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    Study reveals a reaction at the heart of many renewable energy technologies

    A key chemical reaction — in which the movement of protons between the surface of an electrode and an electrolyte drives an electric current — is a critical step in many energy technologies, including fuel cells and the electrolyzers used to produce hydrogen gas.

    For the first time, MIT chemists have mapped out in detail how these proton-coupled electron transfers happen at an electrode surface. Their results could help researchers design more efficient fuel cells, batteries, or other energy technologies.

    “Our advance in this paper was studying and understanding the nature of how these electrons and protons couple at a surface site, which is relevant for catalytic reactions that are important in the context of energy conversion devices or catalytic reactions,” says Yogesh Surendranath, a professor of chemistry and chemical engineering at MIT and the senior author of the study.

    Among their findings, the researchers were able to trace exactly how changes in the pH of the electrolyte solution surrounding an electrode affect the rate of proton motion and electron flow within the electrode.

    MIT graduate student Noah Lewis is the lead author of the paper, which appears today in Nature Chemistry. Ryan Bisbey, a former MIT postdoc; Karl Westendorff, an MIT graduate student; and Alexander Soudackov, a research scientist at Yale University, are also authors of the paper.

    Passing protons

    Proton-coupled electron transfer occurs when a molecule, often water or an acid, transfers a proton to another molecule or to an electrode surface, which stimulates the proton acceptor to also take up an electron. This kind of reaction has been harnessed for many energy applications.

    “These proton-coupled electron transfer reactions are ubiquitous. They are often key steps in catalytic mechanisms, and are particularly important for energy conversion processes such as hydrogen generation or fuel cell catalysis,” Surendranath says.

    In a hydrogen-generating electrolyzer, this approach is used to remove protons from water and add electrons to the protons to form hydrogen gas. In a fuel cell, electricity is generated when protons and electrons are removed from hydrogen gas and added to oxygen to form water.

    Proton-coupled electron transfer is common in many other types of chemical reactions, for example, carbon dioxide reduction (the conversion of carbon dioxide into chemical fuels by adding electrons and protons). Scientists have learned a great deal about how these reactions occur when the proton acceptors are molecules, because they can precisely control the structure of each molecule and observe how electrons and protons pass between them. However, when proton-coupled electron transfer occurs at the surface of an electrode, the process is much more difficult to study because electrode surfaces are usually very heterogenous, with many different sites that a proton could potentially bind to.

    To overcome that obstacle, the MIT team developed a way to design electrode surfaces that gives them much more precise control over the composition of the electrode surface. Their electrodes consist of sheets of graphene with organic, ring-containing compounds attached to the surface. At the end of each of these organic molecules is a negatively charged oxygen ion that can accept protons from the surrounding solution, which causes an electron to flow from the circuit into the graphitic surface.

    “We can create an electrode that doesn’t consist of a wide diversity of sites but is a uniform array of a single type of very well-defined sites that can each bind a proton with the same affinity,” Surendranath says. “Since we have these very well-defined sites, what this allowed us to do was really unravel the kinetics of these processes.”

    Using this system, the researchers were able to measure the flow of electrical current to the electrodes, which allowed them to calculate the rate of proton transfer to the oxygen ion at the surface at equilibrium — the state when the rates of proton donation to the surface and proton transfer back to solution from the surface are equal. They found that the pH of the surrounding solution has a significant effect on this rate: The highest rates occurred at the extreme ends of the pH scale — pH 0, the most acidic, and pH 14, the most basic.

    To explain these results, researchers developed a model based on two possible reactions that can occur at the electrode. In the first, hydronium ions (H3O+), which are in high concentration in strongly acidic solutions, deliver protons to the surface oxygen ions, generating water. In the second, water delivers protons to the surface oxygen ions, generating hydroxide ions (OH-), which are in high concentration in strongly basic solutions.

    However, the rate at pH 0 is about four times faster than the rate at pH 14, in part because hydronium gives up protons at a faster rate than water.

    A reaction to reconsider

    The researchers also discovered, to their surprise, that the two reactions have equal rates not at neutral pH 7, where hydronium and hydroxide concentrations are equal, but at pH 10, where the concentration of hydroxide ions is 1 million times that of hydronium. The model suggests this is because the forward reaction involving proton donation from hydronium or water contributes more to the overall rate than the backward reaction involving proton removal by water or hydroxide.

    Existing models of how these reactions occur at electrode surfaces assume that the forward and backward reactions contribute equally to the overall rate, so the new findings suggest that those models may need to be reconsidered, the researchers say.

    “That’s the default assumption, that the forward and reverse reactions contribute equally to the reaction rate,” Surendranath says. “Our finding is really eye-opening because it means that the assumption that people are using to analyze everything from fuel cell catalysis to hydrogen evolution may be something we need to revisit.”

    The researchers are now using their experimental setup to study how adding different types of ions to the electrolyte solution surrounding the electrode may speed up or slow down the rate of proton-coupled electron flow.

    “With our system, we know that our sites are constant and not affecting each other, so we can read out what the change in the solution is doing to the reaction at the surface,” Lewis says.

    The research was funded by the U.S. Department of Energy Office of Basic Energy Sciences. More

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    Researchers release open-source space debris model

    MIT’s Astrodynamics, Space Robotics, and Controls Laboratory (ARCLab) announced the public beta release of the MIT Orbital Capacity Assessment Tool (MOCAT) during the 2023 Organization for Economic Cooperation and Development (OECD) Space Forum Workshop on Dec. 14. MOCAT enables users to model the long-term future space environment to understand growth in space debris and assess the effectiveness of debris-prevention mechanisms.

    With the escalating congestion in low Earth orbit, driven by a surge in satellite deployments, the risk of collisions and space debris proliferation is a pressing concern. Conducting thorough space environment studies is critical for developing effective strategies for fostering responsible and sustainable use of space resources. 

    MOCAT stands out among orbital modeling tools for its capability to model individual objects, diverse parameters, orbital characteristics, fragmentation scenarios, and collision probabilities. With the ability to differentiate between object categories, generalize parameters, and offer multi-fidelity computations, MOCAT emerges as a versatile and powerful tool for comprehensive space environment analysis and management.

    MOCAT is intended to provide an open-source tool to empower stakeholders including satellite operators, regulators, and members of the public to make data-driven decisions. The ARCLab team has been developing these models for the last several years, recognizing that the lack of open-source implementation of evolutionary modeling tools limits stakeholders’ ability to develop consensus on actions to help improve space sustainability. This beta release is intended to allow users to experiment with the tool and provide feedback to help guide further development.

    Richard Linares, the principal investigator for MOCAT and an MIT associate professor of aeronautics and astronautics, expresses excitement about the tool’s potential impact: “MOCAT represents a significant leap forward in orbital capacity assessment. By making it open-source and publicly available, we hope to engage the global community in advancing our understanding of satellite orbits and contributing to the sustainable use of space.”

    MOCAT consists of two main components. MOCAT-MC evaluates space environment evolution with individual trajectory simulation and Monte Carlo parameter analysis, providing both a high-level overall view for the environment and a fidelity analysis into the individual space objects evolution. MOCAT Source Sink Evolutionary Model (MOCAT-SSEM), meanwhile, uses a lower-fidelity modeling approach that can run on personal computers within seconds to minutes. MOCAT-MC and MOCAT-SSEM can be accessed separately via GitHub.

    MOCAT’s initial development has been supported by the Defense Advanced Research Projects Agency (DARPA) and NASA’s Office of Technology and Strategy.

    “We are thrilled to support this groundbreaking orbital debris modeling work and the new knowledge it created,” says Charity Weeden, associate administrator for the Office of Technology, Policy, and Strategy at NASA headquarters in Washington. “This open-source modeling tool is a public good that will advance space sustainability, improve evidence-based policy analysis, and help all users of space make better decisions.” More

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    The future of motorcycles could be hydrogen

    MIT’s Electric Vehicle Team, which has a long record of building and racing innovative electric vehicles, including cars and motorcycles, in international professional-level competitions, is trying something very different this year: The team is building a hydrogen-powered electric motorcycle, using a fuel cell system, as a testbed for new hydrogen-based transportation.

    The motorcycle successfully underwent its first full test-track demonstration in October. It is designed as an open-source platform that should make it possible to swap out and test a variety of different components, and for others to try their own versions based on plans the team is making freely available online.

    Aditya Mehrotra, who is spearheading the project, is a graduate student working with mechanical engineering professor Alex Slocum, the Walter M. May  and A. Hazel May Chair in Emerging Technologies. Mehrotra was studying energy systems and happened to also really like motorcycles, he says, “so we came up with the idea of a hydrogen-powered bike. We did an evaluation study, and we thought that this could actually work. We [decided to] try to build it.”

    Team members say that while battery-powered cars are a boon for the environment, they still face limitations in range and have issues associated with the mining of lithium and resulting emissions. So, the team was interested in exploring hydrogen-powered vehicles as a clean alternative, allowing for vehicles that could be quickly refilled just like gasoline-powered vehicles.

    Unlike past projects by the team, which has been part of MIT since 2005, this vehicle will not be entering races or competitions but will be presented at a variety of conferences. The team, consisting of about a dozen students, has been working on building the prototype since January 2023. In October they presented the bike at the Hydrogen Americas Summit, and in May they will travel to the Netherlands to present it at the World Hydrogen Summit. In addition to the two hydrogen summits, the team plans to show its bike at the Consumer Electronics Show in Las Vegas this month.

    “We’re hoping to use this project as a chance to start conversations around ‘small hydrogen’ systems that could increase demand, which could lead to the development of more infrastructure,” Mehrotra says. “We hope the project can help find new and creative applications for hydrogen.” In addition to these demonstrations and the online information the team will provide, he adds, they are also working toward publishing papers in academic journals describing their project and lessons learned from it, in hopes of making “an impact on the energy industry.”

    Play video

    For the love of speed: Building a hydrogen-powered motorcycle

    The motorcycle took shape over the course of the year piece by piece. “We got a couple of industry sponsors to donate components like the fuel cell and a lot of the major components of the system,” he says. They also received support from the MIT Energy Initiative, the departments of Mechanical Engineering and Electrical Engineering and Computer Science, and the MIT Edgerton Center.

    Initial tests were conducted on a dynamometer, a kind of instrumented treadmill Mehrotra describes as “basically a mock road.” The vehicle used battery power during its development, until the fuel cell, provided by South Korean company Doosan, could be delivered and installed. The space the group has used to design and build the prototype, the home of the Electric Vehicle Team, is in MIT’s Building N51 and is well set up to do detailed testing of each of the bike’s components as it is developed and integrated.

    Elizabeth Brennan, a senior in mechanical engineering, says she joined the team in January 2023 because she wanted to gain more electrical engineering experience, “and I really fell in love with it.” She says group members “really care and are very excited to be here and work on this bike and believe in the project.”

    Brennan, who is the team’s safety lead, has been learning about the safe handling methods required for the bike’s hydrogen fuel, including the special tanks and connectors needed. The team initially used a commercially available electric motor for the prototype but is now working on an improved version, designed from scratch, she says, “which gives us a lot more flexibility.”

    As part of the project, team members are developing a kind of textbook describing what they did and how they carried out each step in the process of designing and fabricating this hydrogen electric fuel-cell bike. No such motorcycle yet exists as a commercial product, though a few prototypes have been built.

    That kind of guidebook to the process “just doesn’t exist,” Brennan says. She adds that “a lot of the technology development for hydrogen is either done in simulation or is still in the prototype stages, because developing it is expensive, and it’s difficult to test these kinds of systems.” One of the team’s goals for the project is to make everything available as an open-source design, and “we want to provide this bike as a platform for researchers and for education, where researchers can test ideas in both space- and funding-constrained environments.”

    Unlike a design built as a commercial product, Mehrotra says, “our vehicle is fully designed for research, so you can swap components in and out, and get real hardware data on how good your designs are.” That can help people work on implementing their new design ideas and help push the industry forward, he says.

    The few prototypes developed previously by some companies were inefficient and expensive, he says. “So far as we know, we are the first fully open-source, rigorously documented, tested and released-as-a-platform, [fuel cell] motorcycle in the world. No one else has made a motorcycle and tested it to the level that we have, and documented to the point that someone might actually be able to take this and scale it in the future, or use it in research.”

    He adds that “at the moment, this vehicle is affordable for research, but it’s not affordable yet for commercial production because the fuel cell is a very big, expensive component.” Doosan Fuel Cell, which provided the fuel cell for the prototype bike, produces relatively small and lightweight fuel cells mostly for use in drones. The company also produces hydrogen storage and delivery systems.

    The project will continue to evolve, says team member Annika Marschner, a sophomore in mechanical engineering. “It’s sort of an ongoing thing, and as we develop it and make changes, make it a stronger, better bike, it will just continue to grow over the years, hopefully,” she says.

    While the Electric Vehicle Team has until now focused on battery-powered vehicles, Marschner says, “Right now we’re looking at hydrogen because it seems like something that’s been less explored than other technologies for making sustainable transportation. So, it seemed like an exciting thing for us to offer our time and effort to.”

    Making it all work has been a long process. The team is using a frame from a 1999 motorcycle, with many custom-made parts added to support the electric motor, the hydrogen tank, the fuel cell, and the drive train. “Making everything fit in the frame of the bike is definitely something we’ve had to think about a lot because there’s such limited space there. So, it required trying to figure out how to mount things in clever ways so that there are not conflicts,” she says.

    Marschner says, “A lot of people don’t really imagine hydrogen energy being something that’s out there being used on the roads, but the technology does exist.” She points out that Toyota and Hyundai have hydrogen-fueled vehicles on the market, and that some hydrogen fuel stations exist, mostly in California, Japan, and some European countries. But getting access to hydrogen, “for your average consumer on the East Coast, is a huge, huge challenge. Infrastructure is definitely the biggest challenge right now to hydrogen vehicles,” she says.

    She sees a bright future for hydrogen as a clean fuel to replace fossil fuels over time. “I think it has a huge amount of potential,” she says. “I think one of the biggest challenges with moving hydrogen energy forward is getting these demonstration projects actually developed and showing that these things can work and that they can work well. So, we’re really excited to bring it along further.” More

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    MIT researchers outline a path for scaling clean hydrogen production

    Hydrogen is an integral component for the manufacture of steel, fertilizer, and a number of chemicals. Producing hydrogen using renewable electricity offers a way to clean up these and many other hard-to-decarbonize industries.

    But supporting the nascent clean hydrogen industry while ensuring it grows into a true force for decarbonization is complicated, in large part because of the challenges of sourcing clean electricity. To assist regulators and to clarify disagreements in the field, MIT researchers published a paper today in Nature Energy that outlines a path to scale the clean hydrogen industry while limiting emissions.

    Right now, U.S. electric grids are mainly powered by fossil fuels, so if scaling hydrogen production translates to greater electricity use, it could result in a major emissions increase. There is also the risk that “low-carbon” hydrogen projects could end up siphoning renewable energy that would have been built anyway for the grid. It is therefore critical to ensure that low-carbon hydrogen procures electricity from “additional” renewables, especially when hydrogen production is supported by public subsidies. The challenge is allowing hydrogen producers to procure renewable electricity in a cost-effective way that helps the industry grow, while minimizing the risk of high emissions.

    U.S. regulators have been tasked with sorting out this complexity. The Inflation Reduction Act (IRA) is offering generous production tax credits for low-carbon hydrogen. But the law didn’t specify exactly how hydrogen’s carbon footprint should be judged.

    To this end, the paper proposes a phased approach to qualify for the tax credits. In the first phase, hydrogen created from grid electricity can receive the credits under looser standards as the industry gets its footing. Once electricity demand for hydrogen production grows, the industry should be required to adhere to stricter standards for ensuring the electricity is coming from renewable sources. Finally, many years from now when the grid is mainly powered by renewable energy, the standards can loosen again.

    The researchers say the nuanced approach ensures the law supports the growth of clean hydrogen without coming at the expense of emissions.

    “If we can scale low-carbon hydrogen production, we can cut some significant sources of existing emissions and enable decarbonization of other critical industries,” says paper co-author Michael Giovanniello, a graduate student in MIT’s Technology and Policy Program. “At the same time, there’s a real risk of implementing the wrong requirements and wasting lots of money to subsidize carbon-intensive hydrogen production. So, you have to balance scaling the industry with reducing the risk of emissions. I hope there’s clarity and foresight in how this policy is implemented, and I hope our paper makes the argument clear for policymakers.”

    Giovanniello’s co-authors on the paper are MIT Energy Initiative (MITEI) Principal Research Scientist Dharik Mallapragada, MITEI Research Assistant Anna Cybulsky, and MIT Sloan School of Management Senior Lecturer Tim Schittekatte.

    On definitions and disagreements

    When renewable electricity from a wind farm or solar array flows through the grid, it’s mixed with electricity from fossil fuels. The situation raises a question worth billions of dollars in federal tax credits: What are the carbon dioxide emissions of grid users who are also signing agreements to procure electricity from renewables?

    One way to answer this question is via energy system models that can simulate various scenarios related to technology configurations and qualifying requirements for receiving the credit.

    To date, many studies using such models have come up with very different emissions estimates for electrolytic hydrogen production. One source of disagreement is over “time matching,” which refers to how strictly to align the timing of electric hydrogen production with the generation of clean electricity. One proposed approach, known as hourly time matching, would require that electricity consumption to produce hydrogen is accounted for by procured clean electricity at every hour.

    A less stringent approach, called annual time matching, would offer more flexibility in hourly electricity consumption for hydrogen production, so long as the annual consumption matches the annual generation from the procured clean electricity generation. The added flexibility could reduce the cost of hydrogen production, which is critical for scaling its use, but could lead to greater emissions per unit of hydrogen produced.

    Another point of disagreement stems from how hydrogen producers purchase renewable electricity. If an electricity user procures energy from an existing solar farm, it’s simply increasing overall electricity demand and taking clean energy away from other users. But if the tax credits only go to electric hydrogen producers that sign power purchase agreements with new renewable suppliers, they’re supporting clean electricity that wouldn’t have otherwise been contributing to the grid. This concept is known as “additionality.”

    The researchers analyzed previous studies that reached conflicting conclusions, and identified different interpretations of additionality underlying their methodologies. One interpretation of additionality is that new electrolytic hydrogen projects do not compete with nonhydrogen demand for renewable energy resources. The other assumes that they do compete for all newly deployed renewables — and, because of low-carbon hydrogen subsidies, the electrolyzers take priority.

    Using DOLPHYN, an open-source energy systems model, the researchers tested how these two interpretations of additionality (the “compete” and “noncompete” scenarios) impact the cost and emissions of the alternative time-matching requirements (hourly and annual) associated with grid-interconnected hydrogen production. They modeled two regional U.S. grids — in Texas and Florida — which represent the high and low end of renewables deployment. They further tested the interaction of four critical policy factors with the hydrogen tax credits, including renewable portfolio standards, constraints of renewables and energy storage deployment, limits on hydrogen electrolyzer capacity factors, and competition with natural gas-based hydrogen with carbon capture.

    They show that the different modeling interpretations of additionality are the primary factor explaining the vastly different estimates of emissions from electrolyzer hydrogen under annual time-matching.

    Getting policy right

    The paper concludes that the right way to implement the production tax credit qualifying requirements depends on whether you believe we live in a “compete” or “noncompete” world. But reality is not so binary.

    “What framework is more appropriate is going to change with time as we deploy more hydrogen and the grid decarbonizes, so therefore the policy has to be adaptive to those changes,” Mallapragada says. “It’s an evolving story that’s tied to what’s happening in the rest of the energy system, and in particular the electric grid, both from the technological as policy perspective.”

    Today, renewables deployment is driven, in part, by binding factors, such as state renewable portfolio standards and corporate clean-energy commitments, as well as by purely market forces. Since the electrolyzer is so nascent, and today resembles a “noncompete” world, the researchers argue for starting with the less strict annual requirement. But as hydrogen demand for renewable electricity grows, and market competition drives an increasing quantity of renewables deployment, transitioning to hourly matching will be necessary to avoid high emissions.

    This phased approach necessitates deliberate, long-term planning from regulators. “If regulators make a decision and don’t outline when they’ll reassess that decision, they might never reassess that decision, so we might get locked into a bad policy,” Giovanniello explains. In particular, the paper highlights the risk of locking in an annual time-matching requirement that leads to significant emissions in future.

    The researchers hope their findings will contribute to upcoming policy decisions around the Inflation Reduction Act’s tax credits. They started looking into this question around a year ago, making it a quick turnaround by academic standards.

    “There was definitely a sense to be timely in our analysis so as to be responsive to the needs of policy,” Mallapragada says.

    The researchers say the paper can also help policymakers understand the emissions impacts of companies procuring renewable energy credits to meet net-zero targets and electricity suppliers attempting to sell “green” electricity.

    “This question is relevant in a lot of different domains,” Schittekatte says. “Other popular examples are the emission impacts of data centers that procure green power, or even the emission impacts of your own electric car sourcing power from your rooftop solar and the grid. There are obviously differences based on the technology in question, but the underlying research question we’ve answered is the same. This is an extremely important topic for the energy transition.” More

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    Engineers develop a vibrating, ingestible capsule that might help treat obesity

    When you eat a large meal, your stomach sends signals to your brain that create a feeling of fullness, which helps you realize it’s time to stop eating. A stomach full of liquid can also send these messages, which is why dieters are often advised to drink a glass of water before eating.

    MIT engineers have now come up with a new way to take advantage of that phenomenon, using an ingestible capsule that vibrates within the stomach. These vibrations activate the same stretch receptors that sense when the stomach is distended, creating an illusory sense of fullness.

    In animals who were given this pill 20 minutes before eating, the researchers found that this treatment not only stimulated the release of hormones that signal satiety, but also reduced the animals’ food intake by about 40 percent. Scientists have much more to learn about the mechanisms that influence human body weight, but if further research suggests this technology could be safely used in humans, such a pill might offer a minimally invasive way to treat obesity, the researchers say.

    “For somebody who wants to lose weight or control their appetite, it could be taken before each meal,” says Shriya Srinivasan PhD ’20, a former MIT graduate student and postdoc who is now an assistant professor of bioengineering at Harvard University. “This could be really interesting in that it would provide an option that could minimize the side effects that we see with the other pharmacological treatments out there.”

    Srinivasan is the lead author of the new study, which appears today in Science Advances. Giovanni Traverso, an associate professor of mechanical engineering at MIT and a gastroenterologist at Brigham and Women’s Hospital, is the senior author of the paper.

    A sense of fullness

    When the stomach becomes distended, specialized cells called mechanoreceptors sense that stretching and send signals to the brain via the vagus nerve. As a result, the brain stimulates production of insulin, as well as hormones such as C-peptide, Pyy, and GLP-1. All of these hormones work together to help people digest their food, feel full, and stop eating. At the same time, levels of ghrelin, a hunger-promoting hormone, go down.

    While a graduate student at MIT, Srinivasan became interested in the idea of controlling this process by artificially stretching the mechanoreceptors that line the stomach, through vibration. Previous research had shown that vibration applied to a muscle can induce a sense that the muscle has stretched farther than it actually has.

    “I wondered if we could activate stretch receptors in the stomach by vibrating them and having them perceive that the entire stomach has been expanded, to create an illusory sense of distension that could modulate hormones and eating patterns,” Srinivasan says.

    As a postdoc in MIT’s Koch Institute for Integrative Cancer Research, Srinivasan worked closely with Traverso’s lab, which has developed many novel approaches to oral delivery of drugs and electronic devices. For this study, Srinivasan, Traverso, and a team of researchers designed a capsule about the size of a multivitamin, that includes a vibrating element. When the pill, which is powered by a small silver oxide battery, reaches the stomach, acidic gastric fluids dissolve a gelatinous membrane that covers the capsule, completing the electronic circuit that activates the vibrating motor.

    In a study in animals, the researchers showed that once the pill begins vibrating, it activates mechanoreceptors, which send signals to the brain through stimulation of the vagus nerve. The researchers tracked hormone levels during the periods when the device was vibrating and found that they mirrored the hormone release patterns seen following a meal, even when the animals had fasted.

    The researchers then tested the effects of this stimulation on the animals’ appetite. They found that when the pill was activated for about 20 minutes, before the animals were offered food, they consumed 40 percent less, on average, than they did when the pill was not activated. The animals also gained weight more slowly during periods when they were treated with the vibrating pill.

    “The behavioral change is profound, and that’s using the endogenous system rather than any exogenous therapeutic. We have the potential to overcome some of the challenges and costs associated with delivery of biologic drugs by modulating the enteric nervous system,” Traverso says.

    The current version of the pill is designed to vibrate for about 30 minutes after arriving in the stomach, but the researchers plan to explore the possibility of adapting it to remain in the stomach for longer periods of time, where it could be turned on and off wirelessly as needed. In the animal studies, the pills passed through the digestive tract within four or five days.

    The study also found that the animals did not show any signs of obstruction, perforation, or other negative impacts while the pill was in their digestive tract.

    An alternative approach

    This type of pill could offer an alternative to the current approaches to treating obesity, the researchers say. Nonmedical interventions such as diet exercise don’t always work, and many of the existing medical interventions are fairly invasive. These include gastric bypass surgery, as well as gastric balloons, which are no longer used widely in the United States due to safety concerns.

    Drugs such as GLP-1 agonists can also aid weight loss, but most of them have to be injected, and they are unaffordable for many people. According to Srinivasan, the MIT capsules could be manufactured at a cost that would make them available to people who don’t have access to more expensive treatment options.

    “For a lot of populations, some of the more effective therapies for obesity are very costly. At scale, our device could be manufactured at a pretty cost-effective price point,” she says. “I’d love to see how this would transform care and therapy for people in global health settings who may not have access to some of the more sophisticated or expensive options that are available today.”

    The researchers now plan to explore ways to scale up the manufacturing of the capsules, which could enable clinical trials in humans. Such studies would be important to learn more about the devices’ safety, as well as determine the best time to swallow the capsule before to a meal and how often it would need to be administered.

    Other authors of the paper include Amro Alshareef, Alexandria Hwang, Ceara Byrne, Johannes Kuosmann, Keiko Ishida, Joshua Jenkins, Sabrina Liu, Wiam Abdalla Mohammed Madani, Alison Hayward, and Niora Fabian.

    The research was funded by the National Institutes of Health, Novo Nordisk, the Department of Mechanical Engineering at MIT, a Schmidt Science Fellowship, and the National Science Foundation. More

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    MIT in the media: 2023 in review

    It was an eventful trip around the sun for MIT this year, from President Sally Kornbluth’s inauguration and Mark Rober’s Commencement address to Professor Moungi Bawendi winning the Nobel Prize in Chemistry. In 2023 MIT researchers made key advances, detecting a dying star swallowing a planet, exploring the frontiers of artificial intelligence, creating clean energy solutions, inventing tools aimed at earlier detection and diagnosis of cancer, and even exploring the science of spreading kindness. Below are highlights of some of the uplifting people, breakthroughs, and ideas from MIT that made headlines in 2023.

    The gift: Kindness goes viral with Steve HartmanSteve Hartman visited Professor Anette “Peko” Hosoi to explore the science behind whether a single act of kindness can change the world.Full story via CBS News

    Trio wins Nobel Prize in chemistry for work on quantum dots, used in electronics and medical imaging“The motivation really is the basic science. A basic understanding, the curiosity of ‘how does the world work?’” said Professor Moungi Bawendi of the inspiration for his research on quantum dots, for which he was co-awarded the 2023 Nobel Prize in Chemistry.Full story via the Associated Press

    How MIT’s all-women leadership team plans to change science for the betterPresident Sally Kornbluth, Provost Cynthia Barnhart, and Chancellor Melissa Nobles emphasized the importance of representation for women and underrepresented groups in STEM.Full story via Radio Boston

    MIT via community college? Transfer students find a new path to a degreeUndergraduate Subin Kim shared his experience transferring from community college to MIT through the Transfer Scholars Network, which is aimed at helping community college students find a path to four-year universities.Full story via the Christian Science Monitor

    MIT president Sally Kornbluth doesn’t think we can hit the pause button on AIPresident Kornbluth discussed the future of AI, ethics in science, and climate change with columnist Shirley Leung on her new “Say More” podcast. “I view [the climate crisis] as an existential issue to the extent that if we don’t take action there, all of the many, many other things that we’re working on, not that they’ll be irrelevant, but they’ll pale in comparison,” Kornbluth said.Full story via The Boston Globe 

    It’s the end of a world as we know itAstronomers from MIT, Harvard University, Caltech and elsewhere spotted a dying star swallowing a large planet. Postdoc Kishalay De explained that: “Finding an event like this really puts all of the theories that have been out there to the most stringent tests possible. It really opens up this entire new field of research.”Full story via The New York Times

    Frontiers of AI

    Hey, Alexa, what should students learn about AI?The Day of AI is a program developed by the MIT RAISE initiative aimed at introducing and teaching K-12 students about AI. “We want students to be informed, responsible users and informed, responsible designers of these technologies,” said Professor Cynthia Breazeal, dean of digital learning at MIT.Full story via The New York Times

    AI tipping pointFour faculty members from across MIT — Professors Song Han, Simon Johnson, Yoon Kim and Rosalind Picard — described the opportunities and risks posed by the rapid advancements in the field of AI.Full story via Curiosity Stream 

    A look into the future of AI at MIT’s robotics laboratoryProfessor Daniela Rus, director of MIT’s Computer Science and Artificial Intelligence Laboratory, discussed the future of artificial intelligence, robotics, and machine learning, emphasizing the importance of balancing the development of new technologies with the need to ensure they are deployed in a way that benefits humanity.Full story via Mashable

    Health care providers say artificial intelligence could transform medicineProfessor Regina Barzilay spoke about her work developing new AI systems that could be used to help diagnose breast and lung cancer before the cancers are detectable to the human eye.Full story via Chronicle

    Is AI coming for your job? Tech experts weigh in: “They don’t replace human labor”Professor David Autor discussed how the rise of artificial intelligence could change the quality of jobs available.Full story via CBS News

    Big tech is bad. Big AI will be worse.Institute Professor Daron Acemoglu and Professor Simon Johnson made the case that “rather than machine intelligence, what we need is ‘machine usefulness,’ which emphasizes the ability of computers to augment human capabilities.”Full story via The New York Times

    Engineering excitement

    MIT’s 3D-printed hearts could pump new life into customized treatments MIT engineers developed a technique for 3D printing a soft, flexible, custom-designed replica of a patient’s heart.Full story via WBUR

    Mystery of why Roman buildings have survived so long has been unraveled, scientists sayScientists from MIT and other institutions discovered that ancient Romans used lime clasts when manufacturing concrete, giving the material self-healing properties.Full story via CNN

    The most interesting startup in America is in Massachusetts. You’ve probably never heard of it.VulcanForms, an MIT startup, is at the “leading edge of a push to transform 3D printing from a niche technology — best known for new-product prototyping and art-class experimentation — into an industrial force.”Full story via The Boston Globe

    Catalyzing climate innovations

    Can Boston’s energy innovators save the world?Boston Magazine reporter Rowan Jacobsen spotlighted how MIT faculty, students, and alumni are leading the charge in clean energy startups. “When it comes to game-changing breakthroughs in energy, three letters keep surfacing again and again: MIT,” writes Jacobsen.Full story via Boston Magazine

    MIT research could be game changer in combating water shortagesMIT researchers discovered that a common hydrogel used in cosmetic creams, industrial coatings, and pharmaceutical capsules can absorb moisture from the atmosphere even as the temperature rises. “For a planet that’s getting hotter, this could be a game-changing discovery.”Full story via NBC Boston

    Energy-storing concrete could form foundations for solar-powered homesMIT engineers uncovered a new way of creating an energy supercapacitor by combining cement, carbon black, and water that could one day be used to power homes or electric vehicles.Full story via New Scientist

    MIT researchers tackle key question of EV adoption: When to charge?MIT scientists found that delayed charging and strategic placement of EV charging stations could help reduce additional energy demands caused by more widespread EV adoption.Full story via Fast Company

    Building better buildingsProfessor John Fernández examined how to reduce the climate footprints of homes and office buildings, recommending creating airtight structures, switching to cleaner heating sources, using more environmentally friendly building materials, and retrofitting existing homes and offices.Full story via The New York Times

    They’re building an “ice penetrator” on a hillside in WestfordResearchers from MIT’s Haystack Observatory built an “ice penetrator,” a device designed to monitor the changing conditions of sea ice.Full story via The Boston Globe

    Healing health solutions

    How Boston is beating cancerMIT researchers are developing drug-delivery nanoparticles aimed at targeting cancer cells without disturbing healthy cells. Essentially, the nanoparticles are “engineered for selectivity,” explained Professor Paula Hammond, head of MIT’s Department of Chemical Engineering.Full story via Boston Magazine

    A new antibiotic, discovered with artificial intelligence, may defeat a dangerous superbugUsing a machine-learning algorithm, researchers from MIT discovered a type of antibiotic that’s effective against a particular strain of drug-resistant bacteria.Full story via CNN

    To detect breast cancer sooner, an MIT professor designs an ultrasound braMIT researchers designed a wearable ultrasound device that attaches to a bra and could be used to detect early-stage breast tumors.Full story via STAT

    The quest for a switch to turn on hungerAn ingestible pill developed by MIT scientists can raise levels of hormones to help increase appetite and decrease nausea in patients with gastroparesis.Full story via Wired

    Here’s how to use dreams for creative inspirationMIT scientists found that the earlier stages of sleep are key to sparking creativity and that people can be guided to dream about specific topics, further boosting creativity.Full story via Scientific American

    Astounding art

    An AI opera from 1987 reboots for a new generationProfessor Tod Machover discussed the restaging of his opera “VALIS” at MIT, which featured an artificial intelligence-assisted musical instrument developed by Nina Masuelli ’23.Full story via The Boston Globe

    Surfacing the stories hidden in migration dataAssociate Professor Sarah Williams discussed the Civic Data Design Lab’s “Motivational Tapestry,” a large woven art piece that uses data from the United Nations World Food Program to visually represent the individual motivations of 1,624 Central Americans who have migrated to the U.S.Full story via Metropolis

    Augmented reality-infused production of Wagner’s “Parsifal” opens Bayreuth FestivalProfessor Jay Scheib’s augmented reality-infused production of Richard Wagner’s “Parsifal” brought “fantastical images” to audience members.Full story via the Associated Press

    Understanding our universe

    New image reveals violent events near a supermassive black holeScientists captured a new image of M87*, the black hole at the center of the Messier 87 galaxy, showing the “launching point of a colossal jet of high-energy particles shooting outward into space.”Full story via Reuters

    Gravitational waves: A new universeMIT researchers Lisa Barsotti, Deep Chatterjee, and Victoria Xu explored how advances in gravitational wave detection are enabling a better understanding of the universe.Full story via Curiosity Stream 

    Nergis Mavalvala helped detect the first gravitational wave. Her work doesn’t stop thereProfessor Nergis Mavalvala, dean of the School of Science, discussed her work searching for gravitational waves, the importance of skepticism in scientific research, and why she enjoys working with young people.Full story via Wired

    Hitting the books

    “The Transcendent Brain” review: Beyond ones and zeroesIn his book “The Transcendent Brain: Spirituality in the Age of Science,” Alan Lightman, a professor of the practice of humanities, displayed his gift for “distilling complex ideas and emotions to their bright essence.”Full story via The Wall Street Journal

    What happens when CEOs treat workers better? Companies (and workers) win.Professor of the practice Zeynep Ton published a book, “The Case for Good Jobs,” and is “on a mission to change how company leaders think, and how they treat their employees.”Full story via The Boston Globe

    How to wage war on conspiracy theoriesProfessor Adam Berinsky’s book, “Political Rumors: Why We Accept Misinformation and How to Fight it,” examined “attitudes toward both politics and health, both of which are undermined by distrust and misinformation in ways that cause harm to both individuals and society.”Full story via Politico

    What it takes for Mexican coders to cross the cultural border with Silicon ValleyAssistant Professor Héctor Beltrán discussed his new book, “Code Work: Hacking across the U.S./México Techno-Borderlands,” which explores the culture of hackathons and entrepreneurship in Mexico.Full story via Marketplace

    Cultivating community

    The Indigenous rocketeerNicole McGaa, a fourth-year student at MIT, discussed her work leading MIT’s all-Indigenous rocket team at the 2023 First Nations Launch National Rocket Competition.Full story via Nature

    “You totally got this,” YouTube star and former NASA engineer Mark Rober tells MIT graduatesDuring his Commencement address at MIT, Mark Rober urged graduates to embrace their accomplishments and boldly face any challenges they encounter.Full story via The Boston Globe

    MIT Juggling Club going strong after half centuryAfter almost 50 years, the MIT Juggling Club, which was founded in 1975 and then merged with a unicycle club, is the oldest drop-in juggling club in continuous operation and still welcomes any aspiring jugglers to come toss a ball (or three) into the air.Full story via Cambridge Day

    Volpe Transportation Center opens as part of $750 million deal between MIT and fedsThe John A. Volpe National Transportation Systems Center in Kendall Square was the first building to open in MIT’s redevelopment of the 14-acre Volpe site that will ultimately include “research labs, retail, affordable housing, and open space, with the goal of not only encouraging innovation, but also enhancing the surrounding community.”Full story via The Boston Globe

    Sparking conversation

    The future of AI innovation and the role of academics in shaping itProfessor Daniela Rus emphasized the central role universities play in fostering innovation and the importance of ensuring universities have the computing resources necessary to help tackle major global challenges.Full story via The Boston Globe

    Moving the needle on supply chain sustainabilityProfessor Yossi Sheffi examined several strategies companies could use to help improve supply chain sustainability, including redesigning last-mile deliveries, influencing consumer choices and incentivizing returnable containers.Full story via The Hill

    Expelled from the mountain top?Sylvester James Gates Jr. ’73, PhD ’77 made the case that “diverse learning environments expose students to a broader range of perspectives, enhance education, and inculcate creativity and innovative habits of mind.”Full story via Science

    Marketing magic of “Barbie” movie has lessons for women’s sportsMIT Sloan Lecturer Shira Springer explored how the success of the “Barbie” movie could be applied to women’s sports.Full story via Sports Business Journal

    We’re already paying for universal health care. Why don’t we have it?Professor Amy Finkelstein asserted that the solution to health insurance reform in the U.S. is “universal coverage that is automatic, free and basic.”Full story via The New York Times 

    The internet could be so good. Really.Professor Deb Roy described how “new kinds of social networks can be designed for constructive communication — for listening, dialogue, deliberation, and mediation — and they can actually work.”Full story via The Atlantic

    Fostering educational excellence

    MIT students give legendary linear algebra professor standing ovation in last lectureAfter 63 years of teaching and over 10 million views of his online lectures, Professor Gilbert Strang received a standing ovation after his last lecture on linear algebra. “I am so grateful to everyone who likes linear algebra and sees its importance. So many universities (and even high schools) now appreciate how beautiful it is and how valuable it is,” said Strang.Full story via USA Today

    “Brave Behind Bars”: Reshaping the lives of inmates through coding classesGraduate students Martin Nisser and Marisa Gaetz co-founded Brave Behind Bars, a program designed to provide incarcerated individuals with coding and digital literacy skills to better prepare them for life after prison.Full story via MSNBC

    Melrose TikTok user “Ms. Nuclear Energy” teaching about nuclear power through social mediaGraduate student Kaylee Cunningham discussed her work using social media to help educate and inform the public about nuclear energy.Full story via CBS Boston  More

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    Accelerated climate action needed to sharply reduce current risks to life and life-support systems

    Hottest day on record. Hottest month on record. Extreme marine heatwaves. Record-low Antarctic sea-ice.

    While El Niño is a short-term factor in this year’s record-breaking heat, human-caused climate change is the long-term driver. And as global warming edges closer to 1.5 degrees Celsius — the aspirational upper limit set in the Paris Agreement in 2015 — ushering in more intense and frequent heatwaves, floods, wildfires, and other climate extremes much sooner than many expected, current greenhouse gas emissions-reduction policies are far too weak to keep the planet from exceeding that threshold. In fact, on roughly one-third of days in 2023, the average global temperature was at least 1.5 C higher than pre-industrial levels. Faster and bolder action will be needed — from the in-progress United Nations Climate Change Conference (COP28) and beyond — to stabilize the climate and minimize risks to human (and nonhuman) lives and the life-support systems (e.g., food, water, shelter, and more) upon which they depend.

    Quantifying the risks posed by simply maintaining existing climate policies — and the benefits (i.e., avoided damages and costs) of accelerated climate action aligned with the 1.5 C goal — is the central task of the 2023 Global Change Outlook, recently released by the MIT Joint Program on the Science and Policy of Global Change.

    Based on a rigorous, integrated analysis of population and economic growth, technological change, Paris Agreement emissions-reduction pledges (Nationally Determined Contributions, or NDCs), geopolitical tensions, and other factors, the report presents the MIT Joint Program’s latest projections for the future of the earth’s energy, food, water, and climate systems, as well as prospects for achieving the Paris Agreement’s short- and long-term climate goals.

    The 2023 Global Change Outlook performs its risk-benefit analysis by focusing on two scenarios. The first, Current Trends, assumes that Paris Agreement NDCs are implemented through the year 2030, and maintained thereafter. While this scenario represents an unprecedented global commitment to limit greenhouse gas emissions, it neither stabilizes climate nor limits climate change. The second scenario, Accelerated Actions, extends from the Paris Agreement’s initial NDCs and aligns with its long-term goals. This scenario aims to limit and stabilize human-induced global climate warming to 1.5 C by the end of this century with at least a 50 percent probability. Uncertainty is quantified using 400-member ensembles of projections for each scenario.

    This year’s report also includes a visualization tool that enables a higher-resolution exploration of both scenarios.

    Energy

    Between 2020 and 2050, population and economic growth are projected to drive continued increases in energy needs and electrification. Successful achievement of current Paris Agreement pledges will reinforce a shift away from fossil fuels, but additional actions will be required to accelerate the energy transition needed to cap global warming at 1.5 C by 2100.

    During this 30-year period under the Current Trends scenario, the share of fossil fuels in the global energy mix drops from 80 percent to 70 percent. Variable renewable energy (wind and solar) is the fastest growing energy source with more than an 8.6-fold increase. In the Accelerated Actions scenario, the share of low-carbon energy sources grows from 20 percent to slightly more than 60 percent, a much faster growth rate than in the Current Trends scenario; wind and solar energy undergo more than a 13.3-fold increase.

    While the electric power sector is expected to successfully scale up (with electricity production increasing by 73 percent under Current Trends, and 87 percent under Accelerated Actions) to accommodate increased demand (particularly for variable renewables), other sectors face stiffer challenges in their efforts to decarbonize.

    “Due to a sizeable need for hydrocarbons in the form of liquid and gaseous fuels for sectors such as heavy-duty long-distance transport, high-temperature industrial heat, agriculture, and chemical production, hydrogen-based fuels and renewable natural gas remain attractive options, but the challenges related to their scaling opportunities and costs must be resolved,” says MIT Joint Program Deputy Director Sergey Paltsev, a lead author of the 2023 Global Change Outlook.

    Water, food, and land

    With a global population projected to reach 9.9 billion by 2050, the Current Trends scenario indicates that more than half of the world’s population will experience pressures to its water supply, and that three of every 10 people will live in water basins where compounding societal and environmental pressures on water resources will be experienced. Population projections under combined water stress in all scenarios reveal that the Accelerated Actions scenario can reduce approximately 40 million of the additional 570 million people living in water-stressed basins at mid-century.

    Under the Current Trends scenario, agriculture and food production will keep growing. This will increase pressure for land-use change, water use, and use of energy-intensive inputs, which will also lead to higher greenhouse gas emissions. Under the Accelerated Actions scenario, less agricultural and food output is observed by 2050 compared to the Current Trends scenario, since this scenario affects economic growth and increases production costs. Livestock production is more greenhouse gas emissions-intensive than crop and food production, which, under carbon-pricing policies, drives demand downward and increases costs and prices. Such impacts are transmitted to the food sector and imply lower consumption of livestock-based products.

    Land-use changes in the Accelerated Actions scenario are similar to those in the Current Trends scenario by 2050, except for land dedicated to bioenergy production. At the world level, the Accelerated Actions scenario requires cropland area to increase by 1 percent and pastureland to decrease by 4.2 percent, but land use for bioenergy must increase by 44 percent.

    Climate trends

    Under the Current Trends scenario, the world is likely (more than 50 percent probability) to exceed 2 C global climate warming by 2060, 2.8 C by 2100, and 3.8 C by 2150. Our latest climate-model information indicates that maximum temperatures will likely outpace mean temperature trends over much of North and South America, Europe, northern and southeast Asia, and southern parts of Africa and Australasia. So as human-forced climate warming intensifies, these regions are expected to experience more pronounced record-breaking extreme heat events.

    Under the Accelerated Actions scenario, global temperature will continue to rise through the next two decades. But by 2050, global temperature will stabilize, and then slightly decline through the latter half of the century.

    “By 2100, the Accelerated Actions scenario indicates that the world can be virtually assured of remaining below 2 C of global warming,” says MIT Joint Program Deputy Director C. Adam Schlosser, a lead author of the report. “Nevertheless, additional policy mechanisms must be designed with more comprehensive targets that also support a cleaner environment, sustainable resources, as well as improved and equitable human health.”

    The Accelerated Actions scenario not only stabilizes global precipitation increase (by 2060), but substantially reduces the magnitude and potential range of increases to almost one-third of Current Trends global precipitation changes. Any global increase in precipitation heightens flood risk worldwide, so policies aligned with the Accelerated Actions scenario would considerably reduce that risk.

    Prospects for meeting Paris Agreement climate goals

    Numerous countries and regions are progressing in fulfilling their Paris Agreement pledges. Many have declared more ambitious greenhouse gas emissions-mitigation goals, while financing to assist the least-developed countries in sustainable development is not forthcoming at the levels needed. In this year’s Global Stocktake Synthesis Report, the U.N. Framework Convention on Climate Change evaluated emissions reductions communicated by the parties of the Paris Agreement and concluded that global emissions are not on track to fulfill the most ambitious long-term global temperature goals of the Paris Agreement (to keep warming well below 2 C — and, ideally, 1.5 C — above pre-industrial levels), and there is a rapidly narrowing window to raise ambition and implement existing commitments in order to achieve those targets. The Current Trends scenario arrives at the same conclusion.

    The 2023 Global Change Outlook finds that both global temperature targets remain achievable, but require much deeper near-term emissions reductions than those embodied in current NDCs.

    Reducing climate risk

    This report explores two well-known sets of risks posed by climate change. Research highlighted indicates that elevated climate-related physical risks will continue to evolve by mid-century, along with heightened transition risks that arise from shifts in the political, technological, social, and economic landscapes that are likely to occur during the transition to a low-carbon economy.

    “Our Outlook shows that without aggressive actions the world will surpass critical greenhouse gas concentration thresholds and climate targets in the coming decades,” says MIT Joint Program Director Ronald Prinn. “While the costs of inaction are getting higher, the costs of action are more manageable.” More

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    A mineral produced by plate tectonics has a global cooling effect, study finds

    MIT geologists have found that a clay mineral on the seafloor, called smectite, has a surprisingly powerful ability to sequester carbon over millions of years.

    Under a microscope, a single grain of the clay resembles the folds of an accordion. These folds are known to be effective traps for organic carbon.

    Now, the MIT team has shown that the carbon-trapping clays are a product of plate tectonics: When oceanic crust crushes against a continental plate, it can bring rocks to the surface that, over time, can weather into minerals including smectite. Eventually, the clay sediment settles back in the ocean, where the minerals trap bits of dead organisms in their microscopic folds. This keeps the organic carbon from being consumed by microbes and expelled back into the atmosphere as carbon dioxide.

    Over millions of years, smectite can have a global effect, helping to cool the entire planet. Through a series of analyses, the researchers showed that smectite was likely produced after several major tectonic events over the last 500 million years. During each tectonic event, the clays trapped enough carbon to cool the Earth and induce the subsequent ice age.

    The findings are the first to show that plate tectonics can trigger ice ages through the production of carbon-trapping smectite.

    These clays can be found in certain tectonically active regions today, and the scientists believe that smectite continues to sequester carbon, providing a natural, albeit slow-acting, buffer against humans’ climate-warming activities.

    “The influence of these unassuming clay minerals has wide-ranging implications for the habitability of planets,” says Joshua Murray, a graduate student in MIT’s Department of Earth, Atmospheric, and Planetary Sciences. “There may even be a modern application for these clays in offsetting some of the carbon that humanity has placed into the atmosphere.”

    Murray and Oliver Jagoutz, professor of geology at MIT, have published their findings today in Nature Geoscience.

    A clear and present clay

    The new study follows up on the team’s previous work, which showed that each of the Earth’s major ice ages was likely triggered by a tectonic event in the tropics. The researchers found that each of these tectonic events exposed ocean rocks called ophiolites to the atmosphere. They put forth the idea that, when a tectonic collision occurs in a tropical region, ophiolites can undergo certain weathering effects, such as exposure to wind, rain, and chemical interactions, that transform the rocks into various minerals, including clays.

    “Those clay minerals, depending on the kinds you create, influence the climate in different ways,” Murray explains.

    At the time, it was unclear which minerals could come out of this weathering effect, and whether and how these minerals could directly contribute to cooling the planet. So, while it appeared there was a link between plate tectonics and ice ages, the exact mechanism by which one could trigger the other was still in question.

    With the new study, the team looked to see whether their proposed tectonic tropical weathering process would produce carbon-trapping minerals, and in quantities that would be sufficient to trigger a global ice age.

    The team first looked through the geologic literature and compiled data on the ways in which major magmatic minerals weather over time, and on the types of clay minerals this weathering can produce. They then worked these measurements into a weathering simulation of different rock types that are known to be exposed in tectonic collisions.

    “Then we look at what happens to these rock types when they break down due to weathering and the influence of a tropical environment, and what minerals form as a result,” Jagoutz says.

    Next, they plugged each weathered, “end-product” mineral into a simulation of the Earth’s carbon cycle to see what effect a given mineral might have, either in interacting with organic carbon, such as bits of dead organisms, or with inorganic, in the form of carbon dioxide in the atmosphere.

    From these analyses, one mineral had a clear presence and effect: smectite. Not only was the clay a naturally weathered product of tropical tectonics, it was also highly effective at trapping organic carbon. In theory, smectite seemed like a solid connection between tectonics and ice ages.

    But were enough of the clays actually present to trigger the previous four ice ages? Ideally, researchers should confirm this by finding smectite in ancient rock layers dating back to each global cooling period.

    “Unfortunately, as clays are buried by other sediments, they get cooked a bit, so we can’t measure them directly,” Murray says. “But we can look for their fingerprints.”

    A slow build

    The team reasoned that, as smectites are a product of ophiolites, these ocean rocks also bear characteristic elements such as nickel and chromium, which would be preserved in ancient sediments. If smectites were present in the past, nickel and chromium should be as well.

    To test this idea, the team looked through a database containing thousands of oceanic sedimentary rocks that were deposited over the last 500 million years. Over this time period, the Earth experienced four separate ice ages. Looking at rocks around each of these periods, the researchers observed large spikes of nickel and chromium, and inferred from this that smectite must also have been present.

    By their estimates, the clay mineral could have increased the preservation of organic carbon by less than one-tenth of a percent. In absolute terms, this is a miniscule amount. But over millions of years, they calculated that the clay’s accumulated, sequestered carbon was enough to trigger each of the four major ice ages.

    “We found that you really don’t need much of this material to have a huge effect on the climate,” Jagoutz says.

    “These clays also have probably contributed some of the Earth’s cooling in the last 3 to 5 million years, before humans got involved,” Murray adds. “In the absence of humans, these clays are probably making a difference to the climate. It’s just such a slow process.”

    “Jagoutz and Murray’s work is a nice demonstration of how important it is to consider all biotic and physical components of the global carbon cycle,” says Lee Kump, a professor of geosciences at Penn State University, who was not involved with the study. “Feedbacks among all these components control atmospheric greenhouse gas concentrations on all time scales, from the annual rise and fall of atmospheric carbon dioxide levels to the swings from icehouse to greenhouse over millions of years.”

    Could smectites be harnessed intentionally to further bring down the world’s carbon emissions? Murray sees some potential, for instance to shore up carbon reservoirs such as regions of permafrost. Warming temperatures are predicted to melt permafrost and expose long-buried organic carbon. If smectites could be applied to these regions, the clays could prevent this exposed carbon from escaping into and further warming the atmosphere.

    “If you want to understand how nature works, you have to understand it on the mineral and grain scale,” Jagoutz says. “And this is also the way forward for us to find solutions for this climatic catastrophe. If you study these natural processes, there’s a good chance you will stumble on something that will be actually useful.”

    This research was funded, in part, by the National Science Foundation. More