 Research in the region has been less extensive but indicates an overall recline of 7 % between 1977 and 1983 . The Quelccaya Ice Cap is the largest tropical icecap in the world , and all of the outlet glaciers from the icecap are retreating . In the case of <unk> <unk> Glacier , which is one of <unk> ' outlet glaciers , the rate of retreat had reached 155 m ( 509 ft ) per year during the three @-@ year period of 1995 to 1998 . The melting ice has formed a large lake at the front of the glacier since 1983 , and bare ground has been exposed for the first time in thousands of years . 
