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      Oceanographers record the largest predation event ever observed in the ocean

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      There is power in numbers, or so the saying goes. But in the ocean, scientists are finding that fish that group together don’t necessarily survive together. In some cases, the more fish there are, the larger a target they make for predators.This is what MIT and Norwegian oceanographers observed recently when they explored a wide swath of ocean off the coast of Norway during the height of spawning season for capelin — a small Arctic fish about the size of an anchovy. Billions of capelin migrate each February from the edge of the Arctic ice sheet southward to the Norwegian coast, to lay their eggs. Norway’s coastline is also a stopover for capelin’s primary predator, the Atlantic cod. As cod migrate south, they feed on spawning capelin, though scientists have not measured this process over large scales until now.Reporting their findings today in Nature Communications Biology, the MIT team captured interactions between individual migrating cod and spawning capelin, over a huge spatial extent. Using a sonic-based wide-area imaging technique, they watched as random capelin began grouping together to form a massive shoal spanning tens of kilometers. As the capelin shoal formed a sort of ecological “hotspot,” the team observed individual cod begin to group together in response, forming a huge shoal of their own. The swarming cod overtook the capelin, quickly consuming over 10 million fish, estimated to be more than half of the gathered prey.The dramatic encounter, which took place over just a few hours, is the largest such predation event ever recorded, both in terms of the number of individuals involved and the area over which the event occurred.This one event is unlikely to weaken the capelin population as a whole; the preyed-upon shoal represents 0.1 percent of the capelin that spawn in the region. However, as climate change causes the Arctic ice sheet to retreat, capelin will have to swim farther to spawn, making the species more stressed and vulnerable to natural predation events such as the one the team observed. As capelin sustains many fish species, including cod, continuously monitoring their behavior, at a resolution approaching that of individual fish and across large scales spanning tens of thousands of square kilometers, will help efforts to maintain the species and the health of the ocean overall.“In our work we are seeing that natural catastrophic predation events can change the local predator prey balance in a matter of hours,” says Nicholas Makris, professor of mechanical and ocean engineering at MIT. “That’s not an issue for a healthy population with many spatially distributed population centers or ecological hotspots. But as the number of these hotspots deceases due to climate and anthropogenic stresses, the kind of natural ‘catastrophic’ predation event we witnessed of a keystone species could lead to dramatic consequences for that species as well as the many species dependent on them.”Makris’ co-authors on the paper are Shourav Pednekar and Ankita Jain at MIT, and Olav Rune Godø of the Institute of Marine Research in Norway.Bell soundsFor their new study, Makris and his colleagues reanalyzed data that they gathered during a cruise in February of 2014 to the Barents Sea, off the coast of Norway. During that cruise, the team deployed the Ocean Acoustic Waveguide Remote Sensing (OAWRS) system — a sonic imaging technique that employs a vertical acoustic array, attached to the bottom of a boat, to send sound waves down into the ocean and out in all directions. These waves can travel over large distances as they bounce off any obstacles or fish in their path.The same or a second boat, towing an array of acoustic receivers, continuously picks up the scattered and reflected waves, from as far as many tens of kilometers away. Scientists can then analyze the collected waveforms to create instantaneous maps of the ocean over a huge areal extent.Previously, the team reconstructed maps of individual fish and their movements, but could not distinguish between different species. In the new study, the researchers applied a new “multispectral” technique to differentiate between species based on the characteristic acoustic resonance of their swim bladders.“Fish have swim bladders that resonate like bells,” Makris explains. “Cod have large swim bladders that have a low resonance, like a Big Ben bell, whereas capelin have tiny swim bladders that resonate like the highest notes on a piano.”By reanalyzing OAWRS data to look for specific frequencies of capelin versus cod, the researchers were able to image fish groups, determine their species content, and map the movements of each species over a huge areal extent.Watching a waveThe researchers applied the multi-spectral technique to OAWRS data collected on Feb. 27, 2014, at the peak of the capelin spawning season. In the early morning hours, their new mapping showed that capelin largely kept to themselves, moving as random individuals, in loose clusters along the Norwegian coastline. As the sun rose and lit the surface waters, the capelin began to descend to darker depths, possibly seeking places along the seafloor to spawn.The team observed that as the capelin descended, they began shifting from individual to group behavior, ultimately forming a huge shoal of about 23 million fish that moved in a coordinated wave spanning over ten kilometers long.“What we’re finding is capelin have this critical density, which came out of a physical theory, which we have now observed in the wild,” Makris says. “If they are close enough to each other, they can take on the average speed and direction of other fish that they can sense around them, and can then form a massive and coherent shoal.”As they watched, the shoaling fish began to move as one, in a coherent behavior that has been observed in other species but never in capelin until now. Such coherent migration is thought to help fish save energy over large distances by essentially riding the collective motion of the group.In this instance, however, as soon as the capelin shoal formed, it attracted increasing numbers of cod, which quickly formed a shoal of their own, amounting to about 2.5 million fish, based on the team’s acoustic mapping. Over a few short hours, the cod consumed 10.5 million capelin over tens of kilometers before both shoals dissolved and the fish scattered away. Makris suspects that such massive and coordinated predation is a common occurrence in the ocean, though this is the first time that scientists have been able to document such an event.“It’s the first time seeing predator-prey interaction on a huge scale, and it’s a coherent battle of survival,” Makris says. “This is happening over a monstrous scale, and we’re watching a wave of capelin zoom in, like a wave around a sports stadium, and they kind of gather together to form a defense. It’s also happening with the predators, coming together to coherently attack.”“This is a truly fascinating study that documents complex spatial dynamics linking predators and prey, here cod and capelin, at scales previously unachievable in marine ecosystems,” says George Rose, professor of fisheries at the University of British Columbia, who studies the ecology and productivity of cod in the North Atlantic, and was not involved in this work. “Simultaneous species mapping with the OAWRS system…enables insight into fundamental ecological processes with untold potential to enhance current survey methods.”Makris hopes to deploy OAWRS in the future to monitor the large-scale dynamics among other species of fish.“It’s been shown time and again that, when a population is on the verge of collapse, you will have that one last shoal. And when that last big, dense group is gone, there’s a collapse,” Makris says. “So you’ve got to know what’s there before it’s gone, because the pressures are not in their favor.”This work was supported, in part, by the U.S. Office of Naval Research and the Institute of Marine Research in Norway.  More

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      Study: Marshes provide cost-effective coastal protection

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      Images of coastal houses being carried off into the sea due to eroding coastlines and powerful storm surges are becoming more commonplace as climate change brings a rising sea level coupled with more powerful storms. In the U.S. alone, coastal storms caused $165 billion in losses in 2022.Now, a study from MIT shows that protecting and enhancing salt marshes in front of protective seawalls can significantly help protect some coastlines, at a cost that makes this approach reasonable to implement.The new findings are being reported in the journal Communications Earth and Environment, in a paper by MIT graduate student Ernie I. H. Lee and professor of civil and environmental engineering Heidi Nepf. This study, Nepf says, shows that restoring coastal marshes “is not just something that would be nice to do, but it’s actually economically justifiable.” The researchers found that, among other things, the wave-attenuating effects of salt marsh mean that the seawall behind it can be built significantly lower, reducing construction cost while still providing as much protection from storms.“One of the other exciting things that the study really brings to light,” Nepf says, “is that you don’t need a huge marsh to get a good effect. It could be a relatively short marsh, just tens of meters wide, that can give you benefit.” That makes her hopeful, Nepf says, that this information might be applied in places where planners may have thought saving a smaller marsh was not worth the expense. “We show that it can make enough of a difference to be financially viable,” she says.While other studies have previously shown the benefits of natural marshes in attenuating damaging storms, Lee says that such studies “mainly focus on landscapes that have a wide marsh on the order of hundreds of meters. But we want to show that it also applies in urban settings where not as much marsh land is available, especially since in these places existing gray infrastructure (seawalls) tends to already be in place.”The study was based on computer modeling of waves propagating over different shore profiles, using the morphology of various salt marsh plants — the height and stiffness of the plants, and their spatial density — rather than an empirical drag coefficient. “It’s a physically based model of plant-wave interaction, which allowed us to look at the influence of plant species and changes in morphology across seasons,” without having to go out and calibrate the vegetation drag coefficient with field measurements for each different condition, Nepf says.The researchers based their benefit-cost analysis on a simple metric: To protect a certain length of shoreline, how much could the height of a given seawall be reduced if it were accompanied by a given amount of marsh? Other ways of assessing the value, such as including the value of real estate that might be damaged by a given amount of flooding, “vary a lot depending on how you value the assets if a flood happens,” Lee says. “We use a more concrete value to quantify the benefits of salt marshes, which is the equivalent height of seawall you would need to deliver the same protection value.”They used models of a variety of plants, reflecting differences in height and the stiffness across different seasons. They found a twofold variation in the various plants’ effectiveness in attenuating waves, but all provided a useful benefit.To demonstrate the details in a real-world example and help to validate the simulations, Nepf and Lee studied local salt marshes in Salem, Massachusetts, where projects are already underway to try to restore marshes that had been degraded. Including the specific example provided a template for others, Nepf says. In Salem, their model showed that a healthy salt marsh could offset the need for an additional seawall height of 1.7 meters (about 5.5 feet), based on satisfying a rate of wave overtopping that was set for the safety of pedestrians.However, the real-world data needed to model a marsh, including maps of salt marsh species, plant height, and shoots per bed area, are “very labor-intensive” to put together, Nepf says. Lee is now developing a method to use drone imaging and machine learning to facilitate this mapmaking. Nepf says this will enable researchers or planners to evaluate a given area of marshland and say, “How much is this marsh worth in terms of its ability to reduce flooding?”The White House Office of Information and Regulatory Affairs recently released guidance for assessing the value of ecosystem services in planning of federal projects, Nepf explains.  “But in many scenarios, it lacks specific methods for quantifying value, and this study is meeting that need,” she says.The Federal Emergency Management Agency also has a benefit-cost analysis (BCA) toolkit, Lee notes. “They have guidelines on how to quantify each of the environmental services, and one of the novelties of this paper is quantifying the cost and the protection value of marshes. This is one of the applications that policymakers can consider on how to quantify the environmental service values of marshes,” he says.The software that environmental engineers can apply to specific sites has been made available online for free on GitHub. “It’s a one-dimensional model accessible by a standard consulting firm,” Nepf says.“This paper presents a practical tool for translating the wave attenuation capabilities of marshes into economic values, which could assist decision-makers in the adaptation of marshes for nature-based coastal defense,” says Xioaxia Zhang, a professor at Shenzen University in China who was not involved in this work. “The results indicate that salt marshes are not only environmentally beneficial but also cost-effective.”The study “is a very important and crucial step to quantifying the protective value of marshes,” adds Bas Borsje, an associate professor of nature-based flood protection at the University of Twente in the Netherlands, who was not associated with this work. “The most important step missing at the moment is how to translate our findings to the decision makers. This is the first time I’m aware of that decision-makers are quantitatively informed on the protection value of salt marshes.”Lee received support for this work from the Schoettler Scholarship Fund, administered by the MIT Department of Civil and Environmental Engineering. More

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      MIT Energy and Climate Club mobilizes future leaders to address global climate issues

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      One of MIT’s missions is helping to solve the world’s greatest problems — with a large focus on one of the most pressing topics facing the world today, climate change.The MIT Energy and Climate Club, (MITEC) formerly known as the MIT Energy Club, has been working since 2004 to inform and educate the entire MIT community about this urgent issue and other related matters.MITEC, one of the largest clubs on campus, has hundreds of active members from every major, including both undergraduate and graduate students. With a broad reach across the Institute, MITEC is the hub for thought leadership and relationship-building across campus.The club’s co-presidents Laurențiu Anton, doctoral candidate in electrical engineering and computer science; Rosie Keller, an MBA student in the MIT Sloan School of Management; and Thomas Lee, doctoral candidate in the Institute for Data, Systems, and Society, say that faculty, staff, and alumni are also welcome to join and interact with the continuously growing club.While they closely collaborate on all aspects of the club, each of the co-presidents has a focus area to support the student managing directors and vice presidents for several of the club’s committees. Keller oversees the External Relations, Social, Launchpad, and Energy and Climate Hackathon leadership teams. Lee supports the leadership team for next spring’s Energy Conference. He also assists the club treasurer on budget and finance and guides the industry Sponsorships team. Anton oversees marketing, community and education as well as the Energy and Climate Night and Energy and Climate Career Fair leadership teams.“We think of MITEC as the umbrella of all things related to energy and climate on campus. Our goal is to share actionable information and not just have discussions. We work with other organizations on campus, including the MIT Environmental Solutions Initiative, to bring awareness,” says Anton. “Our Community and Education team is currently working with the MIT ESI [Environmental Solutions Initiative] to create an ecosystem map that we’re excited to produce for the MIT community.”To share their knowledge and get more people interested in solving climate and energy problems, each year MITEC hosts a variety of events including the MIT Energy and Climate Night, the MIT Energy and Climate Hack, the MIT Energy and Climate Career Fair, and the MIT Energy Conference to be held next spring March 3-4. The club also offers students the opportunity to gain valuable work experience while engaging with top companies, such as Constellation Energy and GE Vernova, on real climate and energy issues through their Launchpad Program.Founded in 2006, the annual MIT Energy Conference is the largest student-run conference in North America focused on energy and climate issues, where hundreds of participants gather every year with the CEOs, policymakers, investors, and scholars at the forefront of the global energy transition.“The 2025 MIT Energy Conference’s theme is ‘Breakthrough to Deployment: Driving Climate Innovation to Market’ — which focuses on the importance of both cutting-edge research innovation as well as large-scale commercial deployment to successfully reach climate goals,” says Lee.Anton notes that the first of four MITEC flagship events the MIT Energy and Climate Night. This research symposium that takes place every year in the fall at the MIT Museum will be held on Nov. 8. The club invites a select number of keynote speakers and several dozen student posters. Guests are allowed to walk around and engage with students, and in return students get practice showcasing their research. The club’s career fair will take place in the spring semester, shortly after Independent Activities Period.MITEC also provides members opportunities to meet with companies that are working to improve the energy sector, which helps to slow down, as well as adapt to, the effects of climate change.“We recently went to Provincetown and toured Eversource’s battery energy storage facility. This helped open doors for club members,” says Keller. “The Provincetown battery helps address grid reliability problems after extreme storms on Cape Cod — which speaks to energy’s connection to both the mitigation and adaptation aspects of climate change,” adds Lee.“MITEC is also a great way to meet other students at MIT that you might not otherwise have a chance to,” says Keller.“We’d always welcome more undergraduate students to join MITEC. There are lots of leadership opportunities within the club for them to take advantage of and build their resumes. We also have good and growing collaboration between different centers on campus such as the Sloan Sustainability Initiative and the MIT Energy Initiative. They support us with resources, introductions, and help amplify what we’re doing. But students are the drivers of the club and set the agendas,” says Lee.All three co-presidents are excited to hear that MIT President Sally Kornbluth wants to bring climate change solutions to the next level, and that she recently launched The Climate Project at MIT to kick off the Institute’s major new effort to accelerate and scale up climate change solutions.“We look forward to connecting with the new directors of the Climate Project at MIT and Interim Vice President for Climate Change Richard Lester in the near future. We are eager to explore how MITEC can support and collaborate with the Climate Project at MIT,” says Anton.Lee, Keller, and Anton want MITEC to continue fostering solutions to climate issues. They emphasized that while individual actions like bringing your own thermos, using public transportation, or recycling are necessary, there’s a bigger picture to consider. They encourage the MIT community to think critically about the infrastructure and extensive supply chains behind the products everyone uses daily.“It’s not just about bringing a thermos; it’s also understanding the life cycle of that thermos, from production to disposal, and how our everyday choices are interconnected with global climate impacts,” says Anton.“Everyone should get involved with this worldwide problem. We’d like to see more people think about how they can use their careers for change. To think how they can navigate the type of role they can play — whether it’s in finance or on the technical side. I think exploring what that looks like as a career is also a really interesting way of thinking about how to get involved with the problem,” says Keller.“MITEC’s newsletter reaches more than 4,000 people. We’re grateful that so many people are interested in energy and climate change,” says Anton. More

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      Bubble findings could unlock better electrode and electrolyzer designs

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      Industrial electrochemical processes that use electrodes to produce fuels and chemical products are hampered by the formation of bubbles that block parts of the electrode surface, reducing the area available for the active reaction. Such blockage reduces the performance of the electrodes by anywhere from 10 to 25 percent.But new research reveals a decades-long misunderstanding about the extent of that interference. The findings show exactly how the blocking effect works and could lead to new ways of designing electrode surfaces to minimize inefficiencies in these widely used electrochemical processes.It has long been assumed that the entire area of the electrode shadowed by each bubble would be effectively inactivated. But it turns out that a much smaller area — roughly the area where the bubble actually contacts the surface — is blocked from its electrochemical activity. The new insights could lead directly to new ways of patterning the surfaces to minimize the contact area and improve overall efficiency.The findings are reported today in the journal Nanoscale, in a paper by recent MIT graduate Jack Lake PhD ’23, graduate student Simon Rufer, professor of mechanical engineering Kripa Varanasi, research scientist Ben Blaiszik, and six others at the University of Chicago and Argonne National Laboratory. The team has made available an open-source, AI-based software tool that engineers and scientists can now use to automatically recognize and quantify bubbles formed on a given surface, as a first step toward controlling the electrode material’s properties.

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      Gas-evolving electrodes, often with catalytic surfaces that promote chemical reactions, are used in a wide variety of processes, including the production of “green” hydrogen without the use of fossil fuels, carbon-capture processes that can reduce greenhouse gas emissions, aluminum production, and the chlor-alkali process that is used to make widely used chemical products.These are very widespread processes. The chlor-alkali process alone accounts for 2 percent of all U.S. electricity usage; aluminum production accounts for 3 percent of global electricity; and both carbon capture and hydrogen production are likely to grow rapidly in coming years as the world strives to meet greenhouse-gas reduction targets. So, the new findings could make a real difference, Varanasi says.“Our work demonstrates that engineering the contact and growth of bubbles on electrodes can have dramatic effects” on how bubbles form and how they leave the surface, he says. “The knowledge that the area under bubbles can be significantly active ushers in a new set of design rules for high-performance electrodes to avoid the deleterious effects of bubbles.”“The broader literature built over the last couple of decades has suggested that not only that small area of contact but the entire area under the bubble is passivated,” Rufer says. The new study reveals “a significant difference between the two models because it changes how you would develop and design an electrode to minimize these losses.”To test and demonstrate the implications of this effect, the team produced different versions of electrode surfaces with patterns of dots that nucleated and trapped bubbles at different sizes and spacings. They were able to show that surfaces with widely spaced dots promoted large bubble sizes but only tiny areas of surface contact, which helped to make clear the difference between the expected and actual effects of bubble coverage.Developing the software to detect and quantify bubble formation was necessary for the team’s analysis, Rufer explains. “We wanted to collect a lot of data and look at a lot of different electrodes and different reactions and different bubbles, and they all look slightly different,” he says. Creating a program that could deal with different materials and different lighting and reliably identify and track the bubbles was a tricky process, and machine learning was key to making it work, he says.Using that tool, he says, they were able to collect “really significant amounts of data about the bubbles on a surface, where they are, how big they are, how fast they’re growing, all these different things.” The tool is now freely available for anyone to use via the GitHub repository.By using that tool to correlate the visual measures of bubble formation and evolution with electrical measurements of the electrode’s performance, the researchers were able to disprove the accepted theory and to show that only the area of direct contact is affected. Videos further proved the point, revealing new bubbles actively evolving directly under parts of a larger bubble.The researchers developed a very general methodology that can be applied to characterize and understand the impact of bubbles on any electrode or catalyst surface. They were able to quantify the bubble passivation effects in a new performance metric they call BECSA (Bubble-induced electrochemically active surface), as opposed to ECSA (electrochemically active surface area), that is used in the field. “The BECSA metric was a concept we defined in an earlier study but did not have an effective method to estimate until this work,” says Varanasi.The knowledge that the area under bubbles can be significantly active ushers in a new set of design rules for high-performance electrodes. This means that electrode designers should seek to minimize bubble contact area rather than simply bubble coverage, which can be achieved by controlling the morphology and chemistry of the electrodes. Surfaces engineered to control bubbles can not only improve the overall efficiency of the processes and thus reduce energy use, they can also save on upfront materials costs. Many of these gas-evolving electrodes are coated with catalysts made of expensive metals like platinum or iridium, and the findings from this work can be used to engineer electrodes to reduce material wasted by reaction-blocking bubbles.Varanasi says that “the insights from this work could inspire new electrode architectures that not only reduce the usage of precious materials, but also improve the overall electrolyzer performance,” both of which would provide large-scale environmental benefits.The research team included Jim James, Nathan Pruyne, Aristana Scourtas, Marcus Schwarting, Aadit Ambalkar, Ian Foster, and Ben Blaiszik at the University of Chicago and Argonne National Laboratory. The work was supported by the U.S. Department of Energy under the ARPA-E program. More

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      Solar-powered desalination system requires no extra batteries

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      MIT engineers have built a new desalination system that runs with the rhythms of the sun.The solar-powered system removes salt from water at a pace that closely follows changes in solar energy. As sunlight increases through the day, the system ramps up its desalting process and automatically adjusts to any sudden variation in sunlight, for example by dialing down in response to a passing cloud or revving up as the skies clear.Because the system can quickly react to subtle changes in sunlight, it maximizes the utility of solar energy, producing large quantities of clean water despite variations in sunlight throughout the day. In contrast to other solar-driven desalination designs, the MIT system requires no extra batteries for energy storage, nor a supplemental power supply, such as from the grid.The engineers tested a community-scale prototype on groundwater wells in New Mexico over six months, working in variable weather conditions and water types. The system harnessed on average over 94 percent of the electrical energy generated from the system’s solar panels to produce up to 5,000 liters of water per day despite large swings in weather and available sunlight.“Conventional desalination technologies require steady power and need battery storage to smooth out a variable power source like solar. By continually varying power consumption in sync with the sun, our technology directly and efficiently uses solar power to make water,” says Amos Winter, the Germeshausen Professor of Mechanical Engineering and director of the K. Lisa Yang Global Engineering and Research (GEAR) Center at MIT. “Being able to make drinking water with renewables, without requiring battery storage, is a massive grand challenge. And we’ve done it.”The system is geared toward desalinating brackish groundwater — a salty source of water that is found in underground reservoirs and is more prevalent than fresh groundwater resources. The researchers see brackish groundwater as a huge untapped source of potential drinking water, particularly as reserves of fresh water are stressed in parts of the world. They envision that the new renewable, battery-free system could provide much-needed drinking water at low costs, especially for inland communities where access to seawater and grid power are limited.“The majority of the population actually lives far enough from the coast, that seawater desalination could never reach them. They consequently rely heavily on groundwater, especially in remote, low-income regions. And unfortunately, this groundwater is becoming more and more saline due to climate change,” says Jonathan Bessette, MIT PhD student in mechanical engineering. “This technology could bring sustainable, affordable clean water to underreached places around the world.”The researchers report details the new system in a paper appearing today in Nature Water. The study’s co-authors are Bessette, Winter, and staff engineer Shane Pratt.Pump and flowThe new system builds on a previous design, which Winter and his colleagues, including former MIT postdoc Wei He, reported earlier this year. That system aimed to desalinate water through “flexible batch electrodialysis.”Electrodialysis and reverse osmosis are two of the main methods used to desalinate brackish groundwater. With reverse osmosis, pressure is used to pump salty water through a membrane and filter out salts. Electrodialysis uses an electric field to draw out salt ions as water is pumped through a stack of ion-exchange membranes.Scientists have looked to power both methods with renewable sources. But this has been especially challenging for reverse osmosis systems, which traditionally run at a steady power level that’s incompatible with naturally variable energy sources such as the sun.Winter, He, and their colleagues focused on electrodialysis, seeking ways to make a more flexible, “time-variant” system that would be responsive to variations in renewable, solar power.In their previous design, the team built an electrodialysis system consisting of water pumps, an ion-exchange membrane stack, and a solar panel array. The innovation in this system was a model-based control system that used sensor readings from every part of the system to predict the optimal rate at which to pump water through the stack and the voltage that should be applied to the stack to maximize the amount of salt drawn out of the water.When the team tested this system in the field, it was able to vary its water production with the sun’s natural variations. On average, the system directly used 77 percent of the available electrical energy produced by the solar panels, which the team estimated was 91 percent more than traditionally designed solar-powered electrodialysis systems.Still, the researchers felt they could do better.“We could only calculate every three minutes, and in that time, a cloud could literally come by and block the sun,” Winter says. “The system could be saying, ‘I need to run at this high power.’ But some of that power has suddenly dropped because there’s now less sunlight. So, we had to make up that power with extra batteries.”Solar commandsIn their latest work, the researchers looked to eliminate the need for batteries, by shaving the system’s response time to a fraction of a second. The new system is able to update its desalination rate, three to five times per second. The faster response time enables the system to adjust to changes in sunlight throughout the day, without having to make up any lag in power with additional power supplies.The key to the nimbler desalting is a simpler control strategy, devised by Bessette and Pratt. The new strategy is one of “flow-commanded current control,” in which the system first senses the amount of solar power that is being produced by the system’s solar panels. If the panels are generating more power than the system is using, the controller automatically “commands” the system to dial up its pumping, pushing more water through the electrodialysis stacks. Simultaneously, the system diverts some of the additional solar power by increasing the electrical current delivered to the stack, to drive more salt out of the faster-flowing water.“Let’s say the sun is rising every few seconds,” Winter explains. “So, three times a second, we’re looking at the solar panels and saying, ‘Oh, we have more power — let’s bump up our flow rate and current a little bit.’ When we look again and see there’s still more excess power, we’ll up it again. As we do that, we’re able to closely match our consumed power with available solar power really accurately, throughout the day. And the quicker we loop this, the less battery buffering we need.”The engineers incorporated the new control strategy into a fully automated system that they sized to desalinate brackish groundwater at a daily volume that would be enough to supply a small community of about 3,000 people. They operated the system for six months on several wells at the Brackish Groundwater National Desalination Research Facility in Alamogordo, New Mexico. Throughout the trial, the prototype operated under a wide range of solar conditions, harnessing over 94 percent of the solar panel’s electrical energy, on average, to directly power desalination.“Compared to how you would traditionally design a solar desal system, we cut our required battery capacity by almost 100 percent,” Winter says.The engineers plan to further test and scale up the system in hopes of supplying larger communities, and even whole municipalities, with low-cost, fully sun-driven drinking water.“While this is a major step forward, we’re still working diligently to continue developing lower cost, more sustainable desalination methods,” Bessette says.“Our focus now is on testing, maximizing reliability, and building out a product line that can provide desalinated water using renewables to multiple markets around the world,” Pratt adds.The team will be launching a company based on their technology in the coming months.This research was supported in part by the National Science Foundation, the Julia Burke Foundation, and the MIT Morningside Academy of Design. This work was additionally supported in-kind by Veolia Water Technologies and Solutions and Xylem Goulds.  More

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      Study evaluates impacts of summer heat in U.S. prison environments

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      When summer temperatures spike, so does our vulnerability to heat-related illness or even death. For the most part, people can take measures to reduce their heat exposure by opening a window, turning up the air conditioning, or simply getting a glass of water. But for people who are incarcerated, freedom to take such measures is often not an option. Prison populations therefore are especially vulnerable to heat exposure, due to their conditions of confinement.A new study by MIT researchers examines summertime heat exposure in prisons across the United States and identifies characteristics within prison facilities that can further contribute to a population’s vulnerability to summer heat.The study’s authors used high-spatial-resolution air temperature data to determine the daily average outdoor temperature for each of 1,614 prisons in the U.S., for every summer between the years 1990 and 2023. They found that the prisons that are exposed to the most extreme heat are located in the southwestern U.S., while prisons with the biggest changes in summertime heat, compared to the historical record, are in the Pacific Northwest, the Northeast, and parts of the Midwest.Those findings are not entirely unique to prisons, as any non-prison facility or community in the same geographic locations would be exposed to similar outdoor air temperatures. But the team also looked at characteristics specific to prison facilities that could further exacerbate an incarcerated person’s vulnerability to heat exposure. They identified nine such facility-level characteristics, such as highly restricted movement, poor staffing, and inadequate mental health treatment. People living and working in prisons with any one of these characteristics may experience compounded risk to summertime heat. The team also looked at the demographics of 1,260 prisons in their study and found that the prisons with higher heat exposure on average also had higher proportions of non-white and Hispanic populations. The study, appearing today in the journal GeoHealth, provides policymakers and community leaders with ways to estimate, and take steps to address, a prison population’s heat risk, which they anticipate could worsen with climate change.“This isn’t a problem because of climate change. It’s becoming a worse problem because of climate change,” says study lead author Ufuoma Ovienmhada SM ’20, PhD ’24, a graduate of the MIT Media Lab, who recently completed her doctorate in MIT’s Department of Aeronautics and Astronautics (AeroAstro). “A lot of these prisons were not built to be comfortable or humane in the first place. Climate change is just aggravating the fact that prisons are not designed to enable incarcerated populations to moderate their own exposure to environmental risk factors such as extreme heat.”The study’s co-authors include Danielle Wood, MIT associate professor of media arts and sciences, and of AeroAstro; and Brent Minchew, MIT associate professor of geophysics in the Department of Earth, Atmospheric and Planetary Sciences; along with Ahmed Diongue ’24, Mia Hines-Shanks of Grinnell College, and Michael Krisch of Columbia University.Environmental intersectionsThe new study is an extension of work carried out at the Media Lab, where Wood leads the Space Enabled research group. The group aims to advance social and environmental justice issues through the use of satellite data and other space-enabled technologies.The group’s motivation to look at heat exposure in prisons came in 2020 when, as co-president of MIT’s Black Graduate Student Union, Ovienmhada took part in community organizing efforts following the murder of George Floyd by Minneapolis police.“We started to do more organizing on campus around policing and reimagining public safety. Through that lens I learned more about police and prisons as interconnected systems, and came across this intersection between prisons and environmental hazards,” says Ovienmhada, who is leading an effort to map the various environmental hazards that prisons, jails, and detention centers face. “In terms of environmental hazards, extreme heat causes some of the most acute impacts for incarcerated people.”She, Wood, and their colleagues set out to use Earth observation data to characterize U.S. prison populations’ vulnerability, or their risk of experiencing negative impacts, from heat.The team first looked through a database maintained by the U.S. Department of Homeland Security that lists the location and boundaries of carceral facilities in the U.S. From the database’s more than 6,000 prisons, jails, and detention centers, the researchers highlighted 1,614 prison-specific facilities, which together incarcerate nearly 1.4 million people, and employ about 337,000 staff.They then looked to Daymet, a detailed weather and climate database that tracks daily temperatures across the United States, at a 1-kilometer resolution. For each of the 1,614 prison locations, they mapped the daily outdoor temperature, for every summer between the years 1990 to 2023, noting that the majority of current state and federal correctional facilities in the U.S. were built by 1990.The team also obtained U.S. Census data on each facility’s demographic and facility-level characteristics, such as prison labor activities and conditions of confinement. One limitation of the study that the researchers acknowledge is a lack of information regarding a prison’s climate control.“There’s no comprehensive public resource where you can look up whether a facility has air conditioning,” Ovienmhada notes. “Even in facilities with air conditioning, incarcerated people may not have regular access to those cooling systems, so our measurements of outdoor air temperature may not be far off from reality.”Heat factorsFrom their analysis, the researchers found that more than 98 percent of all prisons in the U.S. experienced at least 10 days in the summer that were hotter than every previous summer, on average, for a given location. Their analysis also revealed the most heat-exposed prisons, and the prisons that experienced the highest temperatures on average, were mostly in the Southwestern U.S. The researchers note that with the exception of New Mexico, the Southwest is a region where there are no universal air conditioning regulations in state-operated prisons.“States run their own prison systems, and there is no uniformity of data collection or policy regarding air conditioning,” says Wood, who notes that there is some information on cooling systems in some states and individual prison facilities, but the data is sparse overall, and too inconsistent to include in the group’s nationwide study.While the researchers could not incorporate air conditioning data, they did consider other facility-level factors that could worsen the effects that outdoor heat triggers. They looked through the scientific literature on heat, health impacts, and prison conditions, and focused on 17 measurable facility-level variables that contribute to heat-related health problems. These include factors such as overcrowding and understaffing.“We know that whenever you’re in a room that has a lot of people, it’s going to feel hotter, even if there’s air conditioning in that environment,” Ovienmhada says. “Also, staffing is a huge factor. Facilities that don’t have air conditioning but still try to do heat risk-mitigation procedures might rely on staff to distribute ice or water every few hours. If that facility is understaffed or has neglectful staff, that may increase people’s susceptibility to hot days.”The study found that prisons with any of nine of the 17 variables showed statistically significant greater heat exposures than the prisons without those variables. Additionally, if a prison exhibits any one of the nine variables, this could worsen people’s heat risk through the combination of elevated heat exposure and vulnerability. The variables, they say, could help state regulators and activists identify prisons to prioritize for heat interventions.“The prison population is aging, and even if you’re not in a ‘hot state,’ every state has responsibility to respond,” Wood emphasizes. “For instance, areas in the Northwest, where you might expect to be temperate overall, have experienced a number of days in recent years of increasing heat risk. A few days out of the year can still be dangerous, particularly for a population with reduced agency to regulate their own exposure to heat.”This work was supported, in part, by NASA, the MIT Media Lab, and MIT’s Institute for Data, Systems and Society’s Research Initiative on Combatting Systemic Racism. More

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      Liftoff: The Climate Project at MIT takes flight

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      The leaders of The Climate Project at MIT met with community members at a campus forum on Monday, helping to kick off the Institute’s major new effort to accelerate and scale up climate change solutions.“The Climate Project is a whole-of-MIT mobilization,” MIT President Sally Kornbluth said in her opening remarks. “It’s designed to focus the Institute’s talent and resources so that we can achieve much more, faster, in terms of real-world impact, from mitigation to adaptation.”The event, “Climate Project at MIT: Launching the Missions,” drew a capacity crowd to MIT’s Samberg Center.While the Climate Project has a number of facets, a central component of the effort consists of its six “missions,” broad areas where MIT researchers will seek to identify gaps in the global climate response that MIT can help fill, and then launch and execute research and innovation projects aimed at those areas. Each mission is led by campus faculty, and Monday’s event represented the first public conversation between the mission directors and the larger campus community.“Today’s event is an important milestone,” said Richard Lester, MIT’s interim vice president for climate and the Japan Steel Industry Professor of Nuclear Science and Engineering, who led the Climate Project’s formation. He praised Kornbluth’s sustained focus on climate change as a leading priority for MIT.“The reason we’re all here is because of her leadership and vision for MIT,” Lester said. “We’re also here because the MIT community — our faculty, our staff, our students — has made it abundantly clear that it wants to do more, much more, to help solve this great problem.”The mission directors themselves emphasized the need for deep community involvement in the project — and that the Climate Project is designed to facilitate researcher-driven enterprise across campus.“There’s a tremendous amount of urgency,” said Elsa Olivetti PhD ’07, director of the Decarbonizing Energy and Industry mission, during an onstage discussion. “We all need to do everything we can, and roll up our sleeves and get it done.” Olivetti, the Jerry McAfee Professor in Engineering, has been a professor of materials science and engineering at the Institute since 2014.“What’s exciting about this is the chance of MIT really meeting its potential,” said Jesse Kroll, co-director of the mission for Restoring the Atmosphere, Protecting the Land and Oceans. Kroll is the Peter de Florez Professor in MIT’s Department of Civil and Environmental Engineering, a professor of chemical engineering, and the director of the Ralph M. Parsons Laboratory.MIT, Kroll noted, features “so much amazing work going on in all these different aspects of the problem. Science, engineering, social science … we put it all together and there is huge potential, a huge opportunity for us to make a difference.”MIT has pledged an initial $75 million to the Climate Project, including $25 million from the MIT Sloan School of Management for a complementary effort, the MIT Climate Policy Center. However, the Institute is anticipating that it will also build new connections with outside partners, whose role in implementing and scaling Climate Project solutions will be critical.Monday’s event included a keynote talk from Brian Deese, currently the MIT Innovation and Climate Impact Fellow and the former director of the White House National Economic Council in the Biden administration.“The magnitude of the risks associated with climate change are extraordinary,” Deese said. However, he added, “these are solvable issues. In fact, the energy transition globally will be the greatest economic opportunity in human history. … It has the potential to actually lift people out of poverty, it has the potential to drive international cooperation, it has the potential to drive innovation and improve lives — if we get this right.”Deese’s remarks centered on a call for the U.S. to develop a current-day climate equivalent of the Marshall Plan, the U.S. initiative to provide aid to Western Europe after World War II. He also suggested three characteristics of successful climate projects, noting that many would be interdisciplinary in nature and would “engage with policy early in the design process” to become feasible.In addition to those features, Deese said, people need to “start and end with very high ambition” when working on climate solutions. He added: “The good thing about MIT and our community is that we, you, have done this before. We’ve got examples where MIT has taken something that seemed completely improbable and made it possible, and I believe that part of what is required of this collective effort is to keep that kind of audacious thinking at the top of our mind.” The MIT mission directors all participated in an onstage discussion moderated by Somini Sengupta, the international climate reporter on the climate team of The New York Times. Sengupta asked the group about a wide range of topics, from their roles and motivations to the political constraints on global climate progress, and more.Andrew Babbin, co-director of the mission for Restoring the Atmosphere, Protecting the Land and Oceans, defined part of the task of the MIT missions as “identifying where those gaps of knowledge are and filling them rapidly,” something he believes is “largely not doable in the conventional way,” based on small-scale research projects. Instead, suggested Babbin, who is the Cecil and Ida Green Career Development Professor in MIT’s Program in Atmospheres, Oceans, and Climate, the collective input of research and innovation communities could help zero in on undervalued approaches to climate action.Some innovative concepts, the mission directors noted, can be tried out on the MIT campus, in an effort to demonstrate how a more sustainable infrastructure and systems can operate at scale.“That is absolutely crucial,” said Christoph Reinhart, director of the Building and Adapting Healthy, Resilient Cities mission, expressing the need to have the campus reach net-zero emissions. Reinhart is the Alan and Terri Spoon Professor of Architecture and Climate and director of MIT’s Building Technology Program in the School of Architecture and Planning.In response to queries from Sengupta, the mission directors affirmed that the Climate Project needs to develop solutions that can work in different societies around the world, while acknowledging that there are many political hurdles to worldwide climate action.“Any kind of quality engaged projects that we’ve done with communities, it’s taken years to build trust. … How you scale that without compromising is the challenge I’m faced with,” said Miho Mazereeuw, director of the Empowering Frontline Communities mission, an associate professor of architecture and urbanism, and director of MIT’s Urban Risk Lab.“I think we will impact different communities in different parts of the world in different ways,” said Benedetto Marelli, an associate professor in MIT’s Department of Civil and Environmental Engineering, adding that it would be important to “work with local communities [and] engage stakeholders, and at the same time, use local brains to solve the problem.” The mission he directs, Wild Cards, is centered on identifying unconventional solutions that are high risk and also high reward.Any climate program “has to be politically feasible, it has to be in separate nations’ self-interest,” said Christopher Knittel, mission director for Inventing New Policy Approaches. In an ever-shifting political world, he added, that means people must “think about not just the policy but the resiliency of the policy.” Knittel is the George P. Shultz Professor and professor of applied economics at the MIT Sloan School of Management, director of the MIT Climate Policy Center, and associate dean for Climate and Sustainability.In all, MIT has more than 300 faculty and senior researchers who, along with their students and staff, are already working on climate issues.Kornbluth, for her part, referred to MIT’s first-year students while discussing the larger motivations for taking concerted action to address the challenges of climate change. It might be easy for younger people to despair over the world’s climate trajectory, she noted, but the best response to that includes seeking new avenues for climate progress.“I understand their anxiety and concern,” Kornbluth said. “But I have no doubt at all that together, we can make a difference. I believe that we have a special obligation to the new students and their entire generation to do everything we can to create a positive change. The most powerful antidote to defeat and despair is collection action.” More

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      3 Questions: The past, present, and future of sustainability science

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      It was 1978, over a decade before the word “sustainable” would infiltrate environmental nomenclature, and Ronald Prinn, MIT professor of atmospheric science, had just founded the Advanced Global Atmospheric Gases Experiment (AGAGE). Today, AGAGE provides real-time measurements for well over 50 environmentally harmful trace gases, enabling us to determine emissions at the country level, a key element in verifying national adherence to the Montreal Protocol and the Paris Accord. This, Prinn says, started him thinking about doing science that informed decision making.Much like global interest in sustainability, Prinn’s interest and involvement continued to grow into what would become three decades worth of achievements in sustainability science. The Center for Global Change Science (CGCS) and Joint Program on the Science and Policy Global Change, respectively founded and co-founded by Prinn, have recently joined forces to create the MIT School of Science’s new Center for Sustainability Science and Strategy (CS3), lead by former CGCS postdoc turned MIT professor, Noelle Selin.As he prepares to pass the torch, Prinn reflects on how far sustainability has come, and where it all began.Q: Tell us about the motivation for the MIT centers you helped to found around sustainability.A: In 1990 after I founded the Center for Global Change Science, I also co-founded the Joint Program on the Science and Policy Global Change with a very important partner, [Henry] “Jake” Jacoby. He’s now retired, but at that point he was a professor in the MIT Sloan School of Management. Together, we determined that in order to answer questions related to what we now call sustainability of human activities, you need to combine the natural and social sciences involved in these processes. Based on this, we decided to make a joint program between the CGCS and a center that he directed, the Center for Energy and Environmental Policy Research (CEEPR).It was called the “joint program” and was joint for two reasons — not only were two centers joining, but two disciplines were joining. It was not about simply doing the same science. It was about bringing a team of people together that could tackle these coupled issues of environment, human development and economy. We were the first group in the world to fully integrate these elements together.Q: What has been your most impactful contribution and what effect did it have on the greater public’s overall understanding?A: Our biggest contribution is the development, and more importantly, the application of the Integrated Global System Model [IGSM] framework, looking at human development in both developing countries and developed countries that had a significant impact on the way people thought about climate issues. With IGSM, we were able to look at the interactions among human and natural components, studying the feedbacks and impacts that climate change had on human systems; like how it would alter agriculture and other land activities, how it would alter things we derive from the ocean, and so on.Policies were being developed largely by economists or climate scientists working independently, and we started showing how the real answers and analysis required a coupling of all of these components. We showed, and I think convincingly, that what people used to study independently, must be coupled together, because the impacts of climate change and air pollution affected so many things.To address the value of policy, despite the uncertainty in climate projections, we ran multiple runs of the IGSM with and without policy, with different choices for uncertain IGSM variables. For public communication, around 2005, we introduced our signature Greenhouse Gamble interactive visualization tools; these have been renewed over time as science and policies evolved.Q: What can MIT provide now at this critical juncture in understanding climate change and its impact?A: We need to further push the boundaries of integrated global system modeling to ensure full sustainability of human activity and all of its beneficial dimensions, which is the exciting focus that the CS3 is designed to address. We need to focus on sustainability as a central core element and use it to not just analyze existing policies but to propose new ones. Sustainability is not just climate or air pollution, it’s got to do with human impacts in general. Human health is central to sustainability, and equally important to equity. We need to expand the capability for credibly assessing what the impact policies have not just on developed countries, but on developing countries, taking into account that many places around the world are at artisanal levels of their economies. They cannot be blamed for anything that is changing climate and causing air pollution and other detrimental things that are currently going on. They need our help. That’s what sustainability is in its full dimensions.Our capabilities are evolving toward a modeling system so detailed that we can find out detrimental things about policies even at local levels before investing in changing infrastructure. This is going to require collaboration among even more disciplines and creating a seamless connection between research and decision making; not just for policies enacted in the public sector, but also for decisions that are made in the private sector.  More