Rising seas threaten ‘mass exodus on a biblical scale’, UN chief warns

A flooded residential area in Sindh, Pakistan, last month.

Photograph: Anadolu Agency/Getty Images

From The Guardian by Damian Carrington

António Guterres calls for urgent action as climate-driven rise brings ‘torrent of trouble’ to almost a billion people

An increase in the pace at which sea levels are rising threatens “a mass exodus of entire populations on a biblical scale”, the UN secretary general has warned.

The climate crisis is causing sea levels to rise faster than for 3,000 years, bringing a “torrent of trouble” to almost a billion people, from London to Los Angeles and Bangkok to Buenos Aires, António Guterres said on Tuesday.

Some nations could cease to exist, drowned under the waves, he said.

Addressing the UN security council, Guterres said slashing carbon emissions, addressing problems such as poverty that worsen the impact of the rising seas on communities and developing new international laws to protect those made homeless – and even stateless – were all needed.

He said sea level rise was a threat-multiplier which, by damaging lives, economies and infrastructure, had “dramatic implications” for global peace and security.

Significant sea level rise is already inevitable with current levels of global heating, but the consequences of failing to tackle the problem are “unthinkable”.

Guterres said: “Low-lying communities and entire countries could disappear for ever. We would witness a mass exodus of entire populations on a biblical scale. And we would see ever fiercer competition for fresh water, land and other resources.
“People’s human rights do not disappear because their homes do,” he said. 

“Yes, this means international refugee law.”

The International Law Commission is assessing the legal situation.

In 2020, the UN human rights committee ruled that ​​it was unlawful for governments to return people to countries where their lives might be threatened by the climate crisis.

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A new compilation of data from the World Meteorological Organization (WMO) shows that sea levels are rising fast and the global ocean has warmed faster over the past century than at any time in the past 11,000 years.

Sea levels rise as warmer water expands and ice caps and glaciers melt.

Prof Petteri Taalas, WMO secretary general, said: “Sea level rise imposes risks to economies, livelihoods, settlements, health, wellbeing, food and water security and cultural values in the near to long term.” 

 

Floods in Makassar City, South Sulawesi, Indonesia, on Monday. Photograph: Moh Niaz Sharief/Zuma Press Wire/Rex/Shutterstock

Guterres said: “Even if global heating is miraculously limited to 1.5C, there will still be a sizeable sea level rise.”

A sea level rise of about 50cm by 2100 is likely, but the WMO said there would be a 2-3 metre rise over the next 2,000 years if heating were limited to 1.5C, and 2-6m if it were limited to 2C.

A UN report in October said there was “no credible pathway to 1.5C in place”.

Current national targets, if met, would mean a 2.4C rise in temperature.

 

Links :

• The Guardian : The century of climate migration: why we need to plan for the great upheaval

Russian oligarchs' superyachts have avoided the US west coast and the Mediterranean since Russia invaded Ukraine, heat maps show

Heat map showing Russian oligarch yacht traffic across the world before and after the invasion of Ukraine in February 2022.

Spire Maritime/Ali Balli/Anadolu Agency via Getty Images

From Business Insider by  Kate Duffy

Russian oligarchs' superyachts were detected in different regions after the Ukraine war began.
Heat maps show oligarchs' yachts have avoided America's west coast and the Mediterranean.
Turkey, Dubai, the Maldives, and the Seychelles, were popular destinations for the superyachts.

Some Russian oligarchs have kept their luxurious superyachts at bay from Western sanctions since President Vladimir Putin ordered his troops into Ukraine in February last year.

Heat maps from space-based data and analytics firm Spire, obtained by Insider, showed that oligarchs' superyachts were located in completely different destinations in January this year compared with before the war started in February 2022.

While some of the yachts trekked across the world to steer clear of sanctions against Russian oligarchs, others turned off their tracking signals to avoid detection. 

The Galactica Super Nova reportedly stopped sending tracking signals in March, though the reasons for this were unclear.
Per multiple reports, the vessel was owned by Vagit Alekperov, CEO of Russian oil firm Lukoil.

Below is a world map from Spire displaying the movements of Russian oligarchs' superyachts between February 2021 and February 2022, and then from February 2022 to January 2023.
The yellow spots represent the most heat, indicating there were a high number of yachts detected in the area.

Worldwide

Spire Maritime

The first map shows two popular paths for the yachts — one was straight down the west coast of America all the way to Chile, and another was across the Atlantic Ocean.
The luxury vessels were also common in Iceland, the Mediterranean Sea, and along the coastline of France, Portugal, and Norway, per the map.

One year on, the trends have distinctly changed.
The second map shows within a year, oligarchs' superyachts avoided most of America's west coast and floated close to the Hawaiian Islands, Mexico, and The Caribbean.
Fewer vessels crossed the Atlantic Ocean, and the vast majority stayed away from the Mediterranean.

The Mediterranean

Spire Maritime

Spire's data found that the Mediterranean was a hotspot for Russian oligarchs' superyachts before Russia invaded Ukraine.
Many vessels would linger around Spain, northern Italy, south of France, Croatia, Greece, and Sicily, according to the first heat map.

The second map shows that after Putin invaded Ukraine, there was very little activity from Russian oligarchs' yachts around the Mediterranean coast and some of the popular routes disappeared.

The only country in the region attracting the yachts was Turkey, per Spire's map.
Turkey still offers a safe haven for Russian oligarchs' assets because it's yet to sanction Russia for its aggression against Ukraine.

Two superyachts owned by sanctioned billionaire Roman Abramovich both sailed to Turkey in March and have remained there ever since, according to Marine Traffic data.

"With the yachts steering clear of once favorite vacation spots like Sicily in favor of safe havens like Turkey – and sometimes avoiding detection altogether by turning off their tracking signals – it's clear that the Russian oligarchs who still have their ships know that the threat of seizure is real and have completely changed their travel plans to avoid capture," John Lusk, CEO of Spire Maritime, told Insider.

Northern Europe

Spire Maritime

Before the war, Russian oligarchs' yachts stuck around Iceland, the north coast of France and Germany, and parts of Norway and the UK, per Spire's first map.

From February 25, 2022, Spire said its data showed there was barely any activity from oligarchs' superyachts in Northern Europe.
Only one yacht was detected in the area since the war began, Spire said.

Arabian Sea

Spire Maritime

Spire's data also honed in on the movements of Russian oligarchs' yachts around the Arabian Sea.

The path down the Red Sea still proved a favored sailing route for the vessels after the Ukraine war started in February last year, according to the maps.

Fewer yachts were detected in Dubai, the Maldives, and the Seychelles, but the yellow heat spots on the second map indicate they were still popular destinations.

These sunny locations don't have an extradition treaty with the US and therefore attracted many Russian billionaires' yachts, including Clio, which is owned by Oleg Deripaska, according to SuperYacht Fan and other reports.
A spokesperson for Deripaska said he didn't own Clio.
Deripaska was sanctioned by the US in 2018, as well as by the EU and the UK last year — all three entities described him as an oligarch in their sanctions.
The spokesperson said Deripaska wasn't an oligarch because he became a billionaire before Putin came to power and wasn't involved in politics.

Links :

• GeoGarage blog : Russian-owned super yachts going dark to avoid sanction seizure

Pro navigator Mike Broughton explains why paper charts are still irreplaceable

Libby Greenhalgh double checks the navigation the old fashioned way on board Sun Hung Kai/Scallywag.
Photo: Konrad Frost / Volvo Ocean Race

From YachtingWorld by Mike Broughton explains

 
Smartphone applications have permeated yachting in ever increasing ways and yet paper charts still persist.

We now have sailing apps that help with navigation planning, that explain rules, apps that track you and apps that track all other vessels with AIS.
Weather forecasting apps continue to improve at pace and we can now run an application that can combine six different sophisticated weather models on a device in the palm of your hand.
Apps can import satellite pictures, rain radar data and even wind information from the observation station close to your windward mark.

I’ve been using electronic navigation charts (ENCs) in various ways for 25 years, so is it now time to discard paper charts? 

Pros and cons of paper charts

For over 12 years we’ve had charting apps that can bring the equivalent of hundreds of full-size charts onto a handheld device at a fraction of the cost, size and weight of traditional paper charts.
Electronic charts can be updated in seconds, whereas manual chart updates take hours of toil.
Last century, back in my own days in the Royal Navy, the principal task of the ‘navigator’s yeoman’ on a warship was the updating of charts and almanacs.

Traditionalists will be quick to point out that there have been some infamous incidents where the use of electronic charts has contributed to the reason for groundings, usually where the navigator has not zoomed in far enough to see a hazard, island or shallows.

Team Vestas Wind famously ran aground on Cargados Carajos Shoals in the Indian Ocean.
Photo: Brian Carlin / Team Vestas Wind / Volvo Ocean Race

With paper charts, it is much easier to spot hazards and you can move your eyes across the chart very quickly.
But you do have to have the largest scale charts to hand; not always an easy task on a small or medium sized yacht on an extended passage.
What if we have a total electrical failure, how are we going to cope just with ENCs?

There’s no doubt that electrics are more reliable on yachts these days and usually at least half the crew will have separate electronic charting apps on their own tablets and smartphones.
Those devices have also become increasingly water resistant.
Having additional spare systems, each with their own power source, seems a good starting point to counter electrical failure.

But prudent seamanship surely suggests that we should at least carry paper charts for our sailing area.
The Royal Ocean Racing Club insists on paper charts to cover the area of a race, while the organisers of the Rolex Sydney to Hobart Race require that entrants have 25 detailed charts on board – and these are all physically counted during the pre-race safety inspection.

In practice few modern race navigators use paper charts in everyday competition.
The ability to utilise race navigation software, with its ever-increasingly higher definition grib files (digital weather and ocean current files), yacht polars and routing algorithms, is usually too powerful a solution to ignore.

Software can help monitor your competitors, and just as easily plot vessels or individuals in need of assistance.
It can digitally record position, course and speed as well as many other parameters every second.
I’ve used paper charts for many years for briefing the crew in the cockpit before a race.
Even on a short coastal race, a chart is a great visualisation aid of what to expect.

However, charts and cockpits don’t always mix.
I remember trying to use a paper chart in the dark in the Tour Voile in the Chanel du Four after my deck screen power lead was severed by the mainsheet traveller.
Beating into 25-30 knots of wind against three knots of tidal stream on a Mumm 30 was wet work and my ‘water resistant’ paper chart dissolved into papier mâché in minutes.
I ended up peeling it off the wet cockpit floor in strips.

One advantage of paper charts over ENCs is the speed at which you can scan a chart and see how up to date it is.
You can also easily look up the age of the survey from a small chartlet on an area of land; there are still areas of current charts for the Pacific that date back to 1770 and were surveyed by a certain Captain James Cook!

The advent of side scan sonar in 1972 increased the accuracy of surveys significantly, though it was still 17 years before GPS brought positional accuracy.
Survey date is hard to determine on many small yacht ENCs.

Electronic charts have many advantages, but can you tell how accurate the survey data is?

Larger vessels are now embracing an enhanced standard of electronic charting, which adopts an industry standard for displays, power sources and type of ENCs.
The whole system is called ECDIS (electronic charting displays) and is now required on commercial yachts over 500 GRT, run on two systems, each with independent power supplies.

Survey data has now been replaced on these charts by Category Zone of Confidence (CATZOC).
The CATZOC layer can simply be switched on or off at the operator’s discretion and means an assessment of the accuracy of the chart data can be made easily.

CATZOC info is better than simply the date of the survey, as it is assessed on the accuracy of the horizontal position, depth, nature of seabed and surveying equipment that was used.
Checking CATZOC is now part of the due diligence for navigation planning on commercial vessels.



The most accurate CATZOC is A1, and the scale runs through A, B, C to U (unassessed) They are shown on the charts, usually as triangles or elongated ovals with up to six stars inside; six stars indicating A1 accuracy.
We can expect CATZOC to filter down to smaller yachts – it’s already being incorporated into paper charts.

Paper charts certainly still have their uses.
Skipper of the IRC46 Pata Negra Andy Lis recommends using them on a transatlantic passage.
“I like to plot a noon position each day on crossings.
It’s great for all the crew to be able to monitor progress across the ocean.
Also as a back-up when the batteries fail, even AGM batteries have a life expectancy, and ours finished mid-North Atlantic race in 2019.”

Last month, I had a ‘port state inspection’ on the commercial yacht I’m running.
The French inspector relayed to me that a few days previously a yacht in Spanish waters had been fined €2,500 for not having paper charts.
I’m not sure of the accuracy of this report, but it seems to me simply prudent to carry some paper charts.

While using paper charts for actual navigation has really become a thing of the past for me, I like the idea of having a few of them to hand.
There is something nostalgic and sentimental about poring over a paper chart; it is almost therapeutic.
Besides, what better way to find the best sheltered anchorage for the evening?

Even if I do then use Google satellite imagery to look into the water to see the extent of the sand on the seabed for best holding and even the brightness of the white sand on the beach.

 

Links :

• GeoGarage blog : UKHO delays phase out of Admiralty paper charts till at least 2030

Tracking down mystery boats on the high seas

The high seas are ungoverned, international waters where exploitation is rampant because companies can operate with great anonymity. To put a stop to this behavior researchers are using old technology to spotlight out who’s really fishing in these international waters.

From The Verge by Justine Calma 

How old tech can spot new troubles on the high seas

Out on the high seas, more than 200 miles from shore, seafood companies can operate with almost no oversight.

These are ungoverned, international waters where it’s easier for companies to get away with overfishing and abuses like modern-day slavery.

Scientists using new hacks for old technology are slowly changing that.

Two decades ago, large vessels began carrying a little box that connects to what’s called the maritime Automatic Identification System (AIS).

It sends out a radio signal with information about the ship, like an identifying number, and its size, course, and speed.

That’s supposed to help ships avoid running into each other. It also helps authorities see where vessels are when they’re close to shore.

After the 9/11 attacks, AIS started getting more attention from the US government.

It saw the tech as a way to keep an eye on potential threats to national security at sea.

The US Coast Guard contracted the telecommunications company Orbcomm to launch satellites that could pick up on AIS signals from space.

Meanwhile, the Norwegian government and the European Space Agency were developing similar technology.

When the first AIS-enabled satellites were launched in 2008, that was a game-changer.

Now, satellites can pick up on a vessel’s AIS signals no matter where the ship is sailing.

In 2014, environmental groups and Google partnered up to create a near real-time map that traces the movement of about 60,000 commercial fishing boats with AIS.

The effort is called Global Fishing Watch.

The Verge spoke with Jennifer Jacquet and Gabrielle Carmine, two scientists on a mission to find out who’s doing what out on the open ocean.

Check out the video above to see how they used AIS and some old-school sleuthing to spot corporate actors on the high seas.

Image of the week : an island with its own cloud

The tiny island of Lítla Dímun is often crowned with its own individual cloud.

Located in the Faroe Islands, it's said that the island has it's own 'personal cloud'

Photo: Spumador

 

Localization with the GeoGarage Cloud platform (DGA nautical raster chart)

How the “nine-dash line” fuels tensions in the South China Sea

From The Economist

China has co-opted a cartographic mistake to bully its neighbours

Chart the course of Chinese coastguard ships in the South China Sea and a pattern emerges.
The boats’ patrols often follow a U-shaped route that stretches over 700 nautical miles from China’s coastline, encircling most of a sea that plays an outsize role in global trade and security.
This path is the “nine-dash line”.
China claims everything inside it as its own, ignoring protests from neighbouring countries.
Last year its coastguard spent longer patrolling key reefs along the line than ever before.
China’s assertiveness in enforcing this claim is perhaps the biggest obstacle to calming tensions in the South China Sea.

 

"Location Map of South Sea Islands" (南海諸島位置圖) circa 1947

 

How did this line become so important?

The nine-dash line is partly the result of a cartographic mistake.
Chinese officials had little interest in, or knowledge of, the South China Sea before the 20th century.
But after a series of humiliations at the hands of imperialist powers, map-making became a way to reclaim national pride, at least on paper.
In 1933 Chiang Kai-Shek’s nationalist government created a committee to give Chinese names to islands in the South China Sea.
The committee copied names from Western maps into Chinese, mistranslating the James Shoal, an underwater bank far from China, as “Zengmu tan”.
“Tan” means a sandbank above water.

When Bai Meichu, a private geographer and teacher inspired by the flurry of nationalistic cartography, drew a map with the first U-shaped line, he curved it around the James Shoal.
Two of Bai’s students were later hired by the nationalist Kuomintang (kmt) government and, in 1946, appear to have helped draw the first official map containing the line.
By 1948, a year before the kmt lost power in a civil war, the government began to officially assert the legitimacy of the line—and implicitly claim everything within it.
Officials were documenting new maritime ambitions rather than any historical claim, says Bill Hayton, author of “The South China Sea”.

When the Communists took over in 1949, they retained the nine-dash line and began to build a mythology around it.
In the 1990s China’s government started to say that it had “historic rights” over everything inside the dashes, on the basis of absurd claims that it was first to discover islands within the line.
It has never clarified whether that refers just to territory, or to the fish, oil and water, too.
The vagueness suits China, because its maximalist position allows it to strong-arm its neighbours over issues such as exploration rights in the South China Sea.

China’s claims have no basis in modern maritime law, which is governed by the United Nations Convention on the Law of the Sea (unclos), a treaty agreed in 1982 and ratified by 168 countries, including China.
Coastal countries are entitled to 12 nautical miles of territorial sea, where they have sovereignty.
They also get exclusive rights to drilling, fishing and mining—but only up to 200 nautical miles from their coast (see map).
In 2013 the Philippines challenged China at an international tribunal, which ruled that China’s claims based on the nine-dash line were unlawful.
China rejects the ruling.
It argues that its traditional maritime claims trump the unclosprinciples.

China has considerably expanded its navy and coastguard in the decades since the line was sketched out, and now acts as a maritime bully within it.
Around an eighth of the world’s fish are caught in the South China Sea and it contains untapped oil and gas reserves.
Chinese aggression curtails neighbouring countries’ legal attempts to extract these resources.
Its vessels harass fishing boats and disrupt oil-and-gas drilling carried out by Vietnam, the Philippines, Indonesia and Malaysia.

China is unlikely to change its stance.
Xi Jinping, China’s president, has promised to recover lost territory and with it the country’s place in the world.
In 2013 China added a tenth dash, to emphasise that Taiwan falls within the line.
As long as China continues to flout international law, talks to resolve disputes in the South China Sea are unlikely to succeed, says Ian Storey of the ISEAS-Yusof Ishak Institute, a think-tank.
Tension will continue to bubble in one of the world’s most hotly disputed regions.

Links :

• ABC : What has been happening in the South China Sea and what do experts predict for 2023? 
• Maritime Executive : Sharing Access to Offshore Energy Within China's "Nine-Dash Line"
• Defense News : How a new Vietnam-Indonesia deal will affect South China Sea disputes
• Time : Just Where Exactly Did China Get the South China Sea Nine-Dash Line From?
• GeoGarage blog : Chinese customs seize thousands of maps over missing South China Sea ‘nine-dash line’ / China’s nine-dash line proves stranger than fiction  

A robot finds more trouble under the Doomsday glacier

Photo: Rob Robbins/USAP

From Wired by Matt Simon

Underneath thousands of feet of Thwaites Glacier’s solid ice, a bot filmed peculiar features, where melting is much faster.
It’s an ominous sign for rising sea levels.

ICEFIN THE ROBOT is designed to go where no human can, swimming off the coast of Antarctica under 2,000 feet of ice.
Lowered through a borehole drilled with hot water, the torpedo-shaped machine takes readings and—most strikingly—video of Thwaites Glacier’s vulnerable underbelly.
This Florida-sized chunk of ice is also known as the Doomsday Glacier, and for good reason: It’s rapidly deteriorating, and if it collapses, global sea levels could rise over a foot.
It could also tug on surrounding glaciers as it dies, which would add another 10 feet to rising seas.

In a pair of papers published today in the journal Nature, scientists describe what Icefin and other instruments have discovered underneath all that ice.
Simply put: trouble.
Models of future sea-level rise characterize the bit of Thwaites that’s floating on the ocean—known as an ice shelf—as having a fairly simple, flat underside, but the robot found that 10 percent of it is way more complex.
There are terraces, for instance, of vertical walls over 30 feet high where melting is happening much faster than in flat areas.
That small portion is “contributing 25 percent of the melting that we see,” says Britney Schmidt, an Earth and planetary scientist at Cornell University, who leads the Icefin project.
(She’s the lead author of one of the papers and coauthor on the other.) “So it's a really outsized impact.”

Hot-water drilling of the borehole in Antarctica 

PHOTOGRAPH: PETER DAVIS/BRITISH ANTARCTIC SURVEY

As those features melt, they may be sending shocks through the system.
“What we know about Thwaites is that it's falling apart,” says Schmidt.
“We've been looking at it for the last 30 years, watching rifts and crevasses propagating across the system and destabilizing the whole ice shelf.
And what we're showing here is the way that the ocean kind of works into these weak spots, and in a sense makes it worse.”

To deploy Icefin and other instruments, Schmidt and her colleagues drilled down near the glacier’s grounding line, the point where the ice lifts off the Antarctic land mass and starts floating on the sea.
Thwaites’ risk of melting isn’t due to rising atmospheric temperatures above, but from rising ocean temperatures below.
Its grounding line has retreated 10 miles inland since the late 1990s, which means that now more of the glacier’s ice is making contact with warm saltwater.
A phenomenon known as tidal pumping is not helping: The ice heaves up when the tide comes in, allowing yet more water to rush underneath. 

PHOTOGRAPH: PETER DAVIS/BRITISH ANTARCTIC SURVEY

Scientists have good estimates of where the retreating grounding line is, thanks to satellites watching for tiny changes in the ice’s elevation.
But they haven’t had a good picture of what the glacier’s belly looks like at the grounding line, because it’s under thousands of feet of ice.
“These data are really exciting because we're getting a look into a hidden system,” says University of Waterloo glaciologist Christine Dow, who studies Antarctic glaciers but wasn’t involved in the research.

Icefin at Thwaites Glacier Antarctica 

1. Video from Icefin forward cameras of crevasses and terraces under Thwaites Glacier described in Schmidt et al 2023, Nature 614:7948 Credits: Icefin/ITGC/Schmidt/Washam

2. Supplemental video from Schmidt et al 2023, Nature 614:7948 showing melting basal ice, terraces, and the grounding line of Thwaites Glacier. Credit: Schmidt et al 2023, Nature 614:7948

3. Video of pulling Icefin back up to the surface through the borehole at Thwaites Glacier. The borehole was drilled by the British Antarctic Survey team led by Paul Anker and Keith Nicholls.

Credit: Icefin/ITGC/Schmidt

With Icefin, the researchers could remotely pilot a camera while measuring the salinity, temperature, and oxygen content of the water.

“We saw that the ice base itself was very complex in its topography, so there's lots of staircases, terraces, rifts, and crevasses,” says British Antarctic Survey physical oceanographer Peter Davis, the lead author of one of the papers and coauthor on the other.
“The rate of melting on different surfaces was very different.”

Where the glacier’s underside (or basal ice, in the scientific parlance) is smoother, melting is definitely happening, but at a much slower rate than where the topography is jagged.
That’s because a layer of cold water rests where the ice is flat, insulating it from warmer ocean water like a liquid blanket.
But where the topography is sloped and irregular, there are more vertical surfaces where warm water can attack the ice, including making incursions from the side.
This melting creates a peculiar “scalloped” look, like the surface of a golf ball.

These complex, expanding basal features could then influence the rest of the ice.
“If you open up features underneath the ice, you also get similar reflections of them on the surface, because of the way that the ice is floating,” says Davis.
“So there's a fear that if you're widening these rifts and crevices under the ice, you can destabilize the ice shelf, which could lead to greater disintegration over time.”

If you’re feeling relieved that the flatter bits of basal ice are insulated against melting to a certain degree—don’t be.
“It sounds like what we're saying is that there's less melting than there was before, and that's not true,” says Schmidt.
Instead, they’re showing that the dramatic deterioration of Thwaites has been happening under conditions that are milder than models previously estimated.
“That's important,” she continues.
“That means that it takes less to get this degree of change.”

Put another way: Thwaites’ underside may be much more sensitive than previously believed.
“What it shows us is that it's easier, perhaps, to knock these systems out of equilibrium in the first place,” says Davis.
“In the past, we have associated rapid retreat with rapid melting.
And I think what the results are showing us is that you don't need rapid melting to drive retreat.
What you do need, though, is a change in melting.
So you need something to shift the system away from a balance.”

That’s especially troubling because it means that the retreat of the grounding line can’t be explained by sky-high rates of basal melt, says Alexander Robel, head of the Ice and Climate Group at Georgia Tech, who wasn’t involved in the new papers.
And other factors could set off further melt.
“If ocean temperature or ocean circulation were to change in the future,” says Robel, “we could potentially get even higher basal melt rates that would produce even faster grounding line retreat rates.”

Better understanding how Thwaites is crumbling is critical for projecting how quickly it’ll add to sea-level rise.
Typically, forecasts are based on simplified models that represent the underside of ice sheets as flat or sloped—partly because instruments like Icefin are only just beginning to map them in detail, partly because of the computing power needed to parse such complexity over vast areas.

But the complex features that Icefin has discovered could be essential for modeling the glacier in much finer detail.
“This is such a key region for Antarctic stability,” says Dow.
“Any data we're getting from there is going to be hugely valuable for trying to figure out what that system will do in the future.”

Links :

• Dive Under the Ice With the Brave Robots of Antarctica
• GeoGarage blog : Doomsday glacier “Holding on by its fingernails” – spine-chilling retreat could raise sea levels by 10 feet / Scientists are uncovering ominous waters under Antarctic ice / Thwaites: 'Doomsday Glacier' vulnerability seen in new maps / Antarctica’s Doomsday glacier: how doomed are we?