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      in Energy

      How to pull carbon dioxide out of seawater

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      As carbon dioxide continues to build up in the Earth’s atmosphere, research teams around the world have spent years seeking ways to remove the gas efficiently from the air. Meanwhile, the world’s number one “sink” for carbon dioxide from the atmosphere is the ocean, which soaks up some 30 to 40 percent of all of the gas produced by human activities.

      Recently, the possibility of removing carbon dioxide directly from ocean water has emerged as another promising possibility for mitigating CO2 emissions, one that could potentially someday even lead to overall net negative emissions. But, like air capture systems, the idea has not yet led to any widespread use, though there are a few companies attempting to enter this area.

      Now, a team of researchers at MIT says they may have found the key to a truly efficient and inexpensive removal mechanism. The findings were reported this week in the journal Energy and Environmental Science, in a paper by MIT professors T. Alan Hatton and Kripa Varanasi, postdoc Seoni Kim, and graduate students Michael Nitzsche, Simon Rufer, and Jack Lake.

      The existing methods for removing carbon dioxide from seawater apply a voltage across a stack of membranes to acidify a feed stream by water splitting. This converts bicarbonates in the water to molecules of CO2, which can then be removed under vacuum. Hatton, who is the Ralph Landau Professor of Chemical Engineering, notes that the membranes are expensive, and chemicals are required to drive the overall electrode reactions at either end of the stack, adding further to the expense and complexity of the processes. “We wanted to avoid the need for introducing chemicals to the anode and cathode half cells and to avoid the use of membranes if at all possible” he says.

      The team came up with a reversible process consisting of membrane-free electrochemical cells. Reactive electrodes are used to release protons to the seawater fed to the cells, driving the release of the dissolved carbon dioxide from the water. The process is cyclic: It first acidifies the water to convert dissolved inorganic bicarbonates to molecular carbon dioxide, which is collected as a gas under vacuum. Then, the water is fed to a second set of cells with a reversed voltage, to recover the protons and turn the acidic water back to alkaline before releasing it back to the sea. Periodically, the roles of the two cells are reversed once one set of electrodes is depleted of protons (during acidification) and the other has been regenerated during alkalization.

      This removal of carbon dioxide and reinjection of alkaline water could slowly start to reverse, at least locally, the acidification of the oceans that has been caused by carbon dioxide buildup, which in turn has threatened coral reefs and shellfish, says Varanasi, a professor of mechanical engineering. The reinjection of alkaline water could be done through dispersed outlets or far offshore to avoid a local spike of alkalinity that could disrupt ecosystems, they say.

      “We’re not going to be able to treat the entire planet’s emissions,” Varanasi says. But the reinjection might be done in some cases in places such as fish farms, which tend to acidify the water, so this could be a way of helping to counter that effect.

      Once the carbon dioxide is removed from the water, it still needs to be disposed of, as with other carbon removal processes. For example, it can be buried in deep geologic formations under the sea floor, or it can be chemically converted into a compound like ethanol, which can be used as a transportation fuel, or into other specialty chemicals. “You can certainly consider using the captured CO2 as a feedstock for chemicals or materials production, but you’re not going to be able to use all of it as a feedstock,” says Hatton. “You’ll run out of markets for all the products you produce, so no matter what, a significant amount of the captured CO2 will need to be buried underground.”

      Initially at least, the idea would be to couple such systems with existing or planned infrastructure that already processes seawater, such as desalination plants. “This system is scalable so that we could integrate it potentially into existing processes that are already processing ocean water or in contact with ocean water,” Varanasi says. There, the carbon dioxide removal could be a simple add-on to existing processes, which already return vast amounts of water to the sea, and it would not require consumables like chemical additives or membranes.

      “With desalination plants, you’re already pumping all the water, so why not co-locate there?” Varanasi says. “A bunch of capital costs associated with the way you move the water, and the permitting, all that could already be taken care of.”

      The system could also be implemented by ships that would process water as they travel, in order to help mitigate the significant contribution of ship traffic to overall emissions. There are already international mandates to lower shipping’s emissions, and “this could help shipping companies offset some of their emissions, and turn ships into ocean scrubbers,” Varanasi says.

      The system could also be implemented at locations such as offshore drilling platforms, or at aquaculture farms. Eventually, it could lead to a deployment of free-standing carbon removal plants distributed globally.

      The process could be more efficient than air-capture systems, Hatton says, because the concentration of carbon dioxide in seawater is more than 100 times greater than it is in air. In direct air-capture systems it is first necessary to capture and concentrate the gas before recovering it. “The oceans are large carbon sinks, however, so the capture step has already kind of been done for you,” he says. “There’s no capture step, only release.” That means the volumes of material that need to be handled are much smaller, potentially simplifying the whole process and reducing the footprint requirements.

      The research is continuing, with one goal being to find an alternative to the present step that requires a vacuum to remove the separated carbon dioxide from the water. Another need is to identify operating strategies to prevent precipitation of minerals that can foul the electrodes in the alkalinization cell, an inherent issue that reduces the overall efficiency in all reported approaches. Hatton notes that significant progress has been made on these issues, but that it is still too early to report on them. The team expects that the system could be ready for a practical demonstration project within about two years.

      “The carbon dioxide problem is the defining problem of our life, of our existence,” Varanasi says. “So clearly, we need all the help we can get.”

      The work was supported by ARPA-E. More

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      in Environment

      Featured video: Investigating our blue ocean planet

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      A five-year doctoral degree program, the MIT – Woods Hole Oceanographic Institution (WHOI) Joint Program in Oceanography/Applied Ocean Science and Engineering combines the strengths of MIT and WHOI to create one of the largest oceanographic facilities in the world. Graduate study in oceanography encompasses virtually all the basic sciences as they apply to the marine environment: physics, chemistry, geochemistry, geology, geophysics, and biology.

      “As a species and as a society we really want to understand the planet that we live on and our place in it,” says Professor Michael Follows, who serves as director of the MIT-WHOI Joint Program.

      “The reason I joined the program was because we cannot afford to wait to be able to address the climate crisis,” explains graduate student Paris Smalls. “The freedom to be able to execute on and have your interests come to life has been incredibly rewarding.”

      “If you have a research problem, you can think of the top five people in that particular niche of a topic and they’re either down the hallway or have some association with WHOI,” adds graduate student Samantha Clevenger. “It’s a really incredible place in terms of connections and just having access to really anything you need.”

      Video by: Melanie Gonick/MIT | 5 min, 12 sec More

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      in Environment

      Looking to the past to prepare for an uncertain future

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      Aviva Intveld, an MIT senior majoring in Earth, atmospheric, and planetary sciences, is accustomed to city life. But despite hailing from metropolitan Los Angeles, she has always maintained a love for the outdoors.

      “Growing up in L.A., you just have a wealth of resources when it comes to beautiful environments,” she says, “but you’re also constantly living connected to the environment.” She developed a profound respect for the natural world and its effects on people, from the earthquakes that shook the ground to the wildfires that displaced inhabitants.

      “I liked the lifestyle that environmental science afforded,” Intveld recalls. “I liked the idea that you can make a career out of spending a huge amount of time in the field and exploring different parts of the world.”

      From the moment she arrived at MIT, Intveld threw herself into research on and off campus. During her first semester, she joined Terrascope, a program that encourages first-year students to tackle complex, real-world problems. Intveld and her cohort developed proposals to make recovery from major storms in Puerto Rico faster, more sustainable, and more equitable.

      Intveld also spent a semester studying drought stress in the lab of Assistant Professor David Des Marais, worked as a research assistant at a mineral sciences research lab back in L.A., and interned at the World Wildlife Fund. Most of her work focused on contemporary issues like food insecurity and climate change. “I was really interested in questions about today,” Intveld says.

      Her focus began to shift to the past when she interned as a research assistant at the Marine Geoarchaeology and Micropaleontology Lab at the University of Haifa. For weeks, she would spend eight hours a day hunched over a microscope, using a paintbrush to sort through grains of sand from the coastal town of Caesarea. She was looking for tiny spiral-shaped fossils of foraminifera, an organism that resides in seafloor sediments.

      These microfossils can reveal a lot about the environment in which they originated, including extreme weather events. By cataloging diverse species of foraminifera, Intveld was helping to settle a rather niche debate in the field of geoarchaeology: Did tsunamis destroy the harbor of Caesarea during the time of the ancient Romans?

      But in addition to figuring out if and when these natural disasters occurred, Intveld was interested in understanding how ancient communities prepared for and recovered from them. What methods did they use? Could those same methods be used today?

      Intveld’s research at the University of Haifa was part of the Onward Israel program, which offers young Jewish people the chance to participate in internships, academic study, and fellowships in Israel. Intveld describes the experience as a great opportunity to learn about the culture, history, and diversity of the Israeli community. The trip was also an excellent lesson in dealing with challenging situations.

      Intveld suffers from claustrophobia, but she overcame her fears to climb through the Bar Kokhba caves, and despite a cat allergy, she grew to adore the many stray cats that roam the streets of Haifa. “Sometimes you can’t let your physical limitations stop you from doing what you love,” she quips.

      Over the course of her research, Intveld has often found herself in difficult and even downright dangerous situations, all of which she looks back on with good humor. As part of an internship with the National Oceanic and Atmospheric Administration, she spent three months investigating groundwater in Homer, Alaska. While she was there, she learned to avoid poisonous plants out in the field, got lost bushwhacking, and was twice charged by a moose.

      These days, Intveld spends less time in the field and more time thinking about the ancient past. She works in the lab of Associate Professor David McGee, where her undergraduate thesis research focuses on reconstructing the paleoclimate and paleoecology of northeastern Mexico during the Early Holocene. To get an idea of what the Mexican climate looked like thousands of years ago, Intveld analyzes stable isotopes and trace elements in stalagmites taken from Mexican caves. By analyzing the isotopes of carbon and oxygen present in these stalagmites, which were formed over thousands of years from countless droplets of mineral-rich rainwater, Intveld can estimate the amount of rainfall and average temperature in a given time period.

      Intveld is primarily interested in how the area’s climate may have influenced human migration. “It’s very interesting to learn about the history of human motivation, what drives us to do what we do,” she explains. “What causes humans to move, and what causes us to stay?” So far, it seems the Mexican climate during the Early Holocene was quite inconsistent, with oscillating periods of wet and dry, but Intveld needs to conduct more research before drawing any definitive conclusions.

      Recent research has linked periods of drought in the geological record to periods of violence in the archaeological one, suggesting ancient humans often fought over access to water. “I think you can easily see the connections to stuff that we deal with today,” Intveld says, pointing out the parallels between paleolithic migration and today’s climate refugees. “We have to answer a lot of difficult questions, and one way that we can do so is by looking to see what earlier human communities did and what we can learn from them.”

      Intveld recognizes the impact of the past on our present and future in many other areas. She works as a tour guide for the List Visual Arts Center, where she educates people about public art on the MIT campus. “[Art] interested me as a way to experience history and learn about the story of different communities and people over time,” she says.

      Intveld is also unafraid to acknowledge the history of discrimination and exclusion in science. “Earth science has a big problem when it comes to inclusion and diversity,” she says. As a member of the EAPS Diversity, Equity and Inclusion Committee, she aims to make earth science more accessible.

      “Aviva has a clear drive to be at the front lines of geoscience research, connecting her work to the urgent environmental issues we’re all facing,” says McGee. “She also understands the critical need for our field to include more voices, more perspectives — ultimately making for better science.”

      After MIT, Intveld hopes to pursue an advanced degree in the field of sustainable mining. This past spring, she studied abroad at Imperial College London, where she took courses within the Royal School of Mines. As Intveld explains, mining is becoming crucial to sustainable energy. The rise of electric vehicles in places like California has increased the need for energy-critical elements like lithium and cobalt, but mining for these elements often does more harm than good. “The current mining complex is very environmentally destructive,” Intveld says.

      But Intveld hopes to take the same approach to mining she does with her other endeavors — acknowledging the destructive past to make way for a better future. More

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      in Environment

      Earth can regulate its own temperature over millennia, new study finds

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      The Earth’s climate has undergone some big changes, from global volcanism to planet-cooling ice ages and dramatic shifts in solar radiation. And yet life, for the last 3.7 billion years, has kept on beating.

      Now, a study by MIT researchers in Science Advances confirms that the planet harbors a “stabilizing feedback” mechanism that acts over hundreds of thousands of years to pull the climate back from the brink, keeping global temperatures within a steady, habitable range.

      Just how does it accomplish this? A likely mechanism is “silicate weathering” — a geological process by which the slow and steady weathering of silicate rocks involves chemical reactions that ultimately draw carbon dioxide out of the atmosphere and into ocean sediments, trapping the gas in rocks.

      Scientists have long suspected that silicate weathering plays a major role in regulating the Earth’s carbon cycle. The mechanism of silicate weathering could provide a geologically constant force in keeping carbon dioxide — and global temperatures — in check. But there’s never been direct evidence for the continual operation of such a feedback, until now.

      The new findings are based on a study of paleoclimate data that record changes in average global temperatures over the last 66 million years. The MIT team applied a mathematical analysis to see whether the data revealed any patterns characteristic of stabilizing phenomena that reined in global temperatures on a  geologic timescale.

      They found that indeed there appears to be a consistent pattern in which the Earth’s temperature swings are dampened over timescales of hundreds of thousands of years. The duration of this effect is similar to the timescales over which silicate weathering is predicted to act.

      The results are the first to use actual data to confirm the existence of a stabilizing feedback, the mechanism of which is likely silicate weathering. This stabilizing feedback would explain how the Earth has remained habitable through dramatic climate events in the geologic past.

      “On the one hand, it’s good because we know that today’s global warming will eventually be canceled out through this stabilizing feedback,” says Constantin Arnscheidt, a graduate student in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS). “But on the other hand, it will take hundreds of thousands of years to happen, so not fast enough to solve our present-day issues.”

      The study is co-authored by Arnscheidt and Daniel Rothman, professor of geophysics at MIT.

      Stability in data

      Scientists have previously seen hints of a climate-stabilizing effect in the Earth’s carbon cycle: Chemical analyses of ancient rocks have shown that the flux of carbon in and out of Earth’s surface environment has remained relatively balanced, even through dramatic swings in global temperature. Furthermore, models of silicate weathering predict that the process should have some stabilizing effect on the global climate. And finally, the fact of the Earth’s enduring habitability points to some inherent, geologic check on extreme temperature swings.

      “You have a planet whose climate was subjected to so many dramatic external changes. Why did life survive all this time? One argument is that we need some sort of stabilizing mechanism to keep temperatures suitable for life,” Arnscheidt says. “But it’s never been demonstrated from data that such a mechanism has consistently controlled Earth’s climate.”

      Arnscheidt and Rothman sought to confirm whether a stabilizing feedback has indeed been at work, by looking at data of global temperature fluctuations through geologic history. They worked with a range of global temperature records compiled by other scientists, from the chemical composition of ancient marine fossils and shells, as well as preserved Antarctic ice cores.

      “This whole study is only possible because there have been great advances in improving the resolution of these deep-sea temperature records,” Arnscheidt notes. “Now we have data going back 66 million years, with data points at most thousands of years apart.”

      Speeding to a stop

      To the data, the team applied the mathematical theory of stochastic differential equations, which is commonly used to reveal patterns in widely fluctuating datasets.

      “We realized this theory makes predictions for what you would expect Earth’s temperature history to look like if there had been feedbacks acting on certain timescales,” Arnscheidt explains.

      Using this approach, the team analyzed the history of average global temperatures over the last 66 million years, considering the entire period over different timescales, such as tens of thousands of years versus hundreds of thousands, to see whether any patterns of stabilizing feedback emerged within each timescale.

      “To some extent, it’s like your car is speeding down the street, and when you put on the brakes, you slide for a long time before you stop,” Rothman says. “There’s a timescale over which frictional resistance, or a stabilizing feedback, kicks in, when the system returns to a steady state.”

      Without stabilizing feedbacks, fluctuations of global temperature should grow with timescale. But the team’s analysis revealed a regime in which fluctuations did not grow, implying that a stabilizing mechanism reigned in the climate before fluctuations grew too extreme. The timescale for this stabilizing effect — hundreds of thousands of years — coincides with what scientists predict for silicate weathering.

      Interestingly, Arnscheidt and Rothman found that on longer timescales, the data did not reveal any stabilizing feedbacks. That is, there doesn’t appear to be any recurring pull-back of global temperatures on timescales longer than a million years. Over these longer timescales, then, what has kept global temperatures in check?

      “There’s an idea that chance may have played a major role in determining why, after more than 3 billion years, life still exists,” Rothman offers.

      In other words, as the Earth’s temperatures fluctuate over longer stretches, these fluctuations may just happen to be small enough in the geologic sense, to be within a range that a stabilizing feedback, such as silicate weathering, could periodically keep the climate in check, and more to the point, within a habitable zone.

      “There are two camps: Some say random chance is a good enough explanation, and others say there must be a stabilizing feedback,” Arnscheidt says. “We’re able to show, directly from data, that the answer is probably somewhere in between. In other words, there was some stabilization, but pure luck likely also played a role in keeping Earth continuously habitable.”

      This research was supported, in part, by a MathWorks fellowship and the National Science Foundation. More

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      in Environment

      Ocean microbes get their diet through a surprising mix of sources, study finds

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      One of the smallest and mightiest organisms on the planet is a plant-like bacterium known to marine biologists as Prochlorococcus. The green-tinted microbe measures less than a micron across, and its populations suffuse through the upper layers of the ocean, where a single teaspoon of seawater can hold millions of the tiny organisms.

      Prochlorococcus grows through photosynthesis, using sunlight to convert the atmosphere’s carbon dioxide into organic carbon molecules. The microbe is responsible for 5 percent of the world’s photosynthesizing activity, and scientists have assumed that photosynthesis is the microbe’s go-to strategy for acquiring the carbon it needs to grow.

      But a new MIT study in Nature Microbiology today has found that Prochlorococcus relies on another carbon-feeding strategy, more than previously thought.

      Organisms that use a mix of strategies to provide carbon are known as mixotrophs. Most marine plankton are mixotrophs. And while Prochlorococcus is known to occasionally dabble in mixotrophy, scientists have assumed the microbe primarily lives a phototrophic lifestyle.

      The new MIT study shows that in fact, Prochlorococcus may be more of a mixotroph than it lets on. The microbe may get as much as one-third of its carbon through a second strategy: consuming the dissolved remains of other dead microbes.

      The new estimate may have implications for climate models, as the microbe is a significant force in capturing and “fixing” carbon in the Earth’s atmosphere and ocean.

      “If we wish to predict what will happen to carbon fixation in a different climate, or predict where Prochlorococcus will or will not live in the future, we probably won’t get it right if we’re missing a process that accounts for one-third of the population’s carbon supply,” says Mick Follows, a professor in MIT’s Department of Earth, Atmospheric and Planetary Sciences (EAPS), and its Department of Civil and Environmental Engineering.

      The study’s co-authors include first author and MIT postdoc Zhen Wu, along with collaborators from the University of Haifa, the Leibniz-Institute for Baltic Sea Research, the Leibniz-Institute of Freshwater Ecology and Inland Fisheries, and Potsdam University.

      Persistent plankton

      Since Prochlorococcus was first discovered in the Sargasso Sea in 1986, by MIT Institute Professor Sallie “Penny” Chisholm and others, the microbe has been observed throughout the world’s oceans, inhabiting the upper sunlit layers ranging from the surface down to about 160 meters. Within this range, light levels vary, and the microbe has evolved a number of ways to photosynthesize carbon in even low-lit regions.

      The organism has also evolved ways to consume organic compounds including glucose and certain amino acids, which could help the microbe survive for limited periods of time in dark ocean regions. But surviving on organic compounds alone is a bit like only eating junk food, and there is evidence that Prochlorococcus will die after a week in regions where photosynthesis is not an option.

      And yet, researchers including Daniel Sher of the University of Haifa, who is a co-author of the new study, have observed healthy populations of Prochlorococcus that persist deep in the sunlit zone, where the light intensity should be too low to maintain a population. This suggests that the microbes must be switching to a non-photosynthesizing, mixotrophic lifestyle in order to consume other organic sources of carbon.

      “It seems that at least some Prochlorococcus are using existing organic carbon in a mixotrophic way,” Follows says. “That stimulated the question: How much?”

      What light cannot explain

      In their new paper, Follows, Wu, Sher, and their colleagues looked to quantify the amount of carbon that Prochlorococcus is consuming through processes other than photosynthesis.

      The team looked first to measurements taken by Sher’s team, which previously took ocean samples at various depths in the Mediterranean Sea and measured the concentration of phytoplankton, including Prochlorococcus, along with the associated intensity of light and the concentration of nitrogen — an essential nutrient that is richly available in deeper layers of the ocean and that plankton can assimilate to make proteins.

      Wu and Follows used this data, and similar information from the Pacific Ocean, along with previous work from Chisholm’s lab, which established the rate of photosynthesis that Prochlorococcus could carry out in a given intensity of light.

      “We converted that light intensity profile into a potential growth rate — how fast the population of Prochlorococcus could grow if it was acquiring all it’s carbon by photosynthesis, and light is the limiting factor,” Follows explains.

      The team then compared this calculated rate to growth rates that were previously observed in the Pacific Ocean by several other research teams.

      “This data showed that, below a certain depth, there’s a lot of growth happening that photosynthesis simply cannot explain,” Follows says. “Some other process must be at work to make up the difference in carbon supply.”

      The researchers inferred that, in deeper, darker regions of the ocean, Prochlorococcus populations are able to survive and thrive by resorting to mixotrophy, including consuming organic carbon from detritus. Specifically, the microbe may be carrying out osmotrophy — a process by which an organism passively absorbs organic carbon molecules via osmosis.

      Judging by how fast the microbe is estimated to be growing below the sunlit zone, the team calculates that Prochlorococcus obtains up to one-third of its carbon diet through mixotrophic strategies.

      “It’s kind of like going from a specialist to a generalist lifestyle,” Follows says. “If I only eat pizza, then if I’m 20 miles from a pizza place, I’m in trouble, whereas if I eat burgers as well, I could go to the nearby McDonald’s. People had thought of Prochlorococcus as a specialist, where they do this one thing (photosynthesis) really well. But it turns out they may have more of a generalist lifestyle than we previously thought.”

      Chisholm, who has both literally and figuratively written the book on Prochlorococcus, says the group’s findings “expand the range of conditions under which their populations can not only survive, but also thrive. This study changes the way we think about the role of Prochlorococcus in the microbial food web.”

      This research was supported, in part, by the Israel Science Foundation, the U.S. National Science Foundation, and the Simons Foundation. More

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      in Environment

      Studying floods to better predict their dangers

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      “My job is basically flooding Cambridge,” says Katerina “Katya” Boukin, a graduate student in civil and environmental engineering at MIT and the MIT Concrete Sustainability Hub’s resident expert on flood simulations. 

      You can often find her fine-tuning high-resolution flood risk models for the City of Cambridge, Massachusetts, or talking about hurricanes with fellow researcher Ipek Bensu Manav.

      Flooding represents one of the world’s gravest natural hazards. Extreme climate events inducing flooding, like severe storms, winter storms, and tropical cyclones, caused an estimated $128.1 billion of damages in 2021 alone. 

      Climate simulation models suggest that severe storms will become more frequent in the coming years, necessitating a better understanding of which parts of cities are most vulnerable — an understanding that can be improved through modeling.

      A problem with current flood models is that they struggle to account for an oft-misunderstood type of flooding known as pluvial flooding. 

      “You might think of flooding as the overflowing of a body of water, like a river. This is fluvial flooding. This can be somewhat predictable, as you can think of proximity to water as a risk factor,” Boukin explains.

      However, the “flash flooding” that causes many deaths each year can happen even in places nowhere near a body of water. This is an example of pluvial flooding, which is affected by terrain, urban infrastructure, and the dynamic nature of storm loads.

      “If we don’t know how a flood is propagating, we don’t know the risk it poses to the urban environment. And if we don’t understand the risk, we can’t really discuss mitigation strategies,” says Boukin, “That’s why I pursue improving flood propagation models.”

      Boukin is leading development of a new flood prediction method that seeks to address these shortcomings. By better representing the complex morphology of cities, Boukin’s approach may provide a clearer forecast of future urban flooding.

      Katya Boukin developed this model of the City of Cambridge, Massachusetts. The base model was provided through a collaboration between MIT, the City of Cambridge, and Dewberry Engineering.

      Image: Katya Boukin

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      “In contrast to the more typical traditional catchment model, our method has rainwater spread around the urban environment based on the city’s topography, below-the-surface features like sewer pipes, and the characteristics of local soils,” notes Boukin.

      “We can simulate the flooding of regions with local rain forecasts. Our results can show how flooding propagates by the foot and by the second,” she adds.

      While Boukin’s current focus is flood simulation, her unconventional academic career has taken her research in many directions, like examining structural bottlenecks in dense urban rail systems and forecasting ground displacement due to tunneling. 

      “I’ve always been interested in the messy side of problem-solving. I think that difficult problems present a real chance to gain a deeper understanding,” says Boukin.

      Boukin credits her upbringing for giving her this perspective. A native of Israel, Boukin says that civil engineering is the family business. “My parents are civil engineers, my mom’s parents are, too, her grandfather was a professor in civil engineering, and so on. Civil engineering is my bloodline.”

      However, the decision to follow the family tradition did not come so easily. “After I took the Israeli equivalent of the SAT, I was at a decision point: Should I go to engineering school or medical school?” she recalls.

      “I decided to go on a backpacking trip to help make up my mind. It’s sort of an Israeli rite to explore internationally, so I spent six months in South America. I think backpacking is something everyone should do.”

      After this soul searching, Boukin landed on engineering school, where she fell in love with structural engineering. “It was the option that felt most familiar and interesting. I grew up playing with AutoCAD on the family computer, and now I use AutoCAD professionally!” she notes.

      “For my master’s degree, I was looking to study in a department that would help me integrate knowledge from fields like climatology and civil engineering. I found the MIT Department of Civil and Environmental Engineering to be an excellent fit,” she says.

      “I am lucky that MIT has so many people that work together as well as they do. I ended up at the Concrete Sustainability Hub, where I’m working on projects which are the perfect fit between what I wanted to do and what the department wanted to do.” 

      Boukin’s move to Cambridge has given her a new perspective on her family and childhood. 

      “My parents brought me to Israel when I was just 1 year old. In moving here as a second-time immigrant, I have a new perspective on what my parents went through during the move to Israel. I moved when I was 27 years old, the same age as they were. They didn’t have a support network and worked any job they could find,” she explains.

      “I am incredibly grateful to them for the morals they instilled in my sister, who recently graduated medical school, and I. I know I can call my parents if I ever need something, and they will do whatever they can to help.”

      Boukin hopes to honor her parents’ efforts through her research.

      “Not only do I want to help stakeholders understand flood risks, I want to make awareness of flooding more accessible. Each community needs different things to be resilient, and different cultures have different ways of delivering and receiving information,” she says.

      “Everyone should understand that they, in addition to the buildings and infrastructure around them, are part of a complex ecosystem. Any change to a city can affect the rest of it. If designers and residents are aware of this when considering flood mitigation strategies, we can better design cities and understand the consequences of damage.” More

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      in Environment

      Kerry Emanuel: A climate scientist and meteorologist in the eye of the storm

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      Kerry Emanuel once joked that whenever he retired, he would start a “hurricane safari” so other people could experience what it’s like to fly into the eye of a hurricane.

      “All of a sudden, the turbulence stops, the sun comes out, bright sunshine, and it’s amazingly calm. And you’re in this grand stadium [of clouds miles high],” he says. “It’s quite an experience.”

      While the hurricane safari is unlikely to come to fruition — “You can’t just conjure up a hurricane,” he explains — Emanuel, a world-leading expert on links between hurricanes and climate change, is retiring from teaching in the Department of Earth Atmospheric and Planetary Sciences (EAPS) at MIT after a more than 40-year career.

      Best known for his foundational contributions to the science of tropical cyclones, climate, and links between them, Emanuel has also been a prominent voice in public debates on climate change, and what we should do about it.

      “Kerry has had an enormous effect on the world through the students and junior scientists he has trained,” says William Boos PhD ’08, an atmospheric scientist at the University of California at Berkeley. “He’s a brilliant enough scientist and theoretician that he didn’t need any of us to accomplish what he has, but he genuinely cares about educating new generations of scientists and helping to launch their careers.”

      In recognition of Emanuel’s teaching career and contributions to science, a symposium was held in his honor at MIT on June 21 and 22, organized by several of his former students and collaborators, including Boos. Research presented at the symposium focused on the many fields influenced by Emanuel’s more than 200 published research papers — on everything from forecasting the risks posed by tropical cyclones to understanding how rainfall is produced by continent-sized patterns of atmospheric circulation.

      Emanuel’s career observing perturbations of Earth’s atmosphere started earlier than he can remember. “According to my older brother, from the age of 2, I would crawl to the window whenever there was a thunderstorm,” he says. At first, those were the rolling thunderheads of the Midwest where he grew up, then it was the edges of hurricanes during a few teenage years in Florida. Eventually, he would find himself watching from the very eye of the storm, both physically and mathematically.

      Emanuel attended MIT both as an undergraduate studying Earth and planetary sciences, and for his PhD in meteorology, writing a dissertation on thunderstorms that form ahead of cold fronts. Within the department, he worked with some of the central figures of modern meteorology such as Jule Charney, Fred Sanders, and Edward Lorenz — the founder of chaos theory.

      After receiving his PhD in 1978, Emanuel joined the faculty of the University of California at Los Angeles. During this period, he also took a semester sabbatical to film the wind speeds of tornadoes in Texas and Oklahoma. After three years, he returned to MIT and joined the Department of Meteorology in 1981. Two years later, the department merged with Earth and Planetary Sciences to form EAPS as it is known today, and where Emanuel has remained ever since.

      At MIT, he shifted scales. The thunderstorms and tornadoes that had been the focus of Emanuel’s research up to then were local atmospheric phenomena, or “mesoscale” in the language of meteorologists. The larger “synoptic scale” storms that are hurricanes blew into Emanuel’s research when as a young faculty member he was asked to teach a class in tropical meteorology; in prepping for the class, Emanuel found his notes on hurricanes from graduate school no longer made sense.

      “I realized I didn’t understand them because they couldn’t have been correct,” he says. “And so I set out to try to find a much better theoretical formulation for hurricanes.”

      He soon made two important contributions. In 1986, his paper “An Air-Sea Interaction Theory for Tropical Cyclones. Part 1: Steady-State Maintenance” developed a new theory for upper limits of hurricane intensity given atmospheric conditions. This work in turn led to even larger-scale questions to address. “That upper bound had to be dependent on climate, and it was likely to go up if we were to warm the climate,” Emanuel says — a phenomenon he explored in another paper, “The Dependence of Hurricane Intensity on Climate,” which showed how warming sea surface temperatures and changing atmospheric conditions from a warming climate would make hurricanes more destructive.

      “In my view, this is among the most remarkable achievements in theoretical geophysics,” says Adam Sobel PhD ’98, an atmospheric scientist at Columbia University who got to know Emanuel after he graduated and became interested in tropical meteorology. “From first principles, using only pencil-and-paper analysis and physical reasoning, he derives a quantitative bound on hurricane intensity that has held up well over decades of comparison to observations” and underpins current methods of predicting hurricane intensity and how it changes with climate.

      This and diverse subsequent work led to numerous honors, including membership to the American Philosophical Society, the National Academy of Sciences, and the American Academy of Arts and Sciences.

      Emanuel’s research was never confined to academic circles, however; when politicians and industry leaders voiced loud opposition to the idea that human-caused climate change posed a threat, he spoke up.

      “I felt kind of a duty to try to counter that,” says Emanuel. “I thought it was an interesting challenge to see if you could go out and convince what some people call climate deniers, skeptics, that this was a serious risk and we had to treat it as such.”

      In addition to many public lectures and media appearances discussing climate change, Emanuel penned a book for general audiences titled “What We Know About Climate Change,” in addition to a widely-read primer on climate change and risk assessment designed to influence business leaders.

      “Kerry has an unmatched physical understanding of tropical climate phenomena,” says Emanuel’s colleague, Susan Solomon, the Lee and Geraldine Martin Professor of Environmental Studies at EAPS. “But he’s also a great communicator and has generously given his time to public outreach. His book ‘What We Know About Climate Change’ is a beautiful piece of work that is readily understandable and has captivated many a non-expert reader.”

      Along with a number of other prominent climate scientists, Emanuel also began advocating for expanding nuclear power as the most rapid path to decarbonizing the world’s energy systems.

      “I think the impediment to nuclear is largely irrational in the United States,” he says. “So, I’ve been trying to fight that just like I’ve been trying to fight climate denial.”

      One lesson Emanuel has taken from his public work on climate change is that skeptical audiences often respond better to issues framed in positive terms than to doom and gloom; he’s found emphasizing the potential benefits rather than the sacrifices involved in the energy transition can engage otherwise wary audiences.

      “It’s really not opposition to science, per se,” he says. “It’s fear of the societal changes they think are required to do something about it.”

      He has also worked to raise awareness about how insurance companies significantly underestimate climate risks in their policies, in particular by basing hurricane risk on unreliable historical data. One recent practical result has been a project by the First Street Foundation to assess the true flood risk of every property in the United States using hurricane models Emanuel developed.

      “I think it’s transformative,” Emanuel says of the project with First Street. “That may prove to be the most substantive research I’ve done.”

      Though Emanuel is retiring from teaching, he has no plans to stop working. “When I say ‘retire’ it’s in quotes,” he says. In 2011, Emanuel and Professor of Geophysics Daniel Rothman founded the Lorenz Center, a climate research center at MIT in honor of Emanuel’s mentor and friend Edward Lorenz. Emanuel will continue to participate in work at the center, which aims to counter what Emanuel describes as a trend away from “curiosity-driven” work in climate science.

      “Even if there were no such thing as global warming, [climate science] would still be a really, really exciting field,” says Emanuel. “There’s so much to understand about climate, about the climates of the past, about the climates of other planets.”

      In addition to work with the Lorenz Center, he’s become interested once again in tornadoes and severe local storms, and understanding whether climate also controls such local phenomena. He’s also involved in two of MIT’s Climate Grand Challenges projects focused on translating climate hazards to explicit financial and health risks — what will bring the dangers of climate change home to people, he says, is for the public to understand more concrete risks, like agricultural failure, water shortages, electricity shortages, and severe weather events. Capturing that will drive the next few years of his work.

      “I’m going to be stepping up research in some respects,” he says, now living full-time at his home in Maine.

      Of course, “retiring” does mean a bit more free time for new pursuits, like learning a language or an instrument, and “rediscovering the art of sailing,” says Emanuel. He’s looking forward to those days on the water, whatever storms are to come. More

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      in Environment

      MIT J-WAFS announces 2022 seed grant recipients

      by

      The Abdul Latif Jameel Water and Food Systems Lab (J-WAFS) at MIT has awarded eight MIT principal investigators with 2022 J-WAFS seed grants. The grants support innovative MIT research that has the potential to have significant impact on water- and food-related challenges.

      The only program at MIT that is dedicated to water- and food-related research, J-WAFS has offered seed grant funding to MIT principal investigators and their teams for the past eight years. The grants provide up to $75,000 per year, overhead-free, for two years to support new, early-stage research in areas such as water and food security, safety, supply, and sustainability. Past projects have spanned many diverse disciplines, including engineering, science, technology, and business innovation, as well as social science and economics, architecture, and urban planning. 

      Seven new projects led by eight researchers will be supported this year. With funding going to four different MIT departments, the projects address a range of challenges by employing advanced materials, technology innovations, and new approaches to resource management. The new projects aim to remove harmful chemicals from water sources, develop drought monitoring systems for farmers, improve management of the shellfish industry, optimize water purification materials, and more.

      “Climate change, the pandemic, and most recently the war in Ukraine have exacerbated and put a spotlight on the serious challenges facing global water and food systems,” says J-WAFS director John H. Lienhard. He adds, “The proposals chosen this year have the potential to create measurable, real-world impacts in both the water and food sectors.”  

      The 2022 J-WAFS seed grant researchers and their projects are:

      Gang Chen, the Carl Richard Soderberg Professor of Power Engineering in MIT’s Department of Mechanical Engineering, is using sunlight to desalinate water. The use of solar energy for desalination is not a new idea, particularly solar thermal evaporation methods. However, the solar thermal evaporation process has an overall low efficiency because it relies on breaking hydrogen bonds among individual water molecules, which is very energy-intensive. Chen and his lab recently discovered a photomolecular effect that dramatically lowers the energy required for desalination. 

      The bonds among water molecules inside a water cluster in liquid water are mostly hydrogen bonds. Chen discovered that a photon with energy larger than the bonding energy between the water cluster and the remaining water liquids can cleave off the water cluster at the water-air interface, colliding with air molecules and disintegrating into 60 or even more individual water molecules. This effect has the potential to significantly boost clean water production via new desalination technology that produces a photomolecular evaporation rate that exceeds pure solar thermal evaporation by at least ten-fold. 

      John E. Fernández is the director of the MIT Environmental Solutions Initiative (ESI) and a professor in the Department of Architecture, and also affiliated with the Department of Urban Studies and Planning. Fernández is working with Scott D. Odell, a postdoc in the ESI, to better understand the impacts of mining and climate change in water-stressed regions of Chile.

      The country of Chile is one of the world’s largest exporters of both agricultural and mineral products; however, little research has been done on climate change effects at the intersection of these two sectors. Fernández and Odell will explore how desalination is being deployed by the mining industry to relieve pressure on continental water supplies in Chile, and with what effect. They will also research how climate change and mining intersect to affect Andean glaciers and agricultural communities dependent upon them. The researchers intend for this work to inform policies to reduce social and environmental harms from mining, desalination, and climate change.

      Ariel L. Furst is the Raymond (1921) and Helen St. Laurent Career Development Professor of Chemical Engineering at MIT. Her 2022 J-WAFS seed grant project seeks to effectively remove dangerous and long-lasting chemicals from water supplies and other environmental areas. 

      Perfluorooctanoic acid (PFOA), a component of Teflon, is a member of a group of chemicals known as per- and polyfluoroalkyl substances (PFAS). These human-made chemicals have been extensively used in consumer products like nonstick cooking pans. Exceptionally high levels of PFOA have been measured in water sources near manufacturing sites, which is problematic as these chemicals do not readily degrade in our bodies or the environment. The majority of humans have detectable levels of PFAS in their blood, which can lead to significant health issues including cancer, liver damage, and thyroid effects, as well as developmental effects in infants. Current remediation methods are limited to inefficient capture and are mostly confined to laboratory settings. Furst’s proposed method utilizes low-energy, scaffolded enzyme materials to move beyond simple capture to degrade these hazardous pollutants.

      Heather J. Kulik is an associate professor in the Department of Chemical Engineering at MIT who is developing novel computational strategies to identify optimal materials for purifying water. Water treatment requires purification by selectively separating small ions from water. However, human-made, scalable materials for water purification and desalination are often not stable in typical operating conditions and lack precision pores for good separation. 

      Metal-organic frameworks (MOFs) are promising materials for water purification because their pores can be tailored to have precise shapes and chemical makeup for selective ion affinity. Yet few MOFs have been assessed for their properties relevant to water purification. Kulik plans to use virtual high-throughput screening accelerated by machine learning models and molecular simulation to accelerate discovery of MOFs. Specifically, Kulik will be looking for MOFs with ultra-stable structures in water that do not break down at certain temperatures. 

      Gregory C. Rutledge is the Lammot du Pont Professor of Chemical Engineering at MIT. He is leading a project that will explore how to better separate oils from water. This is an important problem to solve given that industry-generated oil-contaminated water is a major source of pollution to the environment.

      Emulsified oils are particularly challenging to remove from water due to their small droplet sizes and long settling times. Microfiltration is an attractive technology for the removal of emulsified oils, but its major drawback is fouling, or the accumulation of unwanted material on solid surfaces. Rutledge will examine the mechanism of separation behind liquid-infused membranes (LIMs) in which an infused liquid coats the surface and pores of the membrane, preventing fouling. Robustness of the LIM technology for removal of different types of emulsified oils and oil mixtures will be evaluated. César Terrer is an assistant professor in the Department of Civil and Environmental Engineering whose J-WAFS project seeks to answer the question: How can satellite images be used to provide a high-resolution drought monitoring system for farmers? 

      Drought is recognized as one of the world’s most pressing issues, with direct impacts on vegetation that threaten water resources and food production globally. However, assessing and monitoring the impact of droughts on vegetation is extremely challenging as plants’ sensitivity to lack of water varies across species and ecosystems. Terrer will leverage a new generation of remote sensing satellites to provide high-resolution assessments of plant water stress at regional to global scales. The aim is to provide a plant drought monitoring product with farmland-specific services for water and socioeconomic management.

      Michael Triantafyllou is the Henry L. and Grace Doherty Professor in Ocean Science and Engineering in the Department of Mechanical Engineering. He is developing a web-based system for natural resources management that will deploy geospatial analysis, visualization, and reporting to better manage and facilitate aquaculture data.  By providing value to commercial fisheries’ permit holders who employ significant numbers of people and also to recreational shellfish permit holders who contribute to local economies, the project has attracted support from the Massachusetts Division of Marine Fisheries as well as a number of local resource management departments.

      Massachusetts shell fisheries generated roughly $339 million in 2020, accounting for 17 percent of U.S. East Coast production. Managing such a large industry is a time-consuming process, given there are thousands of acres of coastal areas grouped within over 800 classified shellfish growing areas. Extreme climate events present additional challenges. Triantafyllou’s research will help efforts to enforce environmental regulations, support habitat restoration efforts, and prevent shellfish-related food safety issues. More