Aurelia Butler

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    in Environment

    Greening roofs to boost climate resilience

    When the historic cities of Europe were built hundreds of years ago, there were open green spaces all around them. But today’s city centers can be a 30-minute drive or more to the vast open greenery that earlier Europeans took for granted.

    That’s what the startup Roofscapes is trying to change. The company, founded by three students from MIT’s master of architecture program, is using timber structures to turn the ubiquitous pitched roofs of Paris into accessible green spaces.

    The spaces would provide a way to grow local food, anchor biodiversity, reduce the temperatures of buildings, improve air quality, increase water retention, and give residents a new way to escape the dense urban clusters of modern times.

    “We see this as a way to unlock the possibilities of these buildings,” says Eytan Levi MA ’21, SM ’21, who co-founded the company with Olivier Faber MA ’23 and Tim Cousin MA ’23. “These surfaces weren’t being used otherwise but could actually have a highly positive contribution to the value of the buildings, the environment, and the lives of the people.”

    For the co-founders, Roofscapes is about helping build up climate resilience for the future while improving quality of life in cities now.

    “It was always important to us to work with as little contradictions to our values as possible in terms of environmental and social impact,” Faber says. “For us, Roofscapes is a way to apply some of our academic learnings to the real world in a way that is tactical and impactful, because we’re tapping into this whole issue — pitched roof adaptation — that has been ignored by traditional architecture.”

    Three architects with a vision

    The founders, who grew up in France, met while studying architecture as undergraduates in Switzerland, but after graduating and working at design firms for a few years, they began discussing other ways they could make a difference.

    “We knew we wanted to have an impact on the built environment that was different than what a lot of architectural firms were doing. We were thinking about a startup, but mostly we came to MIT because we knew we’d have a lot of agency to grow our skills and competency in adapting the built environment to the climate and biodiversity crises,” Faber explains.

    Three months after coming to MIT, they applied to the DesignX accelerator to explore ways to make cities greener by using timber structures to build flat, green platforms on the ubiquitous pitched roofs of European cities’ older buildings.

    “In European city centers, two thirds of the roofs are pitched, and there’s no solution to make them accessible and put green surfaces on them,” Cousin says. “Meanwhile, we have all these issues with heat islands and excessive heat in urban centers, among other issues like biodiversity collapse, retention of rain water, lack of green spaces. Green roofs are one of the best ways to address all of these problems.”

    They began making small models of their imagined green roofs and talking with structural engineers around campus. The founders also gained operational knowledge from MIT’s Center for Real Estate, where Levi studied.

    In 2021, they showcased a 170-square-foot model at the Seoul Biennale of Architecture and Urbanism in South Korea. The model showed roofs made from different materials and pitched at different angles, along with versions of Roofscapes’ wooden platforms with gardens and vegetation built on top.

    When Levi graduated, he moved to Paris, where Cousin and Faber are joining him this spring. “We’re starting with Paris because all the roofs there are the same height, and you can really feel the potential when you go up there to help the city adapt,” says Cousin.

    Roofscapes’ big break came last year, when the company won a grant from the City of Paris as part of a program to improve the city’s climate resilience. The grant will go toward Roofscapes’ first project on the roof of a former town hall building in the heart of Paris. The company plans to test the project’s impact on the temperature of the buildings, humidity levels, and the biodiversity it can foster.

    “We were just three architects with a vision, and at MIT it became a company, and now in Paris we’re seeing the reality of deploying this vision,” Cousin says. “This is not something you do with three people. You need everyone in the city on the same side. We’re being advocates, and it’s exciting to be in this position.”

    A grassroots roof movement

    The founders say they hear at least once a week from a building owner or tenant who is excited to become a partner, giving them a list of more than 60 buildings to consider for their systems down the line. Still, they plan to focus on running tests on a few pilot projects in Paris before expanding more quickly using prefabricated structures.

    “It’s great to hear that constant interest,” Levi says. “It’s like we’re on the same team, because they’re potential clients, but they’re also cheering us on in our work. We know from the interest that once we have a streamlined process, we can get a lot of projects at once.”

    Even in just the three years since founding the company, the founders say they’ve seen their work take on a new sense of urgency.

    “We’ve seen a shift in people’s minds since we started three years ago,” Levi says. “Global warming is becoming increasingly graspable, and we’re seeing a greater will from building owners and inhabitants. People are very supportive of the notion that we have a heritage environment, but as the climate changes drastically, our building stock doesn’t work anymore the way it worked in the 19th century. It needs to be adapted, and that’s what we are doing.” More

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    in Environment

    Victor K. McElheny Award in science journalism honors series on poultry farming and the environment

    The Knight Science Journalism Program at MIT has announced that the investigative series “Big Poultry,” published by The Charlotte Observer and The Raleigh News & Observer, has been chosen as the 2023 winner of the Victor K. McElheny Award for local and regional journalism. This series of articles uncovered the wide-ranging, unregulated impact of the poultry industry in North Carolina — from odors to pollution to the predatory nature of poultry contract farming.

    The series draws from more than 130 interviews and involved extensive analysis of satellite imagery, industry finances, and state laws, among other data. It expertly merges personal stories and hard data and creates a cohesive and comprehensive deep dive into an underreported, but pervasive, phenomenon in North Carolina. The series has engaged tens of thousands of readers and sparked a debate about the poultry industry in the state legislature.

    “With remarkable enterprise and persistence, these reporters from the Charlotte Observer and the Raleigh News & Observer penetrated the secrecy that obscures the scope and impact of thousands of industrial-scale poultry production farms in North Carolina, which together generate billions of pounds of unchecked agricultural waste,” a judge said of the series.

    “Big Poultry” was reported and written by Charlotte Observer investigative reporters Gavin Off and Ames Alexander and News & Observer environmental reporter Adam Wagner. The series was edited by McClatchy Southeast Investigations Editor Cathy Clabby and was supported by the work of News & Observer investigative reporters David Raynor and Tyler Dukes, and McClatchy newspapers visual journalists.

    “The Victor K. McElheny award recognizes the remarkable science reporting done at the local level by American journalists, and ‘Big Poultry’ is an outstanding example of that,” says Deborah Blum, director of the Knight Science Journalism Program at MIT. “We are proud to honor this series, which raises such important issues and reminds us of the essential role of journalists in protecting our country by illuminating such problems.”

    The 2023 McElheny Award received a robust and diverse pool of submissions from around the United States. Also on the short list of finalists for the award are four other exceptional journalism projects: “Undermined,” a collaboration between Navajo Times, Santa Fe Reporter, Source New Mexico, Capital & Main, and USA Today that uncovered the link between uranium poisoning and increased vulnerability to the Covid-19 virus in the Navajo Nation; “Fighting for Air,” from the Milwaukee Journal Sentinel, which examines the intersection of asthma with substandard housing and health systems; “When the Heat is Unbearable but There’s Nowhere to Go,” a collaboration between High Country News and Type Investigations, which exposed the impact of extreme heat on the incarcerated population of Washington State; and “There Must be Something in the Water,” published by the Minnesota Reformer, which investigated how the company 3M obscured the impact of chemical contamination in the water of Washington Country, Minnesota, and the ongoing health impacts of said contamination on the population.

    Named after the Knight Science Journalism Program’s founding director, the Victor K. McElheny Award was established to honor outstanding coverage of science, public-health, technology, and environmental issues at the local and regional level. The winning team will receive a $10,000 prize. The winners will be honored at the Knight Science Journalism Program’s 40th anniversary celebration on Saturday, April 22.

    The Knight Science Journalism Program extends a special thanks to the 2022 McElheny Award jurors: Jeff DelViscio (senior multimedia editor, Scientific American); Robert Lee Hotz (president, Alicia Patterson Foundation); Brant Houston, (Knight Chair in Investigative and Enterprise Reporting, University of Illinois); Amina Khan (science editor, National Public Radio); and Maya Kapoor (assistant professor of English, North Carolina State University). The program also extends warm appreciation to the award’s screeners: Mary-Rose Abraham, Sebastien Malo, Wojtek Brzezinski, and Kelly Servick.

    The McElheny Award is made possible by generous support from Victor K. McElheny, Ruth McElheny, and the Rita Allen Foundation.

    A complete list of 2023 Victor K. McElheny Award honorees:

    Winner

    “Big Poultry,” by Gavin Off , Ames Alexander, and Adam Wagner (The Charlotte Observer and The Raleigh News & Observer)

    Finalists

    “Undermined,” by Eli Cahan (Navajo Times, Santa Fe Reporter, Source New Mexico, Capital & Main, and USA Today)

    “Fighting for Air,” by Talis Shelbourne (Milwaukee Journal Sentinel)

    “When the Heat is Unbearable but There’s Nowhere to Go,” by Sarah Sax (High Country News and Type Investigations)

    “There Must be Something in the Water,” by Deena Winter (Minnesota Reformer) More

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    in Environment

    3 Questions: Leveraging carbon uptake to lower concrete’s carbon footprint

    To secure a more sustainable and resilient future, we must take a careful look at the life cycle impacts of humanity’s most-produced building material: concrete. Carbon uptake, the process by which cement-based products sequester carbon dioxide, is key to this understanding.

    Hessam AzariJafari, the MIT Concrete Sustainability Hub’s deputy director, is deeply invested in the study of this process and its acceleration, where prudent. Here, he describes how carbon uptake is a key lever to reach a carbon-neutral concrete industry.

    Q: What is carbon uptake in cement-based products and how can it influence their properties?

    A: Carbon uptake, or carbonation, is a natural process of permanently sequestering CO2 from the atmosphere by hardened cement-based products like concretes and mortars. Through this reaction, these products form different kinds of limes or calcium carbonates. This uptake occurs slowly but significantly during two phases of the life cycle of cement-based products: the use phase and the end-of-life phase.

    In general, carbon uptake increases the compressive strength of cement-based products as it can densify the paste. At the same time, carbon uptake can impact the corrosion resistance of concrete. In concrete that is reinforced with steel, the corrosion process can be initiated if the carbonation happens extensively (e.g., the whole of the concrete cover is carbonated) and intensively (e.g., a significant proportion of the hardened cement product is carbonated). [Concrete cover is the layer distance between the surface of reinforcement and the outer surface of the concrete.]

    Q: What are the factors that influence carbon uptake?

    A: The intensity of carbon uptake depends on four major factors: the climate, the types and properties of cement-based products used, the composition of binders (cement type) used, and the geometry and exposure condition of the structure.

    In regard to climate, the humidity and temperature affect the carbon uptake rate. In very low or very high humidity conditions, the carbon uptake process is slowed. High temperatures speed the process. The local atmosphere’s carbon dioxide concentration can affect the carbon uptake rate. For example, in urban areas, carbon uptake is an order of magnitude faster than in suburban areas.

    The types and properties of cement-based products have a large influence on the rate of carbon uptake. For example, mortar (consisting of water, cement, and fine aggregates) carbonates two to four times faster than concrete (consisting of water, cement, and coarse and fine aggregates) because of its more porous structure.The carbon uptake rate of dry-cast concrete masonry units is higher than wet-cast for the same reason. In structural concrete, the process is made slower as mechanical properties are improved and the density of the hardened products’ structure increases.

    Lastly, a structure’s surface area-to-volume ratio and exposure to air and water can have ramifications for its rate of carbonation. When cement-based products are covered, carbonation may be slowed or stopped. Concrete that is exposed to fresh air while being sheltered from rain can have a larger carbon uptake compared to cement-based products that are painted or carpeted. Additionally, cement-based elements with large surface areas, like thin concrete structures or mortar layers, allow uptake to progress more extensively.

    Q: What is the role of carbon uptake in the carbon neutrality of concrete, and how should architects and engineers account for it when designing for specific applications?

    A: Carbon uptake is a part of the life cycle of any cement-based products that should be accounted for in carbon footprint calculations. Our evaluation shows the U.S. pavement network can sequester 5.8 million metric tons of CO2, of which 52 percent will be sequestered when the demolished concrete is stockpiled at its end of life.

    From one concrete structure to another, the percentage of emissions sequestered may vary. For instance, concrete bridges tend to have a lower percentage versus buildings constructed with concrete masonry. In any case, carbon uptake can influence the life cycle environmental performance of concrete.

    At the MIT Concrete Sustainability Hub, we have developed a calculator to enable construction stakeholders to estimate the carbon uptake of concrete structures during their use and end-of-life phases.

    Looking toward the future, carbon uptake’s role in the carbon neutralization of cement-based products could grow in importance. While caution should be taken in regards to uptake when reinforcing steel is embedded in concrete, there are opportunities for different stakeholders to augment carbon uptake in different cement-based products.

    Architects can influence the shape of concrete elements to increase the surface area-to-volume ratio (e.g., making “waffle” patterns on slabs and walls, or having several thin towers instead of fewer large ones on an apartment complex). Concrete manufacturers can adjust the binder type and quantity while delivering concrete that meets performance requirements. Finally, industrial ecologists and life-cycle assessment practitioners need to work on the tools and add-ons to make sure the impact of carbon is well captured when assessing the potential impacts of cement-based products in buildings and infrastructure systems.

    Currently, the cement and concrete industry is working with tech companies as well as local, state, and federal governments to lower and subsidize the code of carbon capture sequestration and neutralization. Accelerating carbon uptake where reasonable could be an additional lever to neutralize the carbon emissions of the concrete value chain.

    Carbon uptake is one more piece of the puzzle that makes concrete a sustainable choice for building in many applications. The sustainability and resilience of the future built environment lean on the use of concrete. There is still much work to be done to truly build sustainably, and understanding carbon uptake is an important place to begin. More

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    in Environment

    Fieldwork class examines signs of climate change in Hawaii

    When Joy Domingo-Kameenui spent two weeks in her native Hawaii as part of MIT class 1.091 (Traveling Research Environmental eXperiences), she was surprised to learn about the number of invasive and endangered species. “I knew about Hawaiian ecology from middle and high school but wasn’t fully aware to the extent of how invasive species and diseases have resulted in many of Hawaii’s endemic species becoming threatened,” says Domingo-Kameenui.  

    Domingo-Kameenui was part of a group of MIT students who conducted field research on the Big Island of Hawaii in the Traveling Research Environmental eXperiences (TREX) class offered by the Department of Civil and Environmental Engineering. The class provides undergraduates an opportunity to gain hands-on environmental fieldwork experience using Hawaii’s geology, chemistry, and biology to address two main topics of climate change concern: sulfur dioxide (SO2) emissions and forest health.

    “Hawaii is this great system for studying the effects of climate change,” says David Des Marais, the Cecil and Ida Green Career Development Professor of Civil and Environmental Engineering and lead instructor of TREX. “Historically, Hawaii has had occasional mild droughts that are related to El Niño, but the droughts are getting stronger and more frequent. And we know these types of extreme weather events are going to happen worldwide.”

    Climate change impacts on forests

    The frequency and intensity of extreme events are also becoming more of a problem for forests and plant life. Forests have a certain distribution of vegetation and as you get higher in elevation, the trees gradually turn into shrubs, and then rock. Trees don’t grow above the timberline, where the temperature and precipitation changes dramatically at the high elevations. “But unlike the Sierra Nevada or the Rockies, where the trees gradually change as you go up the mountains, in Hawaii, they gradually change, and then they just stop,” says Des Marais.

    “Why this is an interesting model for climate change,” explains Des Marais, “is that line where trees stop [growing] is going to move, and it’s going to become more unstable as the trade winds are affected by global patterns of air circulation, which are changing because of climate change.”

    The research question that Des Marais asks students to explore — How is the Hawaiian forest going to be affected by climate change? — uses Hawaii as a model for broader patterns in climate change for forests.

    To dive deeper into this question, students trekked up the mountain taking ground-level measurements of canopy cover with a camera app on their cellphones, estimating how much tree coverage blankets the sky when looking up, and observing how the canopy cover thins until they see no tree coverage at all as they go further up the mountain. Drones also flew above the forest to measure chlorophyll and how much plant matter remains. And then satellite data products from NASA and the European Space Agency were used to measure the distribution of chlorophyll, climate, and precipitation data from space.

    They also worked directly with community stakeholders at three locations around the island to access the forests and use technology to assess the ecology and biodiversity challenges. One of those stakeholders was the Kamehameha Schools Natural and Cultural Ecosystems Division, whose mission is to preserve the land and manage it in a sustainable way. Students worked with their plant biologists to help address and think about what management decisions will support the future health of their forests.

    “Across the island, rising temperatures and abnormal precipitation patterns are the main drivers of drought, which really has significant impacts on biodiversity, and overall human health,” says Ava Gillikin, a senior in civil and environmental engineering.

    Gillikin adds that “a good proportion of the island’s water system relies on rainwater catchment, exposing vulnerabilities to fluctuations in rain patterns that impact many people’s lives.”

    Deadly threats to native plants

    The other threats to Hawaii’s forests are invasive species causing ecological harm, from the prevalence of non-indigenous mosquitoes leading to increases in avian malaria and native bird death that threaten the native ecosystem, to a plant called strawberry guava.

    Strawberry guava is taking over Hawaii’s native ōhiʻa trees, which Domingo-Kameenui says is also contributing to Hawaii’s water production. “The plants absorb water quickly so there’s less water runoff for groundwater systems.”

    A fungal pathogen is also infecting native ōhiʻa trees. The disease, called rapid ʻohiʻa death (ROD), kills the tree within a few days to weeks. The pathogen was identified by researchers on the island in 2014 from the fungal genus, Ceratocystis. The fungal pathogen was likely carried into the forests by humans on their shoes, or contaminated tools, gear, and vehicles traveling from one location to another. The fungal disease is also transmitted by beetles that bore into trees and create a fine powder-like dust. This dust from an infected tree is then mixed with the fungal spores and can easily spread to other trees by wind, or contaminated soil.

    For Gillikin, seeing the effects of ROD in the field highlighted the impact improper care and preparation can have on native forests. “The ‘ohi’a tree is one of the most prominent native trees, and ROD can kill the trees very rapidly by putting a strain on its vascular system and preventing water from reaching all parts of the tree,” says Gillikin.

    Before entering the forests, students sprayed their shoes and gear with ethanol frequently to prevent the spread.

    Uncovering chemical and particle formation

    A second research project in TREX studied volcanic smog (vog) that plagues the air, making visibility problematic at times and causing a lot of health problems for people in Hawaii. The active Kilauea volcano releases SO2 into the atmosphere. When the SO2 mixes with other gasses emitted from the volcano and interacts with sunlight and the atmosphere, particulate matter forms.

    Students in the Kroll Group, led by Jesse Kroll, professor of civil and environmental engineering and chemical engineering, have been studying SO2 and particulate matter over the years, but not the chemistry directly in how those chemical transformations occur.

    “There’s a hypothesis that there is a functional connection between the SO2 and particular matter, but that’s never been directly demonstrated,” says Des Marais.

    Testing that hypothesis, the students were able to measure two different sizes of particulate matter formed from the SO2 and develop a model to show how much vog is generated downstream of the volcano.

    They spent five days at two sites from sunrise to late morning measuring particulate matter formation as the sun comes up and starts creating new particles. Using a combination of data sources for meteorology, such as UV index, wind speed, and humidity, the students built a model that demonstrates all the pieces of an equation that can calculate when new particles are formed.

    “You can build what you think that equation is based on first-principle understanding of the chemical composition, but what they did was measured it in real time with measurements of the chemical reagents,” says Des Marias.

    The students measured what was going to catalyze the chemical reaction of particulate matter — for instance, things like sunlight and ozone — and then calculated numbers to the outputs.

    “What they found, and what seems to be happening, is that the chemical reagents are accumulating overnight,” says Des Marais. “Then as soon as the sun rises in the morning all the transformation happens in the atmosphere. A lot of the reagents are used up and the wind blows everything away, leaving the other side of the island with polluted air,” adds Des Marais.

    “I found the vog particle formation fieldwork a surprising research learning,” adds Domingo-Kameenui who did some atmospheric chemistry research in the Kroll Group. “I just thought particle formation happened in the air, but we found wind direction and wind speed at a certain time of the day was extremely important to particle formation. It’s not just chemistry you need to look at, but meteorology and sunlight,” she adds.

    Both Domingo-Kameenui and Gillikin found the fieldwork class an important and memorable experience with new insight that they will carry with them beyond MIT.  

    How Gillikin approaches fieldwork or any type of community engagement in another culture is what she will remember most. “When entering another country or culture, you are getting the privilege to be on their land, to learn about their history and experiences, and to connect with so many brilliant people,” says Gillikin. “Everyone we met in Hawaii had so much passion for their work, and approaching those environments with respect and openness to learn is what I experienced firsthand and will take with me throughout my career.” More

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    in Environment

    MIT Center for Real Estate advances climate and sustainable real estate research agenda

    Real estate investors are increasingly putting sustainability at the center of their decision-making processes, given the close association between climate risk and real estate assets, both of which are location-based.

    This growing emphasis comes at a time when the real estate industry is one of the biggest contributors to global warming; its embodied and operational carbon accounts for more than one-third of total carbon emissions. More stringent building decarbonization regulations are putting pressure on real estate owners and investors, who must invest heavily to retrofit their buildings or pay “carbon penalties” and see their assets lose value.

    The impacts of acute and chronic climate risks — flooding, hurricanes, wildfires, droughts, sea-level rise, and extreme weather — are becoming more salient. Action across all areas of the real estate sector will be required to limit the social and economic risks arising from the climate crisis. But what business and policy levers are most effective at guiding the industry toward a more sustainable future?

    The MIT Center for Real Estate (MIT/CRE) believes that the real estate industry can be a catalyst for the rapid mobilization of a global transition to a greener society. Since its inception in 1983, MIT/CRE has focused on the physical aspect of real estate, especially the development industry, and how the built environment gets produced and changed.

    “The real estate industry is now at the critical moment to address the climate crisis. That is why our center initiated this major research agenda on climate and real estate two years ago,” says William Wheaton, a former director of MIT/CRE and professor emeritus in MIT’s Department of Economics, who is leading a research project on the impact of flood risks in real estate markets.

    Producing high-quality research to support climate actions

    The work of scientists and practitioners responding to the climate crisis is often bifurcated into mitigation or adaptation responses. Mitigation seeks to reduce the severity of the climate crisis by addressing emissions, while adaptation efforts seek to anticipate the most severe effects of the crisis and minimize potential risks to people and the built environment.

    The fundamental nature of the real estate industry — location-based and capital-intensive — enables potential meaningful action for both mitigation and adaptation interventions. Exploring both avenues, MIT/CRE faculty and researchers have published academic papers exploring how chronic climate events such as extreme temperatures lower people’s expressed happiness and also disrupt habits of daily life; and how acute climate events such as hurricanes damage the built environment and decrease the financial value of real estate.

    “This ongoing research production centers on industry’s imperative to take action quickly, the real losses resulting from inaction, and the potential social and business value creation for early adopters of more sustainable practices,” says Siqi Zheng, a co-author of those papers, who is the MIT/CRE faculty director and the STL Champion Professor of Urban and Real Estate Sustainability.

    Building a global community of academics and industry leaders

    In addition to sponsoring research and related courses, MIT/CRE has created a global network of researchers and industry leaders, centered around sharing ideas and experience to quickly scale more sustainable practices, such as building decarbonization and circular economy in real estate, as well as climate risk modeling and pricing. Collaborating with industry leaders from the investment and real estate sector, such as EY, Veris Residential, Moody’s Analytics, Colliers, Finvest, KPF, Taurus Investment Holdings, Climate Alpha, and CRE alumnus Paul Clayton SM ’02, MIT/CRE blends real-world experiences and questions with applied data and projects to create a “living lab” for MIT/CRE researchers to conduct climate research.

    At an inaugural symposium on climate and real estate held at MIT in December 2022, more than a dozen scholars presented papers on the intersection of real estate and sustainability, which will form the basis of a special issue on climate change and real estate in the Journal of Regional Science. A “fireside chat” connected scholars and industry leaders in practical conversations about how to use research to aid practitioners.

    “Dissemination of research is critical to the success of our efforts to address climate change in the real estate industry,” says David Geltner, post-tenure professor of real estate finance and former director of  MIT/CRE, whose research group is working on climate risks and commercial real estate. “If we produce excellent research but it is cloistered in academic journals, it does no one any good. Similarly, if we do not work with collaborators to focus our research, we run the risk of investigating levers to reduce emissions that are of no use to practitioners.”

    Juan Palacios, coordinator of MIT/CRE’s climate and real estate research team, emphasizes that industry collaboration creates a two-way sharing of information that refines how research is being conducted at the center and ensures that it has positive impact.

    “More and more real estate investors and market players are putting sustainability at the center of their investment approach,” says Zheng. “A broad range of stakeholders (investors, regulators, insurers, and the public) have started to understand that long-term profitability cannot be achieved without embracing multiple dimensions of sustainability such as climate, wealth inequality, public health, and social welfare. Because of its unique relationship with industry collaborators and its place in the MIT innovation ecosystem, MIT/CRE has a responsibility and the opportunity to champion multiple pathways toward greater sustainability in the real estate industry.” More

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    in Security

    Tackling counterfeit seeds with “unclonable” labels

    Average crop yields in Africa are consistently far below those expected, and one significant reason is the prevalence of counterfeit seeds whose germination rates are far lower than those of the genuine ones. The World Bank estimates that as much as half of all seeds sold in some African countries are fake, which could help to account for crop production that is far below potential.

    There have been many attempts to prevent this counterfeiting through tracking labels, but none have proved effective; among other issues, such labels have been vulnerable to hacking because of the deterministic nature of their encoding systems. But now, a team of MIT researchers has come up with a kind of tiny, biodegradable tag that can be applied directly to the seeds themselves, and that provides a unique randomly created code that cannot be duplicated.

    The new system, which uses minuscule dots of silk-based material, each containing a unique combination of different chemical signatures, is described today in the journal Science Advances in a paper by MIT’s dean of engineering Anantha Chandrakasan, professor of civil and environmental engineering Benedetto Marelli, postdoc Hui Sun, and graduate student Saurav Maji.

    The problem of counterfeiting is an enormous one globally, the researchers point out, affecting everything from drugs to luxury goods, and many different systems have been developed to try to combat this. But there has been less attention to the problem in the area of agriculture, even though the consequences can be severe. In sub-Saharan Africa, for example, the World Bank estimates that counterfeit seeds are a significant factor in crop yields that average less than one-fifth of the potential for maize, and less than one-third for rice.

    Marelli explains that a key to the new system is creating a randomly-produced physical object whose exact composition is virtually impossible to duplicate. The labels they create “leverage randomness and uncertainty in the process of application, to generate unique signature features that can be read, and that cannot be replicated,” he says.

    What they’re dealing with, Sun adds, “is the very old job of trying, basically, not to get your stuff stolen. And you can try as much as you can, but eventually somebody is always smart enough to figure out how to do it, so nothing is really unbreakable. But the idea is, it’s almost impossible, if not impossible, to replicate it, or it takes so much effort that it’s not worth it anymore.”

    The idea of an “unclonable” code was originally developed as a way of protecting the authenticity of computer chips, explains Chandrakasan, who is the Vannevar Bush Professor of Electrical Engineering and Computer Science. “In integrated circuits, individual transistors have slightly different properties coined device variations,” he explains, “and you could then use that variability and combine that variability with higher-level circuits to create a unique ID for the device. And once you have that, then you can use that unique ID as a part of a security protocol. Something like transistor variability is hard to replicate from device to device, so that’s what gives it its uniqueness, versus storing a particular fixed ID.” The concept is based on what are known as physically unclonable functions, or PUFs.

    The team decided to try to apply that PUF principle to the problem of fake seeds, and the use of silk proteins was a natural choice because the material is not only harmless to the environment but also classified by the Food and Drug Administration in the “generally recognized as safe” category, so it requires no special approval for use on food products.

    “You could coat it on top of seeds,” Maji says, “and if you synthesize silk in a certain way, it will also have natural random variations. So that’s the idea, that every seed or every bag could have a unique signature.”

    Developing effective secure system solutions has long been one of Chandrakasan’s specialties, while Marelli has spent many years developing systems for applying silk coatings to a variety of fruits, vegetables, and seeds, so their collaboration was a natural for developing such a silk-based coding system toward enhanced security.

    “The challenge was what type of form factor to give to silk,” Sun says, “so that it can be fabricated very easily.” They developed a simple drop-casting approach that produces tags that are less than one-tenth of an inch in diameter. The second challenge was to develop “a way where we can read the uniqueness, in also a very high throughput and easy way.”

    For the unique silk-based codes, Marelli says, “eventually we found a way to add a color to these microparticles so that they assemble in random structures.” The resulting unique patterns can be read out not only by a spectrograph or a portable microscope, but even by an ordinary cellphone camera with a macro lens. This image can be processed locally to generate the PUF code and then sent to the cloud and compared with a secure database to ensure the authenticity of the product. “It’s random so that people cannot easily replicate it,” says Sun. “People cannot predict it without measuring it.”

    And the number of possible permutations that could result from the way they mix four basic types of colored silk nanoparticles is astronomical. “We were able to show that with a minimal amount of silk, we were able to generate 128 random bits of security,” Maji says. “So this gives rise to 2 to the power 128 possible combinations, which is extremely difficult to crack given the computational capabilities of the state-of-the-art computing systems.”

    Marelli says that “for us, it’s a good test bed in order to think out-of-the-box, and how we can have a path that somehow is more democratic.” In this case, that means “something that you can literally read with your phone, and you can fabricate by simply drop casting a solution, without using any advanced manufacturing technique, without going in a clean room.”

    Some additional work will be needed to make this a practical commercial product, Chandrakasan says. “There will have to be a development for at-scale reading” via smartphones. “So, that’s clearly a future opportunity.” But the principle now shows a clear path to the day when “a farmer could at least, maybe not every seed, but could maybe take some random seeds in a particular batch and verify them,” he says.

    The research was partially supported by the U.S. Office of Naval research and the National Science Foundation, Analog Devices Inc., an EECS Mathworks fellowship, and a Paul M. Cook Career Development Professorship. More

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    in Environment

    MIT-led teams win National Science Foundation grants to research sustainable materials

    Three MIT-led teams are among 16 nationwide to receive funding awards to address sustainable materials for global challenges through the National Science Foundation’s Convergence Accelerator program. Launched in 2019, the program targets solutions to especially compelling societal or scientific challenges at an accelerated pace, by incorporating a multidisciplinary research approach.

    “Solutions for today’s national-scale societal challenges are hard to solve within a single discipline. Instead, these challenges require convergence to merge ideas, approaches, and technologies from a wide range of diverse sectors, disciplines, and experts,” the NSF explains in its description of the Convergence Accelerator program. Phase 1 of the award involves planning to expand initial concepts, identify new team members, participate in an NSF development curriculum, and create an early prototype.

    Sustainable microchips

    One of the funded projects, “Building a Sustainable, Innovative Ecosystem for Microchip Manufacturing,” will be led by Anuradha Murthy Agarwal, a principal research scientist at the MIT Materials Research Laboratory. The aim of this project is to help transition the manufacturing of microchips to more sustainable processes that, for example, can reduce e-waste landfills by allowing repair of chips, or enable users to swap out a rogue chip in a motherboard rather than tossing out the entire laptop or cellphone.

    “Our goal is to help transition microchip manufacturing towards a sustainable industry,” says Agarwal. “We aim to do that by partnering with industry in a multimodal approach that prototypes technology designs to minimize energy consumption and waste generation, retrains the semiconductor workforce, and creates a roadmap for a new industrial ecology to mitigate materials-critical limitations and supply-chain constraints.”

    Agarwal’s co-principal investigators are Samuel Serna, an MIT visiting professor and assistant professor of physics at Bridgewater State University, and two MIT faculty affiliated with the Materials Research Laboratory: Juejun Hu, the John Elliott Professor of Materials Science and Engineering; and Lionel Kimerling, the Thomas Lord Professor of Materials Science and Engineering.

    The training component of the project will also create curricula for multiple audiences. “At Bridgewater State University, we will create a new undergraduate course on microchip manufacturing sustainability, and eventually adapt it for audiences from K-12, as well as incumbent employees,” says Serna.

    Sajan Saini and Erik Verlage of the MIT Department of Materials Science and Engineering (DMSE), and Randolph Kirchain from the MIT Materials Systems Laboratory, who have led MIT initiatives in virtual reality digital education, materials criticality, and roadmapping, are key contributors. The project also includes DMSE graduate students Drew Weninger and Luigi Ranno, and undergraduate Samuel Bechtold from Bridgewater State University’s Department of Physics.

    Sustainable topological materials

    Under the direction of Mingda Li, the Class of 1947 Career Development Professor and an Associate Professor of Nuclear Science and Engineering, the “Sustainable Topological Energy Materials (STEM) for Energy-efficient Applications” project will accelerate research in sustainable topological quantum materials.

    Topological materials are ones that retain a particular property through all external disturbances. Such materials could potentially be a boon for quantum computing, which has so far been plagued by instability, and would usher in a post-silicon era for microelectronics. Even better, says Li, topological materials can do their job without dissipating energy even at room temperatures.

    Topological materials can find a variety of applications in quantum computing, energy harvesting, and microelectronics. Despite their promise, and a few thousands of potential candidates, discovery and mass production of these materials has been challenging. Topology itself is not a measurable characteristic so researchers have to first develop ways to find hints of it. Synthesis of materials and related process optimization can take months, if not years, Li adds. Machine learning can accelerate the discovery and vetting stage.

    Given that a best-in-class topological quantum material has the potential to disrupt the semiconductor and computing industries, Li and team are paying special attention to the environmental sustainability of prospective materials. For example, some potential candidates include gold, lead, or cadmium, whose scarcity or toxicity does not lend itself to mass production and have been disqualified.

    Co-principal investigators on the project include Liang Fu, associate professor of physics at MIT; Tomas Palacios, professor of electrical engineering and computer science at MIT and director of the Microsystems Technology Laboratories; Susanne Stemmer of the University of California at Santa Barbara; and Qiong Ma of Boston College. The $750,000 one-year Phase 1 grant will focus on three priorities: building a topological materials database; identifying the most environmentally sustainable candidates for energy-efficient topological applications; and building the foundation for a Center for Sustainable Topological Energy Materials at MIT that will encourage industry-academia collaborations.

    At a time when the size of silicon-based electronic circuit boards is reaching its lower limit, the promise of topological materials whose conductivity increases with decreasing size is especially attractive, Li says. In addition, topological materials can harvest wasted heat: Imagine using your body heat to power your phone. “There are different types of application scenarios, and we can go much beyond the capabilities of existing materials,” Li says, “the possibilities of topological materials are endlessly exciting.”

    Socioresilient materials design

    Researchers in the MIT Department of Materials Science and Engineering (DMSE) have been awarded $750,000 in a cross-disciplinary project that aims to fundamentally redirect materials research and development toward more environmentally, socially, and economically sustainable and resilient materials. This “socioresilient materials design” will serve as the foundation for a new research and development framework that takes into account technical, environmental, and social factors from the beginning of the materials design and development process.

    Christine Ortiz, the Morris Cohen Professor of Materials Science and Engineering, and Ellan Spero PhD ’14, an instructor in DMSE, are leading this research effort, which includes Cornell University, the University of Swansea, Citrine Informatics, Station1, and 14 other organizations in academia, industry, venture capital, the social sector, government, and philanthropy.

    The team’s project, “Mind Over Matter: Socioresilient Materials Design,” emphasizes that circular design approaches, which aim to minimize waste and maximize the reuse, repair, and recycling of materials, are often insufficient to address negative repercussions for the planet and for human health and safety.

    Too often society understands the unintended negative consequences long after the materials that make up our homes and cities and systems have been in production and use for many years. Examples include disparate and negative public health impacts due to industrial scale manufacturing of materials, water and air contamination with harmful materials, and increased risk of fire in lower-income housing buildings due to flawed materials usage and design. Adverse climate events including drought, flood, extreme temperatures, and hurricanes have accelerated materials degradation, for example in critical infrastructure, leading to amplified environmental damage and social injustice. While classical materials design and selection approaches are insufficient to address these challenges, the new research project aims to do just that.

    “The imagination and technical expertise that goes into materials design is too often separated from the environmental and social realities of extraction, manufacturing, and end-of-life for materials,” says Ortiz. 

    Drawing on materials science and engineering, chemistry, and computer science, the project will develop a framework for materials design and development. It will incorporate powerful computational capabilities — artificial intelligence and machine learning with physics-based materials models — plus rigorous methodologies from the social sciences and the humanities to understand what impacts any new material put into production could have on society. More

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    in Environment

    Detailed images from space offer clearer picture of drought effects on plants

    “MIT is a place where dreams come true,” says César Terrer, an assistant professor in the Department of Civil and Environmental Engineering. Here at MIT, Terrer says he’s given the resources needed to explore ideas he finds most exciting, and at the top of his list is climate science. In particular, he is interested in plant-soil interactions, and how the two can mitigate impacts of climate change. In 2022, Terrer received seed grant funding from the Abdul Latif Jameel Water and Food Systems Lab (J-WAFS) to produce drought monitoring systems for farmers. The project is leveraging a new generation of remote sensing devices to provide high-resolution plant water stress at regional to global scales.

    Growing up in Granada, Spain, Terrer always had an aptitude and passion for science. He studied environmental science at the University of Murcia, where he interned in the Department of Ecology. Using computational analysis tools, he worked on modeling species distribution in response to human development. Early on in his undergraduate experience, Terrer says he regarded his professors as “superheroes” with a kind of scholarly prowess. He knew he wanted to follow in their footsteps by one day working as a faculty member in academia. Of course, there would be many steps along the way before achieving that dream. 

    Upon completing his undergraduate studies, Terrer set his sights on exciting and adventurous research roles. He thought perhaps he would conduct field work in the Amazon, engaging with native communities. But when the opportunity arose to work in Australia on a state-of-the-art climate change experiment that simulates future levels of carbon dioxide, he headed south to study how plants react to CO2 in a biome of native Australian eucalyptus trees. It was during this experience that Terrer started to take a keen interest in the carbon cycle and the capacity of ecosystems to buffer rising levels of CO2 caused by human activity.

    Around 2014, he began to delve deeper into the carbon cycle as he began his doctoral studies at Imperial College London. The primary question Terrer sought to answer during his PhD was “will plants be able to absorb predicted future levels of CO2 in the atmosphere?” To answer the question, Terrer became an early adopter of artificial intelligence, machine learning, and remote sensing to analyze data from real-life, global climate change experiments. His findings from these “ground truth” values and observations resulted in a paper in the journal Science. In it, he claimed that climate models most likely overestimated how much carbon plants will be able to absorb by the end of the century, by a factor of three. 

    After postdoctoral positions at Stanford University and the Universitat Autonoma de Barcelona, followed by a prestigious Lawrence Fellowship, Terrer says he had “too many ideas and not enough time to accomplish all those ideas.” He knew it was time to lead his own group. Not long after applying for faculty positions, he landed at MIT. 

    New ways to monitor drought

    Terrer is employing similar methods to those he used during his PhD to analyze data from all over the world for his J-WAFS project. He and postdoc Wenzhe Jiao collect data from remote sensing satellites and field experiments and use machine learning to come up with new ways to monitor drought. Terrer says Jiao is a “remote sensing wizard,” who fuses data from different satellite products to understand the water cycle. With Jiao’s hydrology expertise and Terrer’s knowledge of plants, soil, and the carbon cycle, the duo is a formidable team to tackle this project.

    According to the U.N. World Meteorological Organization, the number and duration of droughts has increased by 29 percent since 2000, as compared to the two previous decades. From the Horn of Africa to the Western United States, drought is devastating vegetation and severely stressing water supplies, compromising food production and spiking food insecurity. Drought monitoring can offer fundamental information on drought location, frequency, and severity, but assessing the impact of drought on vegetation is extremely challenging. This is because plants’ sensitivity to water deficits varies across species and ecosystems. 

    Terrer and Jiao are able to obtain a clearer picture of how drought is affecting plants by employing the latest generation of remote sensing observations, which offer images of the planet with incredible spatial and temporal resolution. Satellite products such as Sentinel, Landsat, and Planet can provide daily images from space with such high resolution that individual trees can be discerned. Along with the images and datasets from satellites, the team is using ground-based observations from meteorological data. They are also using the MIT SuperCloud at MIT Lincoln Laboratory to process and analyze all of the data sets. The J-WAFS project is among one of the first to leverage high-resolution data to quantitatively measure plant drought impacts in the United States with the hopes of expanding to a global assessment in the future.

    Assisting farmers and resource managers 

    Every week, the U.S. Drought Monitor provides a map of drought conditions in the United States. The map has zero resolution and is more of a drought recap or summary, unable to predict future drought scenarios. The lack of a comprehensive spatiotemporal evaluation of historic and future drought impacts on global vegetation productivity is detrimental to farmers both in the United States and worldwide.  

    Terrer and Jiao plan to generate metrics for plant water stress at an unprecedented resolution of 10-30 meters. This means that they will be able to provide drought monitoring maps at the scale of a typical U.S. farm, giving farmers more precise, useful data every one to two days. The team will use the information from the satellites to monitor plant growth and soil moisture, as well as the time lag of plant growth response to soil moisture. In this way, Terrer and Jiao say they will eventually be able to create a kind of “plant water stress forecast” that may be able to predict adverse impacts of drought four weeks in advance. “According to the current soil moisture and lagged response time, we hope to predict plant water stress in the future,” says Jiao. 

    The expected outcomes of this project will give farmers, land and water resource managers, and decision-makers more accurate data at the farm-specific level, allowing for better drought preparation, mitigation, and adaptation. “We expect to make our data open-access online, after we finish the project, so that farmers and other stakeholders can use the maps as tools,” says Jiao. 

    Terrer adds that the project “has the potential to help us better understand the future states of climate systems, and also identify the regional hot spots more likely to experience water crises at the national, state, local, and tribal government scales.” He also expects the project will enhance our understanding of global carbon-water-energy cycle responses to drought, with applications in determining climate change impacts on natural ecosystems as a whole. More