Aurelia Butler

More stories

  • 125 Shares179 Views

    in Environment

    Improving predictions of sea level rise for the next century

    When we think of climate change, one of the most dramatic images that comes to mind is the loss of glacial ice. As the Earth warms, these enormous rivers of ice become a casualty of the rising temperatures. But, as ice sheets retreat, they also become an important contributor to one the more dangerous outcomes of climate change: sea-level rise. At MIT, an interdisciplinary team of scientists is determined to improve sea level rise predictions for the next century, in part by taking a closer look at the physics of ice sheets.

    Last month, two research proposals on the topic, led by Brent Minchew, the Cecil and Ida Green Career Development Professor in the Department of Earth, Atmospheric and Planetary Sciences (EAPS), were announced as finalists in the MIT Climate Grand Challenges initiative. Launched in July 2020, Climate Grand Challenges fielded almost 100 project proposals from collaborators across the Institute who heeded the bold charge: to develop research and innovations that will deliver game-changing advances in the world’s efforts to address the climate challenge.

    As finalists, Minchew and his collaborators from the departments of Urban Studies and Planning, Economics, Civil and Environmental Engineering, the Haystack Observatory, and external partners, received $100,000 to develop their research plans. A subset of the 27 proposals tapped as finalists will be announced next month, making up a portfolio of multiyear “flagship” projects receiving additional funding and support.

    One goal of both Minchew proposals is to more fully understand the most fundamental processes that govern rapid changes in glacial ice, and to use that understanding to build next-generation models that are more predictive of ice sheet behavior as they respond to, and influence, climate change.

    “We need to develop more accurate and computationally efficient models that provide testable projections of sea-level rise over the coming decades. To do so quickly, we want to make better and more frequent observations and learn the physics of ice sheets from these data,” says Minchew. “For example, how much stress do you have to apply to ice before it breaks?”

    Currently, Minchew’s Glacier Dynamics and Remote Sensing group uses satellites to observe the ice sheets on Greenland and Antarctica primarily with interferometric synthetic aperture radar (InSAR). But the data are often collected over long intervals of time, which only gives them “before and after” snapshots of big events. By taking more frequent measurements on shorter time scales, such as hours or days, they can get a more detailed picture of what is happening in the ice.

    “Many of the key unknowns in our projections of what ice sheets are going to look like in the future, and how they’re going to evolve, involve the dynamics of glaciers, or our understanding of how the flow speed and the resistances to flow are related,” says Minchew.

    At the heart of the two proposals is the creation of SACOS, the Stratospheric Airborne Climate Observatory System. The group envisions developing solar-powered drones that can fly in the stratosphere for months at a time, taking more frequent measurements using a new lightweight, low-power radar and other high-resolution instrumentation. They also propose air-dropping sensors directly onto the ice, equipped with seismometers and GPS trackers to measure high-frequency vibrations in the ice and pinpoint the motions of its flow.

    How glaciers contribute to sea level rise

    Current climate models predict an increase in sea levels over the next century, but by just how much is still unclear. Estimates are anywhere from 20 centimeters to two meters, which is a large difference when it comes to enacting policy or mitigation. Minchew points out that response measures will be different, depending on which end of the scale it falls toward. If it’s closer to 20 centimeters, coastal barriers can be built to protect low-level areas. But with higher surges, such measures become too expensive and inefficient to be viable, as entire portions of cities and millions of people would have to be relocated.

    “If we’re looking at a future where we could get more than a meter of sea level rise by the end of the century, then we need to know about that sooner rather than later so that we can start to plan and to do our best to prepare for that scenario,” he says.

    There are two ways glaciers and ice sheets contribute to rising sea levels: direct melting of the ice and accelerated transport of ice to the oceans. In Antarctica, warming waters melt the margins of the ice sheets, which tends to reduce the resistive stresses and allow ice to flow more quickly to the ocean. This thinning can also cause the ice shelves to be more prone to fracture, facilitating the calving of icebergs — events which sometimes cause even further acceleration of ice flow.

    Using data collected by SACOS, Minchew and his group can better understand what material properties in the ice allow for fracturing and calving of icebergs, and build a more complete picture of how ice sheets respond to climate forces. 

    “What I want is to reduce and quantify the uncertainties in projections of sea level rise out to the year 2100,” he says.

    From that more complete picture, the team — which also includes economists, engineers, and urban planning specialists — can work on developing predictive models and methods to help communities and governments estimate the costs associated with sea level rise, develop sound infrastructure strategies, and spur engineering innovation.

    Understanding glacier dynamics

    More frequent radar measurements and the collection of higher-resolution seismic and GPS data will allow Minchew and the team to develop a better understanding of the broad category of glacier dynamics — including calving, an important process in setting the rate of sea level rise which is currently not well understood.  

    “Some of what we’re doing is quite similar to what seismologists do,” he says. “They measure seismic waves following an earthquake, or a volcanic eruption, or things of this nature and use those observations to better understand the mechanisms that govern these phenomena.”

    Air-droppable sensors will help them collect information about ice sheet movement, but this method comes with drawbacks — like installation and maintenance, which is difficult to do out on a massive ice sheet that is moving and melting. Also, the instruments can each only take measurements at a single location. Minchew equates it to a bobber in water: All it can tell you is how the bobber moves as the waves disturb it.

    But by also taking continuous radar measurements from the air, Minchew’s team can collect observations both in space and in time. Instead of just watching the bobber in the water, they can effectively make a movie of the waves propagating out, as well as visualize processes like iceberg calving happening in multiple dimensions.

    Once the bobbers are in place and the movies recorded, the next step is developing machine learning algorithms to help analyze all the new data being collected. While this data-driven kind of discovery has been a hot topic in other fields, this is the first time it has been applied to glacier research.

    “We’ve developed this new methodology to ingest this huge amount of data,” he says, “and from that create an entirely new way of analyzing the system to answer these fundamental and critically important questions.”  More

  • 100 Shares99 Views

    in Environment

    How molecular biology could reduce global food insecurity

    Staple crops like rice, maize, and wheat feed over half of the global population, but they are increasingly vulnerable to severe environmental risks. The effects of climate change, including changing temperatures, rainfall variability, shifting patterns of agricultural pests and diseases, and saltwater intrusion from sea-level rise, all contribute to decreased crop yields. As these effects continue to worsen, there will be less food available for a rapidly growing population. 

    Mary Gehring, associate professor of biology and a member of the Whitehead Institute for Biomedical Research, is growing increasingly concerned about the potentially catastrophic impacts of climate change and has resolved to do something about it.

    The Gehring Lab’s primary research focus is plant epigenetics, which refers to the heritable information that influences plant cellular function but is not encoded in the DNA sequence itself. This research is adding to our fundamental understanding of plant biology and could have agricultural applications in the future. “I’ve been working with seeds for many years,” says Gehring. “Understanding how seeds work is going to be critical to agriculture and food security,” she explains.

    Laying the foundation

    Gehring is using her expertise to help crops develop climate resilience through a 2021 seed grant from MIT’s Abdul Latif Jameel Water and Food Systems Lab (J-WAFS). Her research is aimed at discovering how we can accelerate the production of genetic diversity to generate plant populations that are better suited to challenging environmental conditions.

    Genetic variation gives rise to phenotypic variations that can help plants adapt to a wider range of climates. Traits such as flood resistance and salt tolerance will become more important as the effects of climate change are realized. However, many important plant species do not appear to have much standing genetic variation, which could become an issue if farmers need to breed their crops quickly to adapt to a changing climate. 

    In researching a nutritious crop that has little genetic variation, Gehring came across the pigeon pea, a species she had never worked with before. Pigeon peas are a legume eaten in Asia, Africa, and Latin America. They have some of the highest levels of protein in a seed, so eating more pigeon peas could decrease our dependence on meat, which has numerous negative environmental impacts. Pigeon peas also have a positive impact on the environment; as perennial plants, they live for three to five years and sequester carbon for longer periods of time. They can also help with soil restoration. “Legumes are very interesting because they’re nitrogen-fixers, so they create symbioses with microbes in the soil and fix nitrogen, which can renew soils,” says Gehring. Furthermore, pigeon peas are known to be drought-resistant, so they will likely become more attractive as many farmers transition away from water-intensive crops.

    Developing a strategy

    Using the pigeon pea plant, Gehring began to explore a universal technology that would increase the amount of genetic diversity in plants. One method her research group chose is to enhance transposable element proliferation. Genomes are made up of genes that make proteins, but large fractions are also made up of transposable elements. In fact, about 45 percent of the human genome is made up of transposable elements, Gehring notes. The primary function of transposable elements is to make more copies of themselves. Since our bodies do not need an infinite number of these copies, there are systems in place to “silence” them from copying. 

    Gehring is trying to reverse that silencing so that the transposable elements can move freely throughout the genome, which could create genetic variation by creating mutations or altering the promoter of a gene — that is, what controls a certain gene’s expression. Scientists have traditionally initiated mutagenesis by using a chemical that changes single base pairs in DNA, or by using X-rays, which can cause very large chromosome breaks. Gehring’s research team is attempting to induce transposable element proliferation by treatment with a suite of chemicals that inhibit transposable element silencing. The goal is to impact multiple sites in the genome simultaneously. “This is unexplored territory where you’re changing 50 genes at a time, or 100, rather than just one,” she explains. “It’s a fairly risky project, but sometimes you have to be ambitious and take risks.”

    Looking forward

    Less than one year after receiving the J-WAFS seed grant, the research project is still in its early stages. Despite various restrictions due to the ongoing pandemic, the Gehring Lab is now generating data on the Arabidopsis plant that will be applied to pigeon pea plants. However, Gehring expects it will take a good amount of time to complete this research phase, considering the pigeon pea plants can take upward of 100 days just to flower. While it might take time, this technology could help crops withstand the effects of climate change, ultimately contributing to J-WAFS’ goal of finding solutions to food system challenges.

    “Climate change is not something any of us can ignore. … If one of us has the ability to address it, even in a very small way, that’s important to try to pursue,” Gehring remarks. “It’s part of our responsibility as scientists to take what knowledge we have and try to apply it to these sorts of problems.” More

  • 100 Shares99 Views

    in Environment

    Q&A: Bettina Stoetzer on envisioning a livable future

    In an ongoing series, MIT faculty, students, and alumni in the humanistic fields share perspectives that are significant for solving the economic, political, ethical, and cultural dimensions of climate change, as well as mitigating its myriad social and ecological impacts. Bettina Stoetzer is the Class of 1948 Career Development Associate Professor of Anthropology at MIT; her research combines perspectives on ecology and environmental change with an analysis of migration, race, and social justice. In this conversation with SHASS Communications, she shares insights from anthropology and from her forthcoming book, “Ruderal City: Ecologies of Migration and Urban Life in Berlin” (Duke University Press, 2022).Q: You research “ruderal” ecologies — those rising up like weeds in inhospitable locales such as industrial zones. What does your work reveal about the relationship between humans and the environment, particularly as climate change presents ever more challenges to human habitation?A: The term ruderal originates from the Latin word “rudus,” meaning “rubble.” In urban ecology it refers to organisms that spontaneously inhabit inhospitable environments such as rubble spaces, the cracks in sidewalks, or spaces alongside train tracks and roads. As an anthropologist, I find the ruderal to be a useful lens for examining this historical moment when environmental degradation, war, forced migration, economic inequality, and rising nationalism render much of the world inhospitable to so many beings.

    My book, “Ruderal City: Ecologies of Migration and Urban Life in Berlin,” is inspired by the insights of botany, ecology, as well as by social justice struggles. During my fieldwork in Berlin, I engaged with diverse communities — botanists, environmentalists, public officials, and other Berlin residents, such as white German nature enthusiasts, Turkish migrants who cultivate city gardens, and East African refugees who live in the forested edges of the city.The botanists I spoke with researched so-called “ruderal flora” that flourished in the city’s bombed landscapes after the end of World War II. Berlin’s rubble vegetation was abundant with plants that usually grow in much warmer climate zones, and the botanists realized that many of these plants’ seeds had arrived in the city by chance — hitching a ride via imported materials and vehicles, or the boots of refugees. At the same time, the initial appearance of these plants illustrated that Berlin had become hotter, which shed light on the early signs of climate change. But that is only part of the story. Listening to migrants, refugees, and other Berlin residents during my fieldwork, I also learned that it is important to consider the ways in which people who are often not recognized as experts relate to urban lands. White European environmental discourse often frames migrants and communities of color as having an inappropriate relation to “nature” in the city, and racializes them on that basis. For example, Turkish migrants who barbecue in Berlin’s parks are often portrayed as polluting the “green lungs” of Berlin.Yet from working with these communities, as well as with other Berliners who cultivated urban vegetable gardens, built makeshift shelters in abandoned lots, produced informal food economies in Berlin’s parks, or told stories about their experience in the forest edges of the city, I learned that people, while grappling with experiences of racism, actually carved out alternative ways of relating to urban lands that challenged white European and capitalist traditions.Engaging with these practices, I utilize the concept of the ruderal and expand it as an analytic for tracking seemingly disparate worlds — and for attending to the heterogeneous ways in which people build lives out of the ruins of European nationalism and capitalism. My goal in the book is not to equate people with plants, but rather to ask how people, plants, animals, and other living beings are intertwined in projects of capitalist extraction and in nation-making — and how they challenge and rework these projects.Q: In what ways do you think the tools and insights from anthropology can advance efforts to address climate change and its impacts?A: When tackling complex environmental challenges, climate change included, the focus is often on “the social consequences of” climate change and technological solutions to address it. What is exciting about anthropology is that it gives us tools to interrogate environmental challenges through a broader lens.Anthropologists use in-depth fieldwork to examine how people make sense of and relate to the world. Ethnographic fieldwork can help us examine how climate change affects people in their everyday lives, and it can reveal how different stakeholders approach environmental challenges. By providing a deeper understanding of the ways in which people relate to the material world, to land, and to other beings, anthropological analyses also shed light on the root causes of climate change and expand our imagination of how to live otherwise.Through these close-up analyses, ethnography can also illuminate large-scale political phenomena. For instance, by making visible the relation between climate change denial and the erosion of democratic social structures in people’s everyday lives, it can provide insights into the rise of nationalist and authoritarian movements. This is a question I explore in my new research project. (One case study in the new research focuses on the ways in which pigs, people, and viruses have co-evolved during urbanization, industrial agriculture, and the climate crisis, e.g.: the so-called African Swine Fever virus among wild boar — which proliferate in the ruins of industrial agriculture and climate changes — trigger political responses across Europe, including new border fences.)

    Through several case studies, I examine how the changing mobility patterns of wildlife (due to climate change, habitat loss, and urbanization) pose challenges for tackling the climate crisis across national borders and for developing new forms of care for nonhuman lives.Q: You teach MIT’s class 21A.407 (Gender, Race, and Environmental Justice). Broadly speaking, what are goals of this class? What lessons do you hope students will carry with them into the future?A: The key premise of this class is that the environmental challenges facing the world today cannot be adequately addressed without a deeper understanding of racial, gender, and class inequalities, as well as the legacies of colonialism. Our discussion begins with the lands on which we, at MIT, stand. We read about the colonization of New England and how it radically transformed local economies and landscapes, rearranged gender and racial relations, and led to the genocide and dispossession of Indigenous communities and their way of life.From this foundation, the goal is to expand our ideas of what it means to talk about ecology, the “environment,” and justice. There is not one way in which humans relate to land and to nonhuman beings, or one way of (re-)producing the conditions of our livelihoods (capitalism). These relations are all shaped by history, culture, and power.We read anthropological scholarship that explores how climate change, environmental pollution, and habitat destruction are also the consequences of modes of inhabiting the earth inherited from colonial relations to land that construct human and nonhuman beings as extractable “resources.” Considering these perspectives, it becomes clear that pressing environmental challenges can only be solved by also tackling racism and the legacies of colonialism.Throughout the semester, we read about environmental justice struggles that seek to stop the destruction of land, undo the harm of toxic exposures, and mitigate the effects of climate change. I hope that one of the takeaways students gain from this course is that Black, Indigenous, people-of-color, and feminist activists and scholars have been leading the way in shaping more livable futures.

    Q: In confronting an issue as formidable as global climate change, what gives you hope?A: I am really inspired by youth climate justice activists, especially from the Global South, who insist on new solutions to the climate emergency that counter market-driven perspectives, address global economic inequalities, and raise awareness about climate-driven displacement. Confronting climate change will require building more democratic structures and climate justice activists are at the forefront of this.Here at MIT, I also see a growing enthusiasm among our students to develop solutions to the climate crisis and to social injustices. I am particularly excited about Living Climate Futures, an initiative in Anthropology, History, and the Program on Science, Technology, and Society. We will be hosting a symposium at the end of April featuring environmental and climate justice leaders and youth activists from across the country. It will be a unique opportunity to explore how community leaders and research institutions such as MIT can collaborate more closely to tackle the challenges of climate change.

    Interview prepared by MIT SHASS CommunicationsSenior writer: Kathryn O’NeillSeries editor, designer: Emily Hiestand, communications director More

  • 150 Shares159 Views

    in Security

    Q&A: Latifah Hamzah ’12 on creating sustainable solutions in Malaysia and beyond

    Latifah Hamzah ’12 graduated from MIT with a BS in mechanical engineering and minors in energy studies and music. During their time at MIT, Latifah participated in various student organizations, including the MIT Symphony Orchestra, Alpha Phi Omega, and the MIT Design/Build/Fly team. They also participated in the MIT Energy Initiative’s Undergraduate Research Opportunities Program (UROP) in the lab of former professor of mechanical engineering Alexander Mitsos, examining solar-powered thermal and electrical co-generation systems.

    After graduating from MIT, Latifah worked as a subsea engineer at Shell Global Solutions and co-founded Engineers Without Borders – Malaysia, a nonprofit organization dedicated to finding sustainable and empowering solutions that impact disadvantaged populations in Malaysia. More recently, Latifah received a master of science in mechanical engineering from Stanford University, where they are currently pursuing a PhD in environmental engineering with a focus on water and sanitation in developing contexts.

    Q: What inspired you to pursue energy studies as an undergraduate student at MIT?

    A: I grew up in Malaysia, where I was at once aware of both the extent to which the oil and gas industry is a cornerstone of the economy and the need to transition to a lower-carbon future. The Energy Studies minor was therefore enticing because it gave me a broader view of the energy space, including technical, policy, economic, and other viewpoints. This was my first exposure to how things worked in the real world — in that many different fields and perspectives had to be considered cohesively in order to have a successful, positive, and sustained impact. Although the minor was predominantly grounded in classroom learning, what I learned drove me to want to discover for myself how the forces of technology, society, and policy interacted in the field in my subsequent endeavors.

    In addition to the breadth that the minor added to my education, it also provided a structure and focus for me to build on my technical fundamentals. This included taking graduate-level classes and participating in UROPs that had specific energy foci. These were my first forays into questions that, while still predominantly technical, were more open-ended and with as-yet-unknown answers that would be substantially shaped by the framing of the question. This shift in mindset required from typical undergraduate classes and problem sets took a bit of adjusting to, but ultimately gave me the confidence and belief that I could succeed in a more challenging environment.

    Q: How did these experiences with energy help shape your path forward, particularly in regard to your work with Engineers Without Borders – Malaysia and now at Stanford?

    A: When I returned home after graduation, I was keen to harness my engineering education and explore in practice what the Energy Studies minor curriculum had taught by theory and case studies: to consider context, nuance, and interdisciplinary and myriad perspectives to craft successful, sustainable solutions. Recognizing that there were many underserved communities in Malaysia, I co-founded Engineers Without Borders – Malaysia with some friends with the aim of working with these communities to bring simple and sustainable engineering solutions. Many of these projects did have an energy focus. For example, we designed, sized, and installed micro-hydro or solar-power systems for various indigenous communities, allowing them to continue living on their ancestral lands while reducing energy poverty. Many other projects incorporated other aspects of engineering, such as hydrotherapy pools for folks with special needs, and water and sanitation systems for stateless maritime communities.

    Through my work with Engineers Without Borders – Malaysia, I found a passion for the broader aspects of sustainability, development, and equity. By spending time with communities in the field and sharing in their experiences, I recognized gaps in my skill set that I could work on to be more effective in advocating for social and environmental justice. In particular, I wanted to better understand communities and their perspectives while being mindful of my positionality. In addition, I wanted to address the more systemic aspects of the problems they faced, which I felt in many cases would only be possible through a combination of research, evidence, and policy. To this end, I embarked on a PhD in environmental engineering with a minor in anthropology and pursued a Community-Based Research Fellowship with Stanford’s Haas Center for Public Service. I have also participated in the Rising Environmental Leaders Program (RELP), which helps graduate students “hone their leadership and communications skills to maximize the impact of their research.” RELP afforded me the opportunity to interact with representatives from government, NGOs [nongovernmental organizations], think tanks, and industry, from which I gained a better understanding of the policy and adjacent ecosystems at both the federal and state levels.

    Q: What are you currently studying, and how does it relate to your past work and educational experiences?

    A: My dissertation investigates waste management and monitoring for improved planetary health in three distinct projects. Suboptimal waste management can lead to poor outcomes, including environmental contamination, overuse of resources, and lost economic and environmental opportunities in resource recovery. My first project showed that three combinations of factors resulted in ruminant feces contaminating the stored drinking water supplies of households in rural Kenya, and the results were published in the International Journal of Environmental Research and Public Health. Consequently, water and sanitation interventions must also consider animal waste for communities to have safe drinking water.

    My second project seeks to establish a circular economy in the chocolate industry with indigenous Malaysian farmers and the Chocolate Concierge, a tree-to-bar social enterprise. Having designed and optimized apparatuses and processes to create biochar from cacao husk waste, we are now examining its impact on the growth of cacao saplings and their root systems. The hope is that biochar will increase the resilience of saplings for when they are transplanted from the nursery to the farm. As biochar can improve soil health and yield while reducing fertilizer inputs and sequestering carbon, farmers can accrue substantial economic and environmental benefits, especially if they produce, use, and sell it themselves.

    My third project investigates the gap in sanitation coverage worldwide and potential ways of reducing it. Globally, 46 percent of the population lacks access to safely managed sanitation, while the majority of the 54 percent who do have access use on-site sanitation facilities such as septic tanks and latrines. Given that on-site, decentralized systems typically have a lower space and resource footprint, are cheaper to build and maintain, and can be designed to suit various contexts, they could represent the best chance of reaching the sanitation Sustainable Development Goal. To this end, I am part of a team of researchers at the Criddle Group at Stanford working to develop a household-scale system as part of the Gates Reinvent the Toilet Challenge, an initiative aimed at developing new sanitation and toilet technologies for developing contexts.

    The thread connecting these projects is a commitment to investigating both the technical and socio-anthropological dimensions of an issue to develop sustainable, reliable, and environmentally sensitive solutions, especially in low- and middle-income countries (LMICs). I believe that an interdisciplinary approach can provide a better understanding of the problem space, which will hopefully lead to effective potential solutions that can have a greater community impact.

    Q: What do you plan to do once you obtain your PhD?

    A: I hope to continue working in the spheres of water and sanitation and/or sustainability post-PhD. It is a fascinating moment to be in this space as a person of color from an LMIC, especially as ideas such as community-based research and decolonizing fields and institutions are becoming more widespread and acknowledged. Even during my time at Stanford, I have noticed some shifts in the discourse, although we still have a long way to go to achieve substantive and lasting change. Folks like me are underrepresented in forums where the priorities, policies, and financing of aid and development are discussed at the international or global scale. I hope I’ll be able to use my qualifications, experience, and background to advocate for more just outcomes.

    This article appears in the Autumn 2021 issue of Energy Futures, the magazine of the MIT Energy Initiative More

  • 63 Shares149 Views

    in Environment

    Setting carbon management in stone

    Keeping global temperatures within limits deemed safe by the Intergovernmental Panel on Climate Change means doing more than slashing carbon emissions. It means reversing them.

    “If we want to be anywhere near those limits [of 1.5 or 2 C], then we have to be carbon neutral by 2050, and then carbon negative after that,” says Matěj Peč, a geoscientist and the Victor P. Starr Career Development Assistant Professor in the Department of Earth, Atmospheric, and Planetary Sciences (EAPS).

    Going negative will require finding ways to radically increase the world’s capacity to capture carbon from the atmosphere and put it somewhere where it will not leak back out. Carbon capture and storage projects already suck in tens of million metric tons of carbon each year. But putting a dent in emissions will mean capturing many billions of metric tons more. Today, people emit around 40 billion tons of carbon each year globally, mainly by burning fossil fuels.

    Because of the need for new ideas when it comes to carbon storage, Peč has created a proposal for the MIT Climate Grand Challenges competition — a bold and sweeping effort by the Institute to support paradigm-shifting research and innovation to address the climate crisis. Called the Advanced Carbon Mineralization Initiative, his team’s proposal aims to bring geologists, chemists, and biologists together to make permanently storing carbon underground workable under different geological conditions. That means finding ways to speed-up the process by which carbon pumped underground is turned into rock, or mineralized.

    “That’s what the geology has to offer,” says Peč, who is a lead on the project, along with Ed Boyden, professor of biological engineering, brain and cognitive sciences, and media arts and sciences, and Yogesh Surendranath, professor of chemistry. “You look for the places where you can safely and permanently store these huge volumes of CO2.”

    Peč‘s proposal is one of 27 finalists selected from a pool of almost 100 Climate Grand Challenge proposals submitted by collaborators from across the Institute. Each finalist team received $100,000 to further develop their research proposals. A subset of finalists will be announced in April, making up a portfolio of multiyear “flagship” projects receiving additional funding and support.

    Building industries capable of going carbon negative presents huge technological, economic, environmental, and political challenges. For one, it’s expensive and energy-intensive to capture carbon from the air with existing technologies, which are “hellishly complicated,” says Peč. Much of the carbon capture underway today focuses on more concentrated sources like coal- or gas-burning power plants.

    It’s also difficult to find geologically suitable sites for storage. To keep it in the ground after it has been captured, carbon must either be trapped in airtight reservoirs or turned to stone.

    One of the best places for carbon capture and storage (CCS) is Iceland, where a number of CCS projects are up and running. The island’s volcanic geology helps speed up the mineralization process, as carbon pumped underground interacts with basalt rock at high temperatures. In that ideal setting, says Peč, 95 percent of carbon injected underground is mineralized after just two years — a geological flash.

    But Iceland’s geology is unusual. Elsewhere requires deeper drilling to reach suitable rocks at suitable temperature, which adds costs to already expensive projects. Further, says Peč, there’s not a complete understanding of how different factors influence the speed of mineralization.

    Peč‘s Climate Grand Challenge proposal would study how carbon mineralizes under different conditions, as well as explore ways to make mineralization happen more rapidly by mixing the carbon dioxide with different fluids before injecting it underground. Another idea — and the reason why there are biologists on the team — is to learn from various organisms adept at turning carbon into calcite shells, the same stuff that makes up limestone.

    Two other carbon management proposals, led by EAPS Cecil and Ida Green Professor Bradford Hager, were also selected as Climate Grand Challenge finalists. They focus on both the technologies necessary for capturing and storing gigatons of carbon as well as the logistical challenges involved in such an enormous undertaking.

    That involves everything from choosing suitable sites for storage, to regulatory and environmental issues, as well as how to bring disparate technologies together to improve the whole pipeline. The proposals emphasize CCS systems that can be powered by renewable sources, and can respond dynamically to the needs of different hard-to-decarbonize industries, like concrete and steel production.

    “We need to have an industry that is on the scale of the current oil industry that will not be doing anything but pumping CO2 into storage reservoirs,” says Peč.

    For a problem that involves capturing enormous amounts of gases from the atmosphere and storing it underground, it’s no surprise EAPS researchers are so involved. The Earth sciences have “everything” to offer, says Peč, including the good news that the Earth has more than enough places where carbon might be stored.

    “Basically, the Earth is really, really large,” says Peč. “The reasonably accessible places, which are close to the continents, store somewhere on the order of tens of thousands to hundreds thousands of gigatons of carbon. That’s orders of magnitude more than we need to put back in.” More

  • 113 Shares179 Views

    in Environment

    Microbes and minerals may have set off Earth’s oxygenation

    For the first 2 billion years of Earth’s history, there was barely any oxygen in the air. While some microbes were photosynthesizing by the latter part of this period, oxygen had not yet accumulated at levels that would impact the global biosphere.

    But somewhere around 2.3 billion years ago, this stable, low-oxygen equilibrium shifted, and oxygen began building up in the atmosphere, eventually reaching the life-sustaining levels we breathe today. This rapid infusion is known as the Great Oxygenation Event, or GOE. What triggered the event and pulled the planet out of its low-oxygen funk is one of the great mysteries of science.

    A new hypothesis, proposed by MIT scientists, suggests that oxygen finally started accumulating in the atmosphere thanks to interactions between certain marine microbes and minerals in ocean sediments. These interactions helped prevent oxygen from being consumed, setting off a self-amplifying process where more and more oxygen was made available to accumulate in the atmosphere.

    The scientists have laid out their hypothesis using mathematical and evolutionary analyses, showing that there were indeed microbes that existed before the GOE and evolved the ability to interact with sediment in the way that the researchers have proposed.

    Their study, appearing today in Nature Communications, is the first to connect the co-evolution of microbes and minerals to Earth’s oxygenation.

    “Probably the most important biogeochemical change in the history of the planet was oxygenation of the atmosphere,” says study author Daniel Rothman, professor of geophysics in MIT’s Department of Earth, Atmospheric, and Planetary Sciences (EAPS). “We show how the interactions of microbes, minerals, and the geochemical environment acted in concert to increase oxygen in the atmosphere.”

    The study’s co-authors include lead author Haitao Shang, a former MIT graduate student, and Gregory Fournier, associate professor of geobiology in EAPS.

    A step up

    Today’s oxygen levels in the atmosphere are a stable balance between processes that produce oxygen and those that consume it. Prior to the GOE, the atmosphere maintained a different kind of equilibrium, with producers and consumers of oxygen  in balance, but in a way that didn’t leave much extra oxygen for the atmosphere.

    What could have pushed the planet out of one stable, oxygen-deficient state to another stable, oxygen-rich state?

    “If you look at Earth’s history, it appears there were two jumps, where you went from a steady state of low oxygen to a steady state of much higher oxygen, once in the Paleoproterozoic, once in the Neoproterozoic,” Fournier notes. “These jumps couldn’t have been because of a gradual increase in excess oxygen. There had to have been some feedback loop that caused this step-change in stability.”

    He and his colleagues wondered whether such a positive feedback loop could have come from a process in the ocean that made some organic carbon unavailable to its consumers. Organic carbon is mainly consumed through oxidation, usually accompanied by the consumption of oxygen — a process by which microbes in the ocean use oxygen to break down organic matter, such as detritus that has settled in sediment. The team wondered: Could there have been some process by which the presence of oxygen stimulated its further accumulation?

    Shang and Rothman worked out a mathematical model that made the following prediction: If microbes possessed the ability to only partially oxidize organic matter, the partially-oxidized matter, or “POOM,” would effectively become “sticky,” and chemically bind to minerals in sediment in a way that would protect the material from further oxidation. The oxygen that would otherwise have been consumed to fully degrade the material would instead be free to build up in the atmosphere. This process, they found, could serve as a positive feedback, providing a natural pump to push the atmosphere into a new, high-oxygen equilibrium.

    “That led us to ask, is there a microbial metabolism out there that produced POOM?” Fourier says.

    In the genes

    To answer this, the team searched through the scientific literature and identified a group of microbes that partially oxidizes organic matter in the deep ocean today. These microbes belong to the bacterial group SAR202, and their partial oxidation is carried out through an enzyme, Baeyer-Villiger monooxygenase, or BVMO.

    The team carried out a phylogenetic analysis to see how far back the microbe, and the gene for the enzyme, could be traced. They found that the bacteria did indeed have ancestors dating back before the GOE, and that the gene for the enzyme could be traced across various microbial species, as far back as pre-GOE times.

    What’s more, they found that the gene’s diversification, or the number of species that acquired the gene, increased significantly during times when the atmosphere experienced spikes in oxygenation, including once during the GOE’s Paleoproterozoic, and again in the Neoproterozoic.

    “We found some temporal correlations between diversification of POOM-producing genes, and the oxygen levels in the atmosphere,” Shang says. “That supports our overall theory.”

    To confirm this hypothesis will require far more follow-up, from experiments in the lab to surveys in the field, and everything in between. With their new study, the team has introduced a new suspect in the age-old case of what oxygenated Earth’s atmosphere.

    “Proposing a novel method, and showing evidence for its plausibility, is the first but important step,” Fournier says. “We’ve identified this as a theory worthy of study.”

    This work was supported in part by the mTerra Catalyst Fund and the National Science Foundation. More

  • 138 Shares119 Views

    in Environment

    Study: Ice flow is more sensitive to stress than previously thought

    The rate of glacier ice flow is more sensitive to stress than previously calculated, according to a new study by MIT researchers that upends a decades-old equation used to describe ice flow.

    Stress in this case refers to the forces acting on Antarctic glaciers, which are primarily influenced by gravity that drags the ice down toward lower elevations. Viscous glacier ice flows “really similarly to honey,” explains Joanna Millstein, a PhD student in the Glacier Dynamics and Remote Sensing Group and lead author of the study. “If you squeeze honey in the center of a piece of toast, and it piles up there before oozing outward, that’s the exact same motion that’s happening for ice.”

    The revision to the equation proposed by Millstein and her colleagues should improve models for making predictions about the ice flow of glaciers. This could help glaciologists predict how Antarctic ice flow might contribute to future sea level rise, although Millstein said the equation change is unlikely to raise estimates of sea level rise beyond the maximum levels already predicted under climate change models.

    “Almost all our uncertainties about sea level rise coming from Antarctica have to do with the physics of ice flow, though, so this will hopefully be a constraint on that uncertainty,” she says.

    Other authors on the paper, published in Nature Communications Earth and Environment, include Brent Minchew, the Cecil and Ida Green Career Development Professor in MIT’s Department of Earth, Atmospheric, and Planetary Sciences, and Samuel Pegler, a university academic fellow at the University of Leeds.

    Benefits of big data

    The equation in question, called Glen’s Flow Law, is the most widely used equation to describe viscous ice flow. It was developed in 1958 by British scientist J.W. Glen, one of the few glaciologists working on the physics of ice flow in the 1950s, according to Millstein.

    With relatively few scientists working in the field until recently, along with the remoteness and inaccessibility of most large glacier ice sheets, there were few attempts to calibrate Glen’s Flow Law outside the lab until recently. In the recent study, Millstein and her colleagues took advantage of a new wealth of satellite imagery over Antarctic ice shelves, the floating extensions of the continent’s ice sheet, to revise the stress exponent of the flow law.

    “In 2002, this major ice shelf [Larsen B] collapsed in Antarctica, and all we have from that collapse is two satellite images that are a month apart,” she says. “Now, over that same area we can get [imagery] every six days.”

    The new analysis shows that “the ice flow in the most dynamic, fastest-changing regions of Antarctica — the ice shelves, which basically hold back and hug the interior of the continental ice — is more sensitive to stress than commonly assumed,” Millstein says. She’s optimistic that the growing record of satellite data will help capture rapid changes on Antarctica in the future, providing insights into the underlying physical processes of glaciers.   

    But stress isn’t the only thing that affects ice flow, the researchers note. Other parts of the flow law equation represent differences in temperature, ice grain size and orientation, and impurities and water contained in the ice — all of which can alter flow velocity. Factors like temperature could be especially important in understanding how ice flow impacts sea level rise in the future, Millstein says.

    Cracking under strain

    Millstein and colleagues are also studying the mechanics of ice sheet collapse, which involves different physical models than those used to understand the ice flow problem. “The cracking and breaking of ice is what we’re working on now, using strain rate observations,” Millstein says.

    The researchers use InSAR, radar images of the Earth’s surface collected by satellites, to observe deformations of the ice sheets that can be used to make precise measurements of strain. By observing areas of ice with high strain rates, they hope to better understand the rate at which crevasses and rifts propagate to trigger collapse.

    The research was supported by the National Science Foundation. More

  • 88 Shares149 Views

    in Security

    Using soap to remove micropollutants from water

    Imagine millions of soapy sponges the size of human cells that can clean water by soaking up contaminants. This simplistic model is used to describe technology that MIT chemical engineers have recently developed to remove micropollutants from water — a concerning, worldwide problem.

    Patrick S. Doyle, the Robert T. Haslam Professor of Chemical Engineering, PhD student Devashish Pratap Gokhale, and undergraduate Ian Chen recently published their research on micropollutant removal in the journal ACS Applied Polymer Materials. The work is funded by MIT’s Abdul Latif Jameel Water and Food Systems Lab (J-WAFS).

    In spite of their low concentrations (about 0.01–100 micrograms per liter), micropollutants can be hazardous to the ecosystem and to human health. They come from a variety of sources and have been detected in almost all bodies of water, says Gokhale. Pharmaceuticals passing through people and animals, for example, can end up as micropollutants in the water supply. Others, like endocrine disruptor bisphenol A (BPA), can leach from plastics during industrial manufacturing. Pesticides, dyes, petrochemicals, and per-and polyfluoroalkyl substances, more commonly known as PFAS, are also examples of micropollutants, as are some heavy metals like lead and arsenic. These are just some of the kinds of micropollutants, all of which can be toxic to humans and animals over time, potentially causing cancer, organ damage, developmental defects, or other adverse effects.

    Micropollutants are numerous but since their collective mass is small, they are difficult to remove from water. Currently, the most common practice for removing micropollutants from water is activated carbon adsorption. In this process, water passes through a carbon filter, removing only 30 percent of micropollutants. Activated carbon requires high temperatures to produce and regenerate, requiring specialized equipment and consuming large amounts of energy. Reverse osmosis can also be used to remove micropollutants from water; however, “it doesn’t lead to good elimination of this class of molecules, because of both their concentration and their molecular structure,” explains Doyle.

    Inspired by soap

    When devising their solution for how to remove micropollutants from water, the MIT researchers were inspired by a common household cleaning supply — soap. Soap cleans everything from our hands and bodies to dirty dishes to clothes, so perhaps the chemistry of soap could also be applied to sanitizing water. Soap has molecules called surfactants which have both hydrophobic (water-hating) and hydrophilic (water-loving) components. When water comes in contact with soap, the hydrophobic parts of the surfactant stick together, assembling into spherical structures called micelles with the hydrophobic portions of the molecules in the interior. The hydrophobic micelle cores trap and help carry away oily substances like dirt. 

    Doyle’s lab synthesized micelle-laden hydrogel particles to essentially cleanse water. Gokhale explains that they used microfluidics which “involve processing fluids on very small, micron-like scales” to generate uniform polymeric hydrogel particles continuously and reproducibly. These hydrogels, which are porous and absorbent, incorporate a surfactant, a photoinitiator (a molecule that creates reactive species), and a cross-linking agent known as PEGDA. The surfactant assembles into micelles that are chemically bonded to the hydrogel using ultraviolet light. When water flows through this micro-particle system, micropollutants latch onto the micelles and separate from the water. The physical interaction used in the system is strong enough to pull micropollutants from water, but weak enough that the hydrogel particles can be separated from the micropollutants, restabilized, and reused. Lab testing shows that both the speed and extent of pollutant removal increase when the amount of surfactant incorporated into the hydrogels is increased.

    “We’ve shown that in terms of rate of pullout, which is what really matters when you scale this up for industrial use, that with our initial format, we can already outperform the activated carbon,” says Doyle. “We can actually regenerate these particles very easily at room temperature. Nearly 10 regeneration cycles with minimal change in performance,” he adds.

    Regeneration of the particles occurs by soaking the micelles in 90 percent ethanol, whereby “all the pollutants just come out of the particles and back into the ethanol” says Gokhale. Ethanol is biosafe at low concentrations, inexpensive, and combustible, allowing for safe and economically feasible disposal. The recycling of the hydrogel particles makes this technology sustainable, which is a large advantage over activated carbon. The hydrogels can also be tuned to any hydrophobic micropollutant, making this system a novel, flexible approach to water purification.

    Scaling up

    The team experimented in the lab using 2-naphthol, a micropollutant that is an organic pollutant of concern and known to be difficult to remove by using conventional water filtration methods. They hope to continue testing with real water samples. 

    “Right now, we spike one micropollutant into pure lab water. We’d like to get water samples from the natural environment, that we can study and look at experimentally,” says Doyle. 

    By using microfluidics to increase particle production, Doyle and his lab hope to make household-scale filters to be tested with real wastewater. They then anticipate scaling up to municipal water treatment or even industrial wastewater treatment. 

    The lab recently filed an international patent application for their hydrogel technology that uses immobilized micelles. They plan to continue this work by experimenting with different kinds of hydrogels for the removal of heavy metal contaminants like lead from water. 

    Societal impacts

    Funded by a 2019 J-WAFS seed grant that is currently ongoing, this research has the potential to improve the speed, precision, efficiency, and environmental sustainability of water purification systems across the world. 

    “I always wanted to do work which had a social impact, and I was also always interested in water, because I think it’s really cool,” says Gokhale. He notes, “it’s really interesting how water sort of fits into different kinds of fields … we have to consider the cultures of peoples, how we’re going to use this, and then just the equity of these water processes.” Originally from India, Gokhale says he’s seen places that have barely any water at all and others that have floods year after year. “There’s a lot of interesting work to be done, and I think it’s work in this area that’s really going to impact a lot of people’s lives in years to come,” Gokhale says.

    Doyle adds, “water is the most important thing, perhaps for the next decades to come, so it’s very fulfilling to work on something that is so important to the whole world.” More