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      in Environment

      3 Questions: Boosting concrete’s ability to serve as a natural “carbon sink”

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      Damian Stefaniuk is a postdoc at the MIT Concrete Sustainability Hub (CSHub). He works with MIT professors Franz-Josef Ulm and Admir Masic of the MIT Department of Civil and Environmental Engineering (CEE) to investigate multifunctional concrete. Here, he provides an overview of carbonation in cement-based products, a brief explanation of why understanding carbonation in the life cycle of cement products is key for assessing their environmental impact, and an update on current research to bolster the process.

      Q: What is carbonation and why is it important for thinking about concrete from a life-cycle perspective?

      A: Carbonation is the reaction between carbon dioxide (CO2) and certain compounds in cement-based products, occurring during their use phase and end of life. It forms calcium carbonate (CaCO3) and has important implications for neutralizing the GHG [greenhouse gas] emissions and achieving carbon neutrality in the life cycle of concrete.

      Firstly, carbonation causes cement-based products to act as natural carbon sinks, sequestering CO2 from the air and storing it permanently. This helps mitigate the carbon emissions associated with the production of cement, reducing their overall carbon footprint.

      Secondly, carbonation affects concrete properties. Early-stage carbonation may increase the compressive strength of cement-based products, enhancing their durability and structural performance. However, late-stage carbonation can impact corrosion resistance in steel-reinforced concrete due to reduced alkalinity.

      Considering carbonation in the life cycle of cement-based products is crucial for accurately assessing their environmental impact. Understanding and leveraging carbonation can help industry reduce carbon emissions and maximize carbon sequestration potential. Paying close attention to it in the design process aids in creating durable and corrosion-resistant structures, contributing to longevity and overall sustainability.

      Q: What are some ongoing global efforts to force carbonation?

      A: Some ongoing efforts to force carbonation in concrete involve artificially increasing the amount of CO2 gas present during the early-stage hydration of concrete. This process, known as forced carbonation, aims to accelerate the carbonation reaction and its associated benefits.

      Forced carbonation is typically applied to precast concrete elements that are produced in artificially CO2-rich environments. By exposing fresh concrete to higher concentrations of CO2 during curing, the carbonation process can be expedited, resulting in potential improvements in strength, reduced water absorption, improved resistance to chloride permeability, and improved performance during freeze-thaw. At the same time, it can be difficult to quantify how much CO2 is absorbed and released because of the process.

      These efforts to induce early-stage carbonation through forced carbonation represent the industry’s focus on optimizing concrete performance and environmental impacts. By exploring methods to enhance the carbonation process, researchers and practitioners seek to more efficiently harness its benefits, such as increasing strength and sequestering CO2.

      It is important to note that forced carbonation requires careful implementation and monitoring to ensure desired outcomes. The specific procedures and conditions vary based on the application and intended goals, highlighting the need for expertise and controlled environments.

      Overall, ongoing efforts in forced carbonation contribute to the continuous development of concrete technology, aiming to improve its properties and reduce its carbon footprint throughout the life cycle of the material.

      Q: What is chemically-induced pre-cure carbonation, and what implications does it have?

      A: Chemically-induced pre-cure carbonation (CIPCC) is a method developed by the MIT CSHub to mineralize and permanently store CO2 in cement. Unlike traditional forced carbonation methods, CIPCC introduces CO2 into the concrete mix as a solid powder, specifically sodium bicarbonate. This approach addresses some of the limitations of current carbon capture and utilization technologies.

      The implications of CIPCC are significant. Firstly, it offers convenience for cast-in-place applications, making it easier to incorporate CO2 use in concrete projects. Unlike some other approaches, CIPCC allows for precise control over the quantity of CO2 sequestered in the concrete. This ensures accurate carbonation and facilitates better management of the storage process. CIPCC also builds on previous research regarding amorphous hydration phases, providing an additional mechanism for CO2 sequestration in cement-based products. These phases carbonate through CIPCC, contributing to the overall carbon sequestration capacity of the material.

      Furthermore, early-stage pre-cure carbonation shows promise as a pathway for concrete to permanently sequester a controlled and precise quantity of CO2. Our recent paper in PNAS Nexus suggests that it could theoretically offset at least 40 percent of the calcination emissions associated with cement production, when anticipating advances in the lower-emissions production of sodium bicarbonate. We also found that up to 15 percent of cement (by weight) could be substituted with sodium bicarbonate without compromising the mechanical performance of a given mix. Further research is needed to evaluate long-term effects of this process to explore the potential life-cycle savings and impacts of carbonation.

      CIPCC offers not only environmental benefits by reducing carbon emissions, but also practical advantages. The early-stage strength increase observed in real-world applications could expedite construction timelines by allowing concrete to reach its full strength faster.

      Overall, CIPCC demonstrates the potential for more efficient and controlled CO2 sequestration in concrete. It represents an important development in concrete sustainability, emphasizing the need for further research and considering the material’s life-cycle impacts.

      This research was carried out by MIT CSHub, which is sponsored by the Concrete Advancement Foundation and the Portland Cement Association. More

    • 138 Shares129 Views

      in Energy

      3 Questions: What’s it like winning the MIT $100K Entrepreneurship Competition?

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      Solar power plays a major role in nearly every roadmap for global decarbonization. But solar panels are large, heavy, and expensive, which limits their deployment. But what if solar panels looked more like a yoga mat?

      Such a technology could be transported in a roll, carried to the top of a building, and rolled out across the roof in a matter of minutes, slashing installation costs and dramatically expanding the places where rooftop solar makes sense.

      That was the vision laid out by the MIT spinout Active Surfaces as part of the winning pitch at this year’s MIT $100K Entrepreneurship Competition, which took place May 15. The company is leveraging materials science and manufacturing innovations from labs across MIT to make ultra-thin, lightweight, and durable solar a reality.

      The $100K is one of MIT’s most visible entrepreneurship competitions, and past winners say the prize money is only part of the benefit that winning brings to a burgeoning new company. MIT News sat down with Active Surface founders Shiv Bhakta, a graduate student in MIT’s Leaders for Global Operations dual-degree program within the MIT Sloan School of Management and Department of Civil and Environmental Engineering, and Richard Swartwout SM ’18 PhD ’21, an electrical engineering and computer science graduate and former Research Laboratory of Electronics postdoc and MIT.nano innovation fellow, to learn what the last couple of months have been like since they won.

      Q: What is Active Surfaces’ solution, and what is its potential?

      Bhakta: We’re commercializing an ultrathin film, flexible solar technology. Solar is one of the most broadly distributed resources in the world, but access is limited today. It’s heavy — it weighs 50 to 60 pounds a panel — it requires large teams to move around, and the form factor can only be deployed in specific environments.

      Our approach is to develop a solar technology for the built environment. In a nutshell, we can create flexible solar panels that are as thin as paper, just as efficient as traditional panels, and at unprecedented cost floors, all while being applied to any surface. Same area, same power. That’s our motto.

      When I came to MIT, my north star was to dive deeper in my climate journey and help make the world a better, greener place. Now, as we build Active Surfaces, I’m excited to see that dream taking shape. The prospect of transforming any surface into an energy source, thereby expanding solar accessibility globally, holds the promise of significantly reducing CO2 emissions at a gigaton scale. That’s what gets me out of bed in the morning.

      Swartwout: Solar and a lot of other renewables tend to be pretty land-inefficient. Solar 1.0 is using low hanging fruit: cheap land next to easy interconnects and new buildings designed to handle the weight of current panels. But as we ramp up solar, those things will run out. We need to utilize spaces and assets better. That’s what I think solar 2.0 will be: urban PV deployments, solar that’s closer to demand, and integrated into the built environment. These next-generation use cases aren’t just a racking system in the middle of nowhere.

      We’re going after commercial roofs, which would cover most [building] energy demand. Something like 80-90 percent of building electricity demands in the space can be met by rooftop solar.

      The goal is to do the manufacturing in-house. We use roll-to-roll manufacturing, so we can buy tons of equipment off the shelf, but most roll-to-roll manufacturing is made for things like labeling and tape, and not a semiconductor, so our plan is to be the core of semiconductor roll-to-roll manufacturing. There’s never been roll-to-roll semiconductor manufacturing before.

      Q: What have the last few months been like since you won the $100K competition?

      Bhakta: After winning the $100K, we’ve gotten a lot of inbound contact from MIT alumni. I think that’s my favorite part about the MIT community — people stay connected. They’ve been congratulating us, asking to chat, looking to partner, deploy, and invest.

      We’ve also gotten contacted by previous $100K competition winners and other startups that have spun out of MIT that are a year or two or three ahead of us in terms of development. There are a lot of startup scaling challenges that other startup founders are best equipped to answer, and it’s been huge to get guidance from them.

      We’ve also gotten into top accelerators like Cleantech Open, Venture For Climatetech, and ACCEL at Greentown Labs. We also onboarded two rockstar MIT Sloan interns for the summer. Now we’re getting to the product-development phase, building relationships with potential pilot partners, and scaling up the area of our technology.      

      Swartwout: Winning the $100K competition was a great point of validation for the company, because the judges themselves are well known in the venture capital community as well as people who have been in the startup ecosystem for a long time, so that has really propelled us forward. Ideally, we’ll be getting more MIT alumni to join us to fulfill this mission.

      Q: What are your plans for the next year or so?

      Swartwout: We’re planning on leveraging open-access facilities like those at MIT.nano and the University of Massachusetts Amherst. We’re pretty focused now on scaling size. Out of the lab, [the technology] is a 4-inch by 4-inch solar module, and the goal is to get up to something that’s relevant for the industry to offset electricity for building owners and generate electricity for the grid at a reasonable cost.

      Bhakta: In the next year, through those open-access facilities, the goal is to go from 100-millimeter width to 300-millimeter width and a very long length using a roll-to-roll manufacturing process. That means getting through the engineering challenges of scaling technology and fine tuning the performance.

      When we’re ready to deliver a pilotable product, it’s my job to have customers lined up ready to demonstrate this works on their buildings, sign longer term contracts to get early revenue, and have the support we need to demonstrate this at scale. That’s the goal. More

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      in Environment

      Q&A: Are far-reaching fires the new normal?

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      Where there’s smoke, there is fire. But with climate change, larger and longer-burning wildfires are sending smoke farther from their source, often to places that are unaccustomed to the exposure. That’s been the case this week, as smoke continues to drift south from massive wildfires in Canada, prompting warnings of hazardous air quality, and poor visibility in states across New England, the mid-Atlantic, and the Midwest.

      As wildfire season is just getting going, many may be wondering: Are the air-polluting effects of wildfires a new normal?

      MIT News spoke with Professor Colette Heald of the Department of Civil and Environmental Engineering and the Department of Earth, Atmospheric and Planetary Sciences, and Professor Noelle Selin of the Institute for Data, Systems and Society and the Department of Earth, Atmospheric and Planetary Sciences. Heald specializes in atmospheric chemistry and has studied the climate and health effects associated with recent wildfires, while Selin works with atmospheric models to track air pollutants around the world, which she uses to inform policy decisions on mitigating  pollution and climate change. The researchers shared some of their insights on the immediate impacts of Canada’s current wildfires and what downwind regions may expect in the coming months, as the wildfire season stretches into summer.  

      Q: What role has climate change and human activity played in the wildfires we’ve seen so far this year?

      Heald: Unusually warm and dry conditions have dramatically increased fire susceptibility in Canada this year. Human-induced climate change makes such dry and warm conditions more likely. Smoke from fires in Alberta and Nova Scotia in May, and Quebec in early June, has led to some of the worst air quality conditions measured locally in Canada. This same smoke has been transported into the United States and degraded air quality here as well. Local officials have determined that ignitions have been associated with lightning strikes, but human activity has also played a role igniting some of the fires in Alberta.

      Q: What can we expect for the coming months in terms of the pattern of wildfires and their associated air pollution across the United States?

      Heald: The Government of Canada is projecting higher-than-normal fire activity throughout the 2023 fire season. Fire susceptibility will continue to respond to changing weather conditions, and whether the U.S. is impacted will depend on the winds and how air is transported across those regions. So far, the fire season in the United States has been below average, but fire risk is expected to increase modestly through the summer, so we may see local smoke influences as well.

      Q: How has air pollution from wildfires affected human health in the U.S. this year so far?

      Selin: The pollutant of most concern in wildfire smoke is fine particulate matter (PM2.5) – fine particles in the atmosphere that can be inhaled deep into the lungs, causing health damages. Exposure to PM2.5 causes respiratory and cardiovascular damage, including heart attacks and premature deaths. It can also cause symptoms like coughing and difficulty breathing. In New England this week, people have been breathing much higher concentrations of PM2.5 than usual. People who are particularly vulnerable to the effects are likely experiencing more severe impacts, such as older people and people with underlying conditions. But PM2.5 affects everyone. While the number and impact of wildfires varies from year to year, the associated air pollution from them generally lead to tens of thousands of premature deaths in the U.S. overall annually. There is also some evidence that PM2.5 from fires could be particularly damaging to health.

      While we in New England usually have relatively lower levels of pollution, it’s important also to note that some cities around the globe experience very high PM2.5 on a regular basis, not only from wildfires, but other sources such as power plants and industry. So, while we’re feeling the effects over the past few days, we should remember the broader importance of reducing PM2.5 levels overall for human health everywhere.

      Q: While firefighters battle fires directly this wildfire season, what can we do to reduce the effects of associated air pollution? And what can we do in the long-term, to prevent or reduce wildfire impacts?

      Selin: In the short term, protecting yourself from the impacts of PM2.5 is important. Limiting time outdoors, avoiding outdoor exercise, and wearing a high-quality mask are some strategies that can minimize exposure. Air filters can help reduce the concentrations of particles in indoor air. Taking measures to avoid exposure is particularly important for vulnerable groups. It’s also important to note that these strategies aren’t equally possible for everyone (for example, people who work outside) — stressing the importance of developing new strategies to address the underlying causes of increasing wildfires.

      Over the long term, mitigating climate change is important — because warm and dry conditions lead to wildfires, warming increases fire risk. Preventing the fires that are ignited by people or human activities can help.  Another way that damages can be mitigated in the longer term is by exploring land management strategies that could help manage fire intensity. More

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      in Environment

      Q&A: Gabriela Sá Pessoa on Brazilian politics, human rights in the Amazon, and AI

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      Gabriela Sá Pessoa is a journalist passionate about the intersection of human rights and climate change. She came to MIT from The Washington Post, where she worked from her home country of Brazil as a news researcher reporting on the Amazon, human rights violations, and environmental crimes. Before that, she held roles at two of the most influential media outlets in Brazil: Folha de S.Paulo, covering local and national politics, and UOL, where she was assigned to coronavirus coverage and later joined the investigative desk.

      Sá Pessoa was awarded the 2023 Elizabeth Neuffer Fellowship by the International Women’s Media Foundation, which supports its recipient with research opportunities at MIT and further training at The Boston Globe and The New York Times. She is currently based at the MIT Center for International Studies. Recently, she sat down to talk about her work on the Amazon, recent changes in Brazilian politics, and her experience at MIT.

      Q: One focus of your reporting is human rights and environmental issues in the Amazon. As part of your fellowship, you contributed to a recent editorial in The Boston Globe on fighting deforestation in the region. Why is reporting on this topic important?

      A: For many Brazilians, the Amazon is a remote and distant territory, and people living in other parts of the country aren’t fully aware of all of its problems and all of its potential. This is similar to the United States — like many people here, they don’t see how they could be related to the human rights violations and the destruction of the rainforest that are happening.

      But, we are all complicit in the destruction in some ways because the economic forces driving the deforestation of the rainforest all have a market, and these markets are everywhere, in Brazil and here in the U.S. I think it is part of journalism to show people in the U.S., Brazil, and elsewhere that we are part of the problem, and as part of the problem, we should be part of the solution by being aware of it, caring about it, and taking actions that are within our power.

      In the U.S., for example, voters can influence policy like the current negotiations for financial support for fighting deforestation in the Amazon. And as consumers, we can be more aware — is the beef we are consuming related to deforestation? Is the timber on our construction sites coming from the Amazon?

      Truth is, in Brazil, we have turned our backs to the Amazon for so long. It’s our duty to protect it for the sake of climate change. If we don’t take care of it, there will be serious consequences to our local climate, our local communities, and for the whole world. It’s a huge matter of human rights because our living depends on that, both locally and globally.

      Q: Before coming to MIT, you were at The Washington Post in São Paulo, where you contributed to reporting on the recent presidential election. What changes do you expect to see with the new Lula administration?

      A: To climate and environment, the first signs were positive. But the optimism did not last a semester, as politics is imposing itself. Lula is facing increasing difficulty building a majority in a conservative Congress, over which agribusiness holds tremendous power and influence. As we speak, environmental policy is under Congress’s attack. A committee in the House has just passed a ruling drowning power from the environmental minister, Marina Silva, and from the recently created National Indigenous People Ministry, led by Sonia Guajajara. Both Marina and Sonia are global ecological and human rights champions, and I wonder what the impact would be if Congress ratifies these changes. It is still unclear how it would impact the efforts to fight deforestation.

      In addition, there is an internal dispute in the government between environmentalists and those in favor of mining and big infrastructure projects. Petrobras, the state-run oil company, is trying to get authorization to research and drill offshore oil reserves in the mouth of the Amazon River. The federal environmental protection agency did a conclusive report suspending the operation, saying it is critical and threatens the region’s sensitive environment and indigenous communities. And, of course, it would be another source of greenhouse gas emissions. ​

      That said, it’s not a denialist government. I should mention the quick response from the administration to the Yanomami genocide earlier this year. In January, an independent media organization named Sumaúma reported on the deaths of over five hundred indigenous children from the Yanomami community in the Amazon over the past four years. This was a huge shock in Brazil, and the administration responded immediately. They sent task forces to the region and are now expelling the illegal miners that were bringing diseases and were ultimately responsible for these humanitarian tragedies. To be clear: It is still a problem. It’s not solved. But this is already a good example of positive action.

      Fighting deforestation in the Amazon and the Cerrado, another biome critical to climate regulation in Brazil, will not be easy. Rebuilding the environmental policy will take time, and the agencies responsible for enforcement are understaffed. In addition, environmental crime has become more sophisticated, connecting with other major criminal organizations in the country. In April, for the first time, there was a reduction in deforestation in the Amazon after two consecutive months of higher numbers. These are still preliminary data, and it is still too early to confirm whether they signal a turning point and may indicate a tendency for deforestation to decrease. On the other hand, the Cerrado registered record deforestation in April.

      There are problems everywhere in the economy and politics that Lula will have to face. In the first week of the new term, on Jan. 8, we saw an insurrection in Brasília, the country’s capital, from Bolsonaro voters who wouldn’t accept the election results. The events resembled what Americans saw in the Capitol attacks in 2021. We also seem to have imported problems from the United States, like mass killings in schools. We never used to have them in Brazil, but we are seeing them now. I’m curious to see how the country will address those problems and if the U.S. can also inspire solutions to that. That’s something I’m thinking about, being here: Are there solutions here? What are they?

      Q: What have you learned so far from MIT and your fellowship?

      A: It’s hard to put everything into words! I’m mostly taking courses and attending lectures on pressing issues to humanity, like existential threats such as climate change, artificial intelligence, biosecurity, and more.

      I’m learning about all these issues, but also, as a journalist, I think that I’m learning more about how I can incorporate the scientific approach into my work; for example, being more pro-positive. I am already a rigorous journalist, but I am thinking about how I can be more rigorous and more transparent about my methods. Being in the academic and scientific environment is inspiring that way.

      I am also learning a lot about how to cover scientific topics and thinking about how technology can offer us solutions (and problems). I’m learning so much that I think I will need some time to digest and fully understand what this period means for me!

      Q: You mentioned artificial intelligence. Would you like to weigh in on this subject and what you have been learning?

      A: It has been a particularly good semester to be at MIT. Generative artificial intelligence, which became more popular after ChatGPT, has been a topic of intense discussion this semester, and I was able to attend many classes, seminars, and events about AI here, especially from a policy perspective.

      Algorithms have influenced the economy, society, and public health for many years. It has had great outcomes, but also injustice. Popular systems like ChatGPT have made this technology incredibly popular and accessible, even for those with no computer knowledge. This is scary and, at the same time, very exciting. Here, I learned that we need guardrails for artificial intelligence, just like other technologies. Think of the pharmaceutical or automobile industries, which have to meet safety criteria before putting a new product on the market. But with artificial intelligence, it’s going to be different; supply chains are very complex and sometimes not very transparent, and the speed at which new resources develop is so fast that it challenges the policymaker’s ability to respond.

      Artificial intelligence is changing the world radically. It’s exciting to have the privilege of being here and seeing these discussions take place. After all, I have a future to report on. At least, I hope so!

      Q: What are you working on going forward?

      A: After MIT, I am going to New York, where I’ll be working with The New York Times in their internship program. I’m really excited about that because it will be a different pace from MIT. I am also doing research on carbon credit markets and hope to continue that project, either in a reporting or academic environment. 

      Honestly, I feel inspired to keep studying. I would love to spend more time here at MIT. I would love to do a master’s or join any program here. I’m going to work on coming back to academia because I think that I need to learn more from the academic environment. I hope that it’s at MIT because honestly, it’s the most exciting environment that I’ve ever been in, with all the people here from different fields and different backgrounds. I’m not a scientist, but it’s inspiring to be with them, and if there’s a way that I could contribute to their work in a way that they’re contributing to my work, I’ll be thrilled to spend more time here. More

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      in Environment

      3 Questions: Can disused croplands help mitigate climate change?

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      As the world struggles to meet internationally agreed targets for reducing greenhouse gas emissions, methods of removing carbon dioxide such as reforestation of cleared areas have become an increasingly important strategy. But little attention has been paid to the potential for abandoned or marginal croplands to be restored to natural vegetation as an additional carbon sink, say MIT assistant professor of civil and environmental engineering César Terrer, recent visiting MIT doctoral student Stephen M. Bell, and six others, in a recent open-access paper in the journal Nature Communications. Here, Terrer and Bell explain the potential use of these “post-agricultural” lands to help in the fight against damaging climate change.

      Q: How significant is the potential of unused agricultural lands as a carbon sink to help mitigate climate change?

      Bell: We know of these huge instances of land abandonment and post-agricultural succession throughout history, like following the collapse of major cities from ancient Mesopotamia to the Mayans. And when the Europeans arrived in the Americas in the 15th century, so many people died and so much forest grew back on abandoned farmland that it helped cool the entire planet and was potentially a driver of the coldest part of the so-called “Little Ice Age” period.

      Today, we have abandoned farmland all over the Mediterranean region, where I did my PhD field work. As young people left rural areas for the cities throughout the 20th century, farmers couldn’t pass on their land to anyone, and the land succeeded back into shrub lands and forests. The biggest recent example of abandonment is for sure the collapse of the Soviet Union, where an estimated 60 million hectares of forest regrew when support for collective farming stopped, resulting in one of the largest carbon sinks ever attributed to a single event.

      So, when we look back at the past, we know there’s potential. Of course, these are huge events, and no one is proposing to replicate anything like that. We need to use land for multiple purposes, but looking back at these big examples, we know there is potential for abandoned or restored agricultural land to be carbon sinks. And so that tells us to dig deeper into this question and get a better idea of realistic scenarios, a better understanding of the climate change mitigation potential of agricultural cessation in the most strategic places.

      Terrer: More than 115 billion tons of carbon have been lost from soils due to agricultural practices that disturb soil integrity — such as tilling, monoculture farming, removing crop residue, excessive use of fertilizers and pesticides, and over-grazing. To put this into perspective, the amount of carbon lost is equivalent to the total CO2 emissions ever produced in the United States.

      Our current research synthesizes field data from thousands of experiments, aiming to understand the factors that influence soil carbon accrual in abandoned croplands transitioning back to forests or natural grasslands. We’re working to quantify the potential for carbon sequestration in these soils over 30-, 50-, and 100-year time frames and mapping the areas with the greatest potential for carbon storage. This includes both increases in soil carbon and in vegetation biomass.

      Q: What are some of the key uncertainties in evaluating this potential for unused cropland to serve as a carbon sink, and how could those uncertainties be addressed?

      Bell: We use this word uncertainties in two ways. Specifically, the longevity of potential recarbonization, and the intensity of the potential recarbonization. Those are two factors, two aspects that we need to quantify to reduce our uncertainty.

      So, how long will the land recarbonize, regardless of the intensity? If the carbon level is going up, that’s good. If there’s more carbon increasing in the soil, we know that it came from somewhere, it came from the atmosphere. But how long does that happen? We know soil can get saturated. It can reach its carbon capacity limit, it won’t continue to increase the carbon stock, and the recarbonization curve will flatten out. When does that happen? Is it after a hundred years? Is it after 20 years?

      But the world’s soils are very diverse and complex, so what might be true in one place is not true in another place. It may take a longer time to reach saturation for more fertile soils in the Midwest U.S. than less fertile soils in the Southwest, for example. Alternatively, sometimes soils in drier areas like in the Southwest may never reach true saturation if they are degraded and have stalled recovery following abandonment.

      The second uncertainty is intensity: How high on the y-axis on the chart of recarbonization does saturation occur? With the analogy comparing U.S. soils, you might have a relatively huge carbon increase on an abandoned farm in the Southwest, but because the soil is not very carbon-rich it’s not a large increase in absolute terms. In the Midwest, there might only be a small relative increase, but that increase could be much more in total than in the Southwest. These are just nuances to keep in mind as we look at this at the global scale.

      These nuances are essentially uncertainties. Soil carbon responses to agricultural land abandonment is complicated, and unfortunately it hasn’t been studied in much detail so far. We need to reduce those uncertainties to get a better understanding of the recarbonization potential. This is easier said than done because not only do we have these temporal data uncertainties, but we also have spatial uncertainties. We don’t have very good maps of past and present post-agricultural landscapes.

      Q: Can this potential use of post-agricultural lands be implemented without putting global food supplies at risk? How can these needs be balanced?

      Terrer: As to whether utilizing post-agricultural lands for carbon sequestration can be implemented without jeopardizing global food supplies, and how to balance these needs, our recent research provides valuable insights.

      The challenge, of course, lies in balancing cropland restoration for climate mitigation with food security for a growing global population. Abandoned croplands represent an opportunity for carbon sequestration without impacting active agricultural lands. However, the available area of abandoned croplands is insufficient to make a substantial impact on climate mitigation on its own.

      Thus, our proposal also emphasizes the importance of closing yield gaps, which involves increasing crop production per hectare to its theoretical limits. This would enable us to maintain or even increase global crop yields using only a fraction of the currently cultivated area, allowing the remaining land to be dedicated to climate mitigation efforts. By pursuing this strategy, we estimate that over half of the amount of soil carbon lost so far due to agriculture could be recovered, while ensuring food security for the world’s population. More

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      in Environment

      3 Questions: New MIT major and its role in fighting climate change

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      Launched this month, MIT’s new Bachelor of Science in climate system science and engineering is jointly offered by the departments of Civil and Environmental Engineering (CEE) and Earth, Atmospheric and Planetary Sciences (EAPS). As part of MIT’s commitment to aid the global response to climate change, the new degree program is designed to train the next generation of leaders, providing a foundational understanding of both the Earth system and engineering principles — as well as an understanding of human and institutional behavior as it relates to the climate challenge. Jadbabaie and Van der Hilst discuss the new Course 1-12 multidisciplinary major and why it’s needed now at MIT. 

      Q: What was the idea behind launching this new major at MIT?

      Jadbabaie: Climate change is an incredibly important issue that we must address, and time is of the essence. MIT is in a unique position to play a leadership role in this effort. We not only have the ability to advance the science of climate change and deepen our understanding of the climate system, but also to develop innovative engineering solutions for sustainability that can help us meet the climate goals set forth in the Paris Agreement. It is important that our educational approach also incorporates other aspects of this cross-cutting issue, ranging from climate justice, policy, to economics, and MIT is the perfect place to make this happen. With Course 1’s focus on sustainability across scales, from the nano to the global scale, and with Course 12 studying Earth system science in general, it was a natural fit for CEE and EAPS to tackle this challenge together. It is my belief that we can leverage our collective expertise and resources to make meaningful progress. There has never been a more crucial time for us to advance students’ understanding of both climate science and engineering, as well as their understanding of the societal implications of climate risk.

      Van der Hilst: Climate change is a global issue, and the solutions we urgently need for building a net-zero future must consider how everything is connected. The Earth’s climate is a complex web of cause and effect between the oceans, atmosphere, ecosystems, and processes that shape the surface and environmental systems of the planet. To truly understand climate risks, we need to understand the fundamental science that governs these interconnected systems — and we need to consider the ways that human activity influences their behavior. The types of large-scale engineering projects that we need to secure a sustainable future must take into consideration the Earth system itself. A systems approach to modeling is crucial if we are to succeed at inventing, designing, and implementing solutions that can reduce greenhouse gas emissions, build climate resilience, and mitigate the inevitable climate-related natural disasters that we’ll face. That’s why our two departments are collaborating on a degree program that equips students with foundational climate science knowledge alongside fundamental engineering principles in order to catalyze the innovation we’ll need to meet the world’s 2050 goals.

      Q: How is MIT uniquely positioned to lead undergraduate education in climate system science and engineering? 

      Jadbabaie: It’s a great example of how MIT is taking a leadership role and multidisciplinary approach to tackling climate change by combining engineering and climate system science in one undergraduate major. The program leverages MIT’s academic strengths, focusing on teaching hard analytical and computational skills while also providing a curriculum that includes courses in a wide range of topics, from climate economics and policy to ethics, climate justice, and even climate literature, to help students develop an understanding of the political and social issues that are tied to climate change. Given the strong ties between courses 1 and 12, we want the students in the program to be full members of both departments, as well as both the School of Engineering and the School of Science. And, being MIT, there is no shortage of opportunities for undergraduate research and entrepreneurship — in fact, we specifically encourage students to participate in the active research of the departments. The knowledge and skills our students gain will enable them to serve the nation and the world in a meaningful way as they tackle complex global-scale environmental problems. The students at MIT are among the most passionate and driven people out there. I’m really excited to see what kind of innovations and solutions will come out of this program in the years to come. I think this undergraduate major is a fantastic step in the right direction.

      Q: What opportunities will the major provide to students for addressing climate change?

      Van der Hilst: Both industry and government are actively seeking new talent to respond to the challenges — and opportunities — posed by climate change and our need to build a sustainable future. What’s exciting is that many of the best jobs in this field call for leaders who can combine the analytical skill of a scientist with the problem-solving mindset of an engineer. That’s exactly what this new degree program at MIT aims to prepare students for — in an expanding set of careers in areas like renewable energy, civil infrastructure, risk analysis, corporate sustainability, environmental advocacy, and policymaking. But it’s not just about career opportunities. It’s also about making a real difference and safeguarding our future. It’s not too late to prevent much more damaging changes to Earth’s climate. Indeed, whether in government, industry, or academia, MIT students are future leaders — as such it is critically important that all MIT students understand the basics of climate system science and engineering along with math, physics, chemistry, and biology. The new Course 1-12 degree was designed to forge students who are passionate about protecting our planet into the next generation of leaders who can fast-track high-impact, science-based solutions to aid the global response, with an eye toward addressing some of the uneven social impacts inherent in the climate crisis. More

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      in Environment

      3 Questions: Leveraging carbon uptake to lower concrete’s carbon footprint

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      To secure a more sustainable and resilient future, we must take a careful look at the life cycle impacts of humanity’s most-produced building material: concrete. Carbon uptake, the process by which cement-based products sequester carbon dioxide, is key to this understanding.

      Hessam AzariJafari, the MIT Concrete Sustainability Hub’s deputy director, is deeply invested in the study of this process and its acceleration, where prudent. Here, he describes how carbon uptake is a key lever to reach a carbon-neutral concrete industry.

      Q: What is carbon uptake in cement-based products and how can it influence their properties?

      A: Carbon uptake, or carbonation, is a natural process of permanently sequestering CO2 from the atmosphere by hardened cement-based products like concretes and mortars. Through this reaction, these products form different kinds of limes or calcium carbonates. This uptake occurs slowly but significantly during two phases of the life cycle of cement-based products: the use phase and the end-of-life phase.

      In general, carbon uptake increases the compressive strength of cement-based products as it can densify the paste. At the same time, carbon uptake can impact the corrosion resistance of concrete. In concrete that is reinforced with steel, the corrosion process can be initiated if the carbonation happens extensively (e.g., the whole of the concrete cover is carbonated) and intensively (e.g., a significant proportion of the hardened cement product is carbonated). [Concrete cover is the layer distance between the surface of reinforcement and the outer surface of the concrete.]

      Q: What are the factors that influence carbon uptake?

      A: The intensity of carbon uptake depends on four major factors: the climate, the types and properties of cement-based products used, the composition of binders (cement type) used, and the geometry and exposure condition of the structure.

      In regard to climate, the humidity and temperature affect the carbon uptake rate. In very low or very high humidity conditions, the carbon uptake process is slowed. High temperatures speed the process. The local atmosphere’s carbon dioxide concentration can affect the carbon uptake rate. For example, in urban areas, carbon uptake is an order of magnitude faster than in suburban areas.

      The types and properties of cement-based products have a large influence on the rate of carbon uptake. For example, mortar (consisting of water, cement, and fine aggregates) carbonates two to four times faster than concrete (consisting of water, cement, and coarse and fine aggregates) because of its more porous structure.The carbon uptake rate of dry-cast concrete masonry units is higher than wet-cast for the same reason. In structural concrete, the process is made slower as mechanical properties are improved and the density of the hardened products’ structure increases.

      Lastly, a structure’s surface area-to-volume ratio and exposure to air and water can have ramifications for its rate of carbonation. When cement-based products are covered, carbonation may be slowed or stopped. Concrete that is exposed to fresh air while being sheltered from rain can have a larger carbon uptake compared to cement-based products that are painted or carpeted. Additionally, cement-based elements with large surface areas, like thin concrete structures or mortar layers, allow uptake to progress more extensively.

      Q: What is the role of carbon uptake in the carbon neutrality of concrete, and how should architects and engineers account for it when designing for specific applications?

      A: Carbon uptake is a part of the life cycle of any cement-based products that should be accounted for in carbon footprint calculations. Our evaluation shows the U.S. pavement network can sequester 5.8 million metric tons of CO2, of which 52 percent will be sequestered when the demolished concrete is stockpiled at its end of life.

      From one concrete structure to another, the percentage of emissions sequestered may vary. For instance, concrete bridges tend to have a lower percentage versus buildings constructed with concrete masonry. In any case, carbon uptake can influence the life cycle environmental performance of concrete.

      At the MIT Concrete Sustainability Hub, we have developed a calculator to enable construction stakeholders to estimate the carbon uptake of concrete structures during their use and end-of-life phases.

      Looking toward the future, carbon uptake’s role in the carbon neutralization of cement-based products could grow in importance. While caution should be taken in regards to uptake when reinforcing steel is embedded in concrete, there are opportunities for different stakeholders to augment carbon uptake in different cement-based products.

      Architects can influence the shape of concrete elements to increase the surface area-to-volume ratio (e.g., making “waffle” patterns on slabs and walls, or having several thin towers instead of fewer large ones on an apartment complex). Concrete manufacturers can adjust the binder type and quantity while delivering concrete that meets performance requirements. Finally, industrial ecologists and life-cycle assessment practitioners need to work on the tools and add-ons to make sure the impact of carbon is well captured when assessing the potential impacts of cement-based products in buildings and infrastructure systems.

      Currently, the cement and concrete industry is working with tech companies as well as local, state, and federal governments to lower and subsidize the code of carbon capture sequestration and neutralization. Accelerating carbon uptake where reasonable could be an additional lever to neutralize the carbon emissions of the concrete value chain.

      Carbon uptake is one more piece of the puzzle that makes concrete a sustainable choice for building in many applications. The sustainability and resilience of the future built environment lean on the use of concrete. There is still much work to be done to truly build sustainably, and understanding carbon uptake is an important place to begin. More

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      in Energy

      3 Questions: Antje Danielson on energy education and its role in climate action

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      The MIT Energy Initiative (MITEI) leads energy education at MIT, developing and implementing a robust educational toolkit for MIT graduate and undergraduate students, online learners around the world, and high school students who want to contribute to the energy transition. As MITEI’s director of education, Antje Danielson manages a team devoted to training the next generation of energy innovators, entrepreneurs, and policymakers. Here, she discusses new initiatives in MITEI’s education program and how they are preparing students to take an active role in climate action.

      Q: What role are MITEI’s education efforts playing in climate action initiatives at MIT, and what more could we be doing?

      A: This is a big question. The carbon emissions from energy are such an important factor in climate mitigation; therefore, what we do in energy education is practically synonymous with climate education. This is well illustrated in a 2018 Nature Energy paper by Fuso Nerini, which outlines that affordable, clean energy is related to many of the United Nations Sustainable Development Goals (SDGs) — not just SDG 7, which specifically calls for “affordable, reliable, sustainable, and modern energy for all” by 2030. There are 17 SDGs containing 169 targets, of which 113 (65 percent) require actions to be taken concerning energy systems.

      Now, can we equate education with action? The answer is yes, but only if it is done correctly. From the behavioral change literature, we know that knowledge alone is not enough to change behavior. So, one important part of our education program is practice and experience through research, internships, stakeholder engagement, and other avenues. At a minimum, education must give the learner the knowledge, skills, and courage to be ready to jump into action, but ideally, practice is a part of the offering. We also want our learners to go out into the world and share what they know and do. If done right, education is an energy transition accelerator.

      At MITEI, our learners are not just MIT students. We are creating online offerings based on residential MIT courses to train global professionals, policymakers, and students in research methods and tools to support and accelerate the energy transition. These are free and open to learners worldwide. We have five courses available now, with more to come.

      Our latest program is a collaboration with MIT’s Center for Energy and Environmental Policy Research (CEEPR): Climate Action through Education, or CATE. This is a teach-the-teacher program for high school curriculum and is a part of the MIT Climate Action Plan. The aim is to develop interdisciplinary, solutions-focused climate change curricula for U.S. high school teachers with components in history/social science, English/language arts, math, science, and computer science.

      We are rapidly expanding our programming. In the online space, for our global learners, we are bundling courses for professional development certificates; for our undergraduates, we are redesigning the energy studies minor to reflect what we have learned over the past 12 years; and for our graduate students, we are adding a new program that allows them to garner industry experience related to the energy transition. Meanwhile, CATE is creating a support network for the teachers who adopt the curriculum. We are also working on creating an energy and climate alliance with other universities around the world.

      On the Institute level, I am a member of the Climate Education Working Group, a subgroup of the Climate Nucleus, where we discuss and will soon recommend further climate action the Institute can take. Stay tuned for that.

      Q: You mentioned that you are leading an effort to create a consortium of energy and climate education programs at universities around the world. How does this effort fit into MITEI’s educational mission?

      A: Yes, we are currently calling it the “Energy and Climate Education Alliance.” The background to this is that the problem we are facing — transitioning the entire global energy system from high carbon emissions to low, no, and negative carbon emissions — is global, huge, and urgent. Following the proverbial “many hands make light work,” we believe that the success of this very complex task is accomplished quicker with more participants. There is, of course, more to this as well. The complexity of the problem is such that (1) MIT doesn’t have all the expertise needed to accomplish the educational needs of the climate and energy crisis, (2) there is a definite local and regional component to capacity building, and (3) collaborations with universities around the world will make our mission-driven work more efficient. Finally, these collaborations will be advantageous for our students as they will be able to learn from real-world case studies that are not U.S.-based and maybe even visit other universities abroad, do internships, and engage in collaborative research projects. Also, students from those universities will be able to come here and experience MIT’s unique intellectual environment.

      Right now, we are very much in the beginning stages of creating the alliance. We have signed a collaboration agreement with the Technical University of Berlin, Germany, and are engaged in talks with other European and Southeast Asian universities. Some of the collaborations we are envisioning relate to course development, student exchange, collaborative research, and course promotion. We are very excited about this collaboration. It fits well into MIT’s ambition to take climate action outside of the university, while still staying within our educational mission.

      Q: It is clear to me from this conversation that MITEI’s education program is undertaking a number of initiatives to prepare MIT students and interested learners outside of the Institute to take an active role in climate action. But, the reality is that despite our rapidly changing climate and the immediate need to decarbonize our global economy, climate denialism and a lack of climate and energy understanding persist in the greater global population. What do you think must be done, and what can MITEI do, to increase climate and energy literacy broadly?

      A: I think the basic problem is not necessarily a lack of understanding but an abundance of competing issues that people are dealing with every day. Poverty, personal health, unemployment, inflation, pandemics, housing, wars — all are very immediate problems people have. And climate change is perceived to be in the future.

      The United States is a very bottom-up country, where corporations offer what people buy, and politicians advocate for what voters want and what money buys. Of course, this is overly simplified, but as long as we don’t come up with mechanisms to achieve a monumental shift in consumer and voter behavior, we are up against these immediate pressures. However, we are seeing some movement in this area due to rising gas and heating oil prices and the many natural disasters we are encountering now. People are starting to understand that climate change will hit their pocketbook, whether or not we have a carbon tax. The recent Florida hurricane damage, wildfires in the west, extreme summer temperatures, frequent droughts, increasing numbers of poisonous and disease-carrying insects — they all illustrate the relationship between climate change, health, and financial damage. Fewer and fewer people will be able to deny the existence of climate change because they will either be directly affected or know someone who is.

      The question is one of speed and scale. The more we can help to make the connections even more visible and understood, the faster we get to the general acceptance that this is real. Research projects like CEEPR’s Roosevelt Project, which develops action plans to help communities deal with industrial upheaval in the context of the energy transition, are contributing to this effect, as are studies related to climate change and national security. This is a fast-moving world, and our research findings need to be translated as we speak. A real problem in education is that we have the tendency to teach the tried and true. Our education programs have to become much nimbler, which means curricula have to be updated frequently, and that is expensive. And of course, the speed and magnitude of our efforts are dependent on the funding we can attract, and fundraising for education is more difficult than fundraising for research.

      However, let me pivot: You alluded to the fact that this is a global problem. The immediate pressures of poverty and hunger are a matter of survival in many parts of the world, and when it comes to surviving another day, who cares if climate change will render your fields unproductive in 20 years? Or if the weather turns your homeland into a lake, will you think about lobbying your government to reduce carbon emissions, or will you ask for help to rebuild your existence? On the flip side, politicians and government authorities in those areas have to deal with extremely complex situations, balancing local needs with global demands. We should learn from them. What we need is to listen. What do these areas of the world need most, and how can climate action be included in the calculations? The Global Commission to End Energy Poverty, a collaboration between MITEI and the Rockefeller Foundation to bring electricity to the billion people across the globe who currently live without it, is a good example of what we are already doing. Both our online education program and the Energy and Climate Education Alliance aim to go in this direction.

      The struggle and challenge to solve climate change can be pretty depressing, and there are many days when I feel despondent about the speed and progress we are making in saving the future of humanity. But, the prospect of contributing to such a large mission, even if the education team can only nudge us a tiny bit away from the business-as-usual scenario, is exciting. In particular, working on an issue like this at MIT is amazing. So much is happening here, and there don’t seem to be intellectual limits; in fact, thinking big is encouraged. It is very refreshing when one has encountered the old “you can’t do this” too often in the past. I want our students to take this attitude with them and go out there and think big. More