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    Atmospheric observations in China show rise in emissions of a potent greenhouse gas

    To achieve the aspirational goal of the Paris Agreement on climate change — limiting the increase in global average surface temperature to 1.5 degrees Celsius above preindustrial levels — will require its 196 signatories to dramatically reduce their greenhouse gas (GHG) emissions. Those greenhouse gases differ widely in their global warming potential (GWP), or ability to absorb radiative energy and thereby warm the Earth’s surface. For example, measured over a 100-year period, the GWP of methane is about 28 times that of carbon dioxide (CO2), and the GWP of sulfur hexafluoride (SF6) is 24,300 times that of CO2, according to the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report. 

    Used primarily in high-voltage electrical switchgear in electric power grids, SF6 is one of the most potent greenhouse gases on Earth. In the 21st century, atmospheric concentrations of SF6 have risen sharply along with global electric power demand, threatening the world’s efforts to stabilize the climate. This heightened demand for electric power is particularly pronounced in China, which has dominated the expansion of the global power industry in the past decade. Quantifying China’s contribution to global SF6 emissions — and pinpointing its sources in the country — could lead that nation to implement new measures to reduce them, and thereby reduce, if not eliminate, an impediment to the Paris Agreement’s aspirational goal. 

    To that end, a new study by researchers at the MIT Joint Program on the Science and Policy of Global Change, Fudan University, Peking University, University of Bristol, and Meteorological Observation Center of China Meteorological Administration determined total SF6 emissions in China over 2011-21 from atmospheric observations collected from nine stations within a Chinese network, including one station from the Advanced Global Atmospheric Gases Experiment (AGAGE) network. For comparison, global total emissions were determined from five globally distributed, relatively unpolluted “background” AGAGE stations, involving additional researchers from the Scripps Institution of Oceanography and CSIRO, Australia’s National Science Agency.

    The researchers found that SF6 emissions in China almost doubled from 2.6 gigagrams (Gg) per year in 2011, when they accounted for 34 percent of global SF6 emissions, to 5.1 Gg per year in 2021, when they accounted for 57 percent of global total SF6 emissions. This increase from China over the 10-year period — some of it emerging from the country’s less-populated western regions — was larger than the global total SF6 emissions rise, highlighting the importance of lowering SF6 emissions from China in the future.

    The open-access study, which appears in the journal Nature Communications, explores prospects for future SF6 emissions reduction in China.

    “Adopting maintenance practices that minimize SF6 leakage rates or using SF6-free equipment or SF6 substitutes in the electric power grid will benefit greenhouse-gas mitigation in China,” says Minde An, a postdoc at the MIT Center for Global Change Science (CGCS) and the study’s lead author. “We see our findings as a first step in quantifying the problem and identifying how it can be addressed.”

    Emissions of SF6 are expected to last more than 1,000 years in the atmosphere, raising the stakes for policymakers in China and around the world.

    “Any increase in SF6 emissions this century will effectively alter our planet’s radiative budget — the balance between incoming energy from the sun and outgoing energy from the Earth — far beyond the multi-decadal time frame of current climate policies,” says MIT Joint Program and CGCS Director Ronald Prinn, a coauthor of the study. “So it’s imperative that China and all other nations take immediate action to reduce, and ultimately eliminate, their SF6 emissions.”

    The study was supported by the National Key Research and Development Program of China and Shanghai B&R Joint Laboratory Project, the U.S. National Aeronautics and Space Administration, and other funding agencies.   More

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    A new sensor detects harmful “forever chemicals” in drinking water

    MIT chemists have designed a sensor that detects tiny quantities of perfluoroalkyl and polyfluoroalkyl substances (PFAS) — chemicals found in food packaging, nonstick cookware, and many other consumer products.

    These compounds, also known as “forever chemicals” because they do not break down naturally, have been linked to a variety of harmful health effects, including cancer, reproductive problems, and disruption of the immune and endocrine systems.

    Using the new sensor technology, the researchers showed that they could detect PFAS levels as low as 200 parts per trillion in a water sample. The device they designed could offer a way for consumers to test their drinking water, and it could also be useful in industries that rely heavily on PFAS chemicals, including the manufacture of semiconductors and firefighting equipment.

    “There’s a real need for these sensing technologies. We’re stuck with these chemicals for a long time, so we need to be able to detect them and get rid of them,” says Timothy Swager, the John D. MacArthur Professor of Chemistry at MIT and the senior author of the study, which appears this week in the Proceedings of the National Academy of Sciences.

    Other authors of the paper are former MIT postdoc and lead author Sohyun Park and MIT graduate student Collette Gordon.

    Detecting PFAS

    Coatings containing PFAS chemicals are used in thousands of consumer products. In addition to nonstick coatings for cookware, they are also commonly used in water-repellent clothing, stain-resistant fabrics, grease-resistant pizza boxes, cosmetics, and firefighting foams.

    These fluorinated chemicals, which have been in widespread use since the 1950s, can be released into water, air, and soil, from factories, sewage treatment plants, and landfills. They have been found in drinking water sources in all 50 states.

    In 2023, the Environmental Protection Agency created an “advisory health limit” for two of the most hazardous PFAS chemicals, known as perfluorooctanoic acid (PFOA) and perfluorooctyl sulfonate (PFOS). These advisories call for a limit of 0.004 parts per trillion for PFOA and 0.02 parts per trillion for PFOS in drinking water.

    Currently, the only way that a consumer could determine if their drinking water contains PFAS is to send a water sample to a laboratory that performs mass spectrometry testing. However, this process takes several weeks and costs hundreds of dollars.

    To create a cheaper and faster way to test for PFAS, the MIT team designed a sensor based on lateral flow technology — the same approach used for rapid Covid-19 tests and pregnancy tests. Instead of a test strip coated with antibodies, the new sensor is embedded with a special polymer known as polyaniline, which can switch between semiconducting and conducting states when protons are added to the material.

    The researchers deposited these polymers onto a strip of nitrocellulose paper and coated them with a surfactant that can pull fluorocarbons such as PFAS out of a drop of water placed on the strip. When this happens, protons from the PFAS are drawn into the polyaniline and turn it into a conductor, reducing the electrical resistance of the material. This change in resistance, which can be measured precisely using electrodes and sent to an external device such as a smartphone, gives a quantitative measurement of how much PFAS is present.

    This approach works only with PFAS that are acidic, which includes two of the most harmful PFAS — PFOA and perfluorobutanoic acid (PFBA).

    A user-friendly system

    The current version of the sensor can detect concentrations as low as 200 parts per trillion for PFBA, and 400 parts per trillion for PFOA. This is not quite low enough to meet the current EPA guidelines, but the sensor uses only a fraction of a milliliter of water. The researchers are now working on a larger-scale device that would be able to filter about a liter of water through a membrane made of polyaniline, and they believe this approach should increase the sensitivity by more than a hundredfold, with the goal of meeting the very low EPA advisory levels.

    “We do envision a user-friendly, household system,” Swager says. “You can imagine putting in a liter of water, letting it go through the membrane, and you have a device that measures the change in resistance of the membrane.”

    Such a device could offer a less expensive, rapid alternative to current PFAS detection methods. If PFAS are detected in drinking water, there are commercially available filters that can be used on household drinking water to reduce those levels. The new testing approach could also be useful for factories that manufacture products with PFAS chemicals, so they could test whether the water used in their manufacturing process is safe to release into the environment.

    The research was funded by an MIT School of Science Fellowship to Gordon, a Bose Research Grant, and a Fulbright Fellowship to Park. More

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    With just a little electricity, MIT researchers boost common catalytic reactions

    A simple technique that uses small amounts of energy could boost the efficiency of some key chemical processing reactions, by up to a factor of 100,000, MIT researchers report. These reactions are at the heart of petrochemical processing, pharmaceutical manufacturing, and many other industrial chemical processes.

    The surprising findings are reported today in the journal Science, in a paper by MIT graduate student Karl Westendorff, professors Yogesh Surendranath and Yuriy Roman-Leshkov, and two others.

    “The results are really striking,” says Surendranath, a professor of chemistry and chemical engineering. Rate increases of that magnitude have been seen before but in a different class of catalytic reactions known as redox half-reactions, which involve the gain or loss of an electron. The dramatically increased rates reported in the new study “have never been observed for reactions that don’t involve oxidation or reduction,” he says.

    The non-redox chemical reactions studied by the MIT team are catalyzed by acids. “If you’re a first-year chemistry student, probably the first type of catalyst you learn about is an acid catalyst,” Surendranath says. There are many hundreds of such acid-catalyzed reactions, “and they’re super important in everything from processing petrochemical feedstocks to making commodity chemicals to doing transformations in pharmaceutical products. The list goes on and on.”

    “These reactions are key to making many products we use daily,” adds Roman-Leshkov, a professor of chemical engineering and chemistry.

    But the people who study redox half-reactions, also known as electrochemical reactions, are part of an entirely different research community than those studying non-redox chemical reactions, known as thermochemical reactions. As a result, even though the technique used in the new study, which involves applying a small external voltage, was well-known in the electrochemical research community, it had not been systematically applied to acid-catalyzed thermochemical reactions.

    People working on thermochemical catalysis, Surendranath says, “usually don’t consider” the role of the electrochemical potential at the catalyst surface, “and they often don’t have good ways of measuring it. And what this study tells us is that relatively small changes, on the order of a few hundred millivolts, can have huge impacts — orders of magnitude changes in the rates of catalyzed reactions at those surfaces.”

    “This overlooked parameter of surface potential is something we should pay a lot of attention to because it can have a really, really outsized effect,” he says. “It changes the paradigm of how we think about catalysis.”

    Chemists traditionally think about surface catalysis based on the chemical binding energy of molecules to active sites on the surface, which influences the amount of energy needed for the reaction, he says. But the new findings show that the electrostatic environment is “equally important in defining the rate of the reaction.”

    The team has already filed a provisional patent application on parts of the process and is working on ways to apply the findings to specific chemical processes. Westendorff says their findings suggest that “we should design and develop different types of reactors to take advantage of this sort of strategy. And we’re working right now on scaling up these systems.”

    While their experiments so far were done with a two-dimensional planar electrode, most industrial reactions are run in three-dimensional vessels filled with powders. Catalysts are distributed through those powders, providing a lot more surface area for the reactions to take place. “We’re looking at how catalysis is currently done in industry and how we can design systems that take advantage of the already existing infrastructure,” Westendorff says.

    Surendranath adds that these new findings “raise tantalizing possibilities: Is this a more general phenomenon? Does electrochemical potential play a key role in other reaction classes as well? In our mind, this reshapes how we think about designing catalysts and promoting their reactivity.”

    Roman-Leshkov adds that “traditionally people who work in thermochemical catalysis would not associate these reactions with electrochemical processes at all. However, introducing this perspective to the community will redefine how we can integrate electrochemical characteristics into thermochemical catalysis. It will have a big impact on the community in general.”

    While there has typically been little interaction between electrochemical and thermochemical catalysis researchers, Surendranath says, “this study shows the community that there’s really a blurring of the line between the two, and that there is a huge opportunity in cross-fertilization between these two communities.”

    Westerndorff adds that to make it work, “you have to design a system that’s pretty unconventional to either community to isolate this effect.” And that helps explain why such a dramatic effect had never been seen before. He notes that even their paper’s editor asked them why this effect hadn’t been reported before. The answer has to do with “how disparate those two ideologies were before this,” he says. “It’s not just that people don’t really talk to each other. There are deep methodological differences between how the two communities conduct experiments. And this work is really, we think, a great step toward bridging the two.”

    In practice, the findings could lead to far more efficient production of a wide variety of chemical materials, the team says. “You get orders of magnitude changes in rate with very little energy input,” Surendranath says. “That’s what’s amazing about it.”

    The findings, he says, “build a more holistic picture of how catalytic reactions at interfaces work, irrespective of whether you’re going to bin them into the category of electrochemical reactions or thermochemical reactions.” He adds that “it’s rare that you find something that could really revise our foundational understanding of surface catalytic reactions in general. We’re very excited.”

    “This research is of the highest quality,” says Costas Vayenas, a professor of engineering at the university of Patras, in Greece, who was not associated with the study. The work “is very promising for practical applications, particularly since it extends previous related work in redox catalytic systems,” he says.

    The team included MIT postdoc Max Hulsey PhD ’22 and graduate student Thejas Wesley PhD ’23, and was supported by the Air Force Office of Scientific Research and the U.S. Department of Energy Basic Energy Sciences. More

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    Study: Global deforestation leads to more mercury pollution

    About 10 percent of human-made mercury emissions into the atmosphere each year are the result of global deforestation, according to a new MIT study.

    The world’s vegetation, from the Amazon rainforest to the savannahs of sub-Saharan Africa, acts as a sink that removes the toxic pollutant from the air. However, if the current rate of deforestation remains unchanged or accelerates, the researchers estimate that net mercury emissions will keep increasing.

    “We’ve been overlooking a significant source of mercury, especially in tropical regions,” says Ari Feinberg, a former postdoc in the Institute for Data, Systems, and Society (IDSS) and lead author of the study.

    The researchers’ model shows that the Amazon rainforest plays a particularly important role as a mercury sink, contributing about 30 percent of the global land sink. Curbing Amazon deforestation could thus have a substantial impact on reducing mercury pollution.

    The team also estimates that global reforestation efforts could increase annual mercury uptake by about 5 percent. While this is significant, the researchers emphasize that reforestation alone should not be a substitute for worldwide pollution control efforts.

    “Countries have put a lot of effort into reducing mercury emissions, especially northern industrialized countries, and for very good reason. But 10 percent of the global anthropogenic source is substantial, and there is a potential for that to be even greater in the future. [Addressing these deforestation-related emissions] needs to be part of the solution,” says senior author Noelle Selin, a professor in IDSS and MIT’s Department of Earth, Atmospheric and Planetary Sciences.

    Feinberg and Selin are joined on the paper by co-authors Martin Jiskra, a former Swiss National Science Foundation Ambizione Fellow at the University of Basel; Pasquale Borrelli, a professor at Roma Tre University in Italy; and Jagannath Biswakarma, a postdoc at the Swiss Federal Institute of Aquatic Science and Technology. The paper appears today in Environmental Science and Technology.

    Modeling mercury

    Over the past few decades, scientists have generally focused on studying deforestation as a source of global carbon dioxide emissions. Mercury, a trace element, hasn’t received the same attention, partly because the terrestrial biosphere’s role in the global mercury cycle has only recently been better quantified.

    Plant leaves take up mercury from the atmosphere, in a similar way as they take up carbon dioxide. But unlike carbon dioxide, mercury doesn’t play an essential biological function for plants. Mercury largely stays within a leaf until it falls to the forest floor, where the mercury is absorbed by the soil.

    Mercury becomes a serious concern for humans if it ends up in water bodies, where it can become methylated by microorganisms. Methylmercury, a potent neurotoxin, can be taken up by fish and bioaccumulated through the food chain. This can lead to risky levels of methylmercury in the fish humans eat.

    “In soils, mercury is much more tightly bound than it would be if it were deposited in the ocean. The forests are doing a sort of ecosystem service, in that they are sequestering mercury for longer timescales,” says Feinberg, who is now a postdoc in the Blas Cabrera Institute of Physical Chemistry in Spain.

    In this way, forests reduce the amount of toxic methylmercury in oceans.

    Many studies of mercury focus on industrial sources, like burning fossil fuels, small-scale gold mining, and metal smelting. A global treaty, the 2013 Minamata Convention, calls on nations to reduce human-made emissions. However, it doesn’t directly consider impacts of deforestation.

    The researchers launched their study to fill in that missing piece.

    In past work, they had built a model to probe the role vegetation plays in mercury uptake. Using a series of land use change scenarios, they adjusted the model to quantify the role of deforestation.

    Evaluating emissions

    This chemical transport model tracks mercury from its emissions sources to where it is chemically transformed in the atmosphere and then ultimately to where it is deposited, mainly through rainfall or uptake into forest ecosystems.

    They divided the Earth into eight regions and performed simulations to calculate deforestation emissions factors for each, considering elements like type and density of vegetation, mercury content in soils, and historical land use.

    However, good data for some regions were hard to come by.

    They lacked measurements from tropical Africa or Southeast Asia — two areas that experience heavy deforestation. To get around this gap, they used simpler, offline models to simulate hundreds of scenarios, which helped them improve their estimations of potential uncertainties.

    They also developed a new formulation for mercury emissions from soil. This formulation captures the fact that deforestation reduces leaf area, which increases the amount of sunlight that hits the ground and accelerates the outgassing of mercury from soils.

    The model divides the world into grid squares, each of which is a few hundred square kilometers. By changing land surface and vegetation parameters in certain squares to represent deforestation and reforestation scenarios, the researchers can capture impacts on the mercury cycle.

    Overall, they found that about 200 tons of mercury are emitted to the atmosphere as the result of deforestation, or about 10 percent of total human-made emissions. But in tropical and sub-tropical countries, deforestation emissions represent a higher percentage of total emissions. For example, in Brazil deforestation emissions are 40 percent of total human-made emissions.

    In addition, people often light fires to prepare tropical forested areas for agricultural activities, which causes more emissions by releasing mercury stored by vegetation.

    “If deforestation was a country, it would be the second highest emitting country, after China, which emits around 500 tons of mercury a year,” Feinberg adds.

    And since the Minamata Convention is now addressing primary mercury emissions, scientists can expect deforestation to become a larger fraction of human-made emissions in the future.

    “Policies to protect forests or cut them down have unintended effects beyond their target. It is important to consider the fact that these are systems, and they involve human activities, and we need to understand them better in order to actually solve the problems that we know are out there,” Selin says.

    By providing this first estimate, the team hopes to inspire more research in this area.

    In the future, they want to incorporate more dynamic Earth system models into their analysis, which would enable them to interactively track mercury uptake and better model the timescale of vegetation regrowth.

    “This paper represents an important advance in our understanding of global mercury cycling by quantifying a pathway that has long been suggested but not yet quantified. Much of our research to date has focused on primary anthropogenic emissions — those directly resulting from human activity via coal combustion or mercury-gold amalgam burning in artisanal and small-scale gold mining,” says Jackie Gerson, an assistant professor in the Department of Earth and Environmental Sciences at Michigan State University, who was not involved with this research. “This research shows that deforestation can also result in substantial mercury emissions and needs to be considered both in terms of global mercury models and land management policies. It therefore has the potential to advance our field scientifically as well as to promote policies that reduce mercury emissions via deforestation.

    This work was funded, in part, by the U.S. National Science Foundation, the Swiss National Science Foundation, and Swiss Federal Institute of Aquatic Science and Technology. More

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    3 Questions: The Climate Project at MIT

    MIT is preparing a major campus-wide effort to develop technological, behavioral, and policy solutions to some of the toughest problems now impeding an effective global climate response. The Climate Project at MIT, as the new enterprise is known, includes new arrangements for promoting cross-Institute collaborations and new mechanisms for engaging with outside partners to speed the development and implementation of climate solutions.

    MIT News spoke with Richard K. Lester, MIT’s vice provost for international activities, who has helped oversee the development of the project.

    Q: What is the Climate Project at MIT?

    A: In her inaugural address last May, President Kornbluth called on the MIT community to join her in a “bold, tenacious response” to climate change. The Climate Project at MIT is a response to that call. It aims to mobilize every part of MIT to develop, deliver, and scale up practical climate solutions, as quickly as possible.

    Play video

    At MIT, well over 300 of our faculty are already working with their students and research staff members on different aspects of the climate problem. Almost all of our academic departments and more than a score of our interdepartmental labs and centers are involved in some way. What they are doing is remarkable, and this decentralized structure reflects the best traditions of MIT as a “bottom up,” entrepreneurial institution. But, as President Kornbluth said, we must do much more. We must be bolder in our research choices and more creative in how we organize ourselves to work with each other and with our partners. The purpose of the Climate Project is to support our community’s efforts to do bigger things faster in the climate domain. We will have succeeded if our work changes the trajectory of global climate outcomes for the better.

    I want to be clear that the clay is still wet here. The Climate Project will continue to take shape as more members of the MIT community bring their excellence, their energy, and their ambition to bear on the climate challenge. But I believe we have a vision and a framework for accelerating and amplifying MIT’s real-world climate impact, and I know that President Kornbluth is eager to share this progress report with the MIT community now to convey the breadth and ambition of what we’re planning.

    Q: How will the project be organized?

    A: The Climate Project will have three core components: the Climate Missions; their offshoots, the Climate Frontier Projects; and Climate HQ. A new vice president for climate will lead the enterprise.

    Initially there will be six missions, which you can read about in the plan. Each will address a different domain of climate impact where new solutions are required and where a critical mass of research excellence exists at MIT. One such mission, of course, is to decarbonize energy and industry, an area where we estimate that about 150 of our faculty are already working.

    The mission leaders will build multidisciplinary problem-solving communities reaching across the Institute and beyond. Each of these will be charged with roadmapping and assessing progress toward its mission, identifying critical gaps and bottlenecks, and launching applied research projects to accelerate progress where the MIT community and our partners are well-positioned to achieve impactful results. These projects — the climate frontier projects — will benefit from active, professional project management, with clear metrics and milestones. We are in a critical decade for responding to climate change, so it’s important that these research projects move quickly, with an eye on producing real-world results.

    The new Climate HQ will drive the overall vision for the Climate Project and support the work of the missions. We’ve talked about a core focus on impact-driven research, but much is still unknown about the Earth’s physical and biogeochemical systems, and there is also much to be learned about the behavior of the social and political systems that led us to the very difficult situation the world now faces. Climate HQ will support fundamental research in the scientific and humanistic disciplines related to climate, and will promote engagement between these disciplines and the missions. We must also advance climate-related education, led by departments and programs, as well as policy work, public outreach, and more, including an MIT-wide student-centric Climate Corps to elevate climate-related, community-focused service in MIT’s culture.

    Q: Why are partners a key part of this project?

    A: It is important to build strong partners right from the very start for our innovations, inventions, and discoveries to have any prospect of achieving scale. And in many cases, with climate change, it’s all about scale.

    One of the aims of this initiative is to strengthen MIT’s climate “scaffolding” — the people and processes connecting what we do on campus to the practical world of climate impact and response. We can build on MIT’s highly developed infrastructure for translation, innovation, and entrepreneurship, even as we promote other important pathways to scale involving communities, municipalities, and other not-for-profit organizations. Working with all these different organizations will help us build a broad infrastructure to help us get traction in the world. On a related note, the Sloan School of Management will be sharing details in the coming days of an exciting new effort to enhance MIT’s contributions in the climate policy arena.

    MIT is committing $75 million, including $25 million from Sloan, at the outset of the project. But we anticipate developing new partnerships, including philanthropic partnerships, to increase that scope dramatically. More

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    Reflecting on COP28 — and humanity’s progress toward meeting global climate goals

    With 85,000 delegates, the 2023 United Nations climate change conference, known as COP28, was the largest U.N. climate conference in history. It was held at the end of the hottest year in recorded history. And after 12 days of negotiations, from Nov. 30 to Dec. 12, it produced a decision that included, for the first time, language calling for “transitioning away from fossil fuels,” though it stopped short of calling for their complete phase-out.

    U.N. Climate Change Executive Secretary Simon Stiell said the outcome in Dubai, United Arab Emirates, COP28’s host city, signaled “the beginning of the end” of the fossil fuel era. 

    COP stands for “conference of the parties” to the U.N. Framework Convention on Climate Change, held this year for the 28th time. Through the negotiations — and the immense conference and expo that takes place alongside them — a delegation of faculty, students, and staff from MIT was in Dubai to observe the negotiations, present new climate technologies, speak on panels, network, and conduct research.

    On Jan. 17, the MIT Center for International Studies (CIS) hosted a panel discussion with MIT delegates who shared their reflections on the experience. Asking what’s going on at COP is “like saying, ‘What’s going on in the city of Boston today?’” quipped Evan Lieberman, the Total Professor of Political Science and Contemporary Africa, director of CIS, and faculty director of MIT International Science and Technology Initiatives (MISTI). “The value added that all of us can provide for the MIT community is [to share] what we saw firsthand and how we experienced it.” 

    Phase-out, phase down, transition away?

    In the first week of COP28, over 100 countries issued a joint statement that included a call for “the global phase out of unabated fossil fuels.” The question of whether the COP28 decision — dubbed the “UAE Consensus” — would include this phase-out language animated much of the discussion in the days and weeks leading up to COP28. 

    Ultimately, the decision called for “transitioning away from fossil fuels in energy systems, in a just, orderly and equitable manner.” It also called for “accelerating efforts towards the phase down of unabated coal power,” referring to the combustion of coal without efforts to capture and store its emissions.

    In Dubai to observe the negotiations, graduate student Alessandra Fabbri said she was “confronted” by the degree to which semantic differences could impose significant ramifications — for example, when negotiators referred to a “just transition,” or to “developed vs. developing nations” — particularly where evolution in recent scholarship has produced more nuanced understandings of the terms.

    COP28 also marked the conclusion of the first global stocktake, a core component of the 2015 Paris Agreement. The effort every five years to assess the world’s progress in responding to climate change is intended as a basis for encouraging countries to strengthen their climate goals over time, a process often referred to as the Paris Agreement’s “ratchet mechanism.” 

    The technical report of the first global stocktake, published in September 2023, found that while the world has taken actions that have reduced forecasts of future warming, they are not sufficient to meet the goals of the Paris Agreement, which aims to limit global average temperature increase to “well below” 2 degrees Celsius, while pursuing efforts to limit the increase to 1.5 degrees above pre-industrial levels.

    “Despite minor, punctual advancements in climate action, parties are far from being on track to meet the long-term goals of the Paris Agreement,” said Fabbri, a graduate student in the School of Architecture and Planning and a fellow in MIT’s Leventhal Center for Advanced Urbanism. Citing a number of persistent challenges, including some parties’ fears that rapid economic transition may create or exacerbate vulnerabilities, she added, “There is a noted lack of accountability among certain countries in adhering to their commitments and responsibilities under international climate agreements.” 

    Climate and trade

    COP28 was the first climate summit to formally acknowledge the importance of international trade by featuring an official “Trade Day” on Dec. 4. Internationally traded goods account for about a quarter of global greenhouse gas emissions, raising complex questions of accountability and concerns about offshoring of industrial manufacturing, a phenomenon known as “emissions leakage.” Addressing the nexus of climate and trade is therefore considered essential for successful decarbonization, and a growing number of countries are leveraging trade policies — such as carbon fees applied to imported goods — to secure climate benefits. 

    Members of the MIT delegation participated in several related activities, sharing research and informing decision-makers. Catherine Wolfram, professor of applied economics in the MIT Sloan School of Management, and Michael Mehling, deputy director of the MIT Center for Energy and Environmental Policy Research (CEEPR), presented options for international cooperation on such trade policies at side events, including ones hosted by the World Trade Organization and European Parliament. 

    “While COPs are often criticized for highlighting statements that don’t have any bite, they are also tremendous opportunities to get people from around the world who care about climate and think deeply about these issues in one place,” said Wolfram.

    Climate and health

    For the first time in the conference’s nearly 30-year history, COP28 included a thematic “Health Day” that featured talks on the relationship between climate and health. Researchers from MIT’s Abdul Latif Jameel Poverty Action Lab (J-PAL) have been testing policy solutions in this area for years through research funds such as the King Climate Action Initiative (K-CAI). 

    “An important but often-neglected area where climate action can lead to improved health is combating air pollution,” said Andre Zollinger, K-CAI’s senior policy manager. “COP28’s announcement on reducing methane leaks is an important step because action in this area could translate to relatively quick, cost-effective ways to curb climate change while improving air quality, especially for people living near these industrial sites.” K-CAI has an ongoing project in Colorado investigating the use of machine learning to predict leaks and improve the framework for regulating industrial methane emissions, Zollinger noted.

    This was J-PAL’s third time at COP, which Zollinger said typically presented an opportunity for researchers to share new findings and analysis with government partners, nongovernmental organizations, and companies. This year, he said, “We have [also] been working with negotiators in the [Middle East and North Africa] region in the months preceding COP to plug them into the latest evidence on water conservation, on energy access, on different challenging areas of adaptation that could be useful for them during the conference.”

    Sharing knowledge, learning from others

    MIT student Runako Gentles described COP28 as a “springboard” to greater impact. A senior from Jamaica studying civil and environmental engineering, Gentles said it was exciting to introduce himself as an MIT undergraduate to U.N. employees and Jamaican delegates in Dubai. “There’s a lot of talk on mitigation and cutting carbon emissions, but there needs to be much more going into climate adaptation, especially for small-island developing states like those in the Caribbean,” he said. “One of the things I can do, while I still try to finish my degree, is communicate — get the story out there to raise awareness.”

    At an official side event at COP28 hosted by MIT, Pennsylvania State University, and the American Geophysical Union, Maria T. Zuber, MIT’s vice president for research, stressed the importance of opportunities to share knowledge and learn from people around the world.

    “The reason this two-way learning is so important for us is simple: The ideas we come up with in a university setting, whether they’re technological or policy or any other kind of innovations — they only matter in the practical world if they can be put to good use and scaled up,” said Zuber. “And the only way we can know that our work has practical relevance for addressing climate is by working hand-in-hand with communities, industries, governments, and others.”

    Marcela Angel, research program director at the Environmental Solutions Initiative, and Sergey Paltsev, deputy director of MIT’s Joint Program on the Science and Policy of Global Change, also spoke at the event, which was moderated by Bethany Patten, director of policy and engagement for sustainability at the MIT Sloan School of Management.  More

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    Susan Solomon wins VinFuture Award for Female Innovators

    Lee and Geraldine Martin Professor of Environmental Studies Susan Solomon has been awarded the 2023 VinFuture Award for Female Innovators. Solomon was picked out of almost 1,400 international nominations across four categories for “The discovery of the ozone depletion mechanism in Antarctica, contributing to the establishment of the Montreal Protocol.” The award, which comes with a $500,000 prize, highlights outstanding female researchers and innovators that can serve as role models for aspiring scientists.

    “I’m tremendously humbled by that, and I’ll do my best to live up to it,” says Solomon, who attended the ceremony in Hanoi, Vietnam, on Dec. 20.

    The VinFuture Awards are given annually to “honor scientific research and breakthrough technological innovations that can make a significant difference” according to their site. In addition to Female Innovators, the award has two other special categories, Innovators from Developing Countries and Innovators with Outstanding Achievements in Emerging Fields, as well as their overall grand prize. The awards have been given out by the Vietnam-based VinFuture Foundation since 2021.

    “Countries all around the world are part of scientific progress and innovation, and that a developing country is honoring that is really very lovely,” says Solomon, whose career as an atmospheric chemist has brought her onto the international stage and has shown her firsthand how important developing countries are in crafting global policy.

    In 1986 Solomon led an expedition of 16 scientists to Antarctica to measure the degradation of the ozone layer; she was the only woman on the team. She and her collaborators were able to figure out the atmospheric chemistry of chlorofluorocarbons and other similar chemicals that are now known as ozone-depleting substances. This work became foundational to the creation of the Montreal Protocol, an international agreement that banned damaging chemicals and has allowed the ozone to recover.

    Solomon joined the MIT faculty in 2012 and holds joint appointments in the departments of Chemistry and Earth, Atmospheric and Planetary Sciences. The success of the Montreal Protocol demonstrates the ability for international cooperation to enact effective environmental agreements; Solomon sees it as a blueprint for crafting further policy when it comes to addressing global climate change.

    “Women can do anything, even help save the ozone layer and solve other environmental problems,” she says. “Today’s problem of climate change is for all of us to be involved in solving.” More

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    New tool predicts flood risk from hurricanes in a warming climate

    Coastal cities and communities will face more frequent major hurricanes with climate change in the coming years. To help prepare coastal cities against future storms, MIT scientists have developed a method to predict how much flooding a coastal community is likely to experience as hurricanes evolve over the next decades.

    When hurricanes make landfall, strong winds whip up salty ocean waters that generate storm surge in coastal regions. As the storms move over land, torrential rainfall can induce further flooding inland. When multiple flood sources such as storm surge and rainfall interact, they can compound a hurricane’s hazards, leading to significantly more flooding than would result from any one source alone. The new study introduces a physics-based method for predicting how the risk of such complex, compound flooding may evolve under a warming climate in coastal cities.

    One example of compound flooding’s impact is the aftermath from Hurricane Sandy in 2012. The storm made landfall on the East Coast of the United States as heavy winds whipped up a towering storm surge that combined with rainfall-driven flooding in some areas to cause historic and devastating floods across New York and New Jersey.

    In their study, the MIT team applied the new compound flood-modeling method to New York City to predict how climate change may influence the risk of compound flooding from Sandy-like hurricanes over the next decades.  

    They found that, in today’s climate, a Sandy-level compound flooding event will likely hit New York City every 150 years. By midcentury, a warmer climate will drive up the frequency of such flooding, to every 60 years. At the end of the century, destructive Sandy-like floods will deluge the city every 30 years — a fivefold increase compared to the present climate.

    “Long-term average damages from weather hazards are usually dominated by the rare, intense events like Hurricane Sandy,” says study co-author Kerry Emanuel, professor emeritus of atmospheric science at MIT. “It is important to get these right.”

    While these are sobering projections, the researchers hope the flood forecasts can help city planners prepare and protect against future disasters. “Our methodology equips coastal city authorities and policymakers with essential tools to conduct compound flooding risk assessments from hurricanes in coastal cities at a detailed, granular level, extending to each street or building, in both current and future decades,” says study author Ali Sarhadi, a postdoc in MIT’s Department of Earth, Atmospheric and Planetary Sciences.

    The team’s open-access study appears online today in the Bulletin of the American Meteorological Society. Co-authors include Raphaël Rousseau-Rizzi at MIT’s Lorenz Center, Kyle Mandli at Columbia University, Jeffrey Neal at the University of Bristol, Michael Wiper at the Charles III University of Madrid, and Monika Feldmann at the Swiss Federal Institute of Technology Lausanne.

    The seeds of floods

    To forecast a region’s flood risk, weather modelers typically look to the past. Historical records contain measurements of previous hurricanes’ wind speeds, rainfall, and spatial extent, which scientists use to predict where and how much flooding may occur with coming storms. But Sarhadi believes that the limitations and brevity of these historical records are insufficient for predicting future hurricanes’ risks.

    “Even if we had lengthy historical records, they wouldn’t be a good guide for future risks because of climate change,” he says. “Climate change is changing the structural characteristics, frequency, intensity, and movement of hurricanes, and we cannot rely on the past.”

    Sarhadi and his colleagues instead looked to predict a region’s risk of hurricane flooding in a changing climate using a physics-based risk assessment methodology. They first paired simulations of hurricane activity with coupled ocean and atmospheric models over time. With the hurricane simulations, developed originally by Emanuel, the researchers virtually scatter tens of thousands of “seeds” of hurricanes into a simulated climate. Most seeds dissipate, while a few grow into category-level storms, depending on the conditions of the ocean and atmosphere.

    When the team drives these hurricane simulations with climate models of ocean and atmospheric conditions under certain global temperature projections, they can see how hurricanes change, for instance in terms of intensity, frequency, and size, under past, current, and future climate conditions.

    The team then sought to precisely predict the level and degree of compound flooding from future hurricanes in coastal cities. The researchers first used rainfall models to simulate rain intensity for a large number of simulated hurricanes, then applied numerical models to hydraulically translate that rainfall intensity into flooding on the ground during landfalling of hurricanes, given information about a region such as its surface and topography characteristics. They also simulated the same hurricanes’ storm surges, using hydrodynamic models to translate hurricanes’ maximum wind speed and sea level pressure into surge height in coastal areas. The simulation further assessed the propagation of ocean waters into coastal areas, causing coastal flooding.

    Then, the team developed a numerical hydrodynamic model to predict how two sources of hurricane-induced flooding, such as storm surge and rain-driven flooding, would simultaneously interact through time and space, as simulated hurricanes make landfall in coastal regions such as New York City, in both current and future climates.  

    “There’s a complex, nonlinear hydrodynamic interaction between saltwater surge-driven flooding and freshwater rainfall-driven flooding, that forms compound flooding that a lot of existing methods ignore,” Sarhadi says. “As a result, they underestimate the risk of compound flooding.”

    Amplified risk

    With their flood-forecasting method in place, the team applied it to a specific test case: New York City. They used the multipronged method to predict the city’s risk of compound flooding from hurricanes, and more specifically from Sandy-like hurricanes, in present and future climates. Their simulations showed that the city’s odds of experiencing Sandy-like flooding will increase significantly over the next decades as the climate warms, from once every 150 years in the current climate, to every 60 years by 2050, and every 30 years by 2099.

    Interestingly, they found that much of this increase in risk has less to do with how hurricanes themselves will change with warming climates, but with how sea levels will increase around the world.

    “In future decades, we will experience sea level rise in coastal areas, and we also incorporated that effect into our models to see how much that would increase the risk of compound flooding,” Sarhadi explains. “And in fact, we see sea level rise is playing a major role in amplifying the risk of compound flooding from hurricanes in New York City.”

    The team’s methodology can be applied to any coastal city to assess the risk of compound flooding from hurricanes and extratropical storms. With this approach, Sarhadi hopes decision-makers can make informed decisions regarding the implementation of adaptive measures, such as reinforcing coastal defenses to enhance infrastructure and community resilience.

    “Another aspect highlighting the urgency of our research is the projected 25 percent increase in coastal populations by midcentury, leading to heightened exposure to damaging storms,” Sarhadi says. “Additionally, we have trillions of dollars in assets situated in coastal flood-prone areas, necessitating proactive strategies to reduce damages from compound flooding from hurricanes under a warming climate.”

    This research was supported, in part, by Homesite Insurance. More