NZ scientists to probe climate threat frozen underground

Probing frozen ground in Antarctica's Dry Valleys will give Kiwi scientists more insight into a potentially massive sleeper source of emissions - permafrost. Photo / Jamie Morton

Probing Antarctica's frozen ground will give Kiwi scientists more insight into a potentially massive sleeper source of emissions.

In icy regions of the planet, permafrost - or frozen ground - has locked up carbon from dead plants, animals and microbes over millennia, preventing its breakdown and keeping it out of the atmosphere.

Scientists estimate these icy reserves now keep about twice as much carbon - some 1.6 trillion tonnes - as is contained in the atmosphere.

"We know from the Arctic that the frozen ground holds a lot of carbon that, once thawed, will be biologically altered to produce carbon dioxide and methane," explained Professor Gary Wilson, of GNS Science.

"We have some estimates for potential Arctic permafrost contributions to atmospheric greenhouse gas levels and they could be quite significant – perhaps as much again as current levels of greenhouse gases."

A recent study showed how nitrous oxide emissions from thawing Alaskan permafrost proved to be a dozen times higher than previously assumed.

"We don't know what the situation is for Antarctic permafrost," Wilson said, "though we do know that there is carbon in the frozen soil and sediment and microbial activity so the potential may be there".

Only about 0.3 per cent of the continent is bare ground, but all of that is permafrost – and there may be vast amounts of it lying beneath Antarctica's thick ice sheets.

How far it extended wasn't clear – and what deep boreholes there were hadn't been drilled in a way to study it.

On those exposed places where they could access it, scientists were turning to geophysical methods like electrical resistivity, to cleverly image its structure underground.

Later this month, Wilson and New Zealand and Italian colleagues will head into the Dry Valleys as part of a two-year programme aiming to quantify the continent's potential emissions contribution.

What they glean from imaging work – giving them a virtual look at the frozen ground's faults, fractures and potential fluid pathways – would be matched up with actual measurements of gas leakage.

"We'll measure the gas release at the surface while we are in the field and install a few metres that will run over the 12 months of the year," Wilson said.

Later this month, Professor Gary Wilson colleagues will head into Antarctica's Dry Valleys to help quantify the continent's potential emissions contribution from thawing permafrost. Photo / NZ Herald

Joining the group is 22-year-old Otago University student Rachel Worthington, who was awarded a Blake Antarctic Ambassadorship after being selected from a pool of 100 applicants.

She felt "incredibly excited" to be fulfilling a childhood dream of travelling to the ice.

"As a geologist and oceanographer, this opportunity will allow me to extend and develop my geophysical research skills and to immerse myself in a continent I have been fascinated with throughout my oceanography studies."

Blake Programme Manager, Jacob Anderson, is also taking part in the expedition.
"As we try to understand how Antarctica is changing and what it means for all of us, communicating the science to the public is critical," he said.

"So, it's fantastic to have Rachel joining us in the Dry Valleys this year and educating and sharing the work with others."

Scientist to address London summit

Meanwhile, another prominent Kiwi Antarctic scientist, Victoria University's Professor Tim Naish, will next week address a London summit about how climate change is threatening the continent.

The Antarctic Parliamentarians Assembly brings together parliamentarians from all 53 countries that are signatories Antarctic Treaty, created 60 years ago this month.

Naish, one of only eight scientists from around the world invited to speak, will focus on how melting ice sheets may contribute to future sea level rise.

"Seventy per cent of the world's fresh water is locked up in Antarctic ice. There will be 65 metres of sea level rise if it all melts," he said.

"Sea level has already risen by 20 centimetres in response to 1C of global warming. If we continue going the way we're going, that could be 1.5m of sea level rise by the end of the century.

"If that happens, 800 million people around the world will have their toes in the water."

Naish said his message would be about fighting climate change – but also preparing for it.

"If we can keep temperatures below a 2C increase since industrialisation, then it might be possible we can prevent major meltdown of the ice sheets and limit global sea level rise to half a metre," he said.

"Don't give up on mitigation, but at the same time, be prepared to adapt to what's coming."