from the Quelccaya Ice Cap (14-degrees -S, 71-degrees-W, 5200 m above sea level) have been measured four time s between 1963 and 1991, once by aerial and three times by terrestrial photogrammetry. Drastic and accelerating rates of retreat of the term inus and of ice volume loss have been documented. The rate of retreat was nearly three times as fast between 1983 and 1991 as between 1963 a nd 1978 and the rate of volume loss was over seven times as great. The se results are consistent with the warming in this region and with the behavior of tropical glaciers in the Cordillera Blanca in Peru and in the Ruwenzori Mountains and on Mount Kenya in East Africa.