Earthquake scientists have a new tool in the race to find the next big one

An everyday quirk of physics could be an important missing piece in scientists' efforts to predict the world's most powerful earthquakes.

In a study published in the journal Science, researchers at The University of Texas at Austin discovered that a frictional phenomenon could be key to understanding when and how violently faults move. That's because the phenomenon, which explains why it takes more effort to shove a heavy box from a standstill than it does to keep it moving, governs how quickly the fault surfaces bond together, or heal, after an earthquake. A fault that is slow to heal is more likely to move harmlessly, while one that heals quickly is more likely to stick until it breaks in a large, damaging earthquake.

The discovery could be key to understanding when, and how violently, faults move. That alone won't allow scientists to predict when the next big one will strike -- the forces behind large earthquakes are too complex -- but it does give researchers a valuable new way to investigate the causes and potential for a large, damaging earthquake to happen, the authors said.

"The same physics and logic should apply to all different kinds of faults around the world," said the study's co-lead author Demian Saffer, director of the University of Texas Institute for Geophysics at the Jackson School of Geosciences. "With the right samples and field observations we can now start to make testable predictions about how big and how often large seismic slip events might occur on other major faults, like Cascadia in the Pacific Northwest."

To make the discovery, researchers devised a test that combined rocks from a well-studied fault off the coast of New Zealand and a computer model, to successfully calculate that a harmless kind of "slow motion" earthquake would happen every few years because the clay-rich rocks within the fault are very slow to heal.

The rock samples the researchers tested were drilled from about half a mile under the seafloor in a fault in New Zealand. They squeezed the fault zone rocks in a hydraulic press and found that they were very slow to heal and slipped easily. When they plugged the rock data into a computer model of the fault, the result was a small, slow-motion tremor every two years, a near exact match with observations from the New Zealand fault.

The researchers think the clay-rich rocks, which are common at many large faults, could be regulating earthquakes by allowing plates to slip quietly past each other, which limits the buildup of stress. The discovery could be used to determine whether a fault is prone to slipping in large, damaging earthquakes, said study co-lead Srisharan Shreedharan, affiliate researcher at the University of Texas Institute for Geophysics and assistant professor at Utah State University.

"This doesn't get us any closer to actually predicting earthquakes, but it does tell us whether a fault is likely to slip silently with no earthquakes, or have large ground-shaking earthquakes," he said.

At Cascadia, there is little evidence of shallow, slow-motion tremors. That's one of the reasons the Pacific Northwest Seismic Network wants to place sensors across key areas of the fault. The new study gives them the framework to do so, said network Director Harold Tobin.

"We want to zero in on the processes in the shallow part of the fault because that's what governs the size of the tsunami," said Tobin, who was not part of the study. "Fault healing doesn't explain everything, but it does give us a window into the working of subduction zone faults that we didn't have before."

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Climate: Lessons from the latest global warming

56 million years ago, the Earth experienced one of the largest and most rapid climate warming events in its history: the Paleocene-Eocene Thermal Maximum (PETM), which has similarities to current and future warming. This episode saw global temperatures rise by 5-8°C. It was marked by an increase in the seasonality of rainfalls, which led to the movement of large quantities of clay into the ocean, making it uninhabitable for certain living species. This scenario could be repeated today. This is what a team from the University of Geneva (UNIGE) has revealed, thanks to the analysis of sediments taken from the deep waters of the Gulf of Mexico. These results can be found in the journal Geology.

The Paleocene-Eocene Thermal Maximum (PETM), which occurred 56 million years ago, is the largest and most rapid climatic disturbance of the Cenozoic era (65.5 million years ago to the present day). Exceptional both in terms of its amplitude (5-8°C increase) and its suddenness (5,000 years, a very short time on a geological scale), this episode was marked by a warming of temperatures on a global scale. It lasted for about 200 000 years and led to numerous marine and terrestrial extinctions.

It would have been caused by a high concentration of carbon dioxide -- the famous CO2 -- and methane in the atmosphere, two powerful greenhouse gases. As is the case currently, these gases may have been released by several phenomena, certainly in combination: the release of methane hydrates trapped on the seabed, the sudden and significant melting of the permafrost, and the injection of magma into the organic sediments of the western edge of Norway. The origin of these processes is still under debate. The impact of a meteorite and/or the effects of intense volcanic activity in the depths of the North Atlantic could be responsible.

A geological ''archive'' of unprecedented quality

Because of the many similarities between the PETM and the current warming, the geological remains of this period are being closely studied by scientists. A team from the UNIGE is now reporting new elements. ''The objective of our study was to investigate the influence of these climatic changes on sedimentary systems, i.e. on the processes of sediment formation and deposition, and to understand how these changes could have been transmitted from the atmosphere to the depths of the ocean,'' explains Lucas Vimpere, a post-doctoral scholar at the Section of Earth and Environmental Sciences of the UNIGE's Faculty of Science and first author of the study.

The researchers analysed sediments taken from more than 8km deep in the Gulf of Mexico. This basin acts as a giant ''sink'' into which material eroded and transported from the North American continent over millions of years is discharged. ''For reasons of cost and infrastructure, the sediments used to study the PETM are generally taken from shallow marine or continental environments. Thanks to the collaboration of an oil company, we were able to obtain a sample of unprecedented quality, without any alteration'', says the researcher. The 543-metre-long core contains a 180-metre-thick PETM sedimentary record, making it the most complete geological ''archive'' of this period in the world.

More clay on the ocean floor

The UNIGE scientists found that it was composed first of a large layer of clay and then of a layer of sand, a counter-intuitive result. ''At the time of the PETM, we thought that there had been more precipitation, and therefore more erosion, and that large quantities of sand had then been transported first by the fluvial systems into the oceans. However, thanks to our sample, we were able to determine that it was the clays and not the sands that were transported in the first instance'', explains Sébastien Castelltort, full professor at the Earth and Environmental Sciences Section of the UNIGE Faculty of Science, and last author of the study.

This established that the period was not marked by an increase in the annual rate of precipitation but by an increase in its seasonality and intensity. ''This resulted in increased mobility of the river channels -- the deepest areas of a river -- which in turn transported large quantities of fluvial clays deposited on the adjacent alluvial plains to the ocean depths. We can now consider the presence of clay in deep basins as a marker of increased rainfall seasonality,'' says Lucas Vimpere. The phenomenon has led to an increase in ocean turbidity that is harmful to marine life, especially corals.

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Cohesion and connection drop in aging population

Social cohesion and connection decline in an ageing population, according to a new study of one of humanity's closest relatives.

For decades, researchers have been observing the rhesus macaques on Cayo Santiago (known as "Monkey Island") in Puerto Rico.

Recent research showed that female macaques "actively reduce" the size of their social networks and prioritise existing connections as they age -- something also seen in humans.

The new study, by an international team led by the University of Exeter, examines how this affects the overall cohesion and connection of the groups older monkeys live in.

While the observed macaque populations (which had no more than 20% "old" individuals) were not affected at group level, computer simulations showed higher proportions of old macaques would reduce cohesion and connection.

"For both humans and macaques, focusing on close friends and family in later life may bring a variety of benefits," said Dr Erin Siracusa, from Exeter's Centre for Research in Animal Behaviour.

"Our study aimed to find out what knock-on effect these individual age-related changes have for how well connected a society is overall.

"We had information on six monkey groups collected over eight years, representing in total 19 social networks.

"The first thing we found is that that older female macaques are poor influencers -- by having fewer friends, older females are less able to transmit knowledge and experience outside their immediate social circles."

The researchers tested whether monkey networks with a greater number of old females (over 18 years old) were less cohesive and connected.

In the macaque populations observed, they didn't find a difference between networks that were older compared to those with a greater number of young adults.

However, no more than 20% of monkeys were old in any given group we studied. It was still possible that even older networks would be affected.

So the scientists created a computer model that simulated the effect of higher proportions of old macaques, and found a decline in network cohesiveness and connectedness.

"We found really substantial consequences for network structure, which could affect useful things like information transmission and cooperation, and could also limit the spread of disease," said Professor Lauren Brent, also from the University of Exeter.

"In humans, population ageing is poised to be one of the most significant social transformations of the 21st Century.

"Our findings suggest this could have far-reaching effects on the structure of our societies and the way they function."

With the global human population of over-60s expected to double by 2050, the findings suggest social structures, cohesion and connectedness could all change significantly.

While the human population is ageing, some animal populations are becoming younger on average -- also with potentially serious consequences.

For example, older male elephants are often targeted by trophy hunters for their large tusks -- and a 2021 University of Exeter study found that male elephants are more aggressive to things like tourist vehicles when fewer older males are present.

The new study was carried out by a team including the University of Coimbra (Portugal), the Technical University of Denmark, Arizona State University, New York University, and the University of Pennsylvania (USA).

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Astrophysics: Scientists observe high-speed star formation

Even though SOFIA is no longer in operation, the data collected so far are essential for basic astronomical research because there is no longer an instrument that extensively maps the sky in this wavelength range (typically 60 to 200 micrometres). The now active James Webb Space Telescope observes in the infrared at shorter wavelengths and focuses on spatially small areas. Therefore, the analysis of the data collected by SOFIA is ongoing and continues to provide important insights – also regarding other star-forming regions: “In the list of FEEDBACK sources, there are other gas clouds in different stages of evolution, where we are now looking for the weak CII radiation at the peripheries of the clouds to detect similar interactions as in the Cygnus X region,” Schneider concluded.

al standards. The results of the study ‘Ionized carbon as a tracer for the assembly of interstellar clouds’ will appear in the next issue of Nature Astronomy.

The observations were carried out in an international project led by Dr Nicola Schneider at the University of Cologne and Prof Alexander Tielens at the University of Maryland as part of the FEEDBACK programme on board the flying observatory SOFIA (Stratospheric Observatory for Infrared Astronomy). The new findings modify previous perceptions that this specific process of star formation is quasi-static and quite slow. The dynamic formation process now observed would also explain the formation of particularly massive stars.

By comparing the distribution of ionized carbon, molecular carbon monoxide and atomic hydrogen, the team found that the shells of interstellar gas clouds are made of hydrogen and collide with each other at speeds of up to twenty kilometres per second. “This high speed compresses the gas into denser molecular regions where new, mainly massive stars form. We needed the CII observations to detect this otherwise ‘dark’ gas,” said Dr Schneider. The observations show for the first time the faint CII radiation from the periphery of the clouds, which could not be observed before. Only SOFIA and its sensitive instruments were capable of detecting this radiation.

SOFIA was operated by NASA and the German Aerospace Center (DLR) until September 2022. The observatory consisted of a converted Boeing 747 with a built-in 2.7-metre telescope. It was coordinated by the German SOFIA Institute (DSI) and the Universities Space Research Association (USRA). SOFIA observed the sky from the stratosphere (above 13 kilometres) and covered the infrared region of the electromagnetic spectrum, just beyond what humans can see. The Boeing thus flew above most of the water vapour in the Earth’s atmosphere, which otherwise blocks out infrared light. This allowed the scientists to observe a wavelength range that is not accessible from Earth. For the current results, the team used the upGREAT receiver installed on SOFIA in 2015 by the Max Planck Institute for Radio Astronomy in Bonn and the University of Cologne.

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Rationing: A fairer way to fight climate change?

World War II-style rationing could be an effective way to reduce carbon emissions, according to new research from the University of Leeds.

In a paper published today in the journal Ethics, Policy and Environment, academics argue that rationing could help states to reduce greenhouse gas emissions rapidly and fairly.

Policymakers have considered other schemes to reduce emissions, including carbon taxes and personal carbon trading schemes, but the researchers say these favour the wealthy, who could buy the right to pollute if trading were allowed.

The authors argue that carbon rationing would instead allow people to receive an equitable portion of resources based on their needs, therefore sharing out the effort to protect the planet.

The authors were based across the University of Leeds' Inter-Disciplinary Ethics Applied Centre, Sustainability Research Institute and School of History when they conducted the research.

Joint lead author Dr Nathan Wood, who is now a Postdoctoral Fellow at Utrecht University's Fair Energy Consortium, said: "The concept of rationing could help, not only in the mitigation of climate change, but also in reference to a variety of other social and political issues -- such as the current energy crisis."

Lessons from the past

Records from World War II show that compulsory food rationing was more acceptable to the UK public than voluntary changes to diet when resources became scarce. The policy aimed to share goods and burdens more equally, regardless of wealth, which was an important part of its popularity and success.

Historic rationing policies also introduced price controls on goods to keep key resources affordable for most people. As a result, rates of malnutrition went down during World War II, despite the shortages.

A key difference between World War II rationing and the climate crisis is public perception, the researchers say. The availability of thousands of garments, gadgets and goods at the click of a button can give the illusion that resources are available in abundance, but the reality is starkly different.

Dr Rob Lawlor, joint lead author and Lecturer at Leeds' Inter-Disciplinary Ethics Applied Centre, said: "There is a limit to how much we can emit if we are to reduce the catastrophic impacts of climate change. In this sense, the scarcity is very real."

Dr Wood said: "The cost of living crisis has shown what happens when scarcity drives up prices, with energy prices rising steeply and leaving vulnerable groups unable to pay their bills. Currently, those living in energy poverty cannot use anywhere near their fair share of energy supply, whereas the richest in society are free to use as much energy as they can afford."

Dr Lawlor added: "It seems feasible to reduce emissions overall even while the lowest emitters, often the worst off, may be able to increase their emissions -- not despite rationing, but because of rationing and price controls."

What equitable rationing could look like

The researchers suggest that rationing probably wouldn't be the first step. Instead, policy changes could start with stricter regulations and an accompanying information campaign to communicate the benefits of rationing.

Initially, governments could regulate the biggest polluters, such as oil, gas and petrol, long-haul flights and intensive farming, creating scarcity in products that harm the planet. Rationing could then be introduced gradually, to manage the resulting scarcity with the aim of meeting everyone's basic needs.

The academics identified two options for rationing policy. Policymakers could introduce an all-encompassing carbon allowance, giving out 'carbon cards' like bank cards to track and limit usage. Alternatively, governments could ration specifically selected goods, such as flights, petrol, household energy, or even meat or clothing.

Dr Lawlor said: "Many have proposed carbon allowances and carbon cards before. What is new (or old, taking inspiration from World War II) is the idea that the allowances should not be tradable. Another feature of World War II-style rationing is that price controls on rationed goods would prevent prices from rising with increased demand, benefitting those with the least money."

According to the researchers, it's likely that rationing would accelerate the transition from fossil fuels to cleaner energy and more sustainable lifestyles. Dr Wood said: "For example, rationing petrol could encourage greater use of, and investment in, low carbon public transport, such as railways and local trams."

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Geckos know their own odor

Geckos can use their tongue to differentiate their own odor from that of other members of their species, as researchers from the University of Bern have shown in a new experimental study. The findings show that geckos are able to communicate socially, meaning that they are more intelligent than was previously assumed.

Self-recognition is the ability to detect stimuli which come from oneself. We as people, and also some animals, can identify ourselves visually when we look in the mirror. However, not all animals rely on their sense of sight, first and foremost. Geckos, and also other lizards and snakes, use their tongues to perceive chemicals, so-called pheromones, from other individuals. For instance, when climbing a wall, geckos pause every so often to dart their tongues around. This enables them to detect potential partners or rivals. But can geckos also detect their own odor and recognize themselves by smell?

In a study recently published in the journal Animal Cognition, researchers at the Institute of Ecology and Evolution of the University of Bern focused on whether Tokay geckos can detect skin chemicals that they themselves produce, and whether they can discriminate between these chemicals and those of other geckos of the same sex. The experiments confirmed that geckos are capable of this. During the tests, the animals were more interested in the skin chemicals of other geckos than in their own. This shows that geckos use pheromones for social communication.

Gecko and peppermint odor on cotton swabs

During the experiment, the researchers presented the geckos with various odors on cotton swabs. As well as their own odor, these were odors from other geckos, or control odors such as water and peppermint. When they reacted, the geckos showed two types of behavior: on one hand, they stuck out their tongues in the direction of the odor on the swab and, on the other hand, towards the surrounding area, their own home enclosure. The researchers interpreted this behavior as a sign that the geckos first perceive the odor on the swab, and then compare it with their own odor on the walls of the enclosure. "The geckos have to compare more frequently when confronted with the odor of another gecko, compared to their own odor. This indicates that they know their own odor," explains Birgit Szabo, lead author of the study from the Division of Behavioural Ecology at the University of Bern's Institute of Ecology and Evolution.

In an experiment, the team was also able to show that geckos detect and use the odors of their feces to distinguish themselves from others. Geckos also deposit pheromones on their excrement, for instance, to mark their territory. This is because, just like many mammals, geckos have preferred areas for defecation so that they can communicate their presence.

More social and intelligent than we thought

The findings of the study show that geckos can communicate socially by using chemicals from their skin and excrement, and that they use these chemicals to distinguish themselves from other geckos. "Lizards and reptiles are generally seen as unsocial primitive animals. We must recognize that reptiles are more social and intelligent than we thought," says Birgit Szabo.

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Scientists make breakthrough for 'next generation' cancer treatment

Scientists at the University of East Anglia are a step closer to creating a new generation of light-activated cancer treatments.

The futuristic sounding treatment would work by switching on LED lights embedded close to a tumour, which would then activate biotherapeutic drugs.

These new treatments would be highly targeted and more effective than current state-of-the-art cancer immunotherapies.

New research published today reveals the science behind this innovative idea.

It shows how the UEA team have engineered antibody fragments -- which not only 'fuse' with their target but are also light activated.

It means that in future, immunotherapy treatments could be engineered to attack tumours more precisely than ever before.

The principal scientist for this study, Dr Amit Sachdeva, from UEA's School of Chemistry, said: "Current cancer treatments like chemotherapy kill cancer cells, but they can also damage healthy cells in your body such as blood and skin cells.

"This means that they can cause side effects including hair loss, feeling tired and sick, and they also put patients at increased risk of picking up infections.

"There has therefore been a very big drive to create new treatments that are more targeted and don't have these unwanted side-effects.

"Several antibodies and antibody fragments have already been developed to treat cancer. These antibodies are much more selective than the cytotoxic drugs used in chemotherapy, but they can still cause severe side effects, as antibody targets are also present on healthy cells."

Now, the UEA team has engineered one of the first antibody fragments that binds to, and forms a covalent bond with, its target -- upon irradiation with UV light of a specific wavelength.

Dr Sachdeva said: "A covalent bond is a bit like melting two pieces of plastic and fusing them together. It means that drug molecules could for example be permanently fixed to a tumour.

"We hope that our work will lead to the development of a new class of highly targeted light-responsive biotherapeutics. This would mean that antibodies could be activated at the site of a tumour and covalently stick to their target upon light activation.

"In other words, you could activate antibodies to attack tumour cells by shining light - either directly on to the skin, in the case of skin cancer, or using small LED lights that could be implanted at the site of a tumour inside the body.

"This would allow cancer treatment to be more efficient and targeted because it means that only molecules in the vicinity of the tumour would be activated, and it wouldn't affect other cells.

"This would potentially reduce side effects for patients, and also improve antibody residence time in the body."

"It would work for cancers like skin cancer, or where there is a solid tumour - but not for blood cancers like leukaemia.

"Development of these antibody fragments would not have been possible without pioneering work from several other research groups across the globe who developed and optimised methods for site-specific incorporation of non-natural amino acids into proteins expressed in live cells.

"We employed some of these methods to site-specifically install unique light-sensitive amino acids into antibody fragments."

If the researchers are successful in the next stages of their work, they hope to see the 'next generation' light-activated immunotherapies being used to treat cancer patients within five to 10 years.

Read more at Science Daily

Space travel influences the way the brain works

Scientists of the University of Antwerp and University of Liège have found how the human brain changes and adapts to weightlessness, after being in space for 6 months. Some of the changes turned out to be lasting -- even after 8 months back on Earth. Raphaël Liégeois, soon to be the third Belgian in space, acknowledges the importance of the research, "to prepare the new generation of astronauts for longer missions."

A child who learns not to drop a glass on the floor, or a tennis player predicting the course of an incoming ball to hit it accurately are examples of how the brain incorporates the physical laws of gravity to optimally function on Earth. Astronauts who go to space reside in a weightless environment, where the brain's rules about gravity are no longer applicable. A new study on brain function in cosmonauts has revealed how the brain's organization is changed after a six-month mission to the International Space Station (ISS), demonstrating the adaptation that is required to live in weightlessness.

The University of Antwerp has been leading this BRAIN-DTI scientific project through the European Space Agency. Magnetic resonance imaging (MRI) data were taken from 14 astronaut brains before and several times after their mission to space. Using a special MRI technique, the researchers collected the astronauts' brain data in a resting condition, hence without having them engage in a specific task. This resting-state functional MRI technique enabled the researchers to investigate the brain's default state and to find out whether this changes or not after long-duration spaceflight.

Learning effect

In collaboration with the University of Liège, recent analyses of the brain's activity at rest revealed how functional connectivity, a marker of how activity in some brain areas is correlated with the activity in others, changes in specific regions.

"We found that connectivity was altered after spaceflight in regions which support the integration of different types of information, rather than dealing with only one type each time, such as visual, auditory, or movement information', say Steven Jillings and Floris Wuyts (University of Antwerp). "Moreover, we found that some of these altered communication patterns were retained throughout 8 months of being back on Earth. At the same time, some brain changes returned to the level of how the areas were functioning before the space mission."

Both scenarios of changes are plausible: retained changes in brain communication may indicate a learning effect, while transient changes may indicate more acute adaptation to changed gravity levels.

"This dataset is so special as their participants themselves. Back in 2016, we were historically the first to show how spaceflight may affect brain function on a single cosmonaut. Some years later we are now in a unique position to investigate the brains of more astronauts, several times. Therefore, we are deciphering the potential of the human brain all the more in confidence," says Dr. Athena Demertzi (GIGA Institute, University of Liège), co-supervisor of this this work.

New generation of astronauts

"Understanding physiological and behavioral changes triggered by weightlessness is key to plan human space exploration. Therefore, mapping changes of brain function using neuroimaging techniques as done in this work is an important step to prepare the new generation of astronauts for longer missions," comments Raphaël Liégeois, Doctor of Engineering Science (ULiège) with a Thesis in the field of Neuroscience, future ESA Astronaut.

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How a record-breaking copper catalyst converts CO2 into liquid fuels

Since the 1970s, scientists have known that copper has a special ability to transform carbon dioxide into valuable chemicals and fuels. But for many years, scientists have struggled to understand how this common metal works as an electrocatalyst, a mechanism that uses energy from electrons to chemically transform molecules into different products.

Now, a research team led by Lawrence Berkeley National Laboratory (Berkeley Lab) has gained new insight by capturing real-time movies of copper nanoparticles (copper particles engineered at the scale of a billionth of a meter) as they convert CO2 and water into renewable fuels and chemicals: ethylene, ethanol, and propanol, among others. The work was reported in the journal Nature last week.

"This is very exciting. After decades of work, we're finally able to show -- with undeniable proof -- how copper electrocatalysts excel in CO2 reduction," said Peidong Yang, a senior faculty scientist in Berkeley Lab's Materials Sciences and Chemical Sciences Divisions who led the study. Yang is also a professor of chemistry and materials science and engineering at UC Berkeley. "Knowing how copper is such an excellent electrocatalyst brings us steps closer to turning CO2 into new, renewable solar fuels through artificial photosynthesis."

The work was made possible by combining a new imaging technique called operando 4D electrochemical liquid-cell STEM (scanning transmission electron microscopy) with a soft X-ray probe to investigate the same sample environment: copper nanoparticles in liquid. First author Yao Yang, a UC Berkeley Miller postdoctoral fellow, conceived the groundbreaking approach under the guidance of Peidong Yang while working toward his Ph.D. in chemistry at Cornell University.

Scientists who study artificial photosynthesis materials and reactions have wanted to combine the power of an electron probe with X-rays, but the two techniques typically can't be performed by the same instrument.

Electron microscopes (such as STEM or TEM) use beams of electrons and excel at characterizing the atomic structure in parts of a material. In recent years, 4D STEM (or "2D raster of 2D diffraction patterns using scanning transmission electron microscopy") instruments, such as those at Berkeley Lab's Molecular Foundry, have pushed the boundaries of electron microscopy even further, enabling scientists to map out atomic or molecular regions in a variety of materials, from hard metallic glass to soft, flexible films.

On the other hand, soft (or lower-energy) X-rays are useful for identifying and tracking chemical reactions in real time in an operando, or real-world, environment.

But now, scientists can have the best of both worlds. At the heart of the new technique is an electrochemical "liquid cell" sample holder with remarkable versatility. A thousand times thinner than a human hair, the device is compatible with both STEM and X-ray instruments.

The electrochemical liquid cell's ultrathin design allows reliable imaging of delicate samples while protecting them from electron beam damage. A special electrode custom-designed by co-author Cheng Wang, a staff scientist at Berkeley Lab's Advanced Light Source, enabled the team to conduct X-ray experiments with the electrochemical liquid cell. Combining the two allows researchers to comprehensively characterize electrochemical reactions in real time and at the nanoscale.

Getting granular

During 4D-STEM experiments, Yao Yang and team used the new electrochemical liquid cell to observe copper nanoparticles (ranging in size from 7 nanometers to 18 nanometers) evolve into active nanograins during CO2 electrolysis -- a process that uses electricity to drive a reaction on the surface of an electrocatalyst.

The experiments revealed a surprise: copper nanoparticles combined into larger metallic copper "nanograins" within seconds of the electrochemical reaction.

To learn more, the team turned to Wang, who pioneered a technique known as "resonant soft X-ray scattering (RSoXS) for soft materials," at the Advanced Light Source more than 10 years ago.

With help from Wang, the research team used the same electrochemical liquid cell, but this time during RSoXS experiments, to determine whether copper nanograins facilitate CO2 reduction. Soft X-rays are ideal for studying how copper electrocatalysts evolve during CO2 reduction, Wang explained. By using RSoXS, researchers can monitor multiple reactions between thousands of nanoparticles in real time, and accurately identify chemical reactants and products.

The RSoXS experiments at the Advanced Light Source -- along with additional evidence gathered at Cornell High Energy Synchrotron Source (CHESS) -- proved that metallic copper nanograins serve as active sites for CO2 reduction. (Metallic copper, also known as copper(0), is a form of the element copper.)

During CO2 electrolysis, the copper nanoparticles change their structure during a process called "electrochemical scrambling." The copper nanoparticles' surface layer of oxide degrades, creating open sites on the copper surface for CO2 molecules to attach, explained Peidong Yang. And as CO2 "docks" or binds to the copper nanograin surface, electrons are then transferred to CO2, causing a reaction that simultaneously produces ethylene, ethanol, and propanol along with other multicarbon products.

"The copper nanograins essentially turn into little chemical manufacturing factories," Yao Yang said.

Further experiments at the Molecular Foundry, the Advanced Light Source, and CHESS revealed that size matters. All of the 7-nanometer copper nanoparticles participated in CO2 reduction, whereas the larger nanoparticles did not. In addition, the team learned that only metallic copper can efficiently reduce CO2 into multicarbon products. The findings have implications for "rationally designing efficient CO2 electrocatalysts," Peidong Yang said.

The new study also validated Peidong Yang's findings from 2017: That the 7-nanometer-sized copper nanoparticles require low inputs of energy to start CO2 reduction. As an electrocatalyst, the 7-nanometer copper nanoparticles required a record-low driving force that is about 300 millivolts less than typical bulk copper electrocatalysts. The best-performing catalysts that produce multicarbon products from CO2 typically operate at high driving force of 1 volt.

The copper nanograins could potentially boost the energy efficiency and productivity of some catalysts designed for artificial photosynthesis, a field of research that aims to produce solar fuels from sunlight, water, and CO2. Currently, researchers within the Department of Energy-funded Liquid Sunlight Alliance (LiSA) plan to use the copper nanograin catalysts in the design of future solar fuel devices.

"The technique's ability to record real-time movies of a chemical process opens up exciting opportunities to study many other electrochemical energy conversion processes. It's a huge breakthrough, and it would not have been possible without Yao and his pioneering work," Peidong Yang said.

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Feedback loops make climate action even more urgent, scientists say

An international collaboration led by Oregon State University scientists has identified 27 global warming accelerators known as amplifying feedback loops, including some that the researchers say may not be fully accounted for in climate models.

They note that the findings, published today in the journal One Earth, add urgency to the need to respond to the climate crisis and provide a roadmap for policymakers aiming to avert the most severe consequences of a warming planet.

In climate science, amplifying feedback loops are situations where a climate-caused alteration can trigger a process that causes even more warming, which in turn intensifies the alteration. An example would be warming in the Arctic, leading to melting sea ice, which results in further warming because sea water absorbs rather than reflects solar radiation.

OSU College of Forestry postdoctoral scholar Christopher Wolf and distinguished professor William Ripple led the study, which in all looked at 41 climate change feedbacks.

"Many of the feedback loops we examined significantly increase warming because of their connection to greenhouse gas emissions," Wolf said. "To the best of our knowledge, this is the most extensive list available of climate feedback loops, and not all of them are fully considered in climate models. What's urgently needed is more research and modeling and an accelerated cutback of emissions."

The paper makes two calls to action for "immediate and massive" emissions reductions:
 

• Minimize short-term warming given that "climate disasters" in the form of wildfires, coastal flooding, permafrost thaw, intense storms and other extreme weather are already occurring.
• Mitigate the possible major threats looming from climate tipping points that are drawing ever-closer due to the prevalence of the many amplifying feedback loops. A tipping point is a threshold after which a change in a component of the climate system becomes self-perpetuating.

"Transformative, socially just changes in global energy and transportation, short-lived air pollution, food production, nature preservation and the international economy, together with population policies based on education and equality, are needed to meet these challenges in both the short and long term," Ripple said. "It's too late to fully prevent the pain of climate change, but if we take meaningful steps soon while prioritizing human basic needs and social justice, it could still be possible to limit the harm."

Ripple, Wolf and co-authors from the University of Exeter, the Potsdam Institute for Climate Impact Research, the Woodwell Climate Research Center and Terrestrial Ecosystems Research Associates considered both biological and physical feedbacks. Biological feedbacks include forest dieback, soil carbon loss and wildfire; physical feedbacks involve changes such as reduced snow cover, increased Antarctic rainfall and shrinking arctic sea ice.

Even comparatively modest warming is expected to heighten the likelihood that the Earth will cross various tipping points, the researchers say, causing big changes in the planet's climate system and potentially strengthening the amplifying feedbacks.

"Climate models may be underestimating the acceleration in global temperature change because they aren't fully considering this large and related set of amplifying feedback loops," Wolf said. "The accuracy of climate models is crucial as they help guide mitigation efforts by telling policymakers about the expected effects of human-caused greenhouse gas emissions. While recent climate models do a much better job of incorporating diverse feedback loops, more progress is needed."

Emissions have risen substantially over the last century, the researchers note, despite several decades of warnings that they should be significantly curbed. The scientists say interactions among feedback loops could cause a permanent shift away from the Earth's current climate state to one that threatens the survival of many humans and other life forms.

"In the worst case, if amplifying feedbacks are strong enough, the result is likely tragic climate change that's moved beyond anything humans can control," Ripple said. "We need a rapid transition toward integrated Earth system science because the climate can only be fully understood by considering the functioning and state of all Earth systems together. This will require large-scale collaboration, and the result would provide better information for policymakers."

In addition to the 27 amplifying climate feedbacks the scientists studied were seven that are characterized as dampening -- they act to stabilize the climate system. An example is carbon dioxide fertilization, where rising concentrations of atmospheric CO2 lead to increasing carbon uptake by vegetation.

The effects of the remaining seven feedbacks, including increased atmospheric dust and reduced ocean stability, are not yet known.

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