Tropical mountain top glaciers may melt by next decade, or sooner: Study

PTI, Dec 10, 2019, 12:27 PM IST

New York: The last remaining glaciers in the Earth’s tropical zone between the Himalayas in the North, and the Andes in the South will disappear within the next ten years, or possibly sooner, due to the ongoing climate crisis, according to a study.

The researchers from Ohio State University in the US said the first glaciers to go could be the ones in Papua, Indonesia, which they called “the canaries in the coal mine” for other mountain top glaciers around the world.

The study, published in the journal PNAS, noted that the melting of mountain top glaciers on the western half of New Guinea has increased rapidly due to a strong 2015-2016 El Nino.

The researchers explained that the El Nino, a phenomenon that causes tropical ocean water and atmospheric temperatures to get warmer — is a natural climate process, but has been amplified by global warming.

According to the researchers, the New Guinea mountain glaciers will disappear in the next 10 years — most likely during the next strong El Nino.

Study co-author Lonnie Thompson said it is likely that other tropical glaciers, such as those on Kilimanjaro in Tanzania, and Quelccaya in Peru, will follow.

“I think the Papua, Indonesia, glaciers are the indicators of what’s going to happen around the world,” Thompson said.

The researchers have been monitoring the glacier since 2010 when they drilled ice cores to determine the composition and temperature of the atmosphere around the glacier throughout history.

They also installed a string of polyvinyl chloride (PVC) pipe sections, connected by a rope, into the ice to measure how much ice had been lost by periodically measuring the rope sections left uncovered as the ice melted.

Based on their study, the researchers said the melt started at least 150 years ago but has quickened in the last decade.

Thompson and his team found signs of melting at both the top of the glacier and at the bottom.

In November 2015, the researchers said, about five meters of rope had been uncovered, meaning that the glacier surface was melting at a rate of about one meter per year.

When they went back in May 2016, they saw an additional 4.26 meters of rope uncovered – indicating a rapid melting in just over six months.

They also assessed the extent of the glacier’s melt by measuring its surface area and found that this shrank by about 75 percent from 2010 to 2018.

According to the study, the ice field had shrunk so much that by 2016 it had split into two smaller glaciers.

In August 2019, the researchers said, a mountain climber scaling the peak took a photo of the glacier, showing its near disappearance.

“The glacier’s melt rate is exponentially increasing. It’s similar to visiting a terminal cancer patient, and documenting the change in their body, but not being able to do anything about it,” Thompson said.

The study warned that globally glacier melting is tied to sea-level rise, which along with warming ocean waters can lead to more frequent and more intense storms.

The mountain top glaciers around the world contribute between a third and a half of the annual sea-level rise in the Earth’s oceans, Thompson said.

“They are much more vulnerable to the rising temperatures because they’re small and they’re warmer – they’re closer to the melting threshold. Ice is just a threshold system. It is perfectly happy at freezing temperatures or below, but everything changes at 32 degrees Fahrenheit,” he added.

The researchers said the air around the glacier is hotter due to global warming, which has also changed the altitude at which rain turns to snow.

They said this has, in turn, caused rain to fall in places where snow once fell on top of the glacier, helping rebuild its ice year-by-year.

That rainfall is the kiss of death for a glacier, the researchers warned.

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