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    MIT engineers’ new theory could improve the design and operation of wind farms

    The blades of propellers and wind turbines are designed based on aerodynamics principles that were first described mathematically more than a century ago. But engineers have long realized that these formulas don’t work in every situation. To compensate, they have added ad hoc “correction factors” based on empirical observations.Now, for the first time, engineers at MIT have developed a comprehensive, physics-based model that accurately represents the airflow around rotors even under extreme conditions, such as when the blades are operating at high forces and speeds, or are angled in certain directions. The model could improve the way rotors themselves are designed, but also the way wind farms are laid out and operated. The new findings are described today in the journal Nature Communications, in an open-access paper by MIT postdoc Jaime Liew, doctoral student Kirby Heck, and Michael Howland, the Esther and Harold E. Edgerton Assistant Professor of Civil and Environmental Engineering.“We’ve developed a new theory for the aerodynamics of rotors,” Howland says. This theory can be used to determine the forces, flow velocities, and power of a rotor, whether that rotor is extracting energy from the airflow, as in a wind turbine, or applying energy to the flow, as in a ship or airplane propeller. “The theory works in both directions,” he says.Because the new understanding is a fundamental mathematical model, some of its implications could potentially be applied right away. For example, operators of wind farms must constantly adjust a variety of parameters, including the orientation of each turbine as well as its rotation speed and the angle of its blades, in order to maximize power output while maintaining safety margins. The new model can provide a simple, speedy way of optimizing those factors in real time.“This is what we’re so excited about, is that it has immediate and direct potential for impact across the value chain of wind power,” Howland says.Modeling the momentumKnown as momentum theory, the previous model of how rotors interact with their fluid environment — air, water, or otherwise — was initially developed late in the 19th century. With this theory, engineers can start with a given rotor design and configuration, and determine the maximum amount of power that can be derived from that rotor — or, conversely, if it’s a propeller, how much power is needed to generate a given amount of propulsive force.Momentum theory equations “are the first thing you would read about in a wind energy textbook, and are the first thing that I talk about in my classes when I teach about wind power,” Howland says. From that theory, physicist Albert Betz calculated in 1920 the maximum amount of energy that could theoretically be extracted from wind. Known as the Betz limit, this amount is 59.3 percent of the kinetic energy of the incoming wind.But just a few years later, others found that the momentum theory broke down “in a pretty dramatic way” at higher forces that correspond to faster blade rotation speeds or different blade angles, Howland says. It fails to predict not only the amount, but even the direction of changes in thrust force at higher rotation speeds or different blade angles: Whereas the theory said the force should start going down above a certain rotation speed or blade angle, experiments show the opposite — that the force continues to increase. “So, it’s not just quantitatively wrong, it’s qualitatively wrong,” Howland says.The theory also breaks down when there is any misalignment between the rotor and the airflow, which Howland says is “ubiquitous” on wind farms, where turbines are constantly adjusting to changes in wind directions. In fact, in an earlier paper in 2022, Howland and his team found that deliberately misaligning some turbines slightly relative to the incoming airflow within a wind farm significantly improves the overall power output of the wind farm by reducing wake disturbances to the downstream turbines.In the past, when designing the profile of rotor blades, the layout of wind turbines in a farm, or the day-to-day operation of wind turbines, engineers have relied on ad hoc adjustments added to the original mathematical formulas, based on some wind tunnel tests and experience with operating wind farms, but with no theoretical underpinnings.Instead, to arrive at the new model, the team analyzed the interaction of airflow and turbines using detailed computational modeling of the aerodynamics. They found that, for example, the original model had assumed that a drop in air pressure immediately behind the rotor would rapidly return to normal ambient pressure just a short way downstream. But it turns out, Howland says, that as the thrust force keeps increasing, “that assumption is increasingly inaccurate.”And the inaccuracy occurs very close to the point of the Betz limit that theoretically predicts the maximum performance of a turbine — and therefore is just the desired operating regime for the turbines. “So, we have Betz’s prediction of where we should operate turbines, and within 10 percent of that operational set point that we think maximizes power, the theory completely deteriorates and doesn’t work,” Howland says.Through their modeling, the researchers also found a way to compensate for the original formula’s reliance on a one-dimensional modeling that assumed the rotor was always precisely aligned with the airflow. To do so, they used fundamental equations that were developed to predict the lift of three-dimensional wings for aerospace applications.The researchers derived their new model, which they call a unified momentum model, based on theoretical analysis, and then validated it using computational fluid dynamics modeling. In followup work not yet published, they are doing further validation using wind tunnel and field tests.Fundamental understandingOne interesting outcome of the new formula is that it changes the calculation of the Betz limit, showing that it’s possible to extract a bit more power than the original formula predicted. Although it’s not a significant change — on the order of a few percent — “it’s interesting that now we have a new theory, and the Betz limit that’s been the rule of thumb for a hundred years is actually modified because of the new theory,” Howland says. “And that’s immediately useful.” The new model shows how to maximize power from turbines that are misaligned with the airflow, which the Betz limit cannot account for.The aspects related to controlling both individual turbines and arrays of turbines can be implemented without requiring any modifications to existing hardware in place within wind farms. In fact, this has already happened, based on earlier work from Howland and his collaborators two years ago that dealt with the wake interactions between turbines in a wind farm, and was based on the existing, empirically based formulas.“This breakthrough is a natural extension of our previous work on optimizing utility-scale wind farms,” he says, because in doing that analysis, they saw the shortcomings of the existing methods for analyzing the forces at work and predicting power produced by wind turbines. “Existing modeling using empiricism just wasn’t getting the job done,” he says.In a wind farm, individual turbines will sap some of the energy available to neighboring turbines, because of wake effects. Accurate wake modeling is important both for designing the layout of turbines in a wind farm, and also for the operation of that farm, determining moment to moment how to set the angles and speeds of each turbine in the array.Until now, Howland says, even the operators of wind farms, the manufacturers, and the designers of the turbine blades had no way to predict how much the power output of a turbine would be affected by a given change such as its angle to the wind without using empirical corrections. “That’s because there was no theory for it. So, that’s what we worked on here. Our theory can directly tell you, without any empirical corrections, for the first time, how you should actually operate a wind turbine to maximize its power,” he says.Because the fluid flow regimes are similar, the model also applies to propellers, whether for aircraft or ships, and also for hydrokinetic turbines such as tidal or river turbines. Although they didn’t focus on that aspect in this research, “it’s in the theoretical modeling naturally,” he says.The new theory exists in the form of a set of mathematical formulas that a user could incorporate in their own software, or as an open-source software package that can be freely downloaded from GitHub. “It’s an engineering model developed for fast-running tools for rapid prototyping and control and optimization,” Howland says. “The goal of our modeling is to position the field of wind energy research to move more aggressively in the development of the wind capacity and reliability necessary to respond to climate change.”The work was supported by the National Science Foundation and Siemens Gamesa Renewable Energy. More

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    More durable metals for fusion power reactors

    For many decades, nuclear fusion power has been viewed as the ultimate energy source. A fusion power plant could generate carbon-free energy at a scale needed to address climate change. And it could be fueled by deuterium recovered from an essentially endless source — seawater.Decades of work and billions of dollars in research funding have yielded many advances, but challenges remain. To Ju Li, the TEPCO Professor in Nuclear Science and Engineering and a professor of materials science and engineering at MIT, there are still two big challenges. The first is to build a fusion power plant that generates more energy than is put into it; in other words, it produces a net output of power. Researchers worldwide are making progress toward meeting that goal.The second challenge that Li cites sounds straightforward: “How do we get the heat out?” But understanding the problem and finding a solution are both far from obvious.Research in the MIT Energy Initiative (MITEI) includes development and testing of advanced materials that may help address those challenges, as well as many other challenges of the energy transition. MITEI has multiple corporate members that have been supporting MIT’s efforts to advance technologies required to harness fusion energy.The problem: An abundance of helium, a destructive forceKey to a fusion reactor is a superheated plasma — an ionized gas — that’s reacting inside a vacuum vessel. As light atoms in the plasma combine to form heavier ones, they release fast neutrons with high kinetic energy that shoot through the surrounding vacuum vessel into a coolant. During this process, those fast neutrons gradually lose their energy by causing radiation damage and generating heat. The heat that’s transferred to the coolant is eventually used to raise steam that drives an electricity-generating turbine.The problem is finding a material for the vacuum vessel that remains strong enough to keep the reacting plasma and the coolant apart, while allowing the fast neutrons to pass through to the coolant. If one considers only the damage due to neutrons knocking atoms out of position in the metal structure, the vacuum vessel should last a full decade. However, depending on what materials are used in the fabrication of the vacuum vessel, some projections indicate that the vacuum vessel will last only six to 12 months. Why is that? Today’s nuclear fission reactors also generate neutrons, and those reactors last far longer than a year.The difference is that fusion neutrons possess much higher kinetic energy than fission neutrons do, and as they penetrate the vacuum vessel walls, some of them interact with the nuclei of atoms in the structural material, giving off particles that rapidly turn into helium atoms. The result is hundreds of times more helium atoms than are present in a fission reactor. Those helium atoms look for somewhere to land — a place with low “embedding energy,” a measure that indicates how much energy it takes for a helium atom to be absorbed. As Li explains, “The helium atoms like to go to places with low helium embedding energy.” And in the metals used in fusion vacuum vessels, there are places with relatively low helium embedding energy — namely, naturally occurring openings called grain boundaries.Metals are made up of individual grains inside which atoms are lined up in an orderly fashion. Where the grains come together there are gaps where the atoms don’t line up as well. That open space has relatively low helium embedding energy, so the helium atoms congregate there. Worse still, helium atoms have a repellent interaction with other atoms, so the helium atoms basically push open the grain boundary. Over time, the opening grows into a continuous crack, and the vacuum vessel breaks.That congregation of helium atoms explains why the structure fails much sooner than expected based just on the number of helium atoms that are present. Li offers an analogy to illustrate. “Babylon is a city of a million people. But the claim is that 100 bad persons can destroy the whole city — if all those bad persons work at the city hall.” The solution? Give those bad persons other, more attractive places to go, ideally in their own villages.To Li, the problem and possible solution are the same in a fusion reactor. If many helium atoms go to the grain boundary at once, they can destroy the metal wall. The solution? Add a small amount of a material that has a helium embedding energy even lower than that of the grain boundary. And over the past two years, Li and his team have demonstrated — both theoretically and experimentally — that their diversionary tactic works. By adding nanoscale particles of a carefully selected second material to the metal wall, they’ve found they can keep the helium atoms that form from congregating in the structurally vulnerable grain boundaries in the metal.Looking for helium-absorbing compoundsTo test their idea, So Yeon Kim ScD ’23 of the Department of Materials Science and Engineering and Haowei Xu PhD ’23 of the Department of Nuclear Science and Engineering acquired a sample composed of two materials, or “phases,” one with a lower helium embedding energy than the other. They and their collaborators then implanted helium ions into the sample at a temperature similar to that in a fusion reactor and watched as bubbles of helium formed. Transmission electron microscope images confirmed that the helium bubbles occurred predominantly in the phase with the lower helium embedding energy. As Li notes, “All the damage is in that phase — evidence that it protected the phase with the higher embedding energy.”Having confirmed their approach, the researchers were ready to search for helium-absorbing compounds that would work well with iron, which is often the principal metal in vacuum vessel walls. “But calculating helium embedding energy for all sorts of different materials would be computationally demanding and expensive,” says Kim. “We wanted to find a metric that is easy to compute and a reliable indicator of helium embedding energy.”They found such a metric: the “atomic-scale free volume,” which is basically the maximum size of the internal vacant space available for helium atoms to potentially settle. “This is just the radius of the largest sphere that can fit into a given crystal structure,” explains Kim. “It is a simple calculation.” Examination of a series of possible helium-absorbing ceramic materials confirmed that atomic free volume correlates well with helium embedding energy. Moreover, many of the ceramics they investigated have higher free volume, thus lower embedding energy, than the grain boundaries do.However, in order to identify options for the nuclear fusion application, the screening needed to include some other factors. For example, in addition to the atomic free volume, a good second phase must be mechanically robust (able to sustain a load); it must not get very radioactive with neutron exposure; and it must be compatible — but not too cozy — with the surrounding metal, so it disperses well but does not dissolve into the metal. “We want to disperse the ceramic phase uniformly in the bulk metal to ensure that all grain boundary regions are close to the dispersed ceramic phase so it can provide protection to those regions,” says Li. “The two phases need to coexist, so the ceramic won’t either clump together or totally dissolve in the iron.”Using their analytical tools, Kim and Xu examined about 50,000 compounds and identified 750 potential candidates. Of those, a good option for inclusion in a vacuum vessel wall made mainly of iron was iron silicate.Experimental testingThe researchers were ready to examine samples in the lab. To make the composite material for proof-of-concept demonstrations, Kim and collaborators dispersed nanoscale particles of iron silicate into iron and implanted helium into that composite material. She took X-ray diffraction (XRD) images before and after implanting the helium and also computed the XRD patterns. The ratio between the implanted helium and the dispersed iron silicate was carefully controlled to allow a direct comparison between the experimental and computed XRD patterns. The measured XRD intensity changed with the helium implantation exactly as the calculations had predicted. “That agreement confirms that atomic helium is being stored within the bulk lattice of the iron silicate,” says Kim.To follow up, Kim directly counted the number of helium bubbles in the composite. In iron samples without the iron silicate added, grain boundaries were flanked by many helium bubbles. In contrast, in the iron samples with the iron silicate ceramic phase added, helium bubbles were spread throughout the material, with many fewer occurring along the grain boundaries. Thus, the iron silicate had provided sites with low helium-embedding energy that lured the helium atoms away from the grain boundaries, protecting those vulnerable openings and preventing cracks from opening up and causing the vacuum vessel to fail catastrophically.The researchers conclude that adding just 1 percent (by volume) of iron silicate to the iron walls of the vacuum vessel will cut the number of helium bubbles in half and also reduce their diameter by 20 percent — “and having a lot of small bubbles is OK if they’re not in the grain boundaries,” explains Li.Next stepsThus far, Li and his team have gone from computational studies of the problem and a possible solution to experimental demonstrations that confirm their approach. And they’re well on their way to commercial fabrication of components. “We’ve made powders that are compatible with existing commercial 3D printers and are preloaded with helium-absorbing ceramics,” says Li. The helium-absorbing nanoparticles are well dispersed and should provide sufficient helium uptake to protect the vulnerable grain boundaries in the structural metals of the vessel walls. While Li confirms that there’s more scientific and engineering work to be done, he, along with Alexander O’Brien PhD ’23 of the Department of Nuclear Science and Engineering and Kang Pyo So, a former postdoc in the same department, have already developed a startup company that’s ready to 3D print structural materials that can meet all the challenges faced by the vacuum vessel inside a fusion reactor.This research was supported by Eni S.p.A. through the MIT Energy Initiative. Additional support was provided by a Kwajeong Scholarship; the U.S. Department of Energy (DOE) Laboratory Directed Research and Development program at Idaho National Laboratory; U.S. DOE Lawrence Livermore National Laboratory; and Creative Materials Discovery Program through the National Research Foundation of Korea. More

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    Going Dutch on climate

    When MIT senior Rudiba Laiba saw that stores in the Netherlands eschewed plastic bags to save the planet, her first thought was, “that doesn’t happen in Bangladesh.”Laiba is one of eight MIT students who traveled to the Netherlands in June as part of an MIT Energy Initiative (MITEI)-sponsored trip to experience first-hand the country’s approach to the energy transition. The Netherlands aims to be carbon neutral by 2050, making it one of the top 10 countries leading the charge on climate change, according to U.S. News and World Report.MITEI sponsored the week-long trip to allow undergraduate and graduate students to collaboratively explore clean energy efforts with researchers, corporate leaders, and nongovernmental organizations. The students heard about projects ranging from creating hydrogen pipelines in the North Sea to climate-proofing a fuel-guzzling, asphalt-dense neighborhood.Felipe Abreu from Kissimmee, Florida, a rising second-year student studying materials science and engineering, is working this summer on ways to melt and reuse metal scraps discarded in manufacturing processes. “When MITEI put out this notice about visiting the Netherlands, I wanted to see if there were more advanced approaches to renewable energy that I’d never been exposed to,” Abreu says.Laiba notes that her native Bangladesh has not yet achieved the Netherlands’ nearly universal buy-in to tackling climate change, even though this South Asian country, like the Netherlands, is particularly vulnerable to rising sea levels due to topography and high population density.Laiba, who spent part of her childhood in New York City and lived in Bangladesh from ages 8 to 18, calls Bangladesh “on the front lines of climate change.“Even if I didn’t want to care about climate change, I had to, because I would see the effects of it,” she says.Key playersThe MIT students conducted hands-on exercises on how to switch from traditional energy sources to zero-carbon technologies. “We talked a lot about infrastructure, particularly how to repurpose natural gas infrastructure for hydrogen,” says Antje Danielson, director of education at MITEI, who led the trip with Em Schule, MITEI research and programming assistant. “The students were challenged to grapple with real-world decision-making.”The northern section of the Netherlands is known as the “hydrogen valley” of Europe. At the University of Groningen and Hanze University School of Applied Sciences, also in Groningen, the students heard about how the region profiles itself as a world capital for the energy transition through its push toward a hydrogen-based economy and its state-of-the-art global climate models.Erick Liang, a rising junior from Boston’s Roslindale neighborhood pursuing a dual major in nuclear science and engineering and physics, was intrigued by a massive wind farm in the port city of Eemshaven, one of the group’s first stops in the north of the country. “It was impressive as an engineering challenge, because they must have figured out ways to cheaply and effectively manufacture all these wind turbines,” he says.They visited German energy company RWE, which is generating 15 percent of Eemshaven’s electricity from biomass, replacing coal.Laiba, who is majoring in molecular biology and electrical engineering and computer science with a minor in business management, was intrigued by a presentation on biofuels. “It piqued my interest to see if they would use biomass on a large scale” because of the challenges and unpredictability associated with it as a fuel source.In Paddepoel, the students toured the first of several neighborhoods that once lacked greenery and used fossil fuel-based heating systems and now aim to generate more energy than they consume.“The students got to see what the size of the district heating pipes would be, and how they go through people’s gardens into the houses. We talked about the physical impact on the neighborhood of installing these pipes, as well as the potential social and political implications connected to a really difficult transition like this,” Danielson says.Going greenGreen hydrogen promises to be a key player in the energy transition, and Netherlands officials say they have committed to the new infrastructure and business models needed to move ahead with hydrogen as a fuel source.The students explored how green hydrogen differs from fossil fuel-generated hydrogen. They saw how Dutch companies grappled with siting hydrogen production facilities and handling hydrogen as a gas, which, unlike natural gas, does not yet have a detectable artificial odor. The students heard from energy network operator Gasunie about the science and engineering behind repurposing existing natural gas pipelines for a hydrogen network in the North Sea, and were challenged to solve the puzzle of combining hydrogen production with offshore wind energy. In the port of Rotterdam, they saw how the startup Battolyser Systems — which is working with Delft University of Technology on an electrolysis device that splits water into hydrogen and oxygen and doubles as a battery — is transitioning from lab bench to market.Laiba was impressed by how much capital was going into high-risk ventures and startups, “not only because they’re trying to make something revolutionary, but also because society needs to accept and use” their products.Abreu says that at Battolyser Systems, “I saw people my age on the forefront of green hydrogen, trying to make a difference.”The students visited the Global Center on Adaptation’s carbon-neutral floating offices and learned how this international organization supports climate adaptation actions around the world and the practice of mitigation.Also in Rotterdam, international marine contractor Van Oord took students to view a ship that installs wind turbines and explained how their new technology reduces the sound shockwave impact of the installations on marine life.At the Port of Rotterdam, the students heard about the challenges faced by Europe’s largest port in terms of global shipping and choosing the fuels of the future. The speaker tasked the MIT students with coming up with a plan to transition the privately owned, owner-inhabited barges that ply the region’s inland waterways to a zero-carbon system.“The Port Authority uses this exercise to illustrate the enormous complexity faced by companies in the energy transition,” Danielson says. “The fact that our students performed really well on the spot shows that we are doing something right at MIT.”Defining a path forwardLiang, Abreu, and Laiba were struck by how the Netherlands has come together as a country over climate change. “In the U.S., a lot of people disagree with the concept of climate change as a whole,” Liang says. “But in the Netherlands, everyone is on the same page that this is an issue that we should be working toward. They’re capable of seeing a path forward and trying to take action whenever possible.”Liang, a member of the MIT Solar Electric Vehicle Team, is doing undergraduate research sponsored by MITEI this summer, working to accelerate fusion manufacturing and development at the MIT Plasma Science and Fusion Center. He’s improving 3D printing processes to manufacture components that can accommodate the high temperatures and small space within a tokamak reactor, which uses magnetic fields to confine plasma and produce controlled thermonuclear fusion.“I personally would like to try finding a new solution” to achieving carbon neutrality, he says. That solution, to Liang, is fusion energy, with some entities hoping to demonstrate net energy gain through fusion in the next five years.Laiba is a researcher with the MIT Office of Sustainability, looking at ways to quantify and reduce the level of MIT’s Scope 3 greenhouse gas emissions. Scope 3 emissions are tied to the purchase of goods that use fossil fuels in their manufacture. She says, ​“Whatever I decide to do in the future will involve making a more sustainable future. And to me, renewable energy is the driving force behind that.”In the Netherlands, she says, “what we learned through the entire trip was that renewable energy powers the country to a large amount. Things I could see tangibly was Starbucks having paper cups even for our iced drinks, which I think would flop very hard in the U.S. I don’t think society’s ready for that yet.”Abreu says, “In America, sustainability has always been in the back seat while other things take the forefront. So going to a country where everybody you talk to has a stake (in sustainability) and actually cares, and they’re all pushing together for this common goal, it was inspiring. It gave me hope.” More

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    Tracking emissions to help companies reduce their environmental footprint

    Amidst a global wave of corporate pledges to decarbonize or reach net-zero emissions, a system for verifying actual greenhouse gas reductions has never been more important. Context Labs, founded by former MIT Sloan Fellow and serial entrepreneur Dan Harple SM ’13, is rising to meet that challenge with an analytics platform that brings more transparency to emissions data.The company’s platform adds context to data from sources like equipment sensors and satellites, provides third-party verification, and records all that information on a blockchain. Context Labs also provides an interactive view of emissions across every aspect of a company’s operations, allowing leaders to pinpoint the dirtiest parts of their business.“There’s an old adage: Unless you measure something, you can’t change it,” says Harple, who is the firm’s CEO. “I think of what we’re doing as an AI-driven digital lens into what’s happening across organizations. Our goal is to help the planet get better, faster.”Context Labs is already working with some of the largest energy companies in the world — including EQT, Williams Companies, and Coterra Energy — to verify emissions reductions. A partnership with Microsoft, announced at last year’s COP28 United Nations climate summit, allows any organization on Microsoft’s Azure cloud to integrate their sensor data into Context Lab’s platform to get a granular view of their environmental impact.Harple says the progress enables more informed sustainability initiatives at scale. He also sees the work as a way to combat overly vague statements about sustainable practices that don’t lead to actual emissions reductions, or what’s known as “greenwashing.”“Just producing data isn’t good enough, and our customers realize that, because they know even if they have good intentions to reduce emissions, no one is going to believe them,” Harple says. “One way to think about our platform is as antigreenwashing insurance, because if you get attacked for your emissions, we unbundle the data like it’s in shrink-wrap and roll it back through time on the blockchain. You can click on it and see exactly where and how it was measured, monitored, timestamped, its serial number, everything. It’s really the gold standard of proof.”An unconventional master’sHarple came to MIT as a serial founder whose companies had pioneered several foundational internet technologies, including real-time video streaming technology still used in applications like Zoom and Netflix, as well as some of the core technology for the popular Chinese microblogging website Weibo.Harple’s introduction to MIT started with a paper he wrote for his venture capital contacts in the U.S. to make the case for investment in the Netherlands, where he was living with his family. The paper caught the attention of MIT Professor Stuart Madnick, the John Norris Maguire Professor of Information Technology at the MIT Sloan School of Management, who suggested Harple come to MIT as a Sloan Fellow to further develop his ideas about what makes a strong innovation ecosystem.Having successfully founded and exited multiple companies, Harple was not a typical MIT student when he began the Sloan Fellows program in 2011. At one point, he held a summit at MIT for a group of leading Dutch entrepreneurs and government officials that included tours of major labs and a meeting with former MIT President L. Rafael Reif.“Everyone was super enamored with MIT, and that kicked off what became a course that I started at MIT called REAL, Regional Entrepreneurial Acceleration Lab,” Harple says. REAL was eventually absorbed by what is now REAP — the Regional Entrepreneurship Acceleration Program, which has worked with communities around the world.Harple describes REAL as a framework vehicle to put his theories on supporting innovation into action. Over his time at MIT, which also included collaborating with the Media Lab, he systematized those theories into what he calls pentalytics, which is a way to measure and predict the resilience of innovation ecosystems.“My sense was MIT should be analytical and data-driven,” Harple says. “The thesis I wrote was a framework for AI-driven network graph analytics. So, you can model things using analytics, and you can use AI to do predictive analytics to see where the innovation ecosystem is going to thrive.”Once Harple’s pentalytics theory was established, he wanted to put it to the test with a company. His initial idea for Context Labs was to build a verification platform to combat fake news, deepfakes, and other misinformation on the internet. Around 2018, Harple met climate investor Jeremy Grantham, who he says helped him realize the most important data are about the planet. Harple began to believe that U.S. Environmental Protection Agency (EPA) emissions estimates for things like driving a car or operating an oil rig were just that — estimates — and left room for improvement.“Our approach was very MIT-ish,” Harple says. “We said, ‘Let’s, measure it and let’s monitor it, and then let’s contextualize that data so you can never go back and say they faked it. I think there’s a lot of fakery that’s happened, and that’s why the voluntary carbon markets cratered in the last year. Our view is they cratered because the data wasn’t empirical enough.”Context Labs’ solution starts with a technology platform it calls Immutably that continuously combines disparate data streams, encrypts that information, and records it on a blockchain. Immutably also verifies the information with one or more third parties. (Context Labs has partnered with the global accounting firm KPMG.)On top of Immutably, Context Labs has built applications, including a product called Decarbonization-as-a-Service (DaaS), which uses Immutably’s data to give companies a digital twin of their entire operations. Customers can use DaaS to explore the emissions of their assets and create a certificate of verified CO2-equivalent emissions, which can be used in carbon credit markets.Putting emissions data into contextContext Labs is working with oil and gas companies, utilities, data centers, and large industrial operators, some using the platform to analyze more than 3 billion data points each day. For instance, EQT, the largest natural gas producer in the U.S., uses Context Labs to verify its lower-emission products and create carbon credits. Other customers include the nonprofits Rocky Mountain Institute and the Environmental Defense Fund.“I often get asked how big the total addressable market is,” Harple says. “My view is it’s the largest market in history. Why? Because every country needs a decarbonization plan, along with instrumentation and a digital platform to execute, as does every company.”With its headquarters in Kendall Square in Cambridge, Massachusetts, Context Labs is also serving as a test for Harple’s pentalytics theory for innovation ecosystems. It also has operations in Houston and Amsterdam.“This company is a living lab for pentalytics,” Harple says. “I believe Kendall Square 1.0 was factory buildings, Kendall Square 2.0 is biotech, and Kendall Square 3.0 will be climate tech.” More

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    MIT School of Science launches Center for Sustainability Science and Strategy

    The MIT School of Science is launching a center to advance knowledge and computational capabilities in the field of sustainability science, and support decision-makers in government, industry, and civil society to achieve sustainable development goals. Aligned with the Climate Project at MIT, researchers at the MIT Center for Sustainability Science and Strategy will develop and apply expertise from across the Institute to improve understanding of sustainability challenges, and thereby provide actionable knowledge and insight to inform strategies for improving human well-being for current and future generations.Noelle Selin, professor at MIT’s Institute for Data, Systems and Society and the Department of Earth, Atmospheric and Planetary Sciences, will serve as the center’s inaugural faculty director. C. Adam Schlosser and Sergey Paltsev, senior research scientists at MIT, will serve as deputy directors, with Anne Slinn as executive director.Incorporating and succeeding both the Center for Global Change Science and Joint Program on the Science and Policy of Global Change while adding new capabilities, the center aims to produce leading-edge research to help guide societal transitions toward a more sustainable future. Drawing on the long history of MIT’s efforts to address global change and its integrated environmental and human dimensions, the center is well-positioned to lead burgeoning global efforts to advance the field of sustainability science, which seeks to understand nature-society systems in their full complexity. This understanding is designed to be relevant and actionable for decision-makers in government, industry, and civil society in their efforts to develop viable pathways to improve quality of life for multiple stakeholders.“As critical challenges such as climate, health, energy, and food security increasingly affect people’s lives around the world, decision-makers need a better understanding of the earth in its full complexity — and that includes people, technologies, and institutions as well as environmental processes,” says Selin. “Better knowledge of these systems and how they interact can lead to more effective strategies that avoid unintended consequences and ensure an improved quality of life for all.”    Advancing knowledge, computational capability, and decision supportTo produce more precise and comprehensive knowledge of sustainability challenges and guide decision-makers to formulate more effective strategies, the center has set the following goals:Advance fundamental understanding of the complex interconnected physical and socio-economic systems that affect human well-being. As new policies and technologies are developed amid climate and other global changes, they interact with environmental processes and institutions in ways that can alter the earth’s critical life-support systems. Fundamental mechanisms that determine many of these systems’ behaviors, including those related to interacting climate, water, food, and socio-economic systems, remain largely unknown and poorly quantified. Better understanding can help society mitigate the risks of abrupt changes and “tipping points” in these systems.Develop, establish and disseminate new computational tools toward better understanding earth systems, including both environmental and human dimensions. The center’s work will integrate modeling and data analysis across disciplines in an era of increasing volumes of observational data. MIT multi-system models and data products will provide robust information to inform decision-making and shape the next generation of sustainability science and strategy.Produce actionable science that supports equity and justice within and across generations. The center’s research will be designed to inform action associated with measurable outcomes aligned with supporting human well-being across generations. This requires engaging a broad range of stakeholders, including not only nations and companies, but also nongovernmental organizations and communities that take action to promote sustainable development — with special attention to those who have historically borne the brunt of environmental injustice.“The center’s work will advance fundamental understanding in sustainability science, leverage leading-edge computing and data, and promote engagement and impact,” says Selin. “Our researchers will help lead scientists and strategists across the globe who share MIT’s commitment to mobilizing knowledge to inform action toward a more sustainable world.”Building a better world at MITBuilding on existing MIT capabilities in sustainability, science, and strategy, the center aims to: focus research, education, and outreach under a theme that reflects a comprehensive state of the field and international research directions, fostering a dynamic community of students, researchers, and faculty;raise the visibility of sustainability science at MIT, emphasizing links between science and action, in the context of existing Institute goals and other efforts on climate and sustainability, and in a way that reflects the vital contributions of a range of natural and social science disciplines to understanding human-environment systems; andre-emphasize MIT’s long-standing expertise in integrated systems modeling while leveraging the Institute’s concurrent leading-edge strengths in data and computing, establishing leadership that harnesses recent innovations, including those in machine learning and artificial intelligence, toward addressing the science challenges of global change and sustainability.“The Center for Sustainability Science and Strategy will provide the necessary synergy for our MIT researchers to develop, deploy, and scale up serious solutions to climate change and other critical sustainability challenges,” says Nergis Mavalvala, the Curtis and Kathleen Marble Professor of Astrophysics and dean of the MIT School of Science. “With Professor Selin at its helm, the center will also ensure that these solutions are created in concert with the people who are directly affected now and in the future.”The center builds on more than three decades of achievements by the Center for Global Change Science and the Joint Program on the Science and Policy of Global Change, both of which were directed or co-directed by professor of atmospheric science Ronald Prinn. 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    A bright and airy hub for climate at MIT

    Seen from a distance, MIT’s Cecil and Ida Green Building (Building 54) — designed by renowned architect and MIT alumnus I.M. Pei ’40 — is one of the most iconic buildings on the Cambridge, Massachusetts, skyline. Home to the MIT Department of Earth, Atmospheric and Planetary Sciences (EAPS), the 21-story concrete structure soars over campus, topped with its distinctive spherical radar dome. Close up, however, it was a different story.A sunless, two-story, open-air plaza beneath the tower previously served as a nondescript gateway to the department’s offices, labs, and classrooms above. “It was cold and windy — probably the windiest place on campus,” EAPS department head Robert van der Hilst, the Schlumberger Professor of Earth and Planetary Sciences, told a packed auditorium inside the building in March. “You would pass through the elevators and disappear into the corridors, never to be seen again until the end of the day.”Van der Hilst was speaking at a dedication event to celebrate the opening of the renovated and expanded space, 60 years after the Green Building’s original dedication in 1964. In a dramatic transformation, the perpetually-shaded expanse beneath the tower has been filled with an airy, glassed-in structure that is as inviting as the previous space was forbidding.Designed to meet LEED-platinum certification, the newly-constructed Tina and Hamid Moghadam Building (Building 55) seems to float next to the Brutalist tower, its glass façade both opening up the interior and reflecting the sunlight and green space outside. The 300-seat auditorium within the original tower has been similarly transformed, bringing light and space to the newly dubbed Dixie Lee Bryant (1891) Lecture Hall, named after the first person to earn a geology degree at MIT.Catalyzing collaborationThe project is about more than updating an overlooked space. “The building we’re here to celebrate today does something else,” MIT President Sally Kornbluth said at the dedication.“In its lightness, in its transparency, it calls attention not to itself, but to the people gathered inside it. In its warmth, its openness, it makes room for culture and community. And it welcomes in those who don’t yet belong … as we take on the immense challenges of climate together,” she continued, referencing the recent launch of The Climate Project at MIT — a whole-of-MIT initiative to innovate bold solutions to climate change. In MIT’s famously decentralized structure, the Moghadam Building provides a new physical hub for students, scientists, and engineers interested in climate and the environment to congregate and share ideas.From the start, fostering this kind of multidisciplinary collaboration was part of Van der Hilst’s vision. In addition to serving as the flagship location for EAPS, Building 54 has long been the administrative home of the MIT-WHOI Joint Program in Oceanography/Applied Ocean Science and Engineering — a graduate program in partnership with Woods Hole Oceanographic Institute. With the addition of Building 55, EAPS has now been joined by the MIT Environmental Solutions Initiative (ESI) — a campus-wide program fostering education, outreach, and innovation in earth system science, urban infrastructure, and sustainability — and will welcome closer collaboration with Terrascope — a first-year learning community which invites its students to take on real-world environmental challenges.A shared vision comes to lifeThe building project dovetailed with the long-overdue refurbishment of the Green Building. After a multi-year fundraising campaign where Van der Hilst spearheaded the department’s efforts, the project received a major boost from lead donors Tina and Hamid Moghadam ’77, SM ’78, allowing the department to break ground in November 2021.In Moghadam, chair and CEO of Prologis, which owns 1.2 billion square feet of warehouses and other logistics infrastructure worldwide, EAPS found a fellow champion for climate and environmental innovation. By putting solar panels on the roofs of Prologis buildings, the company is now the second largest on-site producer of solar energy in the United States. “I don’t think there needs to be a trade-off between good sound economics and return on investment and solving climate change problems,” Moghadam said at the dedication. “The solutions that really work are the ones that actually make sense in a market economy.”Architectural firm AW-ARCH designed the Moghadam Building with a light touch, emphasizing spaciousness in contrast to the heavy concrete buildings that surround it. “The kind of delicacy and fragility of the thing is in some ways a depiction of what happens here,” said architect and co-founding partner Alex Anmahian at the dedication reception, giving a nod to the study of the delicate balance of the earth system itself. The sense is further illustrated by the responsiveness of the façade to the surrounding environment, which, depending on the time of day and quality of light, makes the glass alternately reflective and transparent.Inside, the 11,900-square foot pavilion is highly flexible and serves as a showcase for the science that happens in the labs and offices above. Central to the space is a 16-foot by 9-foot video wall featuring vivid footage of field work, lab research, data visualizations, and natural phenomena — visible even to passers-by outside. The video wall is counterposed to an unpretentious set of stair-step bleachers leading to the second floor that could play host to anything from a scientific lecture to a community pizza-and-movie night.Van der Hilst has referred to his vision for the atrium as a “campus living room,” and the furniture throughout is intentionally chosen to allow for impromptu rearrangements, providing a valuable public space on campus for students to work and socialize.The second level is similarly adaptable, featuring three classrooms with state-of-the-art teaching technologies that can be transformed from a single large space for a hackathon to intimate rooms for discussion.“The space is really meant for a yet unforeseen experience,” Anmahian says. “The reason it is so open is to allow for any possibility.”The inviting, dynamic design of the pavilion has also become an instant point of pride for the building’s inhabitants. At the dedication, School of Science dean Nergis Mavalvala quipped that anyone walking into the space “gains two inches in height.”Van der Hilst quoted a colleague with a similar observation: “Now, when I come into this space, I feel respected by it.”The perfect complementAnother significant feature of the project is the List Visual Arts Center Percent-for-Art Program installation by conceptual artist Julian Charrière, entitled “Everything Was Forever Until It Was No More.”Consisting of three interrelated works, the commission includes: “Not All Who Wander Are Lost,” three glacial erratic boulders which sit atop their own core samples in the surrounding green space; “We Are All Astronauts,” a trio of glass pillars containing vintage globes with distinctions between nations, land, and sea removed; and “Pure Waste,” a synthetic diamond embedded in the foundation, created from carbon captured from the air and the breath of researchers who work in the building.Known for themes that explore the transformation of the natural world over time and humanity’s complex relationship with our environment, Charrière was a perfect fit to complement the new Building 55 — offering a thought-provoking perspective on our current environmental challenges while underscoring the value of the research that happens within its walls. 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    Balancing economic development with natural resources protection

    It’s one of the paradoxes of economic development: Many countries currently offer large subsidies to their industrial fishing fleets, even though the harms of overfishing are well-known. Governments might be willing to end this practice, if they saw that its costs outweighed its benefits. But each country, acting individually, faces an incentive to keep subsidies in place.This trap evokes the classic “tragedy of the commons” that economists have studied for generations. But despite the familiarity of the problem in theory, they don’t yet have a lot of hard evidence to offer policymakers about solutions, especially on a global scale. PhD student Aaron Berman is working on a set of projects that may change that.“Our goal is to get some empirical traction on the problem,” he says.Berman and his collaborators are combining a variety of datasets — not only economic data but also projections from ecological models — to identify how these subsidies are impacting fish stocks. They also hope to determine whether countries might benefit instead from sustainability measures to help rebuild fisheries, say through new trade arrangements or other international policy agreements.As a fourth-year doctoral candidate in MIT’s Department of Economics, Berman has a variety of other research projects underway as well, all connected by the central question of how to balance economic development with the pressure it puts on the environment and natural resources. While his study of fishing subsidies is global in scope, other projects are distinctly local: He is studying air pollution generated by road infrastructure in Pakistan, groundwater irrigation in Texas, the scallop fishing industry in New England, and industrial carbon-reduction measures in Turkey. For all of these projects, Berman and his collaborators are bringing data and models from many fields of science to bear on economic questions, from seafloor images taken by NOAA to atmospheric models of pollution dispersion.“One thing I find really exciting and joyful about the work I’m doing in environmental economics is that all of these projects involve some kind of crossover into the natural sciences,” he says.Several of Berman’s projects are so ambitious that he hopes to continue working on them even after completing his PhD. He acknowledges that keeping so many irons in the fire is a lot of work, but says he finds motivation in the knowledge that his research could shape policy and benefit society in a concrete way.“Something that MIT has really instilled in me is the value of going into the field and learning about how the research you’re doing connects to real-world issues,” he says. “You want your findings as a researcher to ultimately be useful to someone.”Testing the watersThe son of two public school teachers, Berman grew up in Maryland and then attended Yale University, where he majored in global affairs as an undergraduate, then stayed to get his master’s in public health, concentrating on global health in both programs.A pivotal moment came while taking an undergraduate class in development economics. “That class helped me realize the same questions I cared a lot about from a public health standpoint were also being studied by economists using very rigorous methods,” Berman says. “Economics has a lot to say about very pressing societal issues.”After reading the work of MIT economists and Nobel laureates Esther Duflo and Abhijit Banerjee in that same class, he decided to pivot and “test the waters of economics a little bit more seriously.” The professor teaching that class also played an important role, by encouraging Berman to pursue a predoctoral research position as a first step toward a graduate degree in economics.Following that advice, Berman landed at the Harvard Kennedy School’s Evidence for Policy Design, a research initiative seeking to foster economic development by improving the policy design process. His time with this organization included five months in Jakarta, Indonesia, where he collaborated with professors Rema Hanna and Ben Olken — of Harvard and MIT, respectively — on a portfolio of projects focused on analyzing social protection and poverty alleviation.The work, which included working closely with government partners, “required me to think creatively about how to talk about economics research to several different types of audiences,” he says. “This also gave me experience thinking about the intersection between what is academically interesting and what is a policy priority.”The experience also gave him the skills and confidence to apply to the economics PhD program at MIT.(Re)discovering teachingAs an economist, Berman is now channeling his interests in global affairs to exploring the relationship between economic development and protecting the natural environment. (He’s aided by an affinity for languages — he speaks five, with varying degrees of proficiency, in addition to English: Mandarin, Cantonese, Spanish, Portuguese, and Indonesian.) His interest in natural resource governance was piqued while co-authoring a paper on the economic drivers of climate-altering tropical deforestation.The review article, written alongside Olken and two professors from the London School of Economics, explored questions such as “What does the current state of the evidence tell us about what causes deforestation in the tropics, and what further evidence is needed?” and “What are the economic barriers to implementing policies to prevent deforestation?” — the kinds of questions he seeks to answer broadly in his ongoing dissertation work.“I gained an appreciation for the importance and complexity of natural resource governance, both in developing and developed countries,” he says. “It really was a launching point for a lot of the things that I’m doing now.”These days, when not doing research, Berman can be found playing on MIT’s club tennis team or working as a teaching assistant, which he particularly enjoys. He’s ever mindful of the Yale professor whose encouragement shaped his own path, and he hopes that he can pay that forward in his own teaching roles.“The fact that he saw I had the ability to make this transition and encouraged me to take a leap of faith is really meaningful to me. I would like to be able to do that for others,” Berman says.His interest in teaching also connects him further with his family: His father is a middle school science teacher and mother is a paraeducator for students with special needs. He says they’ve encouraged him throughout his academic journey, even though they initially didn’t know much about what a PhD in economics entailed. Berman jokes that the most common question people ask economists is what stocks they should invest in, and his family was no exception.“But they’ve always been very excited to hear about the kinds of things I’m working on and very supportive,” he says. “It’s been a really amazing learning experience thus far,” Berman says about his doctoral program. “One of the coolest parts of economics research is to have a sense that you’re tangibly doing something that’s going to have an impact in the world.” More

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    Q&A: “As long as you have a future, you can still change it”

    Tristan Brown is the S.C. Fang Chinese Language and Culture Career Development Professor at MIT. He specializes in law, science, environment and religion of late imperial China, a period running from the 16th through early 20th centuries.In this Q&A, Brown discusses how his areas of historical research can be useful for examining today’s pressing environmental challenges. This is part of an ongoing series exploring how the MIT School of Humanities, Arts, and Social Sciences is addressing the climate crisis.Q: Why does this era of Chinese history resonate so much for you? How is it relevant to contemporary times and challenges?A: China has always been interesting to historians because it has a long-recorded history, with data showing how people have coped with environmental and climate changes over the centuries. We have tons of records of various kinds of ecological issues, environmental crises, and the associated outbreaks of calamities, famine, epidemics, and warfare. Historians of China have a lot to offer ongoing conversations about climate.More specifically, I research conflicts over land and resources that erupted when China was undergoing huge environmental, economic, demographic, and political pressures, and the role that feng shui played as local communities and the state tried to mediate those conflicts. [Feng shui is an ancient Chinese practice combining cosmology, spatial aesthetics, and measurement to divine the right balance between the natural and built environment.] Ultimately, the Qing (1644-1912) state was unable to manage these conflicts, and feng shui–based attempts to make decisions about conserving or exploiting certain areas blew up by the end of the 19th century in the face of pressures to industrialize. This is the subject of my first book, “Laws of the Land: Fengshui and the State in Qing Dynasty China.”Q: Can you give a sense of how feng shui was used to determine outcomes in environmental cases?A: We tend to think of feng shui as a popular design mechanism today. While this isn’t completely inaccurate, there was much more to it than that in Chinese history, when it evolved over many centuries. Specifically, there are lots of insights in feng shui that reflect the ways in which people recorded the natural world, explained how components in the environment related to one another, and understood why and how bad things happened. There is an interesting concept in feng shui that your environment affects your health,and specifically your children’s (i.e., descendants and progeny) health. That concept is found across premodern feng shui literature and is one of fundamental principles of the whole knowledge system.During the period I research, the Qing, the primary fuel energy sources in China came from timber and coal. There were legal cases where communities argued against efforts to mine a local mountain, saying that it could injure the feng shui (i.e., undermine the cosmological balance of natural forces and spatial integrity) of a mountain and hurt the fortunes of an entire region. People were suspicious of coal mining in their communities. They had seen or heard about mines collapsing and flooded mine shafts, they had watched runoff ruin good farmland, causing crops to fail, and even perhaps children to fall ill. Coal mining disturbed the human-earth connection, and thus the relationship between people and nature. People invoked feng shui to express an idea that the extraction of rocks and minerals from the land can have detrimental effects on living communities. Whether out of a sincere community-based concern or out of a more self-interested NIMBYism, feng shui was the primary discourse invoked in these cases.Not all efforts to conserve areas from mining succeeded, especially as foreign imperialism encroached on China, threatening government and local control over the economy. It became gradually clear to China’s elites that the country had to industrialize to survive, and this involved the difficult and even violent process of taking people from farm work and bringing them to cities, building railways, cutting millions of trees, and mining coal to power it all.Q: This makes it seem as if the Chinese swept away feng shui whenever it presented a hurdle, putting the country on the path to coal dependence, pollution, and a carbon-emitting future.A: Feng shui has not disappeared in China, but there’s no doubt about it that development in the form of industrialization took precedence in the 20th century, when it became officially labelled a “superstition” on the national stage. When I first went to China in 2007, city air was so polluted I couldn’t see the horizon. I was 18 years old and the air in some northern cities like Shijiazhuang honestly felt scary. I’ve returned many times since then, of course, and there has been great improvement in air quality, because the government made it a priority.Feng shui is a future-oriented knowledge, concerned with identifying events that have happened in the past that are related to things happening today, and using that information to influence future events. As Richard Smith of Rice University argues, Chinese have used history to order the past, ritual to order the present, and divination to order the future. Consider, for instance, Xiong’an, a new development area outside of Beijing that is physically marking the era of Xi Jinping’s tenure as paramount leader. As soon as the site was selected, people in China started talking about its feng shui, both out of potential environmental concerns and as a subtle form of political commentary. MIT’s own Sol Andrew Stokols in the Department of Urban Studies and Planning (DUSP) has a fantastic new dissertation examining that new area.In short, the feng shui masters of old said there will be floods and droughts and bad stuff happening in the future if a course correction isn’t made. But at the same time, in feng shui there’s never a situation that is hopeless; there is no lost cause. So, there is optimism in the knowledge and rhetoric of feng shui that I think might be applicable as time goes on with climate change. As long as you have a future, you can still change it. Q: In 2023, you were awarded one of the first grants of MIT’s Climate Nucleus, the faculty committee charged with seeing through the Institute’s climate action plan over the decade. What have you been up to courtesy of this fund?A: Well, it all started years ago, when I started thinking about great number of mountains in China associated with Buddhism or Daoism that have become national parks in recent decades. Some of these mountains host trees and plant species that are not found in any other part of China. For my grant, I wanted to find out how these mountains have managed to incubate such rare species for the last 2,000 years. And it’s not as simple as just saying, well, Buddhism, right? Because there are plenty of Buddhist mountains that have not fared as well ecologically. The religious landscape is part of the answer, but there’s also all the messiness of material history that surrounds such a mountain.With this grant, I am bringing together a group of scholars of religion, historians, as well as engineers working in conservation ecology, and we’re trying to figure out what makes some of these places religiously and environmentally distinctive. People come to the project with different approaches. My MIT colleague Serguei Saavedra in the Department of Civil and Environmental Engineering uses new models in system ecology to measure the resilience of environments under various stresses. My colleague in religious studies, Or Porath at Tel Aviv University, is asking when and how Asian religions have centered — or ignored — animals and animal welfare. Another collaboration with MIT’s Siqi Zheng in DUSP and Wen-Chi Liao at the National University of Singapore is looking at how we can use artificial intelligence, machine learning, and classical feng shui manuals to teach computers how to analyze the value of a property’s feng shui in Sinophone communities around the world. There’s a lot going on!Q: How do you bring China’s unique environmental history and law into your classroom, and make it immediate and relevant to the world students face today?A: History is always part of the answer. I mean, whether it’s for an economist, a political scientist, or an architect, history matters. Likewise, when you’re confronting climate change and all these struggles regarding the environment and various crises involving ecosystems, it’s always a good idea to look at how human beings in the past dealt with similar crises. It doesn’t give you a prediction on what would happen in the future, but it gives you some range of possibilities, many of which may at first appear counterintuitive or surprising.That’s exactly what the humanities do. My job is to make MIT undergraduates care about a people who are no longer alive, who walked the earth a thousand years ago, who confronted terrible times of conflict and hunger. Sometimes these people left behind a written record about their world, and sometimes they didn’t. But we try to hear them out regardless. I want students to develop empathy for these strangers and wonder what it would be like to walk in their shoes. Every one of those people is someone’s ancestor, and they very well could have been your ancestor.In my class 21H.186 (Nature and Environment in China), we look at the historical precedents that might be useful for today’s environmental challenges, ranging from urban pollution or domestic recycling systems. The fact we’re still here to ask historical questions is itself significant. When we feel despair about climate change, we can ask, “How did individuals endure the changed course of the Yellow River or the Little Ice Age?” Even when it is recording tragedies, history can be understood as an enduring form of hope.  More