GlobalWarming & ClimateChange News Desk – Research, conducted in 2019 and published this week, has shown why and how this is occurring — and may prove fundamental to understanding the impacts of Antarctic ice-melt.

Ace Press News From Cutting Room Floor: Published: Sept.13: 2023: ABC Climate Change Report: TELEGRAM Ace Daily News Link https://t.me/+PuI36tlDsM7GpOJe

Totten Glacier, the biggest glacier ice shelf in east Antarctica, is enormous, difficult to reach by conventional means, and thinning faster than any other part of the region.

Quick read

• In short: A helicopter expedition has helped scientists confirm warm water is melting the Totten Glacier from below.
• By dropping probes from a helicopter into cracks in the ice, a research team was able to measure temperature and salinity in previously inaccessible areas in East Antarctica.
• The researchers say helicopter-based measurements are better than ships because helicopter operations are “insensitive to sea ice conditions”, faster and more manoeuvrable than ships and “cheaper to operate than an icebreaker”.
• What’s next? The research, conducted in 2019 but only just published, will help researchers fill in the “bigger picture” of the pathways and mechanisms of warm water inflow.

The key research from this project is trying to understand the bigger picture in this Totten area,” Pat Wongpan, a scientist with the Australian Antarctic Program Partnership (AAPP), said.

“It’s melting slowly, but it’s melting from its base, and we’d like to find out how this warm water flows into the bottom of the ice shelf.”

The Hobart-based biogeochemist and ecologist, along with a research team from the 61st Japanese Antarctic Research Expedition, used a novel method to work out why.Totten Glacier in East Antarctica is the most rapidly thinning glacier in the region.

Over six days, a helicopter crew dropped dozens of probes into cracks — ranging from 15 metres to over half a kilometre — in the ice.

The probes measured the temperature and salinity of the water down to a depth of 1,000 metres.

After sinking to the seabed, they transmitted data back to the helicopter.Loading

The data confirmed a long-held theory: warm water — between 0.5 and 1 degrees Celsius — had entered a large and previously unsampled depth under the continental shelf region.

Although the research was conducted over Christmas in 2019, COVID-19 pushed its publication date back by several years.

But its findings are timely.

Antarctic sea ice is in sharp decline, and scientists are keen to understand the impacts, and the role climate change plays.

“This Totten ice shelf is the main exit for the catchment,” Dr Wongpan said.

“It can contribute a three-and-a-half metre sea level rise if it completely melts.”

Study opens door for more ‘airborne oceanography’

It’s the first time helicopters have been used for this type of research in this region, opening the door for a new way of collecting important data from previously unreachable locations.

Although it is already a common way for scientists to measure ice-melt in Greenland, CSIRO fellow and oceanographer Stephen Rintoul is certain that aerial missions will become more common in the southern antipodes.

“This kind of airborne oceanography really does expand the reach of what we can do,” Dr Rintoul said.

“It just allows you to get to places that are very difficult to get to with a ship.”

The way warm water enters under the ice shelf makes conventional access by ship difficult.

The warm water sits about 500 metres below the ocean’s surface. As it follows deep canyons on the shelf, it winds its way up into cavities beneath the floating ice shelf.

As the water moves further in, it hits the ice, causing it to melt from below.

Dr Wongpan said helicopter expeditions would be useful for future expeditions to measure this phenomenon.

He said as helicopters didn’t damage sea ice, were faster, cheaper and more manoeuvrable than icebreakers, the benefits were clear.

“It’s a risky mission,” he said.

“But with a lot of care and planning, we can do it.”

East Antarctic also vulnerable to ice melt

Dr Rintoul said the study’s findings were sobering.

“Once these ice sheets like the Totten start to retreat, they can continue to retreat even when we stop bringing the warm water in,” Dr Rintoul said.

“It might take 1,000 years for the three-and-a-half metre sea level rise from the Totten [Glacier] to occur, but we might commit ourselves to that future in the coming decades.

“That’s why we really need to know what’s going on with these glacial systems.”

Scientists have known for a long time that melting of the Antarctic ice sheet was already contributing to sea level rise.

However, most of the attention had been on West Antarctica.

“That’s because the melt rates were fastest there,” Dr Rintoul said.

“We’ve learned that East Antarctica is also vulnerable to melting by warm ocean waters reaching the ice shelves from below.”

Until now, Antarctic scientists have only been able to guess at the loss of ice mass along the continent’s eastern region.

Satellites, which can effectively “weigh” the ice sheet from space, have tracked the ice sheet as it goes up and down.

But without being able to measure what was happening underneath the ice sheet, scientists didn’t know what was causing the ice loss.

A 2015 expedition on the now-defunct Aurora Australis icebreaker allowed crews to get near the ice shelf and confirm for the first time that warm water was reaching the area.

Dangerous ocean conditions that threatened to encircle the research vessel in ice made further exploration impossible.

“Having additional measurements gives us confidence that yeah, this is really happening,” Dr Rintoul said.

Editor says …Sterling Publishing & Media Service Agency is not responsible for the content of external site or from any reports, posts or links and thanks for following as always appreciate every like, reblog or retweet and comment thank you