It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Tuesday, September 15, 2026
Beyond BMI
Waist size can show who is most at risk from air pollution
Ultrafine particulate air pollution floats through the air like a miasma, leaving heart disease, dementia, and asthma in its wake. But ultrafine pollution doesn’t affect everyone equally. Researchers from the University of Connecticut and Tufts University report on July 28 in the American Journal of Preventive Cardiology that a larger waist—indicating more fat around the organs—makes people more vulnerable.
Particulate air pollution can be big enough to be visible to the naked eye, like dust or wildfire soot, or as small as particles of car exhaust just 1/1000 the width of a human hair. The tiniest particles are capable of the most harm, slipping into the bloodstream and traveling throughout the body. This ultrafine particulate matter, defined as particles less than 100 nanometers in diameter, is known to increase the risk of cardiovascular disease, dementia, high blood pressure, and respiratory illnesses.
UConn School of Medicine environmental researcher Doug Brugge has spent years working with a community living within 200 meters of Interstate-93 in Massachusetts, just north of Boston. Their exposure to ultrafine particulate matter is much higher than average in the US. Recently, Brugge and his colleagues began looking at whether members of the community would benefit from using High Efficiency Particulate Air (HEPA) filters in their homes to protect them from particulate pollution. The study included 116 people who used either a HEPA or a sham filter for 30 days, and then switched. To judge whether the HEPA filters had helped, the researchers measured blood levels of tiny proteins known to promote inflammation and cardiovascular disease. Although the initial results of the study showed that on average, the HEPA filter made no difference, HEPA filtration made a very significant difference for a certain group of people.
Brugge was discussing the results of the study with a biostatistician from Tufts University, Misha Eliasziw. Eliasziw pointed out from her analysis of the data that people who benefited from the HEPA filter shared one specific characteristic: they had excessive visceral fat, meaning fat around the abdominal organs, as indicated by the circumference of their waist compared to their height and weight.
Eliasziw considered this to be a more significant measure of harmful fat than body mass index (BMI). BMI just measures how heavy someone is for their height and includes lean muscle mass.
“Recently it was recognized that it is how much excess fat you have around your organs that increases your risk of serious health conditions, such as heart disease, type 2 diabetes and certain cancers,” Eliasziw says. Excessive visceral fat in the abdomen triggers the release of cytokines such as IL-1 beta, which tend to encourage inflammation. IL-1 beta is the root of a cascade of reactions in the body that lead to cardiovascular disease, dementia, and other diseases of the circulatory and metabolic systems.
“In the initial analysis, there was no association between HEPA filtration and cytokines. But in people who had excessive visceral fat, there was a strong IL-1 beta connection,” Brugge says. People who are lean and healthy are not likely to get much benefit from HEPA filters. But individuals with excessive visceral fat probably will.
Brugge, Eliasziw, and their colleagues also looked at blood pressure and cognitive performance and found a similar pattern; not everyone benefited, but those who had elevated blood pressure or were older did.
Because commercial HEPA filters can be quite expensive, it’s useful for people to know whether they would likely benefit before spending money to buy and run one. Brugge and Eliasziw are now beginning a clinical trial in Hartford and Boston testing inexpensive homemade air filters made of 4 air filters and a box fan, which have been used successfully in other situations.
This study was funded by the National Institute of Environmental Health Sciences and the UConn School of Medicine.
Cocoa farmers in West Africa cannot stop intense downpours from damaging their crops. But they may be able to anticipate the risk and prepare, protecting both their livelihoods and their plants, the source of one of the world’s most beloved foods.
Scientists at Harvard and the University of Ghana say that large-scale weather patterns could make some threats to cocoa harvests predictable months in advance, giving farmers time to act. Cocoa trees live for decades and a successful harvest depends on a long sequence of flowering, pollination, and pod development. Too little or too much rain at the wrong moment can damage the crop for the rest of the season.
“Drought is a real threat to cocoa, and that's well established. What has not been as well articulated is the other extreme of too much rain. Heavy rain arriving while the trees are flowering – or that favors the spread of fungal disease during flowering and early pod development – turns out to matter just as much,” said Anna Lea Albright, who led the research as a postdoctoral fellow at the Harvard University Center for the Environment.
“In Ghana, we found that excess rain during the wet season, together with dry-season drought, explains about two-thirds of the year-to-year swings in the cocoa harvest.”
The resulting price volatility – raw cocoa prices tripled in 2024 – is hitting chocolate lovers, showing up in higher prices, smaller bars, or reformulated products.
Because cocoa is especially vulnerable at certain stages of its growth cycle, adaptation must be precise. Disease control can be timed around periods of heavy rain, especially if forecasts can be provided that give enough time to prepare -- a capacity that the team is currently working to develop.
“We hope the findings will help reduce future crop damage, possibly by encouraging more canopy cover to shield cocoa flowers from large raindrops or by retaining more leaf litter to prevent splashes that transmit infection from soil to cocoa pods,” said senior author Peter Huybers, chair of Harvard's Department of Earth and Planetary Sciences.
Farmers have long worried about drought, and previous studies have warned that rising temperatures could make some cocoa-growing areas less suitable. But this study finds that average rainfall and average temperatures overlook the damage caused by short, intense bursts of rain.
In Ghana, the most damaging rains appear during the April-to-June wet season, when cocoa trees are flowering and young pods are beginning to form. Later, during the November-to-February dry period, too little rain can hurt the crop as pods continue to develop.
Cocoa over time
The researchers began with two decades of newly available district-level data from the Ghana Cocoa Board, a government agency. Production grew over that period as more land came into cultivation, so the researchers removed each district's long-term trend to isolate the year-to-year swings. Then they tested those swings against daily weather records and a range of possible culprits: average rainfall, heavy downpours, dry spells, soil moisture, and temperature extremes. In Ghana, the best predictors were heavy rain during the main wet season and too little rain during the dry season.
Then they asked whether Ghana was an exception. They looked at two other major producers on other continents, Ecuador and Indonesia, and found a similar pattern: Years with heavier wet-season rains tended to be worse for cocoa.
That is why forecasting matters. The team emphasizes that the rains that hurt cocoa are tied to larger climate patterns, such as El Niño or shifts in Atlantic sea-surface temperatures, and therefore some bad years may be predictable before the damage is done – early enough to give farmers a warning. For example, a strong El Niño is currently developing, typically favoring heavy rainfall in coastal Ecuador, and drier weather across West Africa and Indonesia.
Also lurking in the background is the potential for substantial changes in the timing and pattern of rainfall as a consequence of climate change. Current climate models, however, struggle to effectively represent the climatology of rainfall over West Africa, let alone how it will change in coming decades.
The study comes with caveats. Rain is not the only problem Ghanaian cocoa farmers face. Aging trees, gold mining, smuggling, fertilizer costs, pests, and disease can all lead to lower cocoa production. Rainfall data also do not always capture the biggest downpours well, and those are exactly the events that matter most here.
Still, the study clarifies the climate threat. Cocoa’s future is not just about a hotter world. It is also about when the rain falls, how hard it falls, and whether farmers can adapt to those extremes.
Floods, wildfires, conflicts, earthquakes, economic shocks, hurricanes or epidemics; these unexpected and often dramatic events impact people’s lives and jobs, destroy crops, wipe out livestock and stored food, contaminate water, block roads, cut off communities and severely affect their access to markets and food. This picture is certainly a very distressing one—one that is expected to get much worse in the near future due to climate change and an increasingly polarized world. Yet, science says: No, these natural and human-made shocks do not have to lead to more hunger by default.
A new study, published in the prestigious scientific journal Proceedings of the National Academy of Sciences (PNAS), challenges our natural human tendency to think that everything will necessarily get worse after a shock. Instead, the study presents compelling empirical evidence that it is possible to break the link between shocks and food insecurity. The key element for this is RESILIENCE. In simple terms, resilience means the ability of people, communities, ecosystems (and food systems in this particular case study) to withstand disturbance and to continue functioning despite disasters and shocks.
Using a large set of data from several dozen of countries from all over the world, recorded over more than 10 years, the team of international researchers who conducted the study shows that what matters in the face of disasters is not simply how developed a country is or how often it is affected by shocks or disasters (or how severe these are), but perhaps more importantly how prepared and how much resilience capacities that country has built. They found for instance several examples of countries—particularly in Asia—that show improving trends in food security despite being more severely affected by disasters than the rest of the world.
"In the context of increasing shocks and disasters (climate change, conflicts, pandemic), those findings are important – they demonstrate that food crises are not ineluctable and that suffering can be avoid, if countries and in particular their food systems are sufficiently prepared." - Chris Béné, lead-author.
To understand what shapes countries’ ability to maintain food security amid crises and disasters, those researchers studied countries with different income levels and analyzed factors such as the severity of the shocks, the capacities of the countries’ governments, the levels of infrastructures but also economic and social cohesion, and importantly the characteristics of their food systems.
The findings offer important insights for governments seeking to strengthen national preparedness and food security in the face of increasing shocks. Although every country is unique, some general principles emerge. In particular, the study found that having multiple ways to obtain food clearly helps reducing risks of crises. Likewise, government effectiveness (that is, how well public and civil services function) as well as greater capabilities and better access to new technologies and financial markets are critical. Finally, social capital (community networks, social connections and relationships) also appears important in the long-run.
"To strengthen resilient food systems, the government, development agencies and financial institutions shall prioritise the reinforcement of government capacities to anticipate and respond better to shocks and disasters, the promotion of diversity and redundancy in food systems - and not just efficiency or just-in-time food chains- and the investments on human capabilities at household and community level to protect nutrition and household assets." - Jose-Luis Vivero-Pol, co-author.
Thus, amid the increasing number of tragic stories happening around the world, this study stands as a voice of hope. It shows that, although many of these disasters cannot be predicted, their impacts can be reduced. And science is helping us understand how.
Most people think of segregation as a social phenomenon. But a Cary-led special feature in the journal Proceedings of the National Academy of Sciences examines how segregation also has deep ecological legacies that shape things like access to water, safety from floods, and exposure to extreme heat. To foster equitable cities, Segregation and Urban Ecology emphasizes the importance of understanding urban spaces as social-ecological systems to break cycles that reinforce segregation and its harms.
Urban ecologist Steward Pickett, a scientist emeritus at Cary Institute of Ecosystem Studies, organized the special feature together with Cary Research Fellow and NYU professor Timon McPhearson. Pickett explains, “Segregation affects who has access to safe housing, green spaces, climate protections, and other environmental benefits. While these inequalities are deeply rooted in historical and ongoing patterns of segregation, they are not inevitable. There are steps we can take to help ensure that ecological improvements benefit all communities — not just those who are already advantaged.”
McPhearson added, “If you're doing work in urban systems, you can't ignore segregation because it's a big part of the social, economic, spatial, and power structures in any place where people live.”
The special issue brings together ecologists, sociologists, planners, and other urban professionals. In an introduction and seven accompanying papers, they unravel how segregation takes root and evolves over time, the forms it takes in different environments, how its legacies and current forces impact modern communities, and how to begin repairing its damages. The authors hope the series of papers will help to set a research agenda for incorporating segregation as a factor in urban ecology and related fields, as well as spur novel solutions that break the cycle of segregation and support more equitable, biodiverse, and resilient cities.
Segregation: Alive and well, but ecologically understudied
Urban ecologists must consider segregation because of its impacts on environmental quality, human wellbeing, and power dynamics, Pickett and McPhearson note in the introductory paper. Segregated communities are more likely to be located near landfills, polluting facilities, industrial waste storage, and similar hazards, but less likely to have easy access to parks and the benefits of urban nature. They are often at greater risk of landslides, flooding, or severe impacts from hurricanes.
Furthermore, the authors note that segregation continues to affect policies and planning around climate adaptation, urban greening, and disaster risk reduction. When the legacies of segregation are ignored, decision making and urban planning measures can worsen existing inequities.
“Despite significant research in the last decade or so on social and environmental justice,” said McPhearson, “some researchers in ecology, geography, sustainability, and related disciplines have yet to fully engage with the historical and present-day segregation processes that continue to drive social and ecological life in cities.”
According to Pickett, segregation and its impacts are largely overlooked in favor of more measurable factors such as the physical and biological environment. “In an ecology class, they might talk about air, water, soils, nutrient cycling, and energy flow. But what’s not often on that syllabus is power — and power differentials are driven by race and class, access to opportunities that generate wealth, and other social hierarchies. This stuff needs to be included in ecology textbooks. Because if we don’t understand how something works, then we can’t begin to repair it.”
The tangled web of segregation
The papers in the special feature — detailed below — highlight how segregation is deeply entangled in the political, economic, and ecological processes of modern cities. They show that segregation influences flood exposure, biodiversity, infrastructure resilience, and sustainability decision making. The papers also emphasize the need for more inclusive planning, integrated infrastructure governance, equity-oriented climate adaptation, and knowledge co-production with marginalized communities.
This paper explains how ecology can help us understand why racial inequities persist over time. The scientists use examples from Baltimore, Maryland, to show how zoning decisions, tree planting, and the siting of undesirable facilities shape and reinforce environmental inequalities. Segregation functions as a dynamic and resilient social-ecological system, the authors note, with lags and legacies that maintain inequity.
This team identifies five interconnected pathways — including under-greening, nature dispossession, and green gentrification — through which marginalized groups are systematically denied ecological benefits while being disproportionately exposed to hazards. The authors posit that degraded environments are both a result and a driver of segregation, reinforcing social exclusion, ecological harm, and disinvestment. They advocate for planning practices that integrate reparations, community-led solutions, and equitable green infrastructure.
Combining historical redlining maps and modern day market forces, this study looks at how neighborhoods in Portland, Oregon have evolved over time. Neighborhoods that have remained persistently privileged had more tree canopy, less dense development, lower disaster risks, better preventive care, and fewer diseases. Persistently disadvantaged areas faced the most severe conditions, including minimal access to nature, aging infrastructure, the highest pollution and hazard exposure, and the worst health outcomes and disability rates. Other neighborhoods experiencing gentrification and displacement had mixed outcomes. The study shows that segregation is dynamic, shaped by modern market forces, and not always aligned with past redlining maps, underscoring the need to examine how urban areas change over time.
Cary Institute’s Elizabeth Cook and coauthors explore how the ecology of segregation can be applied in the Global South, specifically in Latin America, using Valdivia, Chile as a case study.
“Valdivia is a city of wetlands located in a biodiversity hotspot. It has a complex history that makes the access to and value of those wetlands and other green spaces very inequitable,” Cook explained. With colleagues, she examined three different historic social and ecological drivers of segregation in Valdivia, starting with colonization and the displacement of Indigenous Mapuche communities. They observe that a 9.5-magnitude earthquake locked in the patterns of segregation, and describe how the neoliberal policies from the 1970s Pinochet dictatorship, along with formal and informal development, continue to influence access and management of urban green spaces in the city.
To mitigate entrenched inequalities and foster sustainable development, the authors call for inclusive urban planning, with community-driven approaches and the acknowledgment of Indigenous perspectives.
This paper demonstrates how segregation amplifies climate-related risks. Whereas most flood risk studies focus narrowly on the direct impacts of flooding and demographic exposures, this study incorporates social vulnerability and critical infrastructure. The authors identify multiple locations in New York City where there is both high flood exposure and high social vulnerability, emphasizing the need for equity-centered climate adaptation strategies in dense urban settings.
Using a case study of a stigmatized neighborhood in Copenhagen, Denmark, this study demonstrates how climate adaptation policies applied as a one-size-fits-all solution ultimately exacerbate urban injustices. They show that stormwater management costs and risks fall disproportionately on residents in social housing, despite the city's reputation for equity.
Historical redlining has produced enduring inequities in biodiversity data, according to this study. Analyzing nearly 60 million volunteer science observations across 195 U.S. cities, the authors find consistently lower sampling for plants, animals, and fungi in formerly redlined neighborhoods. The findings indicate that segregation shapes not only ecological conditions but also creates data blind spots that could potentially bias scientific conclusions and conservation decisions.
Diego Ellis-Soto spoke about this research at Cary Institute. Watch the video.
Future directions
The ecology of segregation as a coherent field is still in its early phases of development, and the authors of this special feature hope that it will inspire other researchers and scholars to move the theory forward. According to Pickett, there is still much work to be done. Among the outstanding questions put forward in the special feature are: Where have systems of segregation been broken or replaced, and how? What feedbacks could be shifted to break the vicious cycle of segregation and replace it with a more equitable system? And how can ecology as a field address segregation more directly and overtly?
“Much of the scholarship on segregation emphasizes its social and historical roots, but neglects how it affects ecological contributions to sustainability and environmental justice,” said Pickett. “We hope our feature spurs additional research, innovation, and ultimately, practice, so we can expose and dismantle these previously invisible aspects of segregation.”
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Cary Institute of Ecosystem Studies is an independent nonprofit center for environmental research. Since 1983, our scientists have been investigating the complex interactions that govern the natural world and the impacts of climate change on these systems. Our findings lead to more effective resource management, policy actions, and environmental literacy. Staff are global experts in the ecology of: forests, soils, freshwater, disease, and cities.
