An expedition to document the end days of the last tropical glaciers in Oceania has revealed sombre footage of “planetary destruction on fast-forward”.

The once-mighty ice sheets on Puncak Jaya, a mountain surrounded by dense rainforests in West Papua, Indonesia, have survived beyond projections they would disappear by 2026 but have shrunk to a fraction of their original size.

The most significant of the two remaining glaciers, which are known locally as “eternal snow” and referred to in English as the “eternity glaciers”, has lost 95% of its area since 2002, the expedition found.

“The ice will be gone: it’s not a question of if, it’s a question of when,” said Klaus Thymann, a Danish explorer and the founder of Project Pressure, an environmental charity. “And ‘when’ is coming very, very soon.”

Tropical glaciers are mostly found in the Andes, but also exist in East Africa and Indonesia. They are rapidly losing mass as fossil fuel pollution heats the planet and melts the ice.

Thymann said “it might be weird to have an emotional reaction to an inanimate object” but documenting the loss of the eternity glaciers had left him tearful as he returned to camp after filming on a rare morning of clear skies.

“On a philosophical level, you take eternity – something that’s an abstract, human construct – and we are even now killing our own constructs,” he said. “It raises some very interesting questions, I think, around the little speck we are in geological time, and what amount of chaos we’ve managed to do in such little time.”

The remote Puncak Jaya mountain sits in the disputed territory on the island of New Guinea, where there have been decades of conflict and human rights abuses after Indonesia invaded the former Dutch colony in 1963. The last two major scientific expeditions to the glaciers took place in 1973 and 2011.

Accompanied by soldiers and mountain guides during a two-week expedition in November, the team conducted a photogrammetric survey using drones and satellite positioning systems to create a 3D model of the mountain. The near-incessant rain gave them few windows of opportunity with enough visibility to capture useful images.

“What’s very healthy about being in the mountains is that it makes you humble, because we can’t control the weather,” said Thymann. “But at the same time, as much as the weather controls what I can do in a mountain, the fact that humanity has changed the weather systems is also almost unfathomable.”

“You really understand that it is planetary destruction on fast-forward,” he added. “And that’s both very scary and sad.”

Papua’s tropical glaciers lost 97% of their ice mass between 1980 and 2024, Indonesian researchers found in a study published last month. Four of its six glaciers have completely disappeared, and they project the final two will be gone by the end of the decade.

“It is deeply saddening,” said Francine Hematang, a researcher at Papua University’s forestry faculty and the lead author of the study. “This is the only tropical glacier in Indonesia and south-east Asia, and it continues to shrink at an alarming rate.”

A separate study published in December used satellite imagery and digitised analogue maps to document a decrease of glacier surface area of more than 99% since 1850, and by about 65% since the last survey in 2018. It reached the same conclusion about the impending disappearance of the glaciers.

David Ibel, a researcher at Friedrich-Alexander-University Erlangen-Nürnberg and the lead author of the study, said expeditions helped because satellite surveys were hindered by cloud cover, shadows formed by rugged topography, and the frequency with which satellites pass over areas of interest.

Drones equipped with high-resolution cameras – such as those used by Thymann – can use brief cloud-free windows to capture images and geo-reference them with extreme precision, he added.

Carbon pollution and the destruction of nature has heated the planet by about 1.4C since preindustrial times, making it less hospitable to human life. Glaciers are projected to lose a quarter of their global mass by 2100, even in a best-case scenario for cutting emissions, with devastating consequences for drinking water and food security.

As well as the environmental impacts, the loss for local communities was “indescribable”, said Ibel. “It is highly unlikely that the glaciers are going to reappear in the next hundreds of years, meaning an irretrievable loss for many generations to come. It can be only hoped that the disappearance of tropical glaciers underlines the urgency of action against anthropogenic climate change.”

The Puncak Jaya glaciers are located in one of Earth’s wettest regions and are strongly influenced by the warming El Niño weather pattern, which was particularly powerful in 2023-24 and is expected to return this year.

Thymann said a secondary aim of the expedition, for which Project Pressure partnered with geospatial technology companies Trimble and Pix4D, was to create a “visual Noah’s ark” before the glaciers disappeared entirely.

“Believe me, I would much rather there was ice than we had to resort to creating 3D models for future generations.”