Saturday, February 10, 2024



Atlantic Ocean is headed for a tipping point − once melting glaciers shut down the Gulf Stream, we would see extreme climate change within decades, study shows

René van Westen, Utrecht University; Henk A. Dijkstra, Utrecht University, and Michael Kliphuis, Utrecht University

Fri, February 9, 2024 

Too much fresh water from Greenland's ice sheet can slow the Atlantic Ocean's circulation. Paul Souders/Stone via Getty Images


Superstorms, abrupt climate shifts and New York City frozen in ice. That’s how the blockbuster Hollywood movie “The Day After Tomorrow” depicted an abrupt shutdown of the Atlantic Ocean’s circulation and the catastrophic consequences.

While Hollywood’s vision was over the top, the 2004 movie raised a serious question: If global warming shuts down the Atlantic Meridional Overturning Circulation, which is crucial for carrying heat from the tropics to the northern latitudes, how abrupt and severe would the climate changes be?

Twenty years after the movie’s release, we know a lot more about the Atlantic Ocean’s circulation. Instruments deployed in the ocean starting in 2004 show that the Atlantic Ocean circulation has observably slowed over the past two decades, possibly to its weakest state in almost a millennium. Studies also suggest that the circulation has reached a dangerous tipping point in the past that sent it into a precipitous, unstoppable decline, and that it could hit that tipping point again as the planet warms and glaciers and ice sheets melt.

In a new study using the latest generation of Earth’s climate models, we simulated the flow of fresh water until the ocean circulation reached that tipping point.

The results showed that the circulation could fully shut down within a century of hitting the tipping point, and that it’s headed in that direction. If that happened, average temperatures would drop by several degrees in North America, parts of Asia and Europe, and people would see severe and cascading consequences around the world.

We also discovered a physics-based early warning signal that can alert the world when the Atlantic Ocean circulation is nearing its tipping point.

The ocean’s conveyor belt


Ocean currents are driven by winds, tides and water density differences.

In the Atlantic Ocean circulation, the relatively warm and salty surface water near the equator flows toward Greenland. During its journey it crosses the Caribbean Sea, loops up into the Gulf of Mexico, and then flows along the U.S. East Coast before crossing the Atlantic.

How the Atlantic Ocean circulation changes as it slows. IPCC 6th Assessment Report

This current, also known as the Gulf Stream, brings heat to Europe. As it flows northward and cools, the water mass becomes heavier. By the time it reaches Greenland, it starts to sink and flow southward. The sinking of water near Greenland pulls water from elsewhere in the Atlantic Ocean and the cycle repeats, like a conveyor belt.

Too much fresh water from melting glaciers and the Greenland ice sheet can dilute the saltiness of the water, preventing it from sinking, and weaken this ocean conveyor belt. A weaker conveyor belt transports less heat northward and also enables less heavy water to reach Greenland, which further weakens the conveyor belt’s strength. Once it reaches the tipping point, it shuts down quickly.

What happens to the climate at the tipping point?

The existence of a tipping point was first noticed in an overly simplified model of the Atlantic Ocean circulation in the early 1960s. Today’s more detailed climate models indicate a continued slowing of the conveyor belt’s strength under climate change. However, an abrupt shutdown of the Atlantic Ocean circulation appeared to be absent in these climate models.

 




This is where our study comes in. We performed an experiment with a detailed climate model to find the tipping point for an abrupt shutdown by slowly increasing the input of fresh water.

We found that once it reaches the tipping point, the conveyor belt shuts down within 100 years. The heat transport toward the north is strongly reduced, leading to abrupt climate shifts.

The result: Dangerous cold in the North

Regions that are influenced by the Gulf Stream receive substantially less heat when the circulation stops. This cools the North American and European continents by a few degrees.

The European climate is much more influenced by the Gulf Stream than other regions. In our experiment, that meant parts of the continent warmed at more than 5 degrees Fahrenheit (3 degrees Celsius) per decade – far faster than today’s global warming of about 0.36 F (0.2 C) per decade. We found that parts of Norway would experience temperature drops of more than 36 F (20 C). On the other hand, regions in the Southern Hemisphere would warm by a few degrees.

The annual mean temperature changes after the conveyor belt stops reflect an extreme temperature drop in northern Europe in particular. René M. van Westen

These temperature changes develop over about 100 years. That might seem like a long time, but on typical climate time scales, it is abrupt.

The conveyor belt shutting down would also affect sea level and precipitation patterns, which can push other ecosystems closer to their tipping points. For example, the Amazon rainforest is vulnerable to declining precipitation. If its forest ecosystem turned to grassland, the transition would release carbon to the atmosphere and result in the loss of a valuable carbon sink, further accelerating climate change.

The Atlantic circulation has slowed significantly in the distant past. During glacial periods when ice sheets that covered large parts of the planet were melting, the influx of fresh water slowed the Atlantic circulation, triggering huge climate fluctuations.

So, when will we see this tipping point?

The big question – when will the Atlantic circulation reach a tipping point – remains unanswered. Observations don’t go back far enough to provide a clear result. While a recent study suggested that the conveyor belt is rapidly approaching its tipping point, possibly within a few years, these statistical analyses made several assumptions that give rise to uncertainty.

Instead, we were able to develop a physics-based and observable early warning signal involving the salinity transport at the southern boundary of the Atlantic Ocean. Once a threshold is reached, the tipping point is likely to follow in one to four decades.


A climate model experiment shows how quickly the AMOC slows once it reaches a tipping point with a threshold of fresh water entering the ocean. How soon that will happen remains an open question. René M. van Westen

The climate impacts from our study underline the severity of such an abrupt conveyor belt collapse. The temperature, sea level and precipitation changes will severely affect society, and the climate shifts are unstoppable on human time scales.

It might seem counterintuitive to worry about extreme cold as the planet warms, but if the main Atlantic Ocean circulation shuts down from too much meltwater pouring in, that’s the risk ahead.

This article is republished from The Conversation, a nonprofit, independent news organization bringing you facts and trustworthy analysis to help you make sense of our complex world. It was written by: René van Westen, Utrecht University; Henk A. Dijkstra, Utrecht University, and Michael Kliphuis, Utrecht University

Read more:


Ocean heat is off the charts – here’s what that means for humans and ecosystems around the world


The heroic effort to save Florida’s coral reef from extreme ocean heat as corals bleach across the Caribbean


Scientists envision an ‘internet of the ocean,’ with sensors and autonomous vehicles that can explore the deep sea and monitor its vital signs

René van Westen receives funding from the European Research Council (ERC-AdG project 101055096, TAOC).

Henk A. Dijkstra receives funding from the European Research Council (ERC-AdG project 101055096, TAOC, PI: Dijkstra).

Michael Kliphuis does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.


Critical Atlantic Ocean current system is showing early signs of collapse, prompting warning from scientists

Laura Paddison, CNN
Fri, February 9, 2024 


crucial system of ocean currents may already be on course to collapse, according to a new report, with alarming implications for sea level rise and global weather — leading temperatures to plunge dramatically in some regions and rise in others.

Using exceptionally complex and expensive computing systems, scientists found a new way to detect an early warning signal for the collapse of these currents, according to the study published Friday in the journal Science Advances. And as the planet warms, there are already indications it is heading in this direction.

The Atlantic Meridional Overturning Circulation (the AMOC) — of which the Gulf Stream is part — works like a giant global conveyor belt, taking warm water from the tropics toward the far North Atlantic, where the water cools, becomes saltier and sinks deep into the ocean, before spreading southward.

The currents carry heat and nutrients to different areas of the globe and play a vital role in keeping the climate of large parts of the Northern Hemisphere relatively mild.

For decades, scientists have been sounding the alarm on the circulation’s stability as climate change warms the ocean and melts ice, disrupting the balance of heat and salt that determines the currents’ strength.

While many scientists believe the AMOC will slow under climate change, and could even grind to a halt, there remains huge uncertainty over when and how fast this could happen. The AMOC has only been monitored continuously since 2004.

Scientists do know — from building a picture of the past using things like ice cores and ocean sediments — the AMOC shut down more than 12,000 years ago following rapid glacier melt.

Now they are scrambling to work out if it could happen again.

This new study provides an “important breakthrough,” said René van Westen, a marine and atmospheric researcher at the University of Utrecht in the Netherlands and study co-author.

The scientists used a supercomputer to run complex climate models over a period of three months, simulating a gradual increase of freshwater to the AMOC — representing ice melt as well as rainfall and river runoff, which can dilute the ocean’s salinity and weaken the currents.

As they slowly increased the freshwater in the model, they saw the AMOC gradually weaken until it abruptly collapsed. It’s the first time a collapse has been detectable using these complex models, representing “bad news for the climate system and humanity,” the report says.

What the study doesn’t do, however, is give timeframes for a potential collapse. More research is needed, van Westen told CNN, including models which also mimic climate change impacts, such as increasing levels of planet-heating pollution, which this study did not.

“But we can at least say that we are heading in the direction of the tipping point under climate change,” van Westen said.

The impacts of the AMOC’s collapse could be catastrophic. Some parts of Europe might see temperatures plunge by up to 30 degrees Celsius over a century, the study finds, leading to a completely different climate over the course of just a decade or two.

“No realistic adaptation measures can deal with such rapid temperature changes,” the study authors write.

Countries in the Southern Hemisphere, on the other hand, could see increased warming, while the Amazon’s wet and dry seasons could flip, causing serious disruption to the ecosystem.

The AMOC’s collapse could also cause sea levels to surge by around 1 meter (3.3 feet), van Westen said.

Stefan Rahmstorf, a physical oceanographer at Potsdam University in Germany, who was not involved with the study, said it was “a major advance in AMOC stability science.”

“It confirms that the AMOC has a tipping point beyond which it breaks down if the Northern Atlantic Ocean is diluted with freshwater,” he told CNN.

Previous studies finding the AMOC’s tipping point used much simpler models, he said, giving hope to some scientists that it might not be found under more complex models.

This study crushes those hopes, Rahmstorf said.

Joel Hirschi, associate head of marine systems modeling at the National Oceanography Centre in the UK, said the study was the first to use complex climate models to show the AMOC can flip from “on” to “off” in response to relatively small amounts of freshwater entering the ocean.

But there are reasons to be cautious, he added. Even though the study used a complex model, it still has a low resolution, he said, meaning there could be limitations in representing some parts of the currents.

This study adds to the growing body of evidence that the AMOC may be approaching a tipping point — and that it could even be close.

A 2021 study found that the AMOC was weaker than any other time in the past 1,000 years. And a particularly alarming — and somewhat controversial — report published in July last year, concluded that the AMOC could be on course to collapse potentially as early as 2025.

Yet huge uncertainties remain. Jeffrey Kargel, senior scientist at the Planetary Science Institute in Arizona, said he suspected the theory of a potentially imminent shutdown of the AMOC “will remain somewhat controversial until, one year, we know that it is happening.”

He likened its potential collapse to the “wild gyrations of a stock market that precede a major crash” — it’s nearly impossible to unpick which changes are reversible, and which are a precursor to a disaster.

Modern data shows the AMOC’s strength fluctuates, but there is no observed evidence yet of a decline, Hirschi said. “Whether abrupt changes in the AMOC similar to those seen in the past will occur as our climate continues to warm is an important open question.”

This study is a piece of that puzzle, Rahmstorf said. “(It) adds significantly to the rising concern about an AMOC collapse in the not too distant future,” he said. “We will ignore this risk at our peril.”


Vital ocean currents regulating Earth’s climate ‘on course to a tipping point’

Nilima Marshall, PA Science Reporter
Fri, February 9, 2024

A large and vital system of ocean currents that helps maintain the world’s climate may already be on course to a tipping point, according to scientists.

Known as the Atlantic Meridional Overturning Circulation (Amoc), this network of deep and surface currents help keep temperatures milder in the UK and Western Europe compared to other regions at similar latitudes – such as parts of eastern Canada as well as Siberia.

Scientists say a breakdown of this system could potentially plunge the UK and large parts of the Northern Hemisphere into a new ice age – an outcome that was dramatised in the 2004 Hollywood blockbuster The Day After Tomorrow.

It would also disrupt rainfall that billions rely on for agriculture, cause sea levels to rise in many parts of the world and lead to changes in weather patterns with significant impacts on ecosystems and human societies.

Dr Rene van Westen, a postdoctoral researcher in climate physics at Utrecht University in the Netherlands, said: “Cooler temperatures over Europe may seem positive, but the repercussions are far-reaching, with other regions experiencing accelerated warming and altered precipitation patterns.

“Additionally, a 100cm rise in European sea levels is projected due to the abrupt ocean circulation collapse.”

The Amoc plays a key role in regulating Earth’s climate by transporting heat from the Equator towards the Poles.

But as global temperatures rise due to warming, freshwater is pouring into the system from the melting ice from Antarctica, Greenland and other sources, risking disruption to the circulation patterns that drive the Amoc.

Dr Van Westen, along with a team of researchers at Utrecht University, designed a simulation where they gradually introduced surface freshwater over the course of 2,200 model years.

The findings, published in the journal Science Advances, showed a gradual decline of the Amoc over 1700 model years, followed by an abrupt tipping event beginning around the year 1758 and lasting for about a century.

Simulations showed that during this time, the European climate cooled by about 1C per decade, with regions experiencing over 3C cooling per decade.

The researchers said that comparing these figures to the current global warming rate of 0.2C per decade underscores the devastating impact an Amoc tipping event could have on the planet.

Dr Van Westen said: “Once the Atlantic Ocean circulation collapses, the resulting climate impacts are nearly irreversible on human timescales, as our earlier research has shown.

“Staying clear of this tipping point is imperative for avoiding devastating consequences on climate, society, and the environment.”

Scientists says large parts of the Northern Hemisphere could be plunged into a new ice age (Alamy/PA)

The researchers said that while current observational records are too short to make a reliable estimation, there are early warning indicators suggesting “we are moving in the direction of the tipping point”.

The team also said it also found a new way to detect an early warning signal for the collapse of the Amoc – a minimum of freshwater transport occurring at 34 degrees south of the Equator in the Atlantic.

Commenting on the study, Professor Tim Lenton, director of the Global Systems Institute at University of Exeter, said: “The research makes a convincing case that the Amoc is approaching a tipping point based on a robust, physically-based early warning indicator.

“What it cannot – and does not – say is how close the tipping point, because as it shows that there is insufficient data to make a statistically reliable estimate of that.

“We have to plan for the worst.

“We should invest in collecting relevant data and improving estimation of how close a tipping point is, improving assessment of what its impacts would be, and getting pre-prepared for how we could best manage and adapt to those impacts if they start to unfold.”

Professor Jon Robson, research fellow at the University of Reading’s National Centre for Atmospheric Science, said that although climate models can simulate such abrupt Amoc weakening events, it is important to keep in mind that the current study is based on only one imperfect climate model.

He said: “We need to see if this freshwater diagnostic is really a robust early warning indicator of abrupt Amoc changes.”

Ocean system that moves heat gets closer to collapse, which could cause weather chaos, study says

SETH BORENSTEIN
Updated Fri, February 9, 2024

 People swim in the Atlantic Ocean in Biarritz, southwestern France, Oct. 27, 2021. An abrupt shutdown of Atlantic Ocean currents that could put large parts of Europe in a deep freeze is looking a bit more likely and closer than before, according to a new story. 

(AP Photo/Bob Edme, File)


An abrupt shutdown of Atlantic Ocean currents that could put large parts of Europe in a deep freeze is looking a bit more likely and closer than before as a new complex computer simulation finds a “cliff-like” tipping point looming in the future.

A long-worried nightmare scenario, triggered by Greenland's ice sheet melting from global warming, still is at least decades away if not longer, but maybe not the centuries that it once seemed, a new study in Friday's Science Advances finds. The study, the first to use complex simulations and include multiple factors, uses a key measurement to track the strength of vital overall ocean circulation, which is slowing.

A collapse of the current — called the Atlantic Meridional Overturning Circulation or AMOC — would change weather worldwide because it means a shutdown of one of key the climate and ocean forces of the planet. It would plunge northwestern European temperatures by 9 to 27 degrees (5 to 15 degrees Celsius) over the decades, extend Arctic ice much farther south, turn up the heat even more in the Southern Hemisphere, change global rainfall patterns and disrupt the Amazon, the study said. Other scientists said it would be a catastrophe that could cause worldwide food and water shortages.

“We are moving closer (to the collapse), but we we're not sure how much closer,” said study lead author Rene van Westen, a climate scientist and oceanographer at Utrecht University in the Netherlands. “We are heading towards a tipping point.”

When this global weather calamity — grossly fictionalized in the movie “The Day After Tomorrow” — may happen is “the million-dollar question, which we unfortunately can't answer at the moment,” van Westen said. He said it's likely a century away but still could happen in his lifetime. He just turned 30.

“It also depends on the rate of climate change we are inducing as humanity,” van Westen said.

Studies have shown the AMOC to be slowing, but the issue is about a complete collapse or shutdown. The United Nations' Intergovernmental Panel on Climate Change, which is a group of hundreds of scientists that gives regular authoritative updates on warming, said it has medium confidence that there will not be a collapse before 2100 and generally downplayed disaster scenarios. But van Westen, several outside scientists and a study last year say that may not be right.

Stefan Rahmstorf, head of Earth Systems Analysis at the Potsdam Institute for Climate Research in Germany, was not part of the research, but called it “a major advance in AMOC stability science.”

“The new study adds significantly to the rising concern about an AMOC collapse in the not too distant future,” Rahmstorf said in an email. “We will ignore this at our peril.”

University of Exeter climate scientist Tim Lenton, also not part of the research, said the new study makes him more concerned about a collapse.

An AMOC collapse would cause so many ripples throughout the world's climate that are “so abrupt and severe that they would be near impossible to adapt to in some locations,” Lenton said.

There are signs showing that the AMOC has collapsed in the past, but when and how it will change in the future is still uncertain, said U.S. National Oceanic and Atmospheric Administration oceanographer Wei Cheng, who wasn't part of the research.

The AMOC is part of an intricate global conveyor belt of ocean currents that move different levels of salt and warm water around the globe at different depths in patterns that helps regulate Earth's temperature, absorbs carbon dioxide and fuels the water cycle, according to NASA.

When the AMOC shuts down, there's less heat exchanged across the globe and “it really impacts Europe quite severely,” van Westen said.

For thousands of years, Earth's oceans have relied on a circulation system that runs like a conveyor belt. It's still going but slowing.

The engine of this conveyor belt is off the coast of Greenland, where, as more ice melts from climate change, more freshwater flows into the North Atlantic and slows everything down, van Westen said. In the current system, cold deeper fresher water heads south past both Americas and then east past Africa. Meanwhile saltier warmer ocean water, coming from the Pacific and Indian oceans, pushes past the southern tip of Africa, veers to and around Florida and continues up the U.S. East Coast on up to Greenland.

The Dutch team simulated 2,200 years of its flow, adding in what human-caused climate change does to it. They found after 1,750 years “an abrupt AMOC collapse,” but so far are unable to translate that simulated timeline to Earth's real future. Key to monitoring what happens is a complicated measurement of flow around the tip of Africa. The more negative that measurement, the slower AMOC runs.

"This value is getting more negative under climate change,” van Westen said. When it reaches a certain point it's not a gradual stop but something that is “cliff-like,” he said.

The world should pay attention to potential AMOC collapse, said Joel Hirschi, division leader at the United Kingdom's National Oceanography Centre. But there's a bigger global priority, he said.

“To me, the rapidly increasing temperatures we have been witnessing in recent years and associated temperature extremes are of more immediate concern than the AMOC shutting down,” Hirschi said. “The warming is not hypothetical but is already happening and impacting society now.” ___

Read more of AP’s climate coverage at http://www.apnews.com/climate-and-environment

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Follow Seth Borenstein on X at @borenbears

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The Associated Press’ climate and environmental coverage receives financial support from multiple private foundations. AP is solely responsible for all content. Find AP’s standards for working with philanthropies, a list of supporters and funded coverage areas at AP.org.


Oops, Scientists May Have Miscalculated Our Global Warming Timeline

Darren Orf
Fri, February 9, 2024 

Surasak Suwanmake - Getty Images

The Paris Climate Accords in 2015 set an ambitious (and necessary) goal of keeping global temperatures at 1.5 degrees Celsius above pre-industrial temps. But a new study says we might’ve blown past that threshold several years ago.

A new study from University Western Australia Oceans Institute studied long-lived Caribbean sclerosponges and created an ocean temperature timeline dating back to the 1700s.

While the study claims that we surpassed 1.5 degrees Celsius in 2020, other scientists question if data from just one part of the world is enough to capture the immense thermal complexity of our oceans.

Whatever your stance is on climate change (it’s real, let’s move on), it’s impossible to have missed the near-ubiquitous call to action to “keep temperatures from exceeding 1.5 degrees Celsius compared to pre-industrial levels.” Over the past few years, the somewhat bureaucratic phrase has become a rallying cry for the climate conscious.

This ambitious target first surfaced following the Paris Climate Agreement, and describes a sort of climate threshold—if we pass a long-term average increase in temperature of 1.5 degrees Celsius, and hold at those levels for several years, we’re going to do some serious damage to ourselves and our environment.

Well, a new paper from the University Western Australia Oceans Institute has some bad news: the world might’ve blown past that threshold four years ago. Published in the journal Nature Climate Change, the paper reaches this conclusion via an unlikely route—analyzing six sclerosponges, a kind of sea sponge that clings to underwater caves in the ocean. These sponges are commonly studied by climate scientists and are referred to as “natural archives” because they grow so slowly. Like, a-fraction-of-a-millimeter-a-year slow. This essentially allows them to lock away climate data in their limestone skeletons, not entirely unlike tree rings or ice cores.

By analyzing strontium to calcium ratios in these sponges, the team could effectively calculate water temperatures dating back to 1700. The sponges watery home in the Caribbean is also a plus, as major ocean currents don’t muck up or distort temperature readings. This data could be particularly useful,as direct human measurement of sea temperature only dates back to roughly 1850, when sailors dipped buckets into the ocean. That”s why the Intergovernmental Panel on Climate Change (IPCC) uses 1850 and 1900 as its preindustrial baseline, according to the website Grist.

“The big picture is that the global warming clock for emissions reductions to minimize the risk of dangerous climate change has been brought forward by at least a decade,” Malcolm McCulloch, lead author of the study, told the Associated Press. “Basically, time’s running out.”

The study concludes that the world started warming roughly 80 years before the IPCC’s estimates, and that we already surpassed 1.7 degrees Celsius in 2020. That’s a big “woah, if true” moment, but some scientists are skeptical. One such scientist, speaking with LiveScience, said that “ it begs credulity to claim that the instrumental record is wrong based on paleosponges from one region of the world… It honestly doesn’t make any sense to me.” Other experts expressed wanting to see more data before completely upending the IPCC’s climate goalposts, which say the Earth is currently hovering at a long-term temperature change of around 1.2 degrees Celsius.

Unfortunately, even if the sponges are wrong, there’s mounting evidence that we are in the process of crossing that 1.5 degree threshold as we speak. This January was the hottest on record, clocking in at 1.7 degrees above pre-industrial temperatures. According to New Scientist, that means we’ve been above 1.5 degrees of change for at least a year. That doesn’t jump the long-term average over the 1.5-line, but it’s certainly a sign we’re getting close fast.

Regardless of the percentage, one thing is certain—climate change is an all-hands-on-deck crisis. In order to save the planet for future habitability, humans need to curtail emissions immediately—after all, the sea sponges are telling us so.

Climate change row as British scientists claim ‘Day After Tomorrow’ modelling is wrong

Sarah Knapton
THE TORY TELEGRAPH
Fri, February 9, 2024 

In the film The Day After Tomorrow, the ocean system is disrupted by climate change, plunging the northern hemisphere into a permanent winter
 - 20th CENTURY FOX/EPA


A climate model predicting a devastating ‘Day After Tomorrow’ collapse of ocean systems has been criticised for relying on ‘entirely unrealistic’ scenarios.

A Dutch team from Utrecht University published work in the journal of Science Advances this week suggesting that the Atlantic Meridional Overturning Circulation (AMOC) could reach a tipping point, triggering a new ice age.

The AMOC transports heat and salt throughout the world’s oceans and helps regulate the global climate, driving the Gulf Stream that keeps Britain warmer than it should be for its northerly latitude.

In the apocalyptic science fiction film The Day After Tomorrow, the ocean system is disrupted by climate change, plunging the northern hemisphere into a permanent winter.

Although ice-core data suggests the AMOC can switch off, recent sophisticated modelling has not been able to reproduce the effect, leading many scientists to think a collapse is unlikely to happen.

The new study claims to have shown that AMOC is “on route to tipping”, a prospect that the authors say is “bad news for the climate system and humanity”.

However British scientists warned that the outcome had been “forced” by using unlikely variables, such as assuming large influxes of freshwater into the Atlantic.

Prof Jonathan Bamber, director of the Bristol Glaciology Centre at Bristol University, said: “They did this by imposing a huge freshwater forcing to the North Atlantic that is entirely unrealistic for even the most extreme warming scenario over the next century.

“Their freshwater forcing applied to the North Atlantic is equivalent to six cm/year of sea level rise by the end of the experiment, which is more than seen during the collapse of the ice sheet that covered North America during the last glaciation.”

The UN’s Intergovernmental Panel on Climate Change has said that the AMOC is unlikely to collapse this century, and many scientists do not believe it will fail even if the climate continues to warm.

Observational data for the ocean system only goes back to 2004, making it difficult to predict, and because it spans the globe, most models cannot account for all the nuances and influences.

Commenting on the new research, Prof Andrew Watson, of Exeter University, said “They say it suggests that ‘the present day AMOC is on route to tipping’.
‘Push it quite hard’

“This sounds alarming, but it’s important to note that this is not the same as saying collapse is going to happen imminently. They have to run their model for a long time (1,700 years) and push it quite hard to make the collapse happen.

“Models are not reality. The real system may be more, or less, prone to collapse than this model suggests.”

The authors said that the collapse of the AMOC would result in the “very strong and rapid cooling of Europe” by about 3C per decade, which they said ‘no realistic adaptation measures’ would be able to mitigate.

They said their study had picked up an early warning signal that the collapse was just 25 years away, when the movement of freshwater flowing through the southern Atlantic slows to a minimum.

Other experts said the research was a reminder of the possible unexpected impacts of uncontrollable global warming, which could actually plunge the world into a new ice age.

Prof Jeffrey Kargel, senior scientist at the Planetary Science Institute in Arizona, said: “A shut down of the AMOC would be felt globally, according to the model, from Europe to Antarctica.
‘Sea ice has diminished drastically’

Sea ice in the Arctic, which has diminished drastically in recent decades, would expand in winter to the latitudes of Ireland, the UK and Denmark.

“The projected changes in climate in Scandinavia and parts of Greenland and the United Kingdom and elsewhere may threaten those countries’ humanly habitability if glacier and ice sheet growth extends from the mountains and hill terrains to lowlands.”

Last year a paper published in the journal Nature suggested the AMOC was likely to collapse by 2057, and possibly as early as 2025.

But the study was criticised as “far too simplistic” by the Met Office, which warned readers not to despair.

 

Kick-off for a new polar research project


YESSS to investigate warming in the Arctic during the dark season


Business Announcement

ALFRED WEGENER INSTITUTE, HELMHOLTZ CENTRE FOR POLAR AND MARINE RESEARCH

Sampling on Kongsfjord, Spitsbergen 

IMAGE: 

DR CLARA HOPPE (RIGHT) SAMPLING ON KONGSFJORD, SPITSBERGEN

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CREDIT: ALFRED WEGENER INSTITUTE / PAOLO VERZONE




The new research project YESSS - Year-round EcoSystem Study on Svalbard - is focussing on how Arctic warming is changing over the seasons in Svalbard. The team of around 30 scientists observes the life cycles, foraging and overwintering strategies of selected key species all year round and conducts experiments at the AWIPEV station on Svalbard. The Federal Ministry of Education and Research is funding the project, which is coordinated by the Alfred Wegener Institute, with 2.7 million euros until the end of 2026.

The Arctic is warming more quickly than any other place on Earth. The melting glaciers and dwindling sea ice there have become an iconic image of climate change. But also the entire seasonal development of plants and animals is changing, possibly with serious ecological consequences.

Researchers from seven universities and research institutions met at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research (AWI) in Bremerhaven from 6-8 February 2024 for the kick-off meeting for the 40-month polar research project YESSS. Under the leadership of the AWI, they want to investigate the seasonal aspects of warming in the Arctic, e.g. with respect to life cycles, foraging and overwintering. Until now, little is known about this because our understanding of such ecological processes has mainly been based on studies carried out in spring and summer. This is now set to change: YESSS stands for “Year-round EcoSystem Study on Svalbard”, so it is about year-round research being conducted on the Arctic Archipelago of Svalbard. As part of the German government’s polar strategy, the Federal Ministry of Research and Education (BMBF) is funding the project with around 2.7 million euros.

When it comes to climate change, the Arctic is considered a hotspot, a kind of early warning system for impending global changes. This is due to the fact that the effects of climate change are intensified under the extreme conditions in the Arctic Ocean region. Ocean temperature has risen twice as fast as in other regions of the world. This matters because ocean warming is a stress factor for many organisms: Higher temperatures accelerate processes in the body and thus lead to greater consumption of resources. What consequences does this have for phenology in the Arctic?

“So far, there have been hardly any studies on these developments in the long and dark Arctic winter and also not in the transitional periods in spring and autumn, which are only a few days long. We now want to gain new insights with weekly measurements throughout the year,” says YESSS project leader Dr Clara Hoppe. The AWI biologist has been involved in several research expeditions to Svalbard since 2014 and also in the year-round MOSAiC expedition 2019/2020 in the Central Arctic.

Her special field of research is phytoplankton, microscopically small single-celled organisms that bind the greenhouse gas CO2 through photosynthesis and produce oxygen from water. Phytoplankton is the basis of the food web, so that changes in phytoplankton have an impact on the entire ecosystem. “We want to investigate how these organisms react to the stressor of increased water temperature during the dark months,” says Clara Hoppe.

Such season-specific experiments on temperature sensitivity will also be carried out for other key groups in the food web, for macroalgae (e.g. seaweed), molluscs (e.g. mussels), echinoderms (e.g. sea urchins) and fish (e.g. cod). The higher water temperatures are for example already attracting fish species that did not previously exist in the Arctic. Whether native species will be sufficiently resistant is largely unknown. Based on the data obtained on resilience to higher temperatures and successful overwintering strategies, the scientists will develop an ecosystem model. It is intended to identify potential “winners” and “losers” of climate change as well as temperature tipping points at different times of the year. “When linked together, these different research findings can help to assess the ecological consequences of climate change in the Arctic,” says Clara Hoppe. The YESSS project aims to develop strategic guidelines for the sustainable socio-ecological management of similar Arctic coastal ecosystems and make them available to various interest groups (e.g. indigenous and local communities or countries bordering the Arctic Ocean, as well as politicians).

The development of these governance concepts and the entire communication of the research project, including to the general public, are summarised in a separate work package of YESSS. Experts from the Ecologic Institute and the NGO constructify.media e.V. will support the scientists - a special approach that also convinced the BMBF when selecting the project.

Following a preparatory phase since September 2023 and the kick-off meeting in Bremerhaven, the actual research work in the Kongsfjord on Svalbard is scheduled to begin in summer 2024. Only around 30 people live in Ny-Ålesund, where the AWIPEV research station is located, in winter. For one year, four doctoral students will also work there for the YESSS research project, in groups of two, alternating every six weeks. They will take weekly samples on site and provide measurement results for the project in various experiments. They will be prepared for their new job far north of the Arctic Circle in various training sessions at the AWI and GEOMAR in Kiel, including protection in the event of encounters with polar bears, boat-based sampling at night and a two-day media training programme. This is because the team will regularly report on their extraordinary work in climate research on social media and attempting to appeal to a young audience. At the end of 2026, the project results will be available and presented at the largest annual Arctic conference, the Arctic Circle Assembly in Iceland, among other events.

 

YESSS partners:
1 Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven
2 University of Bremen, Faculty of Biology/Chemistry & MARUM - Centre for Marine Environmental Sciences, Bremen
3 Johannes Gutenberg University Mainz (JGU), Department 10 Biology, Institute of Molecular Physiology, Mainz
4 University of Hamburg - Institute of Marine Ecosystem and Fisheries Sciences, Centre for Earth System Research and Sustainability, Hamburg
5 University of Constance, Limnological Institute, Constance
6 Christian-Albrechts-Universität zu Kiel, Zoological Institute, Kiel
7 GEOMAR Helmholtz Centre for Ocean Research, Kiel

 

Surprising behavior in one of the least studied mammals in the world


Peer-Reviewed Publication

UNIVERSITY OF SOUTHERN DENMARK

beaked whale 

IMAGE: 

BAIRDS BEAKED WHALE,  THE COMMANDER ISLANDS 

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CREDIT: OLGA FILATOVA, UNIVERSITY OF SOUTHERN DENMARK




Some animals live in such remote and inaccessible regions of the globe that it is nearly impossible to study them in their natural habitats. Beaked whales, of which 24 species have been found so far, are among them: They live far from land and in deep oceanic waters, where they search for food at depths of 500 meters and more.

The record holder for the deepest dive by a mammal is a Cuvier's beaked whale, which in 2014 was measured to dive at least 2992 meters. A beaked whale also holds the mammalian record for the longest dive; 222 minutes.

Now, the world gets a new and surprising insight into the world of distant beaked whales through a scientific study of a population of Baird's beaked whales. The population has unexpectedly been found near the coast and in shallower waters than previously observed.

The study is led by whale biologists Olga Filatova and Ivan Fedutin from the University of Southern Denmark/Fjord&Bælt, and it is published in the journal Animal Behaviour.

Filatova and Fedutin have many years of whale studies in the northern Pacific behind them, and it was during an expedition to the Commander Islands in 2008 that they first saw a group of Baird's beaked whales near the coast.

"We were there to look for killer whales and humpback whales, so we just noted that we had seen a group of Baird's beaked whales and didn't do much about it. But we also saw them in the following years, and after five years, we suspected that it was a stable community frequently visiting the same area. We saw them every year until 2020, when Covid 19 prevented us from going back to the Commander Islands," explains Olga Filatova, a whale expert and postdoc at Department of Biology and SDU Climate Cluster, University of Southern Denmark.

The studied population of Baird's beaked whales came close to the coast - within four km from land, and they were observed in shallow water; less than 300 meters.

"It is uncharacteristic for this species," says Olga Filatova, who also points out that the population likely has adapted to this particular habitat and thus deviates from the established perception that all beaked whales roam far out at sea and in deep waters.

"It means that you cannot expect all individuals within a specific species to behave the same way. This makes it difficult to plan species protection - in this case, for example, you cannot plan based on the assumption that beaked whales only live far out in deep sea. We have shown that they can also live in shallow and coastal waters. There may be other different habitats that we are not aware of yet," says Olga Filatova.

There are many examples of individuals from the same whale species not behaving the same. In the whale world, it is common to find groups of the same species living in different places, eating different prey, communicating differently, and not liking to mingle with fellow species in other groups.

Some killer whale groups only hunt marine mammals like seals and porpoises, others only herring. Some humpback whales migrate between the tropics and the Arctic, others are residents in certain areas. Some sperm whale groups develop their own dialects for internal communication and do not like to communicate with others outside the group.

According to Olga Filatova, social learning is at play when groups develop preferences for, for example, habitats and prey.

There are many forms of social learning in the animal world. Imitation is the most complex form; the animal sees what others do and understands the motivation and reasoning behind it. Then there is "local enhancement," where an animal sees another animal heading to a specific place, follows, and learns that the place has value. This has been observed in many animals, including fish.

Olga Filatova believes that the population of Baird's beaked whales at the Commander Islands learns through "local enhancement": They see that some peers go to the shallow water near the coast, follow, and discover that it is a good place, probably because there are many fish.

"It becomes a cultural tradition, and it is the first time a cultural tradition has been observed among beaked whales," she says.

Other examples of cultural traditions in whales include when they develop specific hunting traditions: some slap their tails to stun fish, some generate waves to wash seals off ice floes, some chase fish onto the beach.

The researchers observed a total of 186 individuals of the Baird's beaked whale species at the Commander Islands from 2008-2019. 107 were only observed once and thus assessed to be transient whales. 79 individuals were spotted for more than one year and were thus assessed to be residents.

61 of the transient whales were seen interacting with the residents, and seven of them were seen in shallow water.

"The transients are not as familiar with local conditions as the residents, and therefore, they usually seek food at the depths that are normal for their species. But we actually observed some transients in the shallow area. These were individuals who had some form of social contact with the residents. It must be in that contact that they learned about the shallow water and its advantages," says Olga Filatova.

It is unclear how many Baird's beaked whales exist in the world.

The study was supported by Rufford Small Grants, Whale and Dolphin Conservation, Animal Welfare Institut and Russian Fund for Fundamental Research. Olga Filatova's research is also supported by Human Frontier Science Program.

 

A Baird's beaked whale off the Commander Islands. Two teeth can be seen in the lower jar. The body is covered by scars from fights with other beaked whales. 

Baird's beaked whales off The Commander Islands

CREDIT

Olga Filatova, University of Southern Denmark

Beaked whales We know 24 species of beaked whales, which belong to the toothed whales. Some are known only from strandings and skull finds, and photos of them are generally rare. Baird's beaked whale is the largest of the beaked whales, reaching a length of up to 10 meters. The female is slightly larger than the male. Both females and males have a characteristic underbite with two pairs of teeth in the lower jaw. 

 

Researchers show classical computers can keep up with, and surpass, their quantum counterparts


Researchers adopt innovative method to boost speed and accuracy of traditional computing


Peer-Reviewed Publication

NEW YORK UNIVERSITY




Quantum computing has been hailed as a technology that can outperform classical computing in both speed and memory usage, potentially opening the way to making predictions of physical phenomena not previously possible.

Many see quantum computing’s advent as marking a paradigm shift from classical, or conventional, computing. Conventional computers process information in the form of digital bits  (0s and 1s), while quantum computers deploy quantum bits (qubits) to store quantum information in values between 0 and 1. Under certain conditions this ability to process and store information in qubits can be used to design quantum algorithms that drastically outperform their classical counterparts. Notably, quantum’s ability to store information in values between 0 and 1 makes it difficult for classical computers to perfectly emulate quantum ones. 

However, quantum computers are finicky and have a tendency to lose information. Moreover, even if information loss can be avoided, it is difficult to translate it into classical information—which is necessary to yield a useful computation. 

Classical computers suffer from neither of those two problems. Moreover, cleverly devised classical algorithms can further exploit the twin challenges of information loss and translation to mimic a quantum computer with far fewer resources than previously thought—as recently reported in a research paper in the journal PRX Quantum.

The scientists’ results show that classical computing can be reconfigured to perform faster and more accurate calculations than state-of-the-art quantum computers.  

This breakthrough was achieved with an algorithm that keeps only part of the information stored in the quantum state—and just enough to be able to accurately compute the final outcome. 

“This work shows that there are many potential routes to improving computations, encompassing both classical and quantum approaches,” explains Dries Sels, an assistant professor in New York University’s Department of Physics and one of the paper’s authors. “Moreover, our work highlights how difficult it is to achieve quantum advantage with an error-prone quantum computer.”

In seeking ways to optimize classical computing, Sels and his colleagues at the Simons Foundation focused on a type of tensor network that faithfully represents the interactions between the qubits. Those types of networks have been notoriously hard to deal with, but recent advances in the field now allow these networks to be optimized with tools borrowed from statistical inference.  

The authors compare the work of the algorithm to the compression of an image into a JPEG file, which allows large images to be stored using less space by eliminating information with barely perceivable loss in the quality of the image.

“Choosing different structures for the tensor network corresponds to choosing different forms of compression, like different formats for your image,” says the Flatiron Institute’s Joseph Tindall, who led the project. “We are successfully developing tools for working with a wide range of different tensor networks. This work reflects that, and we are confident that we will soon be raising the bar for quantum computing even further.”

The work was supported by the Flatiron Institute and a grant from the Air Force Office of Scientific Research (FA9550-21-1-0236).

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PLUMBING

Innovative coating prevents limescale formation


Peer-Reviewed Publication

ETH ZURICH

Test object polystyrene beads on the grooved surface. 

IMAGE: 

TEST OBJECT POLYSTYRENE BEADS ON THE GROOVED SURFACE.

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CREDIT: JULIAN SCHMID / ETH ZURICH




Hot water tanks, washing machines, kettles: limescale forms in every domestic appliance that comes into contact with (hot) water – especially in areas where the water is hard, meaning high in calcium. Often the only thing that helps is to use vinegar or a special descaler to dissolve the rock-​hard deposits and restore the appliance’s functionality.

This is a nuisance in households – and an expensive problem in thermal power stations, for example those that generate electricity, where the formation of limescale is known as fouling. Heat exchangers are particularly prone to limescale, which greatly reduces the efficiency of the systems: a layer of limescale just one millimetre thick in the heat exchanger’s pipes reduces the efficiency of electricity production by approximately 1.5 percent. To compensate for these losses an additional 8.7 million tonnes of hard coal would have to be burned. That’s bad for the carbon footprint and the climate, and it’s expensive for the electricity producers.

Innovative limescale-​repellent surface

A research team from ETH Zurich and the University of California, Berkeley has now found a possible solution to this problem: a special limescale-​repellent coating with microscopically small ridges that prevent the adhesion of limescale crystals. The team’s study was recently published in the journal Science Advances.

Fundamental research into the development of limescale-​repellent surfaces has been sparse. So the researchers, led by former ETH Professor Thomas Schutzius, took a close look at the interactions among individual growing limescale crystals, the surrounding water flow and the surface at the microscopic level.

Based on this, Schutzius’ doctoral student Julian Schmid and other team members developed several coatings from various soft materials and tested them in the lab at ETH Zurich.

Hydrogel with microstructure is most effective

The most effective coating turned out to be a polymer hydrogel, the surface of which is covered in tiny ridges thanks to microtextured moulds, which the researchers fabricated using photolithography.

The hydrogel’s microstructure is reminiscent of natural models such as shark scales, which also have a ribbed structure to suppress fouling on the sharks’ skin.

In kettles or boilers, the riblets ensure that the limescale crystals have less contact with the surface, meaning they can’t adhere and are thus easier to remove; water flowing over the hydrogel and through the ribbed structure carries them away. While the coating can’t fully prevent limescale crystals from forming, the constant passive removal of the microscopic crystals stops them growing together to form a tenacious layer.

In producing the different coatings, the researchers primarily varied the polymer content. The lower the polymer content and the higher the water content, the less well the calcium carbonate crystals adhere to the surface.

Tests with model particles made of polystyrene show that the coating’s surface structures must be smaller than the particles that are deposited on it. This reduces the contact surface and thus the adhesive force. “We varied the material’s surface structure to achieve the greatest efficiency, then carried out the crystal experiments with this optimum structure size,” Schmid says.

The team’s experiments show that the hydrogel coating is very effective: when water flowed across the hydrogel-​coated surface, on which limescale crystals with a size of around 10 micrometres had previously been grown, up to 98 percent of the crystals were removed.

Eco-​friendly solution

The researchers emphasise that their solution is more eco-​friendly and more efficient than existing approaches to descaling, some of which involve toxic and aggressive chemicals. In contrast, the hydrogel is biocompatible and environmentally friendly. The technology behind this solution should also be scalable: the coating could be applied in various ways that are already in use in industry today.

Rather than applying for a patent for their development, the researchers have deliberately decided in favour of publication in a scientific journal. This means that all interested parties are free to further develop and utilise the new coating.

Schutzius received an ERC Starting Grant for this research in 2019. He no longer works at ETH Zurich, and is now an assistant professor of mechanical engineering at UC Berkeley.

Test set-​up with which the researchers tested how lime crystals adhere to different surfaces.

Only a few micrometer-​sized lime crystals on the grooved surface under the electron microscope.

CREDIT

Julian Schmid / ETH Zurich

 

When nanoplastics are not what they seem


Release of oligomers from polyester textiles

Peer-Reviewed Publication

SWISS FEDERAL LABORATORIES FOR MATERIALS SCIENCE AND TECHNOLOGY (EMPA)

Bernd Nowack 

IMAGE: 

RESEARCHERS LED BY BERND NOWACK HAVE INVESTIGATED THE RELEASE OF NANOPARTICLES DURING THE WASHING OF POLYESTER TEXTILES.

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CREDIT: EMPA




Plastic household items and clothing made of synthetic fibers release microplastics: particles less than five millimetres in size that can enter the environment unnoticed. A small proportion of these particles are so small that they are measured in nanometers. Such nanoplastics are the subject of intensive research, as nanoplastic particles can be absorbed into the human body due to their small size – but, as of today, little is known about their potential toxicity.

Empa researchers from Bernd Nowack's group in the Technology and Society laboratory have now joined forces with colleagues from China to take a closer look at nanoparticles released from textiles. Tong Yang, first author of the study, carried out the investigations during his doctorate at Empa. In earlier studies, Empa researchers were already able to demonstrate that both micro- and nanoplastics are released when polyester is washed. A detailed examination of the released nanoparticles released has now shown that not everything that appears to be nanoplastic at first glance actually is nanoplastic.

To a considerable extent, the released particles were in fact not nanoplastics, but clumps of so-called oligomers, i.e. small to medium-sized molecules that represent an intermediate stage between the long-chained polymers and their individual building blocks, the monomers. These molecules are even smaller than nanoplastic particles, and hardly anything is known about their toxicity either. The researchers published their findings in the journal Nature Water.

For the study, the researchers examined twelve different polyester fabrics, including microfiber, satin and jersey. The fabric samples were washed up to four times and the nanoparticles released in the process were analyzed and characterized. Not an easy task, says Bernd Nowack. "Plastic, especially nanoplastics, is everywhere, including on our devices and utensils," says the scientist. "When measuring nanoplastics, we have to take this 'background noise' into account."

Large proportion of soluble particles

The researchers used an ethanol bath to distinguish nanoplastics from clumps of oligomers. Plastic pieces, no matter how small, do not dissolve in ethanol, but aggregations of oligomers do. The result: Around a third to almost 90 percent of the nanoparticles released during washing could be dissolved in ethanol. "This allowed us to show that not everything that looks like nanoplastics at first glance is in fact nanoplastics," says Nowack.

It is not yet clear whether the release of so-called nanoparticulate oligomers during the washing of textiles has negative effects on humans and the environment. "With other plastics, studies have already shown that nanoparticulate oligomers are more toxic than nanoplastics," says Nowack. "This is an indication that this should be investigated more closely." However, the researchers were able to establish that the nature of the textile and the cutting method – scissors or laser – have no major influence on the quantity of particles released.

The mechanism of release has not been clarified yet either – neither for nanoplastics nor for the oligomer particles. The good news is that the amount of particles released decreases significantly with repeated washes. It is conceivable that the oligomer particles are created during the manufacturing of the textile or split off from the fibers through chemical processes during storage. Further studies are also required in this area.

Nowack and his team are focusing on larger particles for the time being: In their next project, they want to investigate which fibers are released during washing of textiles made from renewable raw materials and whether these could be harmful to the environment and health. "Semi-synthetic textiles such as viscose or lyocell are being touted as a replacement for polyester," says Nowack. "But we don't yet know whether they are really better when it comes to releasing fibers.

The nanoparticles on the surface of the fleece fiber are visible under a scanning electron microscope (a). The particles detach during washing (b), so that after four washes there are hardly any left.

CREDIT

Empa