Endangered Taonga: How Climate Change Is Melting Our Glaciers

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A timelapse camera, installed in 2012, records the retreat of the Franz Josef/Kā Roimata o Hine Hukatere glacier. Until 2019, the glacier has retreated about 900 m. Video / Victoria University

New Zealand’s beloved glaciers are melting at a frightening rate, with warmer temperatures in recent decades robbing them of a third of their total volume.

As our third consecutive La Niña portends another disastrous summer for these icy wonders, a glaciologist is launching a major new effort to unravel the precise hand of human-caused climate change in their decline.

While glacial melting is often seen as the coal-mining canary of global warming, Dr Lauren Vargo of the University of Victoria said scientists still couldn’t say exactly how much of that melting was due to climate change, especially for individual glaciers and years.

But the signal was probably significant.

In a disastrous melt year – New Zealand’s record summer of 2017-2018 – Vargo and his colleagues estimated that global warming made extreme ice loss at least 10 times more likely.

This study, focused on specific South Island glaciers for which scientists had detailed records of mass change, was only the second to link greenhouse gas emissions to the loss annual ice high.

In his latest project, which just received a three-year grant through the Marsden Fund, Vargo planned to apply the same modeling methods to around 230 glaciers.

“I will ask, for the highest melt years for each glacier, what is the increase in probability of melt with climate change and increase in amount of melt with climate change?” she says.

“We will also assess future glacial melt and ask how much the peak glacier melt years might increase in likelihood and severity as temperatures rise to 1.5°C and 2°C?”

A major study published this year, and which Vargo co-led, found that if contemporary decadal trends continue, the average elevation of the Southern Alps snow line would be shifted at least 200m higher than normal, from 2025 to 2034.

This graph shows how the average Southern Alps snow line has increased over time.  Image / Drew Lorrey, Niwa
This graph shows how the average Southern Alps snow line has increased over time. Image / Drew Lorrey, Niwa

On current trajectories, 11 of the 50 “index glaciers” monitored annually and selected in the late 1970s to track changes are expected to disappear by the middle of the next decade, and another 10 will rapidly approach a similar fate.

“These questions interest me because billions of people around the world depend on melting glaciers for water, electricity generation and agriculture, and the decline in water availability in glacial regions contributes already to human migration,” Vargo said.

“This study will help us better understand the effects of climate change on melting glaciers.”

University of Victoria glaciologist Dr Lauren Vargo is leading a new study funded by the Marsden Fund.  Photo / Fashion Hannah Perrine
University of Victoria glaciologist Dr Lauren Vargo is leading a new study funded by the Marsden Fund. Photo / Fashion Hannah Perrine

She hoped the research would also help fill knowledge gaps around the world, where a third glacier has disappeared in two decades and a temperature rise of 0.5C.

This connection was tragically demonstrated in Pakistan this year, where heavy monsoon rains, heat waves and melting glaciers caused devastating floods that killed more than 1,700 people.

Here in New Zealand, Vargo expected another La Niña-dominating climate system – something that traditionally coincides with the loss of glaciers – combined with background warming would likely mark another year of heavy melting.

Why is pounamu so hard?

Vargo’s program is among 113 projects that have just received a total of $77.3 million through the Marsden Fund, the nation’s premier pool for investigator-led research.

They covered a wide range of disciplines and topics: among them tackling antibiotic resistance, understanding the drivers of solar cell adoption, and uncovering the cultural history of the taniwha.

A study, led by GNS Science, will examine why pounamu – the nephrite jade of Aotearoa – is so resilient.

Project co-lead Dr Simon Cox said the project was built on nearly two decades of pounamu research with Ngāi Tahu.

The prized taonga was renowned for its extreme toughness compared to other rocks, which is why it was historically so revered as a tool that holds a cutting edge.

“This also makes it very suitable for crafts such as carving and shaping,” Cox said.

“We all have lots of theories to explain its particular properties, but this gives us the platform to explore it further using cutting-edge materials science and iwi cultural insights to form a larger picture of the use of the pounamu over time.”

He said the project would bring together scientists unfamiliar with the sculptural properties or history of various samples and Pounamu craftsmen who had not yet included physical science data in their work.

“Ngāi Tahu’s kaupapa and tikanga around their tino tāonga, as well as mātauranga over pounamu, are integral to successful research and knowledge transfer in both directions.”

It was hoped that the research would be useful in informing the process of selecting and cutting high-quality pounamu for carving and informing the future development of super-strong synthetic materials.

GNS Science geologists Dr Nick Mortimer and Dr Simon Cox.  Photo / Provided
GNS Science geologists Dr Nick Mortimer and Dr Simon Cox. Photo / Provided

“With its cultural, geological, archaeological and materials science significance, this project could rewrite the world’s jade textbooks and lead to better management of this precious resource.”

Co-leader and geologist Dr Nick Mortimer said nephrite jade and pounamu were “unusual rocks: in that they had metal-like toughness and were very resistant to fracture.

“Why this should be is a scientific mystery. The mineralogical explanation for pounamu’s physical toughness remains elusive,” he said.

“The minerals in pounamu are all quite soft, but the rock is hard. This makes it excellent for carving and for creating objects that keep a sharp edge.

“We think the longstanding explanation – twisted mineral fibers – is wrong. We will test other theories – including ultra-fine grain size and stored strain.”

Professor David Bilkey, chairman of the Marsden Fund Council, said Maori research and mātauranga Māori had been given particular recognition in the projects, with one in 10 researchers identifying as Maori.

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