Indonesia Carstensz Pyramid: Papua’s ‘eternal snow’ on Puncak Jaya is about to disappear forever

The retreat of Papua’s glaciers is driven by the same forces affecting ice around the world, Šabacká notes, a warming atmosphere caused by human activity, including the burning of fossil fuels like coal, oil and gas.

As temperatures rise, the freezing point moves higher up mountains, so more precipitation falls as rain instead of snow, even in places that once saw regular snowfall.

El Niño events can accelerate this process, while local factors such as cloud cover, snowfall and mountain topography influence its pace.

The mountains in Papua are just 450km (280 miles) south of the equator, where “permanent ice can survive only at very high altitudes and within a narrow range of climatic conditions”, Šabacká says.

A small increase in temperature, a higher freezing point or shift from snowfall to rainfall can determine whether a glacier survives at all, she adds.

The glaciers’ retreat is evidence the Earth has been warming over a long period – and their disappearance “removes both a biological habitat and part of a culturally significant landscape”.