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      in Environment

      A new microneedle-based drug delivery technique for plants

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      Increasing environmental conditions caused by climate change, an ever-growing human population, scarcity of arable land, and limited resources are pressuring the agriculture industry to adopt more sustainable and precise practices that foster more efficient use of resources (e.g., water, fertilizers, and pesticides) and mitigation of environmental impacts. Developing delivery systems that efficiently deploy agrochemicals such as micronutrients, pesticides, and antibiotics in crops will help ensure high productivity and high produce quality, while minimizing the waste of resources, is crucial.

      Now, researchers in Singapore and the U.S. have developed the first-ever microneedle-based drug delivery technique for plants. The method can be used to precisely deliver controlled amounts of agrochemicals to specific plant tissues for research purposes. When applied in the field, it could one day be used in precision agriculture to improve crop quality and disease management.

      The work is led by researchers from the Disruptive and Sustainable Technologies for Agricultural Precision (DiSTAP) interdisciplinary research group at the Singapore-MIT Alliance for Research and Technology (SMART), MIT’s research enterprise in Singapore, and their collaborators from MIT and the Temasek Life Sciences Laboratory (TLL).

      Current and standard practices for agrochemical application in plants, such as foliar spray, are inefficient due to off-target application, quick runoff in the rain, and actives’ rapid degradation. These practices also cause significant detrimental environmental side effects, such as water and soil contamination, biodiversity loss, and degraded ecosystems; and public health concerns, such as respiratory problems, chemical exposure, and food contamination.

      The novel silk-based microneedles technique circumvents these limitations by deploying and targeting a known amount of payload directly into a plant’s deep tissues, which will lead to higher efficacy of plant growth and help with disease management. The technique is minimally invasive, as it delivers the compound without causing long-term damage to the plants, and is environmentally sustainable. It minimizes resource wastage and mitigates the adverse side effects caused by agrochemical contamination of the environment. Additionally, it will help foster precise agricultural practices and provide new tools to study plants and design crop traits, helping to ensure food security.

      Described in a paper titled “Drug Delivery in Plants Using Silk Microneedles,” published in a recent issue of Advanced Materials, the research studies the first-ever polymeric microneedles used to deliver small compounds to a wide variety of plants and the plant response to biomaterial injection. Through gene expression analysis, the researchers could closely examine the reactions to drug delivery following microneedle injection. Minimal scar and callus formation were observed, suggesting minimal injection-induced wounding to the plant. The proof of concept provided in this study opens the door to plant microneedles’ application in plant biology and agriculture, enabling new means to regulate plant physiology and study metabolisms via efficient and effective delivery of payloads.

      The study optimized the design of microneedles to target the systemic transport system in Arabidopsis (mouse-ear cress), the chosen model plant. Gibberellic acid (GA3), a widely used plant growth regulator in agriculture, was selected for the delivery. The researchers found that delivering GA3 through microneedles was more effective in promoting growth than traditional methods (such as foliar spray). They then confirmed the effectiveness using genetic methods and demonstrated that the technique is applicable to various plant species, including vegetables, cereals, soybeans, and rice.

      Professor Benedetto Marelli, co-corresponding author of the paper, principal investigator at DiSTAP, and associate professor of civil and environmental engineering at MIT, shares, “The technique saves resources as compared to current methods of agrochemical delivery, which suffer from wastage. During the application, the microneedles break through the tissue barriers and release compounds directly inside the plants, avoiding agrochemical losses. The technique also allows for precise control of the amounts of the agrochemical used, ensuring high-tech precision agriculture and crop growth to optimize yield.”

      “The first-of-its-kind technique is revolutionary for the agriculture industry. It also minimizes resource wastage and environmental contamination. In the future, with automated microneedle application as a possibility, the technique may be used in high-tech outdoor and indoor farms for precise agrochemical delivery and disease management,” adds Yunteng Cao, the first author of the paper and postdoc at MIT.

      “This work also highlights the importance of using genetic tools to study plant responses to biomaterials. Analyzing these responses at the genetic level offers a comprehensive understanding of these responses, thereby serving as a guide for the development of future biomaterials that can be used across the agri-food industry,” says Sally Koh, the co-first author of this work and PhD candidate from NUS and TLL.

      The future seems promising as Professor Daisuke Urano, co-corresponding author of the paper, TLL principal investigator, and NUS adjunct assistant professor elaborates, “Our research has validated the use of silk-based microneedles for agrochemical application, and we look forward to further developing the technique and microneedle design into a scalable model for manufacturing and commercialization. At the same time, we are also actively investigating potential applications that could have a significant impact on society.”

      The study of drug delivery in plants using silk microneedles expanded upon previous research supervised by Marelli. The original idea was conceived by SMART and MIT: Marelli, Cao, and Professor Nam-Hai Chua, co-lead principal investigator at DiSTAP. Researchers from TLL and the National University of Singapore, Professor Urano Daisuke and Koh, joined the study to contribute biological perspectives. The research is carried out by SMART and supported by the National Research Foundation Singapore (NRF) under its Campus for Research Excellence And Technological Enterprise (CREATE) program.

      SMART was established by MIT and NRF in 2007. SMART is the first entity in CREATE, developed by NRF. SMART serves as an intellectual and innovation hub for research interactions between MIT and Singapore, undertaking cutting-edge research in areas of interest to both parties. SMART currently comprises an Innovation Center and interdisciplinary research groups: Antimicrobial Resistance, Critical Analytics for Manufacturing Personalized-Medicine, DiSTAP, Future Urban Mobility, and Low Energy Electronic Systems. More

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      in Energy

      Study: Shutting down nuclear power could increase air pollution

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      Nearly 20 percent of today’s electricity in the United States comes from nuclear power. The U.S. has the largest nuclear fleet in the world, with 92 reactors scattered around the country. Many of these power plants have run for more than half a century and are approaching the end of their expected lifetimes.

      Policymakers are debating whether to retire the aging reactors or reinforce their structures to continue producing nuclear energy, which many consider a low-carbon alternative to climate-warming coal, oil, and natural gas.

      Now, MIT researchers say there’s another factor to consider in weighing the future of nuclear power: air quality. In addition to being a low carbon-emitting source, nuclear power is relatively clean in terms of the air pollution it generates. Without nuclear power, how would the pattern of air pollution shift, and who would feel its effects?

      The MIT team took on these questions in a new study appearing today in Nature Energy. They lay out a scenario in which every nuclear power plant in the country has shut down, and consider how other sources such as coal, natural gas, and renewable energy would fill the resulting energy needs throughout an entire year.

      Their analysis reveals that indeed, air pollution would increase, as coal, gas, and oil sources ramp up to compensate for nuclear power’s absence. This in itself may not be surprising, but the team has put numbers to the prediction, estimating that the increase in air pollution would have serious health effects, resulting in an additional 5,200 pollution-related deaths over a single year.

      If, however, more renewable energy sources become available to supply the energy grid, as they are expected to by the year 2030, air pollution would be curtailed, though not entirely. The team found that even under this heartier renewable scenario, there is still a slight increase in air pollution in some parts of the country, resulting in a total of 260 pollution-related deaths over one year.

      When they looked at the populations directly affected by the increased pollution, they found that Black or African American communities — a disproportionate number of whom live near fossil-fuel plants — experienced the greatest exposure.

      “This adds one more layer to the environmental health and social impacts equation when you’re thinking about nuclear shutdowns, where the conversation often focuses on local risks due to accidents and mining or long-term climate impacts,” says lead author Lyssa Freese, a graduate student in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS).

      “In the debate over keeping nuclear power plants open, air quality has not been a focus of that discussion,” adds study author Noelle Selin, a professor in MIT’s Institute for Data, Systems, and Society (IDSS) and EAPS. “What we found was that air pollution from fossil fuel plants is so damaging, that anything that increases it, such as a nuclear shutdown, is going to have substantial impacts, and for some people more than others.”

      The study’s MIT-affiliated co-authors also include Principal Research Scientist Sebastian Eastham and Guillaume Chossière SM ’17, PhD ’20, along with Alan Jenn of the University of California at Davis.

      Future phase-outs

      When nuclear power plants have closed in the past, fossil fuel use increased in response. In 1985, the closure of reactors in Tennessee Valley prompted a spike in coal use, while the 2012 shutdown of a plant in California led to an increase in natural gas. In Germany, where nuclear power has almost completely been phased out, coal-fired power increased initially to fill the gap.

      Noting these trends, the MIT team wondered how the U.S. energy grid would respond if nuclear power were completely phased out.

      “We wanted to think about what future changes were expected in the energy grid,” Freese says. “We knew that coal use was declining, and there was a lot of work already looking at the impact of what that would have on air quality. But no one had looked at air quality and nuclear power, which we also noticed was on the decline.”

      In the new study, the team used an energy grid dispatch model developed by Jenn to assess how the U.S. energy system would respond to a shutdown of nuclear power. The model simulates the production of every power plant in the country and runs continuously to estimate, hour by hour, the energy demands in 64 regions across the country.

      Much like the way the actual energy market operates, the model chooses to turn a plant’s production up or down based on cost: Plants producing the cheapest energy at any given time are given priority to supply the grid over more costly energy sources.

      The team fed the model available data on each plant’s changing emissions and energy costs throughout an entire year. They then ran the model under different scenarios, including: an energy grid with no nuclear power, a baseline grid similar to today’s that includes nuclear power, and a grid with no nuclear power that also incorporates the additional renewable sources that are expected to be added by 2030.

      They combined each simulation with an atmospheric chemistry model to simulate how each plant’s various emissions travel around the country and to overlay these tracks onto maps of population density. For populations in the path of pollution, they calculated the risk of premature death based on their degree of exposure.

      System response

      Play video

      Courtesy of the researchers, edited by MIT News

      Their analysis showed a clear pattern: Without nuclear power, air pollution worsened in general, mainly affecting regions in the East Coast, where nuclear power plants are mostly concentrated. Without those plants, the team observed an uptick in production from coal and gas plants, resulting in 5,200 pollution-related deaths across the country, compared to the baseline scenario.

      They also calculated that more people are also likely to die prematurely due to climate impacts from the increase in carbon dioxide emissions, as the grid compensates for nuclear power’s absence. The climate-related effects from this additional influx of carbon dioxide could lead to 160,000 additional deaths over the next century.

      “We need to be thoughtful about how we’re retiring nuclear power plants if we are trying to think about them as part of an energy system,” Freese says. “Shutting down something that doesn’t have direct emissions itself can still lead to increases in emissions, because the grid system will respond.”

      “This might mean that we need to deploy even more renewables, in order to fill the hole left by nuclear, which is essentially a zero-emissions energy source,” Selin adds. “Otherwise we will have a reduction in air quality that we weren’t necessarily counting on.”

      This study was supported, in part, by the U.S. Environmental Protection Agency. More

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      in Environment

      Engineering for social impact

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      A desire to make meaningful contributions to society has influenced Runako Gentles’ path in life. Gentles grew up in Jamaica with a supportive extended family that instilled in him his connection to his faith and his aspiration to aim for greatness.

      “While growing up, I was encouraged to live a life that could potentially bring about major positive changes in my family and many other people’s lives,” says the MIT junior.

      One of those pathways his parents encouraged is pursuing excellence in academics.

      Gentles attended Campion College, a Jesuit high school in Jamaica for academically high-achieving students. Gentles was valedictorian and even won an award “for the member of the valedictory class who most closely resembles the ideal of intellectual competence, openness to growth, and commitment to social justice.”

      Although he did well in all subjects, he naturally gravitated toward biology and chemistry. “There are certain subjects people just make sense of material much faster, and high school biology and chemistry were those subjects for me,” he says. His love of learning often surprised friends and classmates when he could recall science concepts and definitions years later.  

      For several years Gentles wanted to pursue the field of medicine. He remembers becoming more excited about the career of a surgeon after reading a book on the story of retired neurosurgeon Ben Carson. During his advanced studies at Campion, he attended a career event and met with a neurosurgeon who invited him and other classmates to watch a surgical procedure. Gentles had the unique learning experience to observe a spinal operation. Around that same time another learning opportunity presented itself. His biology teacher recommended he apply to a Caribbean Science Foundation initiative called Student Program for Innovation, Science, and Engineering (SPISE) to explore careers in science, technology, engineering, and math. The intensive residential summer program for Caribbean students is modeled after the Minority Introduction to Engineering and Science (MITES) program at MIT. Cardinal Warde, a professor of electrical engineering at MIT who is also from the Caribbean, serves as the faculty director for both MITES and SPISE. The program was Gentles’ first major exposure to engineering.

      “I felt like I was in my first year of college at SPISE. It was an amazing experience and it helped me realize the opportunities that an engineering career path offers,” Gentles says. He excelled in the SPISE program, even winning one of the program’s highest honors for demonstrating overall excellence and leadership.

      SPISE was profoundly impactful to Gentles and he decided to pursue engineering at MIT. While further exploring his engineering interests before his first year at MIT, he remembers reading an article that piqued his interest in industry sectors that met basic human and societal needs.

      “I started thinking more about engineering and ethics,” says Gentles. He wanted to spend his time learning how to use science and engineering to make meaningful change in society.  “I think back to wanting to be a doctor for many years to help sick people, but I took it a step further. I wanted to get closer to addressing some of the root causes of deaths, illnesses, and the poor quality of life for billions of people,” he says of his decision to pursue a degree in civil and environmental engineering.

      Gentles spent his first semester at MIT working as a remote student when the Covid pandemic shut down in-person learning. He participated in 1.097 (Introduction to Civil and Environmental Engineering Research) during the January Independent Activities Period, in which undergraduates work one-on-one with graduate students or postdoc mentors on research projects that align with their interests. Gentles worked in the lab of Ruben Juanes exploring the use of machine learning to analyze earthquake data to determine whether different geologic faults in Puerto Rico resulted in distinguishable earthquake clusters. He joined the lab of Desiree Plata in the summer of his sophomore year on another undergraduate research opportunity (UROP) project, analyzing diesel range organic compounds in water samples collected from shallow groundwater sources near hydraulic fracking sites in West Virginia. The experience even led Gentles to be a co-author in his graduate student mentor’s abstract proposal for the American Geophysical Union Fall Meeting 2022 conference.  

      Gentles says he found the Department of Civil and Environmental Engineering a place for him to have the big-picture mindset of thinking about how technology is going to affect the environment, which ultimately affects society. “Choosing this department was not just about gaining the technical knowledge that most interested me. I wanted to be in a space where I would significantly develop my mindset of using innovation to bring more harmony between society and the environment,” says Gentles.

      Outside of the classroom, learning acoustic guitar is a passion for Gentles. He plays at social events for Cru, a Christian community at MIT, where he serves as a team leader. He credits Cru with helping him feel connected to a lot of different people, even outside of MIT.

      He’s also a member of the Bernard M. Gordon-MIT Engineering Leadership Program, which helps undergraduates gain and hone leadership skills to prepare them for careers in engineering. After learning and exploring more UROPs and classes in civil and environmental engineering, he aspires to hold a position of leadership where he can use his environmental knowledge to impact human lives.

      “Mitigating environmental issues can sometimes be a very complicated endeavor involving many stakeholders,” Gentles says. “We need more bright minds to be thinking of creative ways to address these pressing problems. We need more leaders helping to make society more harmonious with our planet.” More

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      in Environment

      Benjamin Mangrum receives the 2023 Levitan Prize in the Humanities

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      Benjamin Mangrum, assistant professor of literature at MIT, has been awarded the 2023 Levitan Prize in the Humanities. This award, presented each year by a faculty committee, empowers a member of the MIT School of Humanities, Arts, and Social Sciences (SHASS) faculty with funding to enable research in their field. With an award of $30,000, this annual prize continues to power substantial projects among the members of the SHASS community.

      Mangrum will use the award to support research for his upcoming book, which is a cultural and intellectual history of environmental rights. In the book, Mangrum discusses the cultural structures that have helped link rights language to environmental concerns. Mangrum plans to use the funding from the Levitan Prize for research into a chapter involving literary personhood.

      “Assertions of environmental rights are typically the result of pragmatic or strategic alignments between, say, naturalists and labor organizers or indigenous communities and governments,” he writes. “My book examines the compromises and conceptual negotiations that occur for ‘environmental rights’ to be a workable concept.”

      The notion of environmental rights can refer to the right of citizens to live in a healthy environment, but it can also include the attribution of rights to nonhuman entities. Such designation received increased attention when New Zealand gave the Whanganui River a legal identity, bringing the longest-running litigation in New Zealand history to an end. India has named rivers legal entities and Bangladesh has given all its rivers legal rights.

      “Personhood status was a compromise between the government and a group of Māori tribes who demanded recognition for the river based on past treaties,” Mangrum writes. “I’m interested in how these very different kinds of discourse — political rights, environmental science, indigenous culture, public health — have come together during the 20th and 21st centuries.”

      For the chapter, Mangrum explores the argument made by legal theorist Christopher Stone in “Should Trees Have Standing?” First published in 1972, Stone’s essay is a foundational argument in environmental law. Stone maintains that natural objects can be given legal personhood, an argument that is often cited in legal framings of environmental rights. Mangrum explores the literary dimensions of legal personhood.

      “I argue that the intellectual and cultural history of legal personhood shares unacknowledged debts to the evolution in theories of literary personhood,” Mangrum writes. “A reader’s attribution of personhood does not serve the same social and moral functions as the attribution of personhood to corporations and other nonhuman entities. However, I argue that modern ideas about literary personhood are cognitively homologous with legal personhood: despite serving different functions, these conceptions of personhood share conceptual structures and intellectual origins.”

      In one recently published article, he examines the language used by Rachel Carson and others in the nascent environmental movement. In 1963, Carson testified before a U.S. Senate subcommittee on the threat of pesticides. It was considered a watershed moment for environmentalism, but notable also for intellectual history. Her use of the vocabulary of rights and her advocacy for environmental regulations in a public forum were significant forces in the institutionalization of environmental rights.

      Mangrum notes Carson’s claim of “the right of the citizen to be secure in his own home against the intrusion of poisons applied by other persons.” Carson uses the language of rights to introduce environmental concerns within the public sphere, but this language also has implications for how we understand our relationship to the nonhuman world.

      Before arriving at MIT in 2022, Mangrum taught at the University of the South, the University of Michigan, and Davidson College. He is the author of “Land of Tomorrow: Postwar Fiction and the Crisis of American Liberalism” (Oxford 2019), which examines 20th-century literary fiction and popular philosophy to understand shifts in American liberalism after World War II. He received his PhD from the University of North Carolina at Chapel Hill. More

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      in Environment

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

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      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

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      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

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      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 Energy

      An education in climate change

      by

      Several years ago, Christopher Knittel’s father, then a math teacher, shared a mailing he had received at his high school. When he opened the packet, alarm bells went off for Knittel, who is the George P. Shultz Professor of Energy Economics at the MIT Sloan School of Management and the deputy director for policy at the MIT Energy Initiative (MITEI). “It was a slickly produced package of materials purporting to show how to teach climate change,” he says. “In reality, it was a thinly veiled attempt to kindle climate change denial.”

      Knittel was especially concerned to learn that this package had been distributed to schools nationwide. “Many teachers in search of information on climate change might use this material because they are not in a position to judge its scientific validity,” says Knittel, who is also the faculty director of the MIT Center for Energy and Environmental Policy Research (CEEPR). “I decided that MIT, which is committed to true science, was in the perfect position to develop its own climate change curriculum.”

      Today, Knittel is spearheading the Climate Action Through Education (CATE) program, a curriculum rolling out in pilot form this year in more than a dozen Massachusetts high schools, and eventually in high schools across the United States. To spur its broad adoption, says Knittel, the CATE curriculum features a unique suite of attributes: the creation of climate-based lessons for a range of disciplines beyond science, adherence to state-based education standards to facilitate integration into established curricula, material connecting climate change impacts to specific regions, and opportunities for students to explore climate solutions.

      CATE aims to engage both students and teachers in a subject that can be overwhelming. “We will be honest about the threats posed by climate change but also give students a sense of agency that they can do something about this,” says Knittel. “And for the many teachers — especially non-science teachers — starved for knowledge and background material, CATE offers resources to give them confidence to implement our curriculum.”

      Partnering with teachers

      From the outset, CATE sought guidance and hands-on development help from educators. Project manager Aisling O’Grady surveyed teachers to learn about their experiences teaching about climate and to identify the kinds of resources they lacked. She networked with MIT’s K-12 education experts and with Antje Danielson, MITEI director of education, “bouncing ideas off of them to shape the direction of our effort,” she says.

      O’Grady gained two critical insights from this process: “I realized that we needed practicing high school teachers as curriculum developers and that they had to represent different subject areas, because climate change is inherently interdisciplinary,” she says. This echoes the philosophy behind MITEI’s Energy Studies minor, she remarks, which includes classes from MIT’s different schools. “While science helps us understand and find solutions for climate change, it touches so many other areas, from economics, policy, environmental justice and politics, to history and literature.”

      In line with this thinking, CATE recruited Massachusetts teachers representing key subject areas in the high school curriculum: Amy Block, a full-time math teacher, and Lisa Borgatti, a full-time science teacher, both at the Governor’s Academy in Byfield; and Kathryn Teissier du Cros, a full-time language arts teacher at Newton North High School.

      The fourth member of this cohort, Michael Kozuch, is a full-time history teacher at Newton South High School, where he has worked for 24 years. Kozuch became engaged with environmental issues 15 years ago, introducing an elective in sustainability at Newton South. He serves on the coordinating committee for the Climate Action Network at the Massachusetts Teachers Association. He also is president of Earth Day Boston and organized Boston’s 50th anniversary celebration of Earth Day. When he learned that MIT was seeking teachers to help develop a climate education curriculum, he immediately applied.

      “I’ve heard time and again from teachers across the state that they want to incorporate climate change into the curriculum but don’t know how to make it work, given lesson plans and schedules geared toward preparing students for specific tests,” says Kozuch. “I knew that for a climate curriculum to succeed, it had to be part of an integrated approach.”

      Using climate as a lens

      Over the course of a year, Kozuch and fellow educators created units that fit into their pre-existing syllabi but were woven through with relevant climate change themes. Kozuch already had some experience in this vein, describing the role of the Industrial Revolution in triggering the use of fossil fuels and the greenhouse gas emissions that resulted. For CATE, Kozuch explored additional ways of shifting focus in covering U.S. history. There are, for instance, lessons looking at westward expansion in terms of land use, expulsion of Indigenous people, and environmental justice, and at the Baby Boom period and the emergence of the environmental movement.

      In English/language arts, there are units dedicated to explaining terms used by scientists and policymakers, such as “anthropogenic,” as well as lessons devoted to climate change fiction and to student-originated sustainability projects.

      The science and math classes work independently but also dovetail. For instance, there are science lessons that demystify the greenhouse effect, utilizing experiments to track fossil fuel emissions, which link to math lessons that calculate and graph the average rate of change of global carbon emissions. To make these classes even more relevant, there are labs where students compare carbon emissions in Massachusetts to those of a neighboring state, and where they determine the environmental and economic costs of plugging in electric devices in their own homes.

      Throughout this curriculum-shaping process, O’Grady and the teachers sought feedback from MIT faculty from a range of disciplines, including David McGee, associate professor in the Department of Earth, Atmospheric and Planetary Sciences. With the help of CATE undergraduate researcher Heidi Li ’22, the team held a focus group with the Sustainable Energy Alliance, an undergraduate student club. In spring 2022, CATE convened a professional development workshop in collaboration with the Massachusetts Teachers Association Climate Action Network, Earth Day Boston, and MIT’s Office of Government and Community Relations, sponsored by the Beker Foundation, to evaluate 15 discrete CATE lessons. One of the workshop participants, Gary Smith, a teacher from St. John’s Preparatory School in Danvers, Massachusetts, signed on as a volunteer science curriculum developer.

      “We had a diverse pool of teachers who thought the lessons were fantastic, but among their suggestions noted that their student cohorts included new English speakers, who needed simpler language and more pictures,” says O’Grady. “This was extremely useful to us, and we revised the curriculum because we want to reach students at every level of learning.”

      Reaching all the schools

      Now, the CATE curriculum is in the hands of a cohort of Massachusetts teachers. Each of these educators will test one or more of the lessons and lab activities over the next year, checking in regularly with MIT partners to report on their classroom experiences. The CATE team is building a Climate Education Resource Network of MIT graduate students, postdocs, and research staff who can answer teachers’ specific climate questions and help them find additional resources or datasets. Additionally, teachers will have the opportunity to attend two in-person cohort meetings and be paired with graduate student “climate advisors.”

      In spring 2023, in honor of Earth Day, O’Grady and Knittel want to bring CATE first adopters — high school teachers, students, and their families — to campus. “We envision professors giving mini lectures, youth climate groups discussing how to get involved in local actions, and our team members handing out climate change packets to students to spark conversations with their families at home,” says O’Grady.

      By creating a positive experience around their curriculum in these pilot schools, the CATE team hopes to promote its dissemination to many more Massachusetts schools in 2023. The team plans on enhancing lessons, offering more paths to integration in high school studies, and creating a companion resource website for teachers. Knittel wants to establish footholds in school after school, in Massachusetts and beyond.

      “I plan to spend a lot of my time convincing districts and states to adopt,” he says. “If one teacher tells another that the curriculum is useful, with touchpoints in different disciplines, that’s how we get a foot in the door.”

      Knittel is not shying away from places where “climate change is a politicized topic.” He hopes to team up with universities in states where there might be resistance to including such lessons in schools to develop the curriculum. Although his day job involves computing household-level carbon footprints, determining the relationship between driving behavior and the price of gasoline, and promoting wise climate policy, Knittel plans to push CATE as far as he can. “I want this curriculum to be adopted by everybody — that’s my goal,” he says.

      “In one sense, I’m not the natural person for this job,” he admits. “But I share the mission and passion of MITEI and CEEPR for decarbonizing our economy in ways that are socially equitable and efficient, and part of doing that is educating Americans about the actual costs and consequences of climate change.”

      The CATE program is sponsored by MITEI, CEEPR, and the MIT Vice President for Research.

      This article appears in the Winter 2023 issue of Energy Futures, the magazine of the MIT Energy Initiative. More