Shrinking Tropical Ice Areas

Ten selected false-color Landsat images from 1980 to 2020 show the progressive loss of ice from the highest part of the Surdiman Range, part of the Maoke ‘Snow’ Mountains in the Indonesian Province of Papua on the island of New Guinea. This location is about 4 degrees south of the Equator but the rocky peaks near Puncak Jaya (4884 m or 16,020 ft at the highest point) are known to have had extensive glacial ice cover for thousands of years.

Excluding the small ice area once found near Ngga Pilimsit, from an initial ice area of ~6.3 km² in 1980 near the highest peaks east of the vast Grasberg Mine, only about 0.3 km² of glacial ice remains in these mountains. The imagery series also gives the approximate dates of when specific ice remnants disappeared. Each image in the time series has an area of about 16.9 x 9.5 km (10.5 x 5.9 mi).

Location for Puncak Jaya

Earth’s two largest remaining tropical ice caps are both found in Peru’s Andes Mountains. Until recently, the Quelccaya Ice Cap (about 5680 m or 18635 ft at its highest point) was the largest tropical ice mass but due to progressive ice melt, it has recently seen its shrinking glacial ice area become smaller than the ice cap atop the higher volcanic peaks of nearby Nevado Coropuna (6425 m, 21079 ft).

Using selected false-color Landsat images with no cloud cover and little to no snow allows visualization of the ice area losses and the increasing exposure of bare ice at the lowest elevations of the Quelccaya Ice Cap between 1975 and 2019. Decades ago, Quelccaya’s ice cover was greater than 70 km² in extent but is now slightly more than 40 km². Each image in the time series has an area of about 24.3 x 16.4 km (about 15 x 10 mi).

Location for Quelccaya