This tropical glacier is rare, revered, and could be gone by next year
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Lorentz National Park, in Indonesia's disputed Papua province of New Guinea, is home to the region's last tropical glacier.
Some call it the Eternity Glacier, but it might not be there for much longer.
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"Puncak Jaya doesn't have ice on the peak, but around it there are several ice masses, that used to be one large glacier."
Tropical glaciers are one of the most sensitive indicators of climate change, and there are only a handful left in the world — in Papua, South America, and Africa.
Puncak Jaya is the highest mountain in Indonesia and the highest peak between the Himalayas and the Andes.
At an elevation of 4,884 metres above sea level, temperatures drop and rain turns to snow, which in turn compacts down into the glacier.
As one of Earth's wettest regions it rains nearly 300 days a year, but warming temperatures mean that rain isn't turning into snow anymore.
The glacier is melting from the top and the bottom.
"We call it basal melting, melting from the bottom. As the darker area around the glacier gets bigger it absorbs more solar radiation, so it gets warmer," Dr Permana tells ABC RN's Earshot.
"It's a feedback loop. Also, the terrain the glacier is on is not flat, and so ice can slide away even faster."
The numbers confirm the exponential melt. In 1850 the glacier area was 19.3 square kilometres. In 1972 it was 7.3km2. In 2018 it was just 0.5km2.
Scientists predict the glacier will be completely gone, at best, by 2026 — but more than likely by next year.
It will take vital clues about the Earth's changing climate with it.
Extracts from a dying glacier
The Papuan glacier is one of three areas with tropical glaciers left.
In the Andes mountain range in Peru and scattered across Africa, tropical glaciers are shrinking, but as Puncak Jaya is the lowest in elevation it will be the first to go.
The glaciers have their own individual characteristics influenced by their surroundings.
In Africa and South America there are discernible dry seasons, where dust is gathered up by rain and eventually turned into snow.
If you were to slice into these glaciers like a cake, you'd see the annual dust layers and be able to calculate the age of the glacier.
"The Peruvian ice core has been dated to about 1,800 years. And in Africa they can go back to 11,000 years. But in Papua, because it always rains, we can't date it as easily," Dr Permana says.
In 2010 he was part of a research team that extracted ice cores from the Papuan glacier. Thirty-two-metre-long tubes of ice were drilled right down to the bedrock.
"We thought we might be able to find leaves or insects to do some carbon dating. But we only found one indicator of time," Dr Permana says.
"At 24-metre depth, we found deposits of tritium, which is associated with nuclear tests conducted in 1964."
In 1964 the Soviet Union and China conducted a series of nuclear tests, showering the planet with tritium and leaving trace elements in the ice.
What exists today on Puncak Jaya is thought to be the remnants of glaciers that have existed for approximately 5,000 years, however many of those years have melted away.
"The bottom, at 32-metre depth, it is associated with the 1920s, so we can say the glacier is about 90 years old," Dr Permana says.
"But it's melting from the top and the bottom so it's hard to say just how old it is."
A cross-continental climate puzzle
Extracting the Papuan ice cores provided the second piece of a climate puzzle.
"We already had ice cores from the eastern side of the Pacific Ocean. The South American cores were extracted in the 1980s, so we wanted a record on the other side — the western side, in Papua. We wanted to see what the ENSO looked like based on two tropical glaciers," Dr Permuna says.
ENSO, the El Niño Southern Oscillation, occurs every two to seven years. The 2015/2016 El Niño event brought warmer and dryer conditions, which could lead to an increase in ice loss.
That is exactly what the research team found when comparing the two cores.
They also concluded that "regional warming has passed a threshold such that the next very strong strong El Niño event could lead to the demise of the only remaining tropical glaciers between the Himalayas and the Andes".
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https://www.abc.net.au/news/2020-12-04/indonesia-tropical-glacier-threatened-climate-change/12914584
