Tropical Indian Ocean warming: A key player shaping the Hadley Circulation

Science China Press

 

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Researchers focus on changes in (A) Southern and (B) northern Hadley cell extent (LatSHC and LatNHC), (C) ITCZ position (LatITCZ), and (D) Northern Hadley cell intensity (IntensityNHC; units, 1010kg∙s-1) during boreal winter (December-January-February, DJF).

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Credit: ©Science China Press

The Role of Hadley Circulation and Its Recent Changes

The Hadley Circulation (HC) plays a crucial role in distributing heat and moisture around the planet. Over recent decades, surface warming has caused the HC to expand poleward, expanding subtropical arid zones toward mid-latitudes and impacting ecosystems. This trend has become a topic of public concern, prompting the Intergovernmental Panel on Climate Change (IPCC) to dedicate sections of its reports to HC’s changes and their impacts. While there is a consensus that HC may weaken and continue expanding under climate change, substantial uncertainties persist in future projections.

Understanding the Impacts of Rapid Ocean Warming on Climate

With sea surface temperatures (SST) reaching record highs and projected to rise further due to greenhouse gas emissions, scientists are keen to understand how these changes will affect climate systems. The CLIVAR program of the World Climate Research Program’s (WCRP) has highlighted this issue, emphasizing the importance of understanding regional ocean warming effects on HC. However, HC's sensitivity to changes in individual ocean basins remains an open question.

Multi-Model Analysis: Linking SST warming and HC’s Future Changes and uncertainty

By examining a broad range of climate model simulations, researchers have confirmed that the future expansion of the HC, shifts in its ascending branch—the Intertropical Convergence Zone (ITCZ)—and uncertainties in HC intensity are all closely linked to variations in SST (Fig. 1). This result prompted the team to investigate the specific contributions of individual ocean basins to HC changes, uncovering key regional influences of HC behavior and associated uncertainties.

Idealized Warming Experiments: Identifying Critical Ocean Basins Driving Future HC Changes

Through a series of idealized ocean warming experiments, researchers identified the ocean basins most influential in shaping future changes to the HC. By systematically analyzing HC’s responses to incremental warming across various ocean regions, the study identified the tropical Indian Ocean (TIO), tropical Pacific Ocean (TPO), North Atlantic (NA), and South Atlantic (SA) as potentially crucial drivers of future changes in HC and uncertainty (Fig. 2).

Paris Agreement Threshold Simulations: Distinct Basin Responses and Uncertainties

Using 430 large ensemble simulations at warming thresholds of 1.5°C, 2°C, and 3°C, researchers assessed HC’s sensitivity to SST warming patterns in these basins (animated Fig.3). The results revealed distinct responses: TIO warming drives significant HC weakening and a poleward shift, while NA and SA warming affect the ITCZ in opposite directions. TIO and SA warming exert contrasting effects on HC intensity which decreases as TIO warms and increasing with SA warming. Notably, a significant model spread in TPO warming pattern emerged as the main source of uncertainty in HC projections (Fig.4). Finally, the study explained the mechanisms driving HC's different responses to future warming in the four ocean basins (figures omitted; see main text for details).

Innovations and Impacts: Toward Improved Climate Models and Policy Guidance

This study is the first to definitively establish the TIO as the primary driver of HC’s future weakening and poleward shifts, with the TPO as the main source of uncertainty in HC projections. These insights help advance Earth system modeling and strengthen our ability to predict changes in tropical atmospheric circulation. They also provide a scientific basis for monitoring early warnings related to HC changes, which can support key decision-making.

Lead author Dr. Sun Yong from the Institute of Tibetan Plateau Research, Chinese Academy of Sciences (ITPCAS), emphasizes that this study not only elucidates the distinct role of tropical ocean warming in shaping future atmospheric circulation but also contributes to the CLIVAR program's mission. As one of the six core projects under the WCRP, CLIVAR has primarily focused on the impacts of historical climate patterns, such as the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillation (AMO), on regional climates. This study addresses a notable gap by concentrating on basin-specific designs that consider the effects of future ocean warming.

The study, entitled "Tropical Indian Ocean Drives Hadley Circulation Change in a Warming Climate," was led by Dr. Sun Yong (ITPCAS), with contributions from Professor Ramstein Gilles (LSCE), Professor Fedorov Alexey (Yale University), Professor Ding Lin (ITPCAS), and Professor Liu Bo (Chengdu University of Information Technology). The research is published in National Science Review (Paper link: https://doi.org/10.1093/nsr/nwae375).

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See the article:

Tropical Indian Ocean drives Hadley circulation change in a warming climate

 https://doi.org/10.1093/nsr/nwae375

 (red).

The spatial patterns of projected SST changes at the 1.5°C and 2°C thresholds in the RCP4.5 scenario, as well as the 3°C threshold in the RCP8.5 scenario, are compared to the present-day baseline (1986–2005). These SST patterns serve as forcings for individual ocean basin experiments targeting 1.5°C, 2°C, and 3°C warming thresholds in different CMIP5 models.

Journal

National Science Review

DOI

10.1093/nsr/nwae375 

 

Transplanting healthy reef ecosystems to damaged reefs improves coral health

Innovative study led by Bar-Ilan University raises hope for coral reef restoration by transplanting vibrant invertebrate and microbial communities to damaged reefs in the Red Sea

Bar-Ilan University

 

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A healthy reef site in the southern part of the Gulf of Eilat/Aqaba

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Credit: Meron Segev

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A pioneering study has revealed significant improvements in coral health through an innovative approach of transplanting healthy reef ecosystems to damaged reefs. The study offers new hope for coral reef restoration and the fight against widespread coral decline.

The study, just published in the journal Nature Communications, was led by Dr. Natalie Levy and Prof. Oren Levy from Bar-Ilan University’s Mina and Everard Goodman Faculty of Life Sciences, in collaboration with Prof. Ezri Tarazi of the Technion – Israel Institute of Technology, and Prof. David Bourne of James Cook University and the Australian Institute of Marine Science.

The study introduces a method known as "a coral reef ecosystem transplant" (aCRET), where researchers transferred biomimetic terracotta tiles embedded with a diverse community of organisms—including invertebrates and beneficial microorganisms—from a healthy reef to a nearby damaged reef. The corals from the damaged reef were then attached to these tiles. The results demonstrated notable improvements in coral health, including increased photosynthetic efficiency, higher populations of symbiotic algae, and reduced stress levels. These findings suggest that transplanting a healthy ecosystem can significantly boost coral resilience and physiological function.

The researchers designed the biomimetic terracotta tiles to replicate the complex 3D structure of natural coral reefs, providing a perfect environment for diverse organisms to thrive. After allowing the organisms to grow on the tiles for six months, the tiles—along with their rich, biologically active substrate—were transported to the damaged reef located six km away. Following an additional six months, corals on these tiles showed substantial improvements compared to corals grown on tiles with substrate from the damaged reef. In a parallel experiment, the researchers confirmed that the transfer of substrate from a damaged reef to a healthy reef produced less favorable results, reinforcing the benefits of the healthy reef ecosystem transplant.

"This innovative approach underscores the critical role of healthy reef ecosystems in restoring coral health and resilience," said Dr. Natalie Levy, lead researcher of the study. "The results highlight the potential of ecosystem transplantation as an effective, sustainable restoration tool that can be integrated with other coral restoration methods like coral gardening and artificial reefs."

The study’s findings point to aCRETs as a viable and flexible solution for coral reef restoration globally, especially in areas facing significant environmental stress. This cost-effective technique could complement and enhance existing restoration strategies, helping to protect and restore coral ecosystems vital for marine biodiversity. However, the researchers stress that for the best outcomes, local reefs should be selected as close as possible for transplanting, and additional long-term studies are essential to fully understand the ecological impacts on different coral species and reef environments.

"This research advances our understanding of coral restoration and provides an invaluable tool to help address the ongoing global coral crisis," said Prof. Oren Levy. "By using healthy ecosystems to regenerate damaged reefs, we can work towards more resilient, sustainable coral ecosystems that may one day recover from climate change and other threats."

This pioneering study paves the way for a new wave of coral conservation efforts and offers hope for reversing the alarming degradation of coral reefs worldwide.

A healthy reef site in the southern part of the Gulf of Eilat/Aqaba 

A healthy reef site in the southern part of the Gulf of Eilat/Aqaba 

3D ceramic tiles with coral fragments in the healthy site in the Gulf of Eilat/Aqaba. These tiles, exhibiting high complexity, are similar to those used in this current work .

Credit

Meron Segev

Journal

Nature Communications

Article Title

Ecosystem transplant from a healthy reef boosts coral health at a degraded reef

 

Researchers show complex relationship between Arctic warming and Arctic dust

Nagoya University

 

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As the Arctic warms, dust from snow- and ice-free areas increases. It promotes the formation of ice crystals in clouds, making clouds thinner.

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Credit: Reiko Matsushita

The Arctic is warming two to four times faster than the global average. A recent study by researchers in Japan found that dust from snow- and ice-free areas of the Arctic may be an important contributor to climate change in the region. The findings were published in the journal npj Climate and Atmospheric Science.

According to one view, higher temperatures in the Arctic are thought to lead to the region's clouds containing more liquid droplets and fewer ice crystals. Clouds become thicker, longer lasting, and more likely to reflect sunlight. As a result, this might cool the region during summer (temperature feedback).

However, the new study showed that as the Arctic warms, snow- and ice-free areas increase, leading to an increase in dust emissions. The dust promotes the formation of ice crystals in the clouds. It is possible that more ice crystals in the clouds are making the clouds thinner and shorter-lived, thus reflecting less sunlight, which might heat the region during summer (emission feedback).

"Increasing amounts of dust due to Arctic warming may cause the opposite phenomenon of the conventional understanding of ice crystal changes," said Associate Professor Hitoshi Matsui of Nagoya University, the lead author of the study. "Our previous study found that a large amount of Arctic dust is distributed in the lower troposphere (below about 3 km altitude) over the region in summer and early fall, with the dust acting as a very efficient nucleus for ice formation in clouds at this altitude during the season."

To estimate the impact of Arctic dust on the clouds of the region, Matsui and Dr. Kei Kawai of Nagoya University, in collaboration with researchers from the National Institute of Polar Research and Hokkaido University, conducted a study using the CAM-ATRAS global aerosol-climate model.

They first looked at changes in the amount of dust released from the Arctic land surface over the past 40 years, between 1981 and 2020. The simulations showed that dust emissions increased by 20% during this period as the Arctic warmed. This increase promotes ice nucleation in clouds in the lower troposphere, weakening the efficiency of clouds to contain more liquid droplets and fewer ice crystals as the Arctic warms. Increased dust levels promote ice crystal formation, outweighing the decrease in ice crystal formation by the temperature feedback in 30% of the region annually and 70% in summer.

"Most climate models have not considered the effects of dust from the Arctic land surface," Matsui said. "Our research suggests that the counterbalancing temperature and emission feedbacks should be considered to improve the accuracy of climate change predictions in the Arctic."

 

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Journal

npj Climate and Atmospheric Science

DOI

10.1038/s41612-024-00811-1 

Method of Research

Computational simulation/modeling

Article Title

Increasing Arctic dust suppresses the reduction of ice nucleation in the Arctic lower troposphere by warming

 

Researchers discover key gene that affects rice leaf growth and methane emissions

Hefei Institutes of Physical Science, Chinese Academy of Sciences

 

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Phenotypic Analysis of SM1 Mutant 

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Credit: YE Yafeng

A research team led by Dr. WU Yuejin from the Hefei Institutes of Physical Science of the Chinese Academy of Sciences, discovered that the SM1 gene plays a crucial role in the development of rice leaf veins and affects methane emissions from rice plants.

Their findings were published in Plant Science.

Rice leaf veins are essential for the plant's growth and development. They help support the leaves and transport important substances like water, gases, and nutrients throughout the plant. However, scientists didn't fully understand molecular underlying mechanism how these veins form and develop.

In this study, the team used ion beam mutagenesis technology and identified a rice mutant, which leaf veins become solid instead of hollow. These mutant plants were shorter and had 49% less dry weight compared to their wild type plants. Through further research, the team identified a key gene, named SM1, that plays a crucial role in controlling the development of rice leaf veins.

The SM1 gene encodes a litter zipper protein that interacts with another protein, OSHB1, to regulate the expression of OSH1, which controls the growth of the plant's stem cells. This interaction affects how the rice plant's vascular system develops.

Researchers also discovered that in the mutant plants, the solid veins were filled with different types of cells, which limited the plant's ability to transport oxygen to its roots. This led to enhanced methanogenic activity in the rhizosphere and a 96.8% increase in total methane emissions.

This research highlights the importance of the rice plant's vascular system in both growth and methane emissions. It also provides new ideas for rice breeding. 

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Journal

Plant Science

DOI

10.1016/j.plantsci.2024.112312 

Article Title

Mutation of rice SM1 enhances solid leaf midrib formation and increases methane emissions

 

Delay and pay: Tipping point costs quadruple after waiting

Reversing climate change grows more costly the longer you wait, with costs quickly quadrupling immediately after tipping points are crossed

DOE/Pacific Northwest National Laboratory

RICHLAND, Wash. —Tip the first tile in a line of dominoes and you’ll set off a chain reaction, one tile falling after another. Cross a tipping point in the climate system and, similarly, you might spark a cascading set of consequences like hastened warming, rising sea levels and increasingly extreme weather. 

It turns out there’s more to weigh than catastrophic environmental change as tipping points draw near, though. Another point to consider, a new study reveals, is the cost of undoing the damage. 

The cost of reversing the effects of climate change—restoring melted polar sea ice, for example—quickly climbs nearly fourfold soon after a tipping point is crossed, according to new work published today in the journal npj Climate and Atmospheric Science. Much work has been done to explore the environmental costs tied to climate change. But this new study marks the first time researchers have quantified the costs of controlling tipping points before and after they unfold. 

Common examples of Earth’s tipping points include melting ice sheets and dwindling tropical coral reefs. As ice melts and reefs die off, drastic environmental effects like flooded coastal cities and lost biodiversity soon follow—a shared trait among what the Intergovernmental Panel on Climate Change defines as “critical thresholds in a system that, when exceeded, can lead to a significant change in the state of the system.” 

Despite the well-established dangers of crossing a tipping point, little is known about the cost of controlling them. How much effort would it take to stop and reverse course just before crossing a tipping point? 

In the case of polar sea ice, which is melting at a pace unrivaled by any period in the past 1,500 years, a reversal would entail halting melt and reestablishing ice cover. But how about after we tip—how might the cost of intervention change if we wait? 

Cross a tipping point threshold, said mathematician and lead author Parvathi Kooloth, and it costs nearly four times the effort to reverse the effects and reestablish the climate system to where it was just before tipping, as opposed to reversing course before the threshold. The message applies to most tipping points, said Kooloth, whether they involve tropical coral reefs or frigid sea ice. 

“You either shoulder the cost now, just before the threshold is crossed,” said Kooloth, “or you wait. And if you wait, the degree of intervention needed to bring the climate system back to where it was rises steeply. A key insight from this work is the confirmation that corrective action after the fact is much more costly and intrusive than preventive action.”

Each tipping point is unique. The physical qualities that determine its behavior—the extent of cloud cover or, say, the transport of heat in the nearest ocean waters—determine how post-tipping changes take shape in the climate system. In turn, those qualities dictate the nuts and bolts of an actual intervention strategy.

At the heart of each tipping point, however, is a shared, core equation that describes its basic nature. This universality allows researchers like Kooloth to probe the fundamental, shared behavior of tipping points using simplified mathematical models. 

From their findings, scientists can then glean broad stroke details that could inform future intervention plans and perhaps, as Kooloth hopes, even a way to identify early warning signals that a tipping point is drawing near.

 “It’s actually really hard to pin a tipping point down,” said Kooloth. “We know a great deal about the climate system today. But even now we’re never really sure how far or close we are to a tipping point. Could we one day use observable precursors to provide early warning? My hope is that we can.” 

The team behind the new study uncovered one other interesting phenomenon: that some tipping points have an “overshoot window.” In this window of time just after a tipping point is crossed, the cost of intervention doesn’t start its steep climb right away. Instead, cost only grows linearly with time. This can happen because nearby ocean waters take longer to heat up, for example, delaying the onset of rapid change. 

It’s a fortunate thing, Kooloth points out, a gift of additional time before dire changes start piling on. But this is “no free lunch,” she adds. The extra leeway comes with an even steeper increase in intervention costs once the overshoot window is fully crossed. The bigger the overshoot window, the mightier the cost. 

The authors point out that not all effects of climate change are reversible, like flora and fauna lost to rapid and prolonged environmental change. And some effects could demand a great deal of effort to reverse—even more than the effort it took to push the climate system past a tipping point. 

There is an asymmetry at play, said Kooloth. We could approach and pass a tipping point rather quickly, but the journey to revert the climate system to where it was could take much, much longer. 

“The path forward and the path backward are often not the same,” said Kooloth. “Imagine that we go down a high-emissions pathway, where the planet warms enough to melt all our sea ice by the end of the century. If we arrive in the year 2100 with no sea ice, it may not be sufficient to bring the ice back if we dialed our emissions down to the levels we’re emitting now in 2024, when we still have some ice left. We may need to dial emissions down much further, to levels predating 2024—that asymmetry is important for us to consider as we choose our path forward.” 

This work, “How Optimal Control of Polar Sea-ice Depends on its Tipping Points,” was supported by the Department of Energy’s Office of Science. In addition to Kooloth, other Pacific Northwest National Laboratory coauthors include Jian Lu, Craig Bakker, and Adam Rupe. Derek DeSantis of Los Alamos National Laboratory is also a coauthor. 

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Journal

npj Climate and Atmospheric Science

DOI

10.1038/s41612-024-00768-1 

Method of Research

Computational simulation/modeling

Article Title

How Optimal Control of Polar Sea-ice Depends on its Tipping Points

Article Publication Date

26-Nov-2024

 

Sports betting and financial market data show how people misinterpret new information in predictable ways

In a new paper published in the Quarterly Journal of Economics, researchers found an interesting pattern in how people interpret new information.

University of California - Berkeley Haas School of Business

Let’s say it’s a home game for the Golden State Warriors and Steph Curry shows he’s still got it, sinking back-to-back three-pointers minutes into the first quarter. The fans at Chase Center take notice, and so do the betting markets, where the odds move in the Warriors’ favor.

Yet it’s a long game. The away team comes back, and with just 10 seconds to go, the Warriors are down by two and have just missed a shot. A victory is unlikely, and the betting odds should have shifted to reflect that near-certainty. But they don’t.

“If you look at the history of NBA games, the probability that a team with the ball, up by two with 10 seconds left, wins is north of 90%,” says Eben Lazarus, an assistant professor of finance at UC Berkeley’s Haas School of Business. “But what shows up in the betting markets is that people treat baskets as too similar over the course of the game. They overreact to information that’s not very important—early baskets—and underreact to strong signals at the end.”

This interesting pattern in how people interpret new information holds true across a range of settings, from sports betting to financial markets, according to a new paper published in the Quarterly Journal of Economics. Lazarus and coauthors Ned Augenblick from UC Berkeley Haas and Michael Thaler of University College London conducted three experiments and analyzed millions of betting transactions and prices on options contracts, and found that people consistently overreact to weak information and underreact to strong information.

“There are all kinds of situations where I might know whether piece of news is good or bad, but struggle to judge exactly how important it is,” Lazarus says. “We saw this pattern everywhere we looked, which was surprising to us given the stakes involved in betting and financial markets.”

Building on decades of behavioral science and economics research

Lazarus and his coauthors wanted a way to unify different theories about how people act in ways that aren’t quite rational when processing new information. The study builds on decades of behavioral psychology and economics research about how people update their beliefs given new information, dating back to a classic 1966 paper arguing people are overly cautious in updating, and a 1992 paper by Dale Griffin and Amos Tversky showing people tend to overfocus on information that seems dramatic but give less weight to how reliable it is.

More recent papers have shown that people make systematic errors as a result of mistakes in calculating probabilities, and when people are uncertain about what decision to make they tend to pick a middle-ground option. The paper also connects to studies looking at how financial markets sometimes overreact and sometimes underreact to news.

“We think that we have a simple framework for thinking systematically through a lot of situations in the financial markets and the real world,” he says.

As humans, we take in information all the time, whether it’s a new poll that favors our preferred candidate or feedback from a boss. The researchers theorized that most of the time we don’t have the information to accurately judge just how important that information is, so we tend default to a middle ground.

“In cases where it’s easy to figure out which direction to update your beliefs, but not quite how much you should update, people will tend to treat all ‘good’ information somewhat similarly,” he says. “Given this difficulty, you’re going to see people overreacting to news that’s fairly weak and underreacting to news that should move you close to certainty.”

Experimental evidence

The research team first tested their theory in lab experiments, including both a classic experiment involving determining which deck a particular card came from and a novel sports-related experiment where they recruited 500 NBA fans and presented them with sequences of events in a simulated basketball game. The simulations started with 2:40 left in each quarter, and participants then saw a sequence of four possessions. After each possession, participants had to predict the probability of each team winning (they could earn a $50 bonus based on their accuracy).

The researchers established the “correct” probabilities of wins in each scenario using data from the website inpredictable.com. But they found that while people understood that late-game baskets were more important than those scored early in the, they still overreacted to first-quarter baskets—giving them 60% more importance than they should—and underweighted fourth-quarter baskets by 33%.

“This gave us a good sense that people were over- or under-reacting to information in experiments, but we needed to come up with some ways to test this in higher-stakes settings in the real world,” Lazarus says.

Sports betting data from Betfair

To do that, the research team turned to sports prediction market Betfair, analyzing over 5 million betting transactions across 260,000 basketball, soccer, football, and ice hockey games. Since the researchers had no way to determine the “correct” probability of a win with certainty, they developed a new empirical method to measure whether prices were over- or underreacting to information. Again, they found that early in games, events like scores created bigger shifts in betting odds than they should have, given the high uncertainty about the outcome. Meanwhile, important events like fourth-quarter goals caused smaller shifts in the market than is justified.

Data from options markets

Lazarus and his coauthors also tested their theory in a sophisticated financial market, using option price quotes for S&P index options traded on the Chicago Board Options Exchange from 1996 to 2018. After applying multiple filters, they had over 4 million option prices corresponding to 955 expiration dates. To give a clear time horizon, they focused on those expiring in 100 trading days (~4.5 months).

They found the same pattern they observed in the sports betting market.

“…News today appears to hold relatively little information about the value of the S&P in multiple months, but the market acts as if it (does),” the authors write. “However, within two weeks of a contract’s resolution, the relationship reverses…as signals become stronger, the market begins to underreact.”

Real-world implications

While the research explains some puzzling patterns in how people and markets respond to news, Lazarus cautions that being aware of these patterns does not remove all risk.

“It’s still not a free lunch if you know that on average markets are underreacting or overreacting at different points in time,” he says. “You can still lose a lot of money if you bet against these moves.”

Still, the findings suggest that it’s wise to pay attention to how much weight to give different pieces of information, even in situations that are far more ambiguous.

“Let’s say I have a negative interaction with my boss and I’ve spent all week fretting about it,” he says. “How important is it really for my future at this company? I think people would do well to take that step back and think about how much to react.”

About the paper

Overinference from Weak Signals and Underinference from Strong Signals
By Ned Augenblick, Eben Lazarus, and Michael Thaler
The Quarterly Journal of Economics, October 14, 2024

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Journal

The Quarterly Journal of Economics

DOI

10.1093/qje/qjae032 

Method of Research

Data/statistical analysis

Subject of Research

People

Article Title

Overinference from Weak Signals and Underinference from Strong Signals

A complex structure created by Neanderthals discovered in Gibraltar

 News Release 26-Nov-2024
University of Seville

All cultures, however primitive, have used glues, resins and pitches obtained from various plants for their mechanical or medicinal properties. Neanderthals were no exception.

This species commonly used birch pitch as an adhesive to bind lithic pieces and even as a chewing agent, possibly medicinal.

However, until now, it was not known how they could obtain this pitch.

Theoretical work distinguished two methods of obtaining pitch: a simple, not very productive one, by open-air combustion of birch bark, and a more complex one requiring anoxic heating of birch chips.

That is, using buried pieces of wood heated with a fire so that they exuded the resin while they could not burn because they were insulated from oxygen.

Whether they used one method or the other has major implications for rating their cognitive ability. The more complex method requires a significant degree of organisation and practice.

Caves that are a reflection of the past

A scientific study, involving the University of Seville, has for the first time described a structure compatible with theoretical studies of anoxic heating.

The structure looks like a simple pit, and this simplicity may be why this structure has not been identified.

Only through a multitude of analyses and the collaboration of a multidisciplinary team has it been possible to demonstrate its use as an anoxic heating chamber.

The discovery was made in Vanguard Cave (Gibraltar, UK), part of the ‘Gorham’s Caves Complex,’ which has been recognised as a UNESCO World Heritage Site since 2016.

This complex has once again proved its ability to preserve authentic snapshots of past human activities due to the rapid advance of a dune that has sealed its remains.

To reach the conclusion that this structure could only have been made by Neanderthals some 60,000 years ago, 31 researchers from more than 5 countries, specialists in 15 different disciplines, worked together.

Its branches of knowledge include palaeobonatics, archaeology, ichnology, geochemistry and mineralogy.

“They were not the brutes of the popular imagination”

Fernando Muñiz, a lecturer in the Department of Crystallography, Mineralogy and Agricultural Chemistry at the University of Seville, explains that “our extinct cousins were not the brutalised humans of popular imagination.”

This human species has been shown to have cognitive abilities, as reflected in research showing mastery of industrial processes for making resin as an adhesive to attach stone points to spear handles.

On the other hand, excavation manager Clive Finlayson explains that:

“Neanderthals had to go through a series of thought processes, choosing which plants to select and figuring out how to extract resin without burning them.”

To demonstrate that the structure created by Neanderthals is viable, methodologies have been developed and an experimental archaeology exercise has even been completed.

The geochemical and fossil pollen evidence suggests that the resin was obtained from prickly rockrose (cistus ladanifer) rather than birch, a rarer tree in Mediterranean latitudes at the time.

It is known that until the 20th century oil of labdanum was obtained from rockroses to be used as perfume, cough syrup and as an antiseptic in a method very similar to the one described in this study.

This project, led by the Museum of Gibraltar, the University of Murcia and the Andalusian Institute of Earth Sciences (CSIC), with the participation of the University of Seville, sets a precedent in understanding of the technological and organisational capacity of Neanderthals, while also opening up new opportunities to identify and analyse similar structures at other sites.

Signs of primitive art

In 2012, Finlayson’s team found a strange hashtag-like mark on a piece of limestone, which has interpreted by some experts as a sign of primitive art.

They collected feathers, but only black ones, from a wide variety of birds, possibly for aesthetic or ceremonial purposes.

“They used medicinal plants, buried their dead, made jewellery and specialist tools, as well as ochre and other pigments, perhaps to paint their faces or bodies.

Their tracheal anatomy suggests that they could speak and probably had high-pitched, hoarse voices,” Muñiz says.

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Journal

Quaternary Science Reviews

DOI

10.1016/j.quascirev.2024.109025 

Article Title

A Neanderthal's specialised burning structure compatible with tar obtention