Category:Antarctica

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Thwaites Glacier, Antarctica

Thwaites.jpg


2023


October 2023

Where’s All the Antarctic Sea Ice? Annual Peak Is the Lowest Ever Recorded

National Snow and Ice Data Center reports record lows for each month since April.


“Things got really strange,” said Walt Meier, a senior research scientist at the National Snow and Ice Data Center. “It started diverging from anything we’d seen before.”


Antarctic sea ice 1989-2023 chart as of July2023.png

* https://en.wikipedia.org/wiki/Antarctic_sea_ice


July 2023 | Antarctica's sea ice has melted so fast — and the Earth has remained so much warmer than usual — that scientists are sounding a global alarm. The reason is simple: Antarctic sea ice that always comes back after first melting has not returned. Vast regions of Antarctic coast are exposed that were never bare before.

As physical oceanographer Edward Doddridge put it, referring to this development as "unprecedented" simply "isn't strong enough. For those of you who are interested in statistics, this is a five-sigma event. So it's five standard deviations beyond the mean."

In other words: "If nothing had changed, we'd expect to see a winter like this about once every 7.5 million years."


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The Ice Core Story & Disruptions of the Current Era

Measuring Gasses & Looking at Outgassing of CO2, Methane, & 'Business-as-Usual

Warming, Ice Melt, Interupted Water Flow & Nutrients, Ocean Life ... Connections & the Trendlines


Note the 'Rare gases', also known as the noble gases or the inert gases, a group of six gaseous elements found in small amounts in the atmosphere (and being investigated in current times as they were trapped historically in the Antarctic and are now being retrieved in deep-drilled ice cores): helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn)

(Visit the recent Nature journal science study reported here below at GreenPolicy360)


Full Audio Interview

"A CLOSER VISIT WITH DR. JEFFREY SEVERINGHAUS: HOW DANGEROUS IS THE NEW ANTARCTIC ICE MELT FOR CLIMATE CHANGE?"

"The regular supply of very cold water has been cut off..."


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Ice loss from Greenland and Antarctica hits new record

Ice loss from Greenland and Antarctica has increased fivefold since the 1990s, and now accounts for a quarter of sea-level rise.

It is without doubt that climate change is causing our polar ice sheets to melt, thereby driving up sea levels and putting coastal regions around the world at risk.

Since 1992, when satellite records of ice-sheet melt began, the polar ice sheets have lost ice every single year. The highest rates of melt have occurred in the past decade.

Scientists use data from satellites such as ESA’s CryoSat and the European Union’s Copernicus Sentinel-1 to measure changes in ice volume and flow, as well as satellites that provide information on gravity, to work out how much ice is being lost.

A team of scientists compile these records in the Ice Sheet Mass Balance Intercomparison Exercise (IMBIE), which is funded by ESA and NASA. This is used widely, including by the International Panel on Climate Change (IPCC), to understand and respond to the climate crisis.

The latest IMBIE assessment, which was published today, states that between 1992 and 2020, the polar ice sheets lost 7560 billion tonnes of ice – equivalent to an ice cube measuring 20 km each side...


ESA re ice loss - April 2023.png


* https://www.esa.int/Applications/Observing_the_Earth/FutureEO/CryoSat/Ice_loss_from_Greenland_and_Antarctica_hits_new_record
* https://twitter.com/ESA_EO/status/1648952388651212802


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Major Study of Ice-melt Impacts Reported in the Nature Journal:


Melting Antarctic ice predicted to cause rapid slowdown of deep ocean current by 2050

New research by Australian scientists suggests 40% slowdown in just three decades could alter world’s climate for centuries


Abyssal ocean overturning slowdown and warming driven by Antarctic meltwater


Li, Q., England, M.H., Hogg, A.M. et al. Abyssal ocean overturning slowdown and warming driven by Antarctic meltwater. Nature 615, 841–847 (2023). https://doi.org/10.1038/s41586-023-05762-w

Received 20 March 2022; Accepted 25 January 2023; Published 29 March 2023

Nature Issue Date: 30 March 2023

DOI: https://doi.org/10.1038/s41586-023-05762-w | (DOI/Digital Object Identifier)


Abstract

The abyssal ocean circulation is a key component of the global meridional overturning circulation, cycling heat, carbon, oxygen and nutrients throughout the world ocean. The strongest historical trend observed in the abyssal ocean is warming at high southern latitudes, yet it is unclear what processes have driven this warming, and whether this warming is linked to a slowdown in the ocean’s overturning circulation. Furthermore, attributing change to specific drivers is difficult owing to limited measurements, and because coupled climate models exhibit biases in the region. In addition, future change remains uncertain, with the latest coordinated climate model projections not accounting for dynamic ice-sheet melt. Here we use a transient forced high-resolution coupled ocean–sea-ice model to show that under a high-emissions scenario, abyssal warming is set to accelerate over the next 30 years. We find that meltwater input around Antarctica drives a contraction of Antarctic Bottom Water (AABW), opening a pathway that allows warm Circumpolar Deep Water greater access to the continental shelf. The reduction in AABW formation results in warming and ageing of the abyssal ocean, consistent with recent measurements. In contrast, projected wind and thermal forcing has little impact on the properties, age and volume of AABW. These results highlight the critical importance of Antarctic meltwater in setting the abyssal ocean overturning, with implications for global ocean biogeochemistry and climate that could last for centuries.


If greenhouse gas emissions continue at today’s levels, the current in the deepest parts of the ocean could slow down by 40% in only three decades.

This, the scientists said, could generate a cascade of impacts that could push up sea levels, alter weather patterns and starve marine life of a vital source of nutrients.


Antarctic ice melt could disrupt the world’s oceans

The Antarctic overturning circulation is part of a global network of currents that shift heat, oxygen and nutrients around the globe

What happens in Antarctica doesn't stay in the Antarctic


Global warming is accelerating the melting of ice in Antarctica, and the increased amount of fresh water flooding into the ocean is disrupting the flow of the Antarctic overturning circulation, according to a study published in the journal Nature.


“Changes that happen in one location, such as Antarctica, can then have a global influence because those waters move all throughout the planet,” said study co-author Adele Morrison, a research fellow from the Research School of Earth Sciences at the Australian National University in Canberra.


But there are signs the overturning circulation is slowing, disrupted by the increasing amount of meltwater from Antarctica that is making the waters less salty, and therefore less dense and not sinking with the same force.

And the melting is increasing as growing amounts of greenhouse gas emissions, mainly from burning fossil fuels, are heating up the atmosphere and oceans.

“Our modelling shows that if global carbon emissions continue at the current rate, then the Antarctic overturning will slow by more than 40 per cent in the next 30 years – and on a trajectory that looks headed towards collapse,” said co-author Matthew England, deputy director of the ARC Centre for Excellence in Antarctic Science at the University of New South Wales in Sydney.


Bill McKibben, former GreenPolicy360 adviser explains:

Basically, as melting ice pours fresh water into the ocean around Antarctica, it dilutes the salinity of the sea; that reduces its density and it’s no longer heavy enough to sink, pushing out the water that’s already there. The decomposing organisms that have dropped to the sea floor thus remain locked there, as the whole vast conveyor belt begins to slow. This phenomenon has already been observed in the Arctic, where melting water pouring off Greenland and from melting sea ice has slowed the Arctic Meridional Overturning Current, or AMOC; the Australian scientists behind this new study have confirmed that the same thing is underway in the antipodes. The water that once flowed north, carrying nutrients to the Pacific, Atlantic and Indian oceans will stagnate in place."

"Other studies have predicted additional problems as these currents decline, including moving rainfall bands by a thousand kilometers from their present position. As one scientist put it, the Antarctic current is “on a trajectory that looks headed towards collapse,” and not on a scale of centuries, or even century. On a scale of decades and years. We’re as far from 2050 as we are from Bill Clinton denying he’d had “sexual relations” with “that woman,” which is to say not very far (and also reminder that embarrassing presidents are not in themselves a new phenomenon, even if Trump took it to an entirely new and endlessly more dangerous level).

The scale of the systems we’re now affecting is almost incomprehensible—the flow of the Arctic current is a hundred times larger than the Amazon river. And the speed is incomprehensible. “In the past, these circulations have taken more than 1,000 years or so to change, but this is happening over just a few decades,” one of the study’s author’s said. “It’s way faster than we thought these circulations could slow down.”

But that’s because we’ve built a new planet, one with a markedly different atmosphere. Which changes everything. Even before the epochal news from the Antarctic, the earth’s oceans had been sending distressing signals this spring. In late March, scientists reported that the temperature of ocean waters around the planet was rising abruptly, reaching record levels in recent weeks.


Antarctica science - warming water, shrinking ice.png


'Doomsday Glacier' Shows Its Underside (It's Breached with Terraces)


Antarctic Sea Ice Cover at Record Low

There is currently less sea ice in the Antarctic than at any time in the forty years since the beginning of satellite observation: in early February 2023, only 2.20 million square kilometres of the Southern Ocean were covered with sea ice. Researchers from the Alfred Wegener Institute and the University of Bremen analyse the situation for the Sea Ice Portal. January 2023 had already set a new record for its monthly mean extent (3.22 million square kilometres), even though the melting phase in the Southern Hemisphere continues until the end of February. The current expedition team on board RV Polarstern has just reported virtually ice-free conditions in its current research area, the Bellingshausen Sea.


2022


Antarctica Is in Trouble


It’s 70 degrees warmer than normal in eastern Antarctica

‘This event is completely unprecedented and upended our expectations about the Antarctic climate system.’

The coldest location on the planet has experienced an episode of warm weather this week unlike any ever observed, with temperatures over the eastern Antarctic ice sheet soaring 50 to 90 degrees above normal. The warmth has smashed records and shocked scientists.

 

2021


Doomsday Glacier in Antarctica

"If there is going to be a climate catastrophe, it’s probably going to start at Thwaites.”


Changes in Land Ice - Antarctica - Greenland (2002-2020) - GIF


Biggest icebergs calve, drift, and crack up


World's ice melting faster than ever


2020


Warming at more than three times the global average over the past 30 years

Study via the journal Nature Climate Change


It's all connected

The scientists said the main cause of the warming was increasing sea surface temperatures thousands of miles away in the tropics. Over the past 30 years, warming in the western tropical Pacific Ocean -- a region near the equator north of Australia and Papua New Guinea -- meant there was an increase in warm air being carried to the South Pole.

"It is wild. It is the most remote place on the planet. The significance is how extreme temperatures swing and shift over the Antarctic interior, and the mechanisms that drive them are linked 10,000 kilometers (6,200 miles) north of the continent on the tropical Pacific."


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The Deepest Dive in Antarctica


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Algae in Antarctica


Earth Science from Space-Monitoring Ice Melt.jpg


This summer’s Antarctic weather, as elsewhere in the world, was unprecedented in the observed record


Thwaites Glacier-2020.jpg


Thwaites, Ominous and Changing as Scientists Watch


 

2019


What Happens in Antarctica Doesn't Stay in Antarctica

Via National Geographic / Watching Thwaites Glacier Up Close and Personal by Elizabeth Rush

The Thwaites Glacier is often considered one of the most important when it comes to changes in sea level....


  • More re: Thwaites

-- https://www.nytimes.com/2020/01/29/climate/thwaites-glacier-melting-antarctica.html


Along with Thwaites the overwhelming majority of the world’s glaciers have begun to withdraw...

Never forget: The ice is telling you what to do and not you are telling the ice what to do. Thwaites speaks, its calving a message we must now labor to hear.


Elizabeth Rush is the author of Rising: Dispatches from the New American Shore.


Scientists Detect an Enormous Cavity Growing Beneath Antarctica


Researchers say the cavity would once have been large enough to hold some 14 billion tonnes of ice. Even more disturbing, the researchers say it lost most of this ice volume over the last three years alone.
"We have suspected for years that the Thwaites glacier was not tightly attached to the bedrock beneath it," says glaciologist Eric Rignot from the University of California, Irvine, and NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California.
"Thanks to a new generation of satellites, we can finally see the detail."
"For global sea-level change in the next century, this Thwaites glacier is almost the entire story."
Rignot and fellow researchers discovered the cavity using ice-penetrating radar as part of NASA's Operation IceBridge, with additional data supplied by German and French scientists.


Antarctica is losing ice 6 times faster today than in 1980s
Antarctic melting study... 'reasons for concern'


Antarctica ice losses chart-NASA re study.jpg


Read this research data thread and Antarctic sea-level rise connection from @chriscmooney, environmental reporter from the Washington Post:


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REMA-hillshade-rendering-800px-768x768.jpg


Scientists release the most accurate, high-resolution terrain map ever created (2018)

The new Antarctic map shows a resolution of 2 to 8 meters – compared to the previous standard of 1,000 meters.


Reference Elevation Model of Antarctica / Release 1

Accurate Antarctica / Phys.org


Large-format poster map of the Reference Elevation Model of Antarctica (REMA), rendered with a hillshade. Does not include any cartographic elements.


Large-format poster map of the Reference Elevation Model of Antarctica (REMA), rendered with a hillshade. Includes cartographic elements such as place name labels, graticules...


Use the links below to browse the directory for the entire REMA dataset. Refer to Documentation to see the directory structure, naming schemes, and download contents.

HTTP: http://data.pgc.umn.edu/elev/dem/setsm/REMA

FTP: ftp://ftp.data.pgc.umn.edu/elev/dem/setsm/REMA


"Considering that Antarctica is the highest, driest, and one of the most remote places on Earth, we now have an incredible topographic model to measure against in the future," said Paul Morin, a University of Minnesota earth sciences researcher and the director of the Polar Geospatial Center.

"Up until now, we've had a better map of Mars than we've had of Antarctica," said Ian Howat, professor of earth sciences and director of the Byrd Polar and Climate Research Center at The Ohio State University. "Now it is the best-mapped continent on Earth."

"It is the highest-resolution terrain map by far of any continent,’ said Ian Howat, professor of Earth sciences and director of the Byrd Polar and Climate Research Center at The Ohio State University.


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Antarctic Treaty System


NASA IceBridge Antarctica


Antarctica's Flowing Ice


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2018


Antarctic Melt Needs to be Monitored More Closely


What's Happening in Antarctica Won't Stay in Antarctica

East Antarctic Ice Sheet at Risk


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2017


Icebergs Breaking Off That Are Four Times the Size of Manhattan


How active are newly discovered Antarctic volcanoes?


A new volcanic province: an inventory of subglacial volcanoes in West Antarctica

...the biggest cluster of volcanoes in the world.


The study, published in the Geological Society Special Publications series, does not indicate whether the volcanoes are active but the team is trying to find out.

As Dr. Robert Bingham, a glacier expert and one of the paper's authors noted to the Guardian, "The big question is: how active are these volcanoes?"

"That is something we need to determine as quickly as possible," Bingham continued. "Anything that causes the melting of ice—which an eruption certainly would—is likely to speed up the flow of ice into the sea."

Ominously, other experts have warned that a reverse situation could also happen — volcanic activity can be triggered by thinning ice sheets from rising global temperatures.


Iceberg breaks off from Antarctica photo from ESA July 12, 2017.jpg


 

Trillion Ton Iceberg Breaks Off


To Us It's 'Icebergia' & Away It Goes on the High Seas

As 'Icebergia' Comes Into View


Icebergia Time July 12, 2017.png


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Antarctic Ice Shelf June 2017.png


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The Future of the US Antarctica Station and Research


Antarctic Science Vision


Climate News Now

Time to act to make a positive difference


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For more news on Global Warming from GreenPolicy360, beginning with scientific data in the 1970s...


With a Special Tip of Our Green Hat to George E. Brown and his key role in launching/overseeing Earth & Atmospheric Science missions from space


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Media in category "Antarctica"

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