 A large region of population surrounding the central and southern Andes of Argentina and Chile reside in arid areas that are dependent on water supplies from melting glaciers . The water from the glaciers also supplies rivers that have in some cases been dammed for hydroelectric power . Some researchers believe that by 2030 , many of the large ice caps on the highest Andes will be gone if current climate trends continue . In Patagonia on the southern tip of the continent , the large ice caps have retreated a 1 km ( 0 @.@ 62 mi ) since the early 1990s and 10 km ( 6 @.@ 2 mi ) since the late 19th century . It has also been observed that Patagonian glaciers are receding at a faster rate than in any other world region . The Northern Patagonian Ice Field lost 93 km2 ( 36 sq mi ) of glacier area during the years between 1945 and 1975 , and 174 km2 ( 67 sq mi ) from 1975 to 1996 , which indicates that the rate of retreat is increasing . This represents a loss of 8 % of the ice field , with all glaciers experiencing significant retreat . The Southern Patagonian Ice Field has exhibited a general trend of retreat on 42 glaciers , while four glaciers were in equilibrium and two advanced during the years between 1944 and 1986 . The largest retreat was on O 'Higgins Glacier , which during the period 1896 – 1995 retreated 14 @.@ 6 km ( 9 @.@ 1 mi ) . The Perito Moreno Glacier is 30 km ( 19 mi ) long and is a major outflow glacier of the Patagonian ice sheet , as well as the most visited glacier in Patagonia . Perito Moreno Glacier is in equilibrium , but has undergone frequent oscillations in the period 1947 – 96 , with a net gain of 4 @.@ 1 km ( 2 @.@ 5 mi ) . This glacier has advanced since 1947 , and has been essentially stable since 1992 . Perito Moreno Glacier is one of three glaciers in Patagonia known to have advanced , compared to several hundred others in retreat . The two major glaciers of the Southern Patagonia Icefield to the north of Moreno , Upsala and <unk> Glacier have retreated 4 @.@ 6 km ( 2 @.@ 9 mi ) in 21 years and 1 km ( 0 @.@ 62 mi ) in 13 years respectively . In the Aconcagua River Basin , glacier retreat has resulted in a 20 % loss in glacier area , declining from 151 km2 ( 58 sq mi ) to 121 km2 ( 47 sq mi ) . The Marinelli Glacier in Tierra del Fuego has been in retreat since at least 1960 through 2008 . 
