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      Smart irrigation technology covers “more crop per drop”

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      In agriculture today, robots and drones can monitor fields, temperature and moisture sensors can be automated to meet crop needs, and a host of other systems and devices make farms more efficient, resource-conscious, and profitable. The use of precision agriculture, as these technologies are collectively known, offers significant advantages. However, because the technology can be costly, it remains out of reach for the majority of the world’s farmers.

      “Many of the poor around the world are small, subsistence farmers,” says Susan Amrose, research scientist with the Global Engineering and Research (GEAR) Lab at MIT. “With intensification of food production needs, worsening soil, water scarcity, and smaller plots, these farmers can’t continue with their current practices.”

      By some estimates, the global demand for fresh water will outstrip supply by as much as 40 percent by the end of the decade. Nearly 80 percent of the world’s 570 million farms are classed as smallholder farms, with many located in under-resourced and water-stressed regions. With rapid population growth and climate change driving up demand for food, and with more strain on natural resources, increasing the adoption of sustainable agricultural practices among smallholder farmers is vital. 

      Amrose, who helps lead desalination, drip irrigation, water, and sanitation projects for GEAR Lab, says these small farmers need to move to more mechanized practices. “We’re trying to make it much, much more affordable for farmers to utilize solar-powered irrigation, and to have access to tools that, right now, they’re priced out of,” she says. “More crop per drop, more crop per area, that’s our goal.”

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      No Drop to Spare: MIT creates affordable, user-driven smart irrigation technology | MIT Mechanical Engineering

      Drip irrigation systems release water and nutrients in controlled volumes directly to the root zone of the crop through a network of pipes and emitters. These systems can reduce water consumption by 20 to 60 percent when compared to conventional flood irrigation methods.

      “Agriculture uses 70 percent of the fresh water that’s in use across the globe. Large-scale adoption and correct management of drip irrigation could help to reduce consumption of fresh water, which is especially critical for regions experiencing water shortages or groundwater depletion,” says Carolyn Sheline SM ’19, a PhD student and member of the GEAR Lab’s Drip Irrigation team. “A lot of irrigation technology is developed for larger farms that can put more money into it — but inexpensive doesn’t need to mean ‘not technologically advanced.’”

      GEAR Lab has created several drip irrigation technology solutions to date, including a low-pressure drip emitter that has been shown to reduce pumping energy by more than 50 percent when compared to existing emitters; a systems-level optimization model that analyzes factors like local weather conditions and crop layouts, to cut overall system operation costs by up to 30 percent; and a low-cost precision irrigation controller that optimizes system energy and water use, enabling farmers to operate the system on an ideal schedule given their specific resources, needs, and preferences. The controller has recently been shown to reduce water consumption by over 40 percent when compared to traditional practices.

      To build these new, affordable technologies, the team tapped into a critical knowledge source — the farmers themselves.

      “We didn’t just create technology in isolation — we also advanced our understanding of how people would interact with and value this technology, and we did that before the technology had come to fruition,” says Amos Winter SM ’05, PhD ’11, associate professor of mechanical engineering and MIT GEAR Lab principal investigator. “Getting affirmations that farmers would value what the technology would do before we finished it was incredibly important.”

      The team held “Farmer Field Days” and conducted interviews with more than 200 farmers, suppliers, and industry professionals in Kenya, Morocco, and Jordan, the regions selected to host field pilot test sites. These specific sites were selected for a variety of reasons, including solar availability and water scarcity, and because all were great candidate markets for eventual adoption of the technology.

      “People usually understand their own problems really well, and they’re very good at coming up with solutions to them,” says Fiona Grant ’17, SM ’19, also a PhD candidate with the GEAR Lab Drip Irrigation team. “As designers, our role really is to provide a different set of expertise and another avenue for them to get the tools or the resources that they need.”

      The controller, for example, takes in weather information, like relative humidity, temperature, wind speed values, and precipitation. Then, using artificial intelligence, it calculates and predicts the area’s solar exposure for the day and the exact irrigation needs for the farmer, and sends information to their smartphone. How much, or how little, automation an individual site uses remains up to the farmer. In its first season of operation on a Moroccan test site, GEAR Lab technology reduced water consumption by 44 percent and energy by 38 percent when compared to a neighboring farm using traditional drip irrigation practice.

      “The way you’re going to operate a system is going to have a big impact on the way you design it,” says Grant. “We gained a sense of what farmers would be willing to change, or not, regarding interactions with the system. We found that what we might change, and what would be acceptable to change, were not necessarily the same thing.”

      GEAR Lab alumna Georgia Van de Zande ’15, SM ’18, PhD ’23, concurs. “It’s about more than just delivering a lower-cost system, it’s also about creating something they’re going to want to use and want to trust.”

      In Jordan, researchers at a full-scale test farm are operating a solar-powered drip system with a prototype of the controller and are receiving smartphone commands on when to open and close the manual valves. In Morocco, the controller is operating at a research farm with a fully automated hydraulic system; researchers are monitoring the irrigation and conducting additional agronomic tasks. In Kenya, where precision agriculture and smart irrigation haven’t yet seen very much adoption, a simpler version of the controller serves to provide educational and training information in addition to offering scheduling and control capabilities.

      Knowledge is power for the farmers, and for designers and engineers, too. If an engineer can know a user’s requirements, Winter says, they’re much more likely to create a successful solution.

      “The most powerful tool a designer can have is perspective. I have one perspective — the math and science and tech innovation side — but I don’t know a thing about what it’s like to live every day as a farmer in Jordan or Morocco,” says Winter. “I don’t know what clogs the filters, or who shuts off the water. If you can see the world through the eyes of stakeholders, you’re going to spot requirements and constraints that you wouldn’t have picked up on otherwise.”

      Winter says the technology his team is building is exciting for a lot of reasons.

      “To be in a situation where the world is saying, ‘we need to deal with water stress, we need to deal with climate adaptation, and we need to particularly do this in resource-constrained countries,’ and to be in a position where we can do something about it and produce something of tremendous value and efficacy is incredible,” says Winter. “Solving the right problem at the right time, on a massive scale, is thrilling.” More

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      Bringing the environment to the forefront of engineering

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      In a recent podcast interview with MIT President Sally Kornbluth, Associate Professor Desirée Plata described her childhood pastime of roaming the backyards and businesses of her grandmother’s hometown of Gray, Maine. Through her wanderings, Plata noticed a disturbing pattern.

      “I was 7 or 8 when I caught wind of all the illness,” Plata recalls. “It seemed like in every other house there was somebody who had a neurological disorder or a cancer of some sort.”

      While driving home one night with her mom, Plata made her first environmental hypothesis from the back seat. “I told my mom, ‘I think there’s something in the water or air where these people live.’”

      The conversation happened in the late 1980s. Plata was a little older when she learned her intuition was correct: The Environmental Protection Agency determined that a waste disposal facility had contaminated drinking water in the area while processing more than 1 million gallons of waste between 1965 and 1978.

      “There was a New York Times article on it, but it was sort of buried in a Sunday paper and a lot of folks up in Maine didn’t hear about it,” Plata says.

      What most struck Plata was that Gray was a tight-knit community, and the people who owned the waste disposal facility were friends with everybody. Eventually, some of the owner’s children even got sick.

      “People don’t poison their neighbors on purpose,” Plata says. “A lot of industrial contamination happens either by accident or because the engineers don’t know better. As an environmental scientist and engineer, it’s part of my job to help industrial engineers of any variety design their systems and processes such that they are thinking about what’s going into the environment from the start.”

      The insight led Plata to MIT, first as a PhD student, then as a visiting professor, and today as the newly tenured associate professor of civil and environmental engineering.

      These days Plata’s work is a bit more complex than her early backseat musings. In fact, her efforts extend far beyond research and include mentoring students, entrepreneurship, coalition-building, and coordination across industry, academia, and government. But the work can still be traced back to the childhood insight that environmental optimization needs to be a more tangible and important part of everyone’s thinking.

      “People think sustainability is this nebulous thing they can’t get their hands around,” Plata says. “But there are actually a set of rigorous principles you can use, and each one of those has a metric or a thing you can measure to go with it. MIT is such an innovative place. If we can incorporate environmental objectives into design at a place like MIT, the hope is the world can engage as well.”

      Taking the plunge

      Plata was first introduced to environmental research in high school, but it wasn’t until she attended Union College and got to work in a research lab that she knew it was what she’d do for the rest of her life.

      After graduating from Union, Plata decided to skip a master’s degree and “take the plunge” into the MIT-Woods Hole Oceanographic Institution (WHOI) joint doctoral program.

      “Talk about drinking from a firehose,” Plata says. “Everybody you bump into knows something that can help you solve the very hard problem you’re working on.”

      Plata began the program studying oil spills, and a paper she co-authored helped spur a law that changed the way oil is transported off the coast of Massachusetts. But developments in her personal life made her want to prevent environmental disasters before they happen.

      In her last year at Union, Plata’s aunt was diagnosed with breast cancer — a disease that’s been linked to one of the chemicals dumped in Gray, Maine. While Plata was at MIT, her aunt was receiving treatment at Massachusetts General Hospital down the road, so Plata would work at the lab at night, stay with her aunt during treatments all day, and go home with her on the weekends.

      “As I’m sampling oil, I’m recognizing that nothing I’m doing is going to help women like her escape the illness,” Plata recalls.

      In her third year of the MIT-WHOI program, Plata shifted her research to explore how industrial emissions generated during the creation of materials known as carbon nanotubes could inform how those valuable new materials were forming. The work led to a dramatically more sustainable way to make the materials, which are needed for important environmental applications themselves.

      After earning her PhD, Plata served as a visiting professor at MIT for two years before working in faculty positions at Duke University and Yale University, where she studied green chemistry and green optimization. She returned to MIT as an assistant professor in civil and environmental engineering in 2018.

      Working beyond academia

      While at Yale, Plata started a company, Nth Cycle, which uses electric currents to extract critical minerals like cobalt and nickel from lithium-ion batteries and other electronic waste. The company began commercial production last year.

      Plata also works extensively with government and industry, serving on a Massachusetts committee that published a roadmap to decarbonizing the state by 2050 and advising companies both formally and informally. (She estimates she gets a call every two weeks from a new company working on a sustainability problem.)

      “It’s undeniable that industry has an enormous impact on the environment,” Plata says. “Some like to think the government can wave a magic wand and make some regulation and we won’t be in this situation, but that’s not the case. There are technical challenges that need to be solved and businesses play an incredibly important role as agents of change.”

      Plata’s research at MIT, meanwhile, is focused increasingly on methane. Last year she helped create the MIT Methane Network, which she directs.

      Plata’s research has explored ways to convert methane into less harmful carbon dioxide and other fuels in places like dairy farms and coal plants. This past summer she took a team of students to dairy barns to conduct field tests.

      “If you could take methane from coal mining out of the air globally, it’s equivalent to taking all of the combustion engine vehicles off the road, even accounting for the small generation of CO2 that we have [as the result of our process],” Plata says. “If you can fix the problem at dairy farms, it’s like all the combustion engine vehicle emissions times three. It’s a hugely impactful number.”

      Taking action

      When Plata was in fourth grade, her teacher had students pick up trash around a nearby bay. She’s since done the exercise with other fourth graders.

      “You ask them what they think they’ll find, and they say, ‘Nothing. I didn’t see any trash on the way to school today,’ but when you ask them to look, everybody fills their bag by the end of the trip, and you start to realize how much fugitive emissions of waste exists, and then you start to start thinking about all of the chemical contamination that you can’t see,” Plata says.

      One of Plata’s chief research goals can be summed up with that exercise: getting people to appreciate the importance of environmental criteria and motivating them to take action.

      “Today, I see people looking for these silver bullet solutions to solve environmental problems,” Plata says. “That’s not how we got into this mess, and it’s not how we’re going to get out of it. The problem is really distributed, so what we really need is the sum of a lot of small actions to change the system.” More

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      Solve Challenge Finals 2023: Action in service to the world

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      In a celebratory convergence of innovation and global impact, the 2023 Solve Challenge Finals, hosted by MIT Solve, unfolded to welcome the 2023 Solver Class. These teams, resolute in their commitment to addressing Solve’s 2023 Global Challenges and rooted in advancing the United Nation’s Sustainable Development Goals, serve as the perfect examples of the impact technology can have when addressed toward social good.

      To set the tone of the day, Cynthia Barnhart, MIT provost, called for bold action in service to the world, and Hala Hanna, MIT Solve executive director, urged the new Solver teams and attendees to harness the power of technology for benevolent purposes. “Humans have lived with the dichotomy of technology since the dawn of time. Today we find ourselves at another juncture with generative AI, and we have choices to make. So, what if we choose that every line of code heals, and every algorithm uplifts, and every device includes?” she said during the opening plenary, Tech-Powered and Locally-Led: Solutions for Global Progress.

      Global, intergenerational, and contextual change for good

      This year’s Solve Challenge Finals served as a global platform for reflection. Majid Al Suwaidi, director-general of COP28, shared the experiences that have shaped his approach to climate negotiation. He recounted a poignant visit to a United Nations High Commissioner for Refugees-facilitated refugee camp housing 300,000 climate migrants. There he met a mother and her nine children. In a sprawling camp housing 300,000 people, scarcity was evident, with just one toilet for every 100 residents. “There are people who contribute nothing to the problem but are impacted the most,” Majid emphasized, stressing the need to prioritize those most affected by climate change when crafting solutions.

      Moderator Lysa John, secretary-general of CIVICUS, steered the conversation toward Africa’s growing influence during her fireside chat with David Sengeh SM ’12, PhD ’16, chief minister of Sierra Leone, and Toyin Saraki, president of the Wellbeing Foundation. The African Union was recently named a permanent member of the G20. Saraki passionately advocated for Africa to assert itself: “I would like this to be more than just the North recognizing the South. This is the time now for us to bring African intelligence to the forefront. We have to bring our own people, our own data, our own resources.” She also called for an intergenerational shift, recognizing the readiness of the younger generation to lead.

      Sengeh, who is 36 himself, emphasized that young people are natural leaders, especially in a nation where 70 percent of the population is youth. He challenged the status quo, urging society to entrust leadership roles to the younger generation.

      Saraki praised Solve as a vital incubation hub, satisfying the need for contextual innovation while contributing to global progress. She views Solve as a marketplace of solutions to systemic weaknesses, drawing upon the diverse approaches of innovators both young and old. “That is the generation of intelligence that needs to grow, not just in Africa. Solve is amazing for that, it’s an investor’s delight,” she said.

      Henrietta Fore, managing partner, chair, and CEO of Radiate Capital, Holsman International, shared an example of entrepreneurship catalyzed by country-level leaders, referencing India’s Swachh Bharat program aimed at promoting cleaner environments. The government initiative led to a burst of entrepreneurial activity, with women opening various shops for toilets and bathroom commodities. Fore highlighted the potential for companies to collaborate with countries on such programs, creating momentum and innovation.

      Trust as capital

      Trust was a prevalent theme throughout the event, from personal to business levels.

      Johanna Mair, academic editor of the Stanford Social Innovation Review, asked Sarah Chandler, vice president of environment and supply chain innovation at Apple, for advice she may have for corporations and startups thinking about their holistic climate goals. Chandler emphasized the importance of trust that businesses must have that environmental goals can align with business goals, highlighting Apple’s 45 percent reduction in carbon footprint since 2015 and 65 percent revenue increase.

      Neela Montgomery, board partner at Greycroft, discussed her initial skepticism around collaborating with large entities, seeking advice from Ilan Goldfajn, president of the Inter-American Development Bank. “Don’t be shy to come … take advantage of a multilateral bank … think about multilateral organizations as the ones to make connections. We can be your support commercially and financially, we could be your clients, and we could be your promoters,” said Goldfajn.

      During a fireside chat among Janti Soeripto, president and CEO of Save the Children USA, and Imran Ahmed, founder and CEO of Center for Countering Digital, Soeripto shared her belief that the most effective change comes from the country and local community level. She pointed to a contextual example of this where Save the Children invested in scaling a small Austrian ed-tech startup — Library for All. The partnership positively impacted literacy for other communities around the world by making literature more accessible.

      There still exist major hurdles for small enterprises to enter the global market. Imran points to sclerosis and hesitancy to trust small-scale innovation as a roadblock to meaningful change. 

      The final discussion of the closing plenary, Funding the Future: Scaling up Inclusive Impact, featured Fore; Mohammed Nanabhay, managing partner of Mozilla Ventures; and Alfred Ironside, vice president of communications at MIT, who asked the two panelists, “What do you [look for] when thinking about putting money into leaders and organizations who are on this mission to create impact and achieve scale?”

      Beyond aligning principles with organizations, Nanabhay said that he looks for tenacity and, most importantly, trust in oneself. “Entrepreneurship is a long journey, it’s a hard journey — whether you’re on the for-profit side or the nonprofit side. It’s easy to say people should have grit, everyone says this. When the time comes and you’re struggling … you need to have the fundamental belief that what you’re working on is meaningful and that it’s going to make the world better.” More

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      in Environment

      A reciprocal relationship with the land in Hawaiʻi

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      Aja Grande grew up on the Hawaiian island of Oʻahu, between the Kona and ʻEwa districts, nurtured by her community and the natural environment. Her family has lived in Hawaiʻi for generations; while she is not “Kanaka ʻŌiwi,” of native Hawaiian descent, she is proud to trace her family’s history to the time of the Hawaiian Kingdom in the 19th century. Grande is now a PhD candidate in MIT’s HASTS (History, Anthropology, Science, Technology and Society) program, and part of her dissertation tracks how Hawaiian culture and people’s relationship with the land has evolved throughout time.

      “The fondest memories I have are camping on the north shore every summer with my friends,” says Grande. “I loved being in ‘ke kai’ (the sea) and ‘ma uka,’ (inland, in the mountains) with my friends when I was younger. It was just pure fun exploring ‘ʻāina’ like that.” “‘Āina” in the Hawaiian language is often defined as “land,” but is understood to the people of Hawaiʻi as “that which feeds.”

      “Now that I’m older,” Grande adds, “I’m connecting the dots and realizing how much knowledge about the complex systems of ‘ahupuaʻa’ [traditional Hawaiian divisions of land that extend from the mountains to the sea], I actually gained through these experiences.”

      Grande recently completed a year of fieldwork in Hawaiʻi where she volunteered with land-based, or ‘āina-based organizations. In the movement to restore ‘āina to “momona,” or  “fertile and abundant lands,” the land and the people who serve as its stewards are of equal importance.

      “I’m looking at how people who are not Kanaka ‘Ōiwi, or native Hawaiian, by descent can participate in this kind of restoration, and what it means for both Kanaka ‘Ōiwi and non-Kanaka ‘Ōiwi to participate in it,” says Grande, who herself descends from immigrants of other island nations. “Some of my ancestors were born and raised in Hawaiʻi before the U.S. subjected Hawaiʻi as a state and territory, meaning that some of them were Hawaiian Kingdom subjects. While, I am not Kanaka ʻŌiwi by lineage, some of my ‘ohana nui (extended family), from these same ancestors, are Kanaka ʻŌiwi. I’m writing about how being Hawaiian, from a Hawaiian sovereignty standpoint, is not just about race and ethnicity. When Hawaiʻi was a sovereign nation, Hawaiian citizenship was never afforded on the basis of race alone. It was also based on your lifelong commitment to ‘āina and the people of Hawaiʻi.”

      The project is personal to Grande, who describes both the content and the process of writing it as part of her healing journey. She hopes to lay the groundwork for others who are “hoaʻāina,” or “those who actively care for ʻāina,” in Hawaiʻi, but not Kanaka ʻŌiwi to better articulate their identities and foster a deeper connection with the ʻāina and the “kaiāulu,” or “community,” they love and actively care for.

      Returning home

      Grande has spent her academic career on the East Coast, first at Brown University, where she received a degree in science, technology, and society, and now at MIT in the HASTS program. She swam competitively through her second year of college, and had earlier represented Hawaiʻi at the 2012 Oceania Games in New Caledonia. Once she stopped swimming, Grande first used her newfound time to travel the world. Tired of this transient lifestyle, she realized she was more interested in exploring her connection to land in a more rooted way.

      “Moving around, especially as a college student, it’s very hard to grow things,” says Grande. “People are a lot like plants. You really just need to let plants do their thing in place. We do really well and we thrive when we can be connected to place.”

      Grande started by founding the Ethnobotany Society at Brown to explore the relationship people have to plants. With the group she organized nature walks, collaborated with local farms, and connected it to the history she was learning in class.

      Still, the East Coast never quite felt like home to Grande. When she started planning for the fieldwork portion of her program, she envisioned spending half the year in New England and half in Hawaiʻi. But she soon realized how important it was for both her research and herself to dedicate everything to Hawai’i.

      “When I came back, it just felt so right to be back home,” says Grande. “The feeling in your naʻau — your ‘gut’ — of knowing that you have to contribute to Hawaiʻi is very powerful, and I think a lot of people here understand what that means. It’s kind of like a calling.”

      Hoaʻāina, community, family

      Once Grande made the decision to return home for her field work, she says everything fell into place.

      “I knew that I wanted to do something close to my heart. It’s a huge privilege because I was able to come home and learn more about myself and my family and how we are connected to Hawaiʻi,” she says.

      During her year of fieldwork, Grande learned how hoaʻāina cultivate spaces where the community can can work alongside one another to plant traditional food and medicinal crops, control invasive species, and more. She wasn’t just an observer, either. As much as Grande learned from an academic perspective, her personal growth has been intertwined with the entire process.

      “The most interesting part was that all the hoaʻāina I volunteered with helped me to understand my place back home,” says Grande. “They were my informants but also — this usually happens with anthropologists — people become your friends. The hoaʻāina I volunteered with treated me like family. They also got to know some of my family members, who joined me to volunteer at different sites. It’s sometimes hard to drop a hard line between what fieldwork is and what your personal life is because when you’re in the field, there’s so many events that are connected to your work. It was so fun and meaningful to write about the ʻāina and people I consider my community and family.”

      The movement doesn’t start or end with Grande’s dissertation. Pursuing this project has given her the language to articulate her own relationship with ‘āina, and she hopes it will empower others to reexamine how they exist in relation to land.

      After completing her program, Grande intends to stay in Hawaiʻi and continue philanthropy work while contributing to the movement of ʻāina momona.

      “We want the land to live and to keep a relationship with the land. That’s the emotional part. I have a ‘kuleana,’ (duty and responsibility) to everything that I learned while growing up, including the ʻāina and ‘kaiāulu,’ (community) who raised me. The more you learn, there’s so much that you want to protect about the culture and this ‘āina.” More

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      Improving US air quality, equitably

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      Decarbonization of national economies will be key to achieving global net-zero emissions by 2050, a major stepping stone to the Paris Agreement’s long-term goal of keeping global warming well below 2 degrees Celsius (and ideally 1.5 C), and thereby averting the worst consequences of climate change. Toward that end, the United States has pledged to reduce its greenhouse gas emissions by 50-52 percent from 2005 levels by 2030, backed by its implementation of the 2022 Inflation Reduction Act. This strategy is consistent with a 50-percent reduction in carbon dioxide (CO2) by the end of the decade.

      If U.S. federal carbon policy is successful, the nation’s overall air quality will also improve. Cutting CO2 emissions reduces atmospheric concentrations of air pollutants that lead to the formation of fine particulate matter (PM2.5), which causes more than 200,000 premature deaths in the United States each year. But an average nationwide improvement in air quality will not be felt equally; air pollution exposure disproportionately harms people of color and lower-income populations.

      How effective are current federal decarbonization policies in reducing U.S. racial and economic disparities in PM2.5 exposure, and what changes will be needed to improve their performance? To answer that question, researchers at MIT and Stanford University recently evaluated a range of policies which, like current U.S. federal carbon policies, reduce economy-wide CO2 emissions by 40-60 percent from 2005 levels by 2030. Their findings appear in an open-access article in the journal Nature Communications.

      First, they show that a carbon-pricing policy, while effective in reducing PM2.5 exposure for all racial/ethnic groups, does not significantly mitigate relative disparities in exposure. On average, the white population undergoes far less exposure than Black, Hispanic, and Asian populations. This policy does little to reduce exposure disparities because the CO2 emissions reductions that it achieves primarily occur in the coal-fired electricity sector. Other sectors, such as industry and heavy-duty diesel transportation, contribute far more PM2.5-related emissions.

      The researchers then examine thousands of different reduction options through an optimization approach to identify whether any possible combination of carbon dioxide reductions in the range of 40-60 percent can mitigate disparities. They find that that no policy scenario aligned with current U.S. carbon dioxide emissions targets is likely to significantly reduce current PM2.5 exposure disparities.

      “Policies that address only about 50 percent of CO2 emissions leave many polluting sources in place, and those that prioritize reductions for minorities tend to benefit the entire population,” says Noelle Selin, supervising author of the study and a professor at MIT’s Institute for Data, Systems and Society and Department of Earth, Atmospheric and Planetary Sciences. “This means that a large range of policies that reduce CO2 can improve air quality overall, but can’t address long-standing inequities in air pollution exposure.”

      So if climate policy alone cannot adequately achieve equitable air quality results, what viable options remain? The researchers suggest that more ambitious carbon policies could narrow racial and economic PM2.5 exposure disparities in the long term, but not within the next decade. To make a near-term difference, they recommend interventions designed to reduce PM2.5 emissions resulting from non-CO2 sources, ideally at the economic sector or community level.

      “Achieving improved PM2.5 exposure for populations that are disproportionately exposed across the United States will require thinking that goes beyond current CO2 policy strategies, most likely involving large-scale structural changes,” says Selin. “This could involve changes in local and regional transportation and housing planning, together with accelerated efforts towards decarbonization.” More

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      Ancient Amazonians intentionally created fertile “dark earth”

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      The Amazon river basin is known for its immense and lush tropical forests, so one might assume that the Amazon’s land is equally rich. In fact, the soils underlying the forested vegetation, particularly in the hilly uplands, are surprisingly infertile. Much of the Amazon’s soil is acidic and low in nutrients, making it notoriously difficult to farm.

      But over the years, archaeologists have dug up mysteriously black and fertile patches of ancient soils in hundreds of sites across the Amazon. This “dark earth” has been found in and around human settlements dating back hundreds to thousands of years. And it has been a matter of some debate as to whether the super-rich soil was purposefully created or a coincidental byproduct of these ancient cultures.

      Now, a study led by researchers at MIT, the University of Florida, and in Brazil aims to settle the debate over dark earth’s origins. The team has pieced together results from soil analyses, ethnographic observations, and interviews with modern Indigenous communities, to show that dark earth was intentionally produced by ancient Amazonians as a way to improve the soil and sustain large and complex societies.

      “If you want to have large settlements, you need a nutritional base. But the soil in the Amazon is extensively leached of nutrients, and naturally poor for growing most crops,” says Taylor Perron, the Cecil and Ida Green Professor of Earth, Atmospheric and Planetary Sciences at MIT. “We argue here that people played a role in creating dark earth, and intentionally modified the ancient environment to make it a better place for human populations.”

      And as it turns out, dark earth contains huge amounts of stored carbon. As generations worked the soil, for instance by enriching it with scraps of food, charcoal, and waste, the earth accumulated the carbon-rich detritus and kept it locked up for hundreds to thousands of years. By purposely producing dark earth, then, early Amazonians may have also unintentionally created a powerful, carbon-sequestering soil.

      “The ancient Amazonians put a lot of carbon in the soil, and a lot of that is still there today,” says co-author Samuel Goldberg, who performed the data analysis as a graduate student at MIT and is now an assistant professor at the University of Miami. “That’s exactly what we want for climate change mitigation efforts. Maybe we could adapt some of their indigenous strategies on a larger scale, to lock up carbon in soil, in ways that we now know would stay there for a long time.”

      The team’s study appears today in Science Advances. Other authors include former MIT postdoc and lead author Morgan Schmidt, anthropologist Michael Heckenberger of the University of Florida, and collaborators from multiple institutions across Brazil.

      Modern intent

      In their current study, the team synthesized observations and data that Schmidt, Heckenberger, and others had previously gathered, while working with Indigenous communities in the Amazon since the early 2000s,  with new data collected in 2018-19. The scientists focused their fieldwork in the Kuikuro Indigenous Territory in the Upper Xingu River basin in the southeastern Amazon. This region is home to modern Kuikuro villages as well as archaeological sites where the ancestors of the Kuikuro are thought to have lived. Over multiple visits to the region, Schmidt, then a graduate student at the University of Florida, was struck by the darker soil around some archaeological sites.

      “When I saw this dark earth and how fertile it was, and started digging into what was known about it, I found it was a mysterious thing — no one really knew where it came from,” he says.

      Schmidt and his colleagues began making observations of the modern Kuikuro’s practices of managing the soil. These practices include generating “middens” — piles of waste and food scraps, similar to compost heaps, that are maintained in certain locations around the center of a village. After some time, these waste piles decompose and mix with the soil to form a dark and fertile earth, that residents then use to plant crops. The researchers also observed that Kuikuro farmers spread organic waste and ash on farther fields, which also generates dark earth, where they can then grow more crops.

      “We saw activities they did to modify the soil and increase the elements, like spreading ash on the ground, or spreading charcoal around the base of the tree, which were obviously intentional actions,” Schmidt says.

      In addition to these observations, they also conducted interviews with villagers to document the Kuikuro’s beliefs and practices relating to dark earth. In some of these interviews, villagers referred to dark earth as “eegepe,” and described their daily practices in creating and cultivating the rich soil to improve its agricultural potential.

      Based on these observations and interviews with the Kuikuro, it was clear that Indigenous communities today intentionally produce dark earth, through their practices to improve the soil. But could the dark earth found in nearby archaeological sites have been made through similar intentional practices?

      A bridge in soil

      In search of a connection, Schmidt joined Perron’s group as a postdoc at MIT. Together, he, Perron, and Goldberg carried out a meticulous analysis of soils in both archaeological and modern sites in the Upper Xingu region. They discovered similarities in dark earth’s spatial structure: Deposits of dark earth were found in a radial pattern, concentrating mostly in the center of both modern and ancient settlements, and stretching, like spokes of a wheel, out to the edges. Modern and ancient dark earth was also similar in composition, and was enriched in the same elements, such as carbon, phosphorus, and other nutrients.

      “These are all the elements that are in humans, animals, and plants, and they’re the ones that reduce the aluminum toxicity in soil, which is a notorious problem in the Amazon,” Schmidt says. “All these elements make the soil better for plant growth.”

      “The key bridge between the modern and ancient times is the soil,” Goldberg adds. “Because we see this correspondence between the two time periods, we can infer that these practices that we can observe and ask people about today, were also happening in the past.”

      In other words, the team was able to show for the first time that ancient Amazonians intentionally worked the soil, likely through practices similar to today’s, in order to grow enough crops to sustain large communities.

      Going a step further, the team calculated the amount of carbon in ancient dark earth. They combined their measurements of soil samples, with maps of where dark earth has been found through several ancient settlements. Their estimates revealed that each ancient village contains several thousand tons of carbon that has been sequestered in the soil for hundreds of years as a result of Indigenous, human activities.

      As the team concludes in their paper, “modern sustainable agriculture and climate change mitigation efforts, inspired by the persistent fertility of ancient dark earth, can draw on traditional methods practiced to this day by Indigenous Amazonians.”

      This research at MIT was supported, in part, by the Abdul Latif Jameel Water and Food Systems Lab and the Department of the Air Force Artificial Intelligence Accelerator. Field research was supported by grants to the University of Florida from the National Science Foundation, the Wenner-Gren Foundation and the William Talbott Hillman Foundation, and was sponsored in Brazil by the Museu Goeldi and Museu Nacional. More

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      in Environment

      How to tackle the global deforestation crisis

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      Imagine if France, Germany, and Spain were completely blanketed in forests — and then all those trees were quickly chopped down. That’s nearly the amount of deforestation that occurred globally between 2001 and 2020, with profound consequences.

      Deforestation is a major contributor to climate change, producing between 6 and 17 percent of global greenhouse gas emissions, according to a 2009 study. Meanwhile, because trees also absorb carbon dioxide, removing it from the atmosphere, they help keep the Earth cooler. And climate change aside, forests protect biodiversity.

      “Climate change and biodiversity make this a global problem, not a local problem,” says MIT economist Ben Olken. “Deciding to cut down trees or not has huge implications for the world.”

      But deforestation is often financially profitable, so it continues at a rapid rate. Researchers can now measure this trend closely: In the last quarter-century, satellite-based technology has led to a paradigm change in charting deforestation. New deforestation datasets, based on the Landsat satellites, for instance, track forest change since 2000 with resolution at 30 meters, while many other products now offer frequent imaging at close resolution.

      “Part of this revolution in measurement is accuracy, and the other part is coverage,” says Clare Balboni, an assistant professor of economics at the London School of Economics (LSE). “On-site observation is very expensive and logistically challenging, and you’re talking about case studies. These satellite-based data sets just open up opportunities to see deforestation at scale, systematically, across the globe.”

      Balboni and Olken have now helped write a new paper providing a road map for thinking about this crisis. The open-access article, “The Economics of Tropical Deforestation,” appears this month in the Annual Review of Economics. The co-authors are Balboni, a former MIT faculty member; Aaron Berman, a PhD candidate in MIT’s Department of Economics; Robin Burgess, an LSE professor; and Olken, MIT’s Jane Berkowitz Carlton and Dennis William Carlton Professor of Microeconomics. Balboni and Olken have also conducted primary research in this area, along with Burgess.

      So, how can the world tackle deforestation? It starts with understanding the problem.

      Replacing forests with farms

      Several decades ago, some thinkers, including the famous MIT economist Paul Samuelson in the 1970s, built models to study forests as a renewable resource; Samuelson calculated the “maximum sustained yield” at which a forest could be cleared while being regrown. These frameworks were designed to think about tree farms or the U.S. national forest system, where a fraction of trees would be cut each year, and then new trees would be grown over time to take their place.

      But deforestation today, particularly in tropical areas, often looks very different, and forest regeneration is not common.

      Indeed, as Balboni and Olken emphasize, deforestation is now rampant partly because the profits from chopping down trees come not just from timber, but from replacing forests with agriculture. In Brazil, deforestation has increased along with agricultural prices; in Indonesia, clearing trees accelerated as the global price of palm oil went up, leading companies to replace forests with palm tree orchards.

      All this tree-clearing creates a familiar situation: The globally shared costs of climate change from deforestation are “externalities,” as economists say, imposed on everyone else by the people removing forest land. It is akin to a company that pollutes into a river, affecting the water quality of residents.

      “Economics has changed the way it thinks about this over the last 50 years, and two things are central,” Olken says. “The relevance of global externalities is very important, and the conceptualization of alternate land uses is very important.” This also means traditional forest-management guidance about regrowth is not enough. With the economic dynamics in mind, which policies might work, and why?

      The search for solutions

      As Balboni and Olken note, economists often recommend “Pigouvian” taxes (named after the British economist Arthur Pigou) in these cases, levied against people imposing externalities on others. And yet, it can be hard to identify who is doing the deforesting.

      Instead of taxing people for clearing forests, governments can pay people to keep forests intact. The UN uses Payments for Environmental Services (PES) as part of its REDD+ (Reducing Emissions from Deforestation and forest Degradation) program. However, it is similarly tough to identify the optimal landowners to subsidize, and these payments may not match the quick cash-in of deforestation. A 2017 study in Uganda showed PES reduced deforestation somewhat; a 2022 study in Indonesia found no reduction; another 2022 study, in Brazil, showed again that some forest protection resulted.

      “There’s mixed evidence from many of these [studies],” Balboni says. These policies, she notes, must reach people who would otherwise clear forests, and a key question is, “How can we assess their success compared to what would have happened anyway?”

      Some places have tried cash transfer programs for larger populations. In Indonesia, a 2020 study found such subsidies reduced deforestation near villages by 30 percent. But in Mexico, a similar program meant more people could afford milk and meat, again creating demand for more agriculture and thus leading to more forest-clearing.

      At this point, it might seem that laws simply banning deforestation in key areas would work best — indeed, about 16 percent of the world’s land overall is protected in some way. Yet the dynamics of protection are tricky. Even with protected areas in place, there is still “leakage” of deforestation into other regions. 

      Still more approaches exist, including “nonstate agreements,” such as the Amazon Soy Moratorium in Brazil, in which grain traders pledged not to buy soy from deforested lands, and reduced deforestation without “leakage.”

      Also, intriguingly, a 2008 policy change in the Brazilian Amazon made agricultural credit harder to obtain by requiring recipients to comply with environmental and land registration rules. The result? Deforestation dropped by up to 60 percent over nearly a decade. 

      Politics and pulp

      Overall, Balboni and Olken observe, beyond “externalities,” two major challenges exist. One, it is often unclear who holds property rights in forests. In these circumstances, deforestation seems to increase. Two, deforestation is subject to political battles.

      For instance, as economist Bard Harstad of Stanford University has observed, environmental lobbying is asymmetric. Balboni and Olken write: “The conservationist lobby must pay the government in perpetuity … while the deforestation-oriented lobby need pay only once to deforest in the present.” And political instability leads to more deforestation because “the current administration places lower value on future conservation payments.”

      Even so, national political measures can work. In the Amazon from 2001 to 2005, Brazilian deforestation rates were three to four times higher than on similar land across the border, but that imbalance vanished once the country passed conservation measures in 2006. However, deforestation ramped up again after a 2014 change in government. Looking at particular monitoring approaches, a study of Brazil’s satellite-based Real-Time System for Detection of Deforestation (DETER), launched in 2004, suggests that a 50 percent annual increase in its use in municipalities created a 25 percent reduction in deforestation from 2006 to 2016.

      How precisely politics matters may depend on the context. In a 2021 paper, Balboni and Olken (with three colleagues) found that deforestation actually decreased around elections in Indonesia. Conversely, in Brazil, one study found that deforestation rates were 8 to 10 percent higher where mayors were running for re-election between 2002 and 2012, suggesting incumbents had deforestation industry support.

      “The research there is aiming to understand what the political economy drivers are,” Olken says, “with the idea that if you understand those things, reform in those countries is more likely.”

      Looking ahead, Balboni and Olken also suggest that new research estimating the value of intact forest land intact could influence public debates. And while many scholars have studied deforestation in Brazil and Indonesia, fewer have examined the Democratic Republic of Congo, another deforestation leader, and sub-Saharan Africa.

      Deforestation is an ongoing crisis. But thanks to satellites and many recent studies, experts know vastly more about the problem than they did a decade or two ago, and with an economics toolkit, can evaluate the incentives and dynamics at play.

      “To the extent that there’s ambuiguity across different contexts with different findings, part of the point of our review piece is to draw out common themes — the important considerations in determining which policy levers can [work] in different circumstances,” Balboni says. “That’s a fast-evolving area. We don’t have all the answers, but part of the process is bringing together growing evidence about [everything] that affects how successful those choices can be.” More

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      in Environment

      Desirée Plata appointed co-director of the MIT Climate and Sustainability Consortium

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      Desirée Plata, associate professor of civil and environmental engineering at MIT, has been named co-director of the MIT Climate and Sustainability Consortium (MCSC), effective Sept. 1. Plata will serve on the MCSC’s leadership team alongside Anantha P. Chandrakasan, dean of the MIT School of Engineering, the Vannevar Bush Professor of Electrical Engineering and Computer Science, and MCSC chair; Elsa Olivetti, the Jerry McAfee Professor in Engineering, a professor of materials science and engineering, and associate dean of engineering, and MCSC co-director; and Jeremy Gregory, MCSC executive director.Plata succeeds Jeffrey Grossman, the Morton and Claire Goulder and Family Professor in Environmental Systems, who has served as co-director since the MCSC’s launch in January 2021. Grossman, who played a central role in the ideation and launch of the MCSC, will continue his work with the MCSC as strategic advisor.“Professor Plata is a valued member of the MIT community. She brings a deep understanding of and commitment to climate and sustainability initiatives at MIT, as well as extensive experience working with industry, to her new role within the MCSC,” says Chandrakasan. The MIT Climate and Sustainability Consortium is an academia-industry collaboration working to accelerate implementation of large-scale solutions across sectors of the global economy. It aims to lay the groundwork for one critical aspect of MIT’s continued and intensified commitment to climate: helping large companies usher in, adapt to, and prosper in a decarbonized world.“We are thrilled to bring Professor Plata’s knowledge, vision, and passion to our leadership team,” says Olivetti. “Her experience developing sustainable technologies that have the potential to improve the environment and reduce the impacts of climate change will help move our work forward in meaningful ways. We have valued Professor Plata’s contributions to the consortium and look forward to continuing our work with her.”Plata played a pivotal role in the creation and launch of the MCSC’s Climate and Sustainability Scholars Program and its yearlong course for MIT rising juniors and seniors — an effort that she and Olivetti were recently recognized for with the Class of 1960 Innovation in Education Fellowship. She has also been a member of the MCSC’s Faculty Steering Committee since the consortium’s launch, helping to shape and guide its vision and work.Plata is a dedicated researcher, educator, and mentor. A member of MIT’s faculty since 2018, Plata and her team at the Plata Lab are helping to guide industry to more environmentally sustainable practices and develop new ways to protect the health of the planet — using chemistry to understand the impact that industrial materials and processes have on the environment. By coupling devices that simulate industrial systems with computation, she helps industry develop more environmentally friendly practices.To celebrate her work in the lab, classroom, and community, Plata has received many awards and honors. In 2020, she won MIT’s prestigious Harold E. Edgerton Faculty Achievement Award, recognizing her innovative approach to environmentally sustainable industrial practices, her inspirational teaching and mentoring, and her service to MIT and the community. She is a two-time National Academy of Sciences Kavli Frontiers of Science Fellow, a two-time National Academy of Engineers Frontiers of Engineering Fellow, and a Caltech Young Investigator Sustainability Fellow. She has also won the ACS C. Ellen Gonter Environmental Chemistry Award, an NSF CAREER award, and the 2016 Odebrecht Award for Sustainable Development.Beyond her work in the academic space, Plata is co-founder of two climate- and energy-related startups: Nth Cycle and Moxair, illustrating her commitment to translating academic innovations for real-world implementation — a core value of the MCSC.Plata received her bachelor’s degree from Union College and her PhD from the MIT and Woods Hole Oceanographic Institution (MIT-WHOI) joint program in oceanography/applied ocean science and engineering. After receiving her doctorate, Plata held positions at Mount Holyoke College, Duke University, and Yale University.  More