Environment and Health: The Hidden Link in Climate Change Conferences

Environment and Health: The Hidden Link in Climate Change Conferences

M Hasan    10:40 AM   

The Interconnectedness of Climate, Environment, and Health

In a recent conversation, Sandra Hacon, a researcher at Fiocruz and an environmental health specialist, shared her insights on the critical link between climate change, the environment, and public health. With over two decades of experience in this field, Hacon has focused on understanding how ecological changes impact human well-being. Her work spans various domains, including biology, ecology, and public health, and she is actively involved in several scientific panels and networks that address environmental and health issues.

Hacon's research has centered on the effects of climate change on health, particularly how social determinants exacerbate these impacts. She has studied deforestation, ecological transformations, and inequalities, examining how they influence the spread of viruses, vectors, and other biological agents across different regions.

A Holistic Approach to Environmental Health

Hacon's background in biology and ecology has shaped her perspective on the importance of integrating environmental and health considerations. She emphasizes that human well-being is intrinsically tied to a healthy environment. At Fiocruz, her work focuses on environmental health, which involves assessing the impacts of large-scale projects and ongoing environmental changes.

Deforestation in the Amazon, for instance, is not just an environmental issue but part of a broader process of degradation. This includes changes to the hydrological cycle, pollution, loss of biodiversity, and illegal mining. These factors collectively affect the region's ecosystems and, by extension, human health.

The Role of Politics in Environmental Health

During COP30 in Belém, Hacon noted that while climate discussions are central, politics plays a significant role in shaping environmental outcomes. She pointed out that Brazil, like many other countries, often waits for crises to occur before taking action. This reactive approach has led to devastating natural disasters in various regions, including Rio Grande do Sul, São Sebastião, Petrópolis, and Rio de Janeiro.

Health, however, remains a latecomer in climate change discussions. Until the fourth report of the Intergovernmental Panel on Climate Change (IPCC), health was largely overlooked. Hacon argues that this separation is artificial, as health and the environment have always been interconnected. Indigenous communities, riverine populations, and quilombolas have long understood this connection, yet it is only recently that scientific discourse has begun to recognize it.

The Impact of Environmental Changes on Disease

Environmental changes significantly influence the spread of diseases. Viruses, such as the Oropouche virus, respond to environmental pressures like temperature, humidity, and ecological shifts. As these conditions change, viruses mutate, finding new environments where they can thrive. Dengue fever is a prime example: rising temperatures create ideal conditions for the Aedes aegypti mosquito and the virus to multiply rapidly, leading to outbreaks.

Similarly, chikungunya has seen increased cases in Latin America, linked to imbalances in rainfall and extreme weather events. These changes facilitate the faster circulation of viruses, bacteria, and fungi, posing new challenges for public health.

Preparing for the Climate Crisis

Institutions like Fiocruz are developing new vaccine platforms to address emerging threats. However, healthcare systems are still unprepared for the speed and scale of climate-related health challenges. Hacon highlights the need for proactive measures, including early warning systems, integrated surveillance, and coordinated responses.

Prevention remains a weak point in Brazil and Latin America. The culture of reacting after the fact must shift toward anticipatory actions. Initiatives like the app developed by Márcia Chame, which helps monitor wildlife deaths, demonstrate the potential of technology in preventing epidemics. Such tools are crucial for tracking diseases that may not have clear indicators.

The Need for Political Action

Despite having the technical capacity and resources, Brazil lacks the political will to implement effective climate and health policies. Hacon points out that while there are excellent institutions and researchers, the country remains in a holding pattern. This is evident at events like COP30, where the connection between climate, environment, and health is often overlooked.

High temperatures and humidity during the conference have affected attendees, highlighting the direct impact of climate on health. People with chronic conditions, such as hypertension or diabetes, are particularly vulnerable. Hacon emphasizes the urgent need to place health at the center of climate discussions, as the evidence is clear and the consequences are dire.

Conclusion

The integration of climate, environment, and health is essential for addressing the complex challenges of our time. Through research, innovation, and political commitment, it is possible to build a more resilient future. Hacon's work serves as a reminder that the health of our planet and its people are deeply intertwined, and that proactive, holistic approaches are necessary to safeguard both.

How Tiny Plastics Can Destroy Ocean Life

How Tiny Plastics Can Destroy Ocean Life

M Hasan    2:20 AM   

Scientists Are Finally Putting a Number on “Too Much Plastic”

For years, I’ve seen photos of seabirds and turtles tangled in trash, but I rarely saw a clear answer to the basic question: how much plastic actually kills an animal? A new wave of research is changing that by treating plastic like any other pollutant, defining dose, response and lethal limits instead of relying only on dramatic anecdotes. Scientists have combed through necropsies, lab experiments and field observations to estimate how many ingested pieces push different species from stressed to dying, turning a sprawling environmental crisis into something that can be measured in grams and fragments rather than just emotions.

In one synthesis of earlier work, researchers examined documented deaths of seabirds, turtles and marine mammals and found that ingesting a surprisingly small number of items could be fatal, especially for smaller animals with limited gut space. That analysis, described in coverage of how little plastic can be lethal, shows that once plastic reaches a certain share of an animal’s stomach contents, the odds of death rise sharply. Follow-up reporting on new research that measures lethal plastic loads and a similar account of dose-based plastic risk for marine life underscores the same point: scientists are no longer just counting pieces in the water, they are quantifying how many pieces it takes to kill.

Even a Few Pieces Can Be Deadly for Turtles, Seabirds and Fish

What stands out to me in this research is how low the lethal threshold can be for some animals. Sea turtles, for example, can die after swallowing only a small number of plastic fragments if those pieces lodge in the gut or block the intestines. Because turtles mistake floating bags and films for jellyfish, they can fill their digestive tract with material that has no nutritional value, leaving them unable to process real food. The risk isn’t just about massive tangles of trash; it’s about a few deceptively soft pieces that happen to get stuck in exactly the wrong place.

Seabirds face a similar danger when they scoop up floating pellets and bottle caps, mistaking them for fish eggs or crustaceans. Studies summarized in reporting on how little plastic can kill marine animals and a companion piece on plastic-linked deaths in the ocean describe birds whose stomachs were packed with dozens of fragments, leaving no room for real food. Fish and invertebrates, which often ingest microplastics smaller than a grain of rice, may be harmed by even fewer particles because their bodies are so small. In all of these cases, the lethal dose is not measured in kilograms of trash but in a handful of pieces that disrupt digestion, puncture tissue or deliver a concentrated hit of toxic chemicals.

Plastic Kills in More Ways Than One

When I look at the full picture, it’s clear that ingestion is only one part of the story. Plastic harms marine animals through a mix of physical and chemical pathways that often interact. Entanglement in discarded fishing gear can cause drowning, deep cuts and infections, while floating bags and straps can cinch around necks or flippers as animals grow. At the same time, microplastics and fibers can lodge in gills and guts, triggering inflammation and internal injuries that may not be obvious until an animal is already weakened or dead.

On top of the physical damage, plastic acts like a sponge for pollutants, concentrating substances such as persistent organic pollutants and heavy metals that then move up the food chain. An overview of how plastic in the ocean hurts animals details how ingestion can lead to starvation, reduced fertility and organ damage, while entanglement can cause slow, painful deaths. Another account of plastic killing marine mammals highlights cases where whales and dolphins have been found with stomachs full of debris or wrapped in nets, showing that a single rope or a cluster of bags can be just as deadly as a cloud of microplastics. The lethal dose, in other words, is not just about how many pieces are swallowed; it’s about how those pieces interact with bodies and ecosystems.

Scale Matters: Millions of Animals, Each Vulnerable to a “Small” Dose

It’s tempting to think that if only a few pieces can kill, then the problem is mostly about tragic one-off encounters. The numbers tell a different story. When I zoom out from individual animals to entire populations, the scale of plastic exposure becomes staggering. Billions of plastic items are floating in the world’s oceans, and coastal currents concentrate them in hotspots where wildlife feeds and migrates. In those zones, the odds that any given turtle, bird or fish will hit its lethal threshold over a lifetime rise dramatically.

Data compiled on how many marine animals ocean plastic kills point to hundreds of thousands of marine mammals and turtles and well over a million seabirds dying each year from plastic-related causes. Those figures include animals that starve with stomachs full of debris, drown in nets or suffer infections from entanglement wounds. When I connect those mortality estimates with the new dose-based research, the picture sharpens: each of those deaths likely began with what looked like a small, manageable amount of plastic—one bag, a few fragments, a single loop of fishing line—that turned out to be more than the animal’s body could handle.

From Research to Responsibility: What a “Lethal Dose” Means for People

Knowing that a few pieces of plastic can be deadly changes how I think about everyday choices. If a single shopping bag or bottle cap can push a turtle or seabird over its lethal threshold, then the margin for error in our waste systems is vanishingly small. It’s not enough to keep “most” plastic out of the ocean; the science suggests that every stray item carries a non-trivial risk for the animals that encounter it. That reality raises hard questions about how much plastic packaging, fishing gear and single-use products we can justify when the cost is measured in lives, not just litter.

Researchers and advocates are using these lethal-dose estimates to argue for stricter controls on plastic production, better waste management and stronger protections for key habitats. Visual campaigns, including a widely shared social media post showing plastic-choked wildlife, translate the science into images that are hard to ignore. At the same time, coverage of plastic pollution’s toll on marine life is pushing the issue into mainstream political debates, where policymakers are weighing bans on certain products, extended producer responsibility rules and international agreements to curb plastic at the source. For me, the takeaway is simple but uncomfortable: when the lethal dose is this low, the only truly safe amount of plastic in the ocean is as close to zero as we can get.

Urban Life and the Rise of Chronic Stress in Modern Society

Urban Life and the Rise of Chronic Stress in Modern Society

M Hasan    11:00 AM   

The Rise of Chronic Stress and the Evolutionary Mismatch

Chronic stress is becoming more prevalent, according to evolutionary anthropologist Colin Shaw. He argues that this increase stems from an evolutionary mismatch—our bodies and brains, which have evolved over hundreds of thousands of years for hunter-gatherer conditions, are now exposed to industrialized, urban environments. Is there a solution?

It's the end of July, and it's raining heavily in Zurich. I'm sitting on a foldable chair under the canopy of old-growth beech trees, protected by an umbrella. I take deep breaths as I listen to birdsong breaking through the steady sound of raindrops hitting the forest floor. Water flows down the wide tree trunks, having collected from the branches above. A knotty maze of roots ahead seems to form a natural enclosure. "How was it?" asks a voice.

Colin Shaw walks over from where he had been standing barefoot, in his trekking sandals in the rain for the past few minutes. As an evolutionary anthropologist and head of the Human Evolutionary EcoPhysiology (HEEP) research group at the University of Zurich, he gave me an assignment when we arrived at this clearing on the edge of Zürichberg forest: choose your favorite spot, take in the environment, and focus on each sense step by step. What sounds can you hear? What can you smell? What movements can you observe?

Rolling in the Mud for Science

With these instructions, we aim to recreate part of an experiment that Shaw and his research group conducted last summer. The team, consisting of specialists from ecology, immunology, microbiology, cognitive psychology, and exercise science, had 160 people spend three hours walking and sitting in one of three different environments: Sihlwald, a coniferous forest just outside Zurich; Mont Tendre, a deciduous forest outside Lausanne; and Zurich's Hardbrücke area, an urban setting.

"In the forest," Shaw laughs, "we got people down and dirty, hugging trees, playing with the soil microbiome, and everything else."

Before and after being exposed to the natural and urban environments, the researchers measured a range of biomarkers in participants' blood, saliva, and cognitive capacity. In the woods, people showed significantly lower blood pressure, better immune response, and improved psychological state. In contrast, those in the urban environment exhibited higher blood pressure and strong physiological and psychological stress reactions.

Although we aren't taking any measurements in today’s torrential rain, I can feel the effect of the experiment. In the woodland environment—which, as Shaw points out, is "closer to our ancestral condition than a city environment"—I feel calm. My pulse is steady, and my stress level dissipates. Shaw jokes that the rain may have even improved the dispersal of phytoncides, volatile organic compounds released by trees that offer immune-boosting benefits to humans—as demonstrated by the forest bathing (shinrin-yoku) movement in Japan.

Lions Everywhere

The next experimental setting for today will be a busy intersection. As we walk along a small path and climb over fallen branches to rejoin the main forest road, Shaw gives me a summary of his main research hypothesis. From an evolutionary standpoint, he says, the industrialized, urbanized environments we've built place a chronic stress load on our bodies, taking a toll on both physical and mental health.

"Whereas physicians would talk about this as 'ill health,' we try to determine the evolutionary context to understand whether our surroundings are making us sick—and which environment will help us recover," he says.

In a recent research paper co-authored with Daniel Longman, a longtime collaborator and fellow Cambridge alumnus from Loughborough University, Shaw argues that the extensive environmental shifts of the Anthropocene have undermined human evolutionary fitness.

Evolutionary success of a species amounts to survival and reproduction, and, according to the authors, both factors have been severely compromised in the last 300 years since the beginning of the Industrial Revolution. They support their theory with evidence of declining global fertility rates and increases in chronic inflammatory conditions such as autoimmune diseases. They also cite impaired cognitive function in urban environments. Chronic stress plays a key role as the cause of many of these conditions.

"In our ancestral state, we were well-adapted to deal with acute stress to evade or confront predators. Fight or flight. The lion would come around occasionally, and you had to be ready to defend yourself—or run," Shaw explains. "The key is that the lion goes away again. Such an all-out effort guaranteed survival, but it was very costly and required lengthy recovery."

This acute stress response was ideal for mobilizing adrenaline and cortisol while fighting for survival in our hunter-gatherer past. However, it is mismatched for today's steady stream of challenges.

"Our body reacts as though all these stressors were lions," he continues. "Whether it's a difficult discussion with your partner or your boss, or traffic noise, your stress response system is still pretty much the same as if you were facing lion after lion after lion. As a result, you have this very powerful response from your nervous system, but no comedown."

The Hidden Costs of Progress

As we continue our walk down Letzistrasse into the city, the water gushes down the gutter, and the traffic noise, amplified by the rain, swells. "Essentially, there's a paradox where, on the one hand, over the last three hundred years we've created this tremendous wealth and comfort and healthcare for a lot of people on the planet," Shaw speaks louder to be heard over the roar of a large construction vehicle passing by on Winterthurerstrasse.

"But on the other hand, some of these industrial achievements are having quite detrimental effects on our immune, cognitive, physical, and reproductive functions. For example, since the 1950s sperm count and motility rates have dropped dramatically in men, which is tied to pesticides and herbicides in food, but also to microplastics," Shaw says.

As we arrive at the intersection with Irchelstrasse, I get to choose where to set up my foldable chair again. Instinctively, I opt for a corner where I can at least feel the greenery from Irchel Campus behind me. For the next 15 minutes, I observe the heavy traffic approaching from all sides, my eyes darting around. The deafening noise—a mix of roaring engines, water spraying from the wheels, plus jackhammers from roadworks—drowns out any other thought in my brain. My breathing becomes shallower, the entire body tenses up. I'm relieved when Colin Shaw tells me we can now move on to friendlier surroundings, and we head into Irchel Park.

"There was no real danger, yet my jaw is clenched," he states. "It's the constant stimulation. We didn't evolve to be constantly stimulated."

Of course, compared to megacities with tens of millions of inhabitants, such as Tokyo, Delhi, and Shanghai, "Zurich is barely a city," Shaw concedes. "It's surrounded by forests; there's a lake and a river. It also has a comfortable public transit system."

However, research by the HEEP group clearly indicates that even in a city that is frequently ranked among the most livable, urban exposure is physiologically and psychologically stressful and impairs immune function.

Today, an estimated 4.5 billion people—more than half the world's population—live in urban agglomerations. By 2050, that figure is projected to rise to 6.5 billion, or more than two-thirds of humanity. Recognizing industrialization and urbanization as health risks will be crucial for safeguarding public health—or, in evolutionary terms: the fitness of our species.

We Can't Adapt Our Way Out of This

It's hard to believe that our brains have grown accustomed to juggling ever-new digital innovations—yet remain rooted in a prehistoric past when it comes to regulating our nervous systems. Why haven't we adapted to the living conditions that our species has created?

"You could argue that the stress responses we're seeing today are a form of adaptation. However, biological adaptation is very slow. Longer-term genetic adaptations are multigenerational. So that's tens to hundreds of thousands of years," Shaw points out.

"From an evolutionary perspective, if people are dying from chronic stress or stress-related diseases, you could say that this is natural selection taking place. If you let that go on for hundreds of generations, people would probably become better able to deal with chronic stress," he says. Clearly, that's not a feasible solution to our current predicament—a physiological conundrum with no quick evolutionary fix.

So, if there's no way our current physiology will buffer chronic stress, how can we redress this mismatch? According to Colin Shaw, one solution is to fundamentally rethink our relationship with nature—treating it as a key health factor and protecting or regenerating spaces that resemble those from our hunter-gatherer past. Another is to design healthier, more resilient cities.

"I'm not an engineer or an architect," he says, "but our research can identify which stimuli most affect blood pressure or heart rate and pass that knowledge on to decisionmakers."

And both avenues are deeply interconnected, he argues: "We need to get our cities right—and at the same time regenerate, value, and spend more time in natural spaces."

We have returned to his office with a standing desk and no chair. It seems like a small act of defiance against today's sedentary lifestyle, which is so distant from our ancestral condition.

"As an evolutionary anthropologist, my earlier work focused on Neanderthals and bone adaptation, which was fascinating in its own right," Shaw reflects. "But the challenges we face today feel more urgent. Those with the resources—financial or intellectual—have a responsibility to invest them in solving these problems. To me, it's a moral imperative to do the right thing."

Pests and the Secret Threat to Home Comfort

Pests and the Secret Threat to Home Comfort

M Hasan    7:20 AM   

The Hidden Impact of Pests on Home Comfort

A home is meant to be a sanctuary, a place where individuals feel safe and at ease. However, the presence of pests can quietly undermine this sense of comfort, creating disturbances that often go unnoticed until they start affecting daily life. These small issues can have a significant impact on how a home feels, making it essential for homeowners to recognize and address them before they escalate.

Subtle Noises and Disturbances

One of the earliest signs of pest activity is the presence of unusual sounds. A faint scratching behind walls or light tapping in the ceiling might initially seem harmless, but over time, these noises can become increasingly disruptive. Even if the source remains hidden, the knowledge that something is moving around can create stress and affect sleep quality. This constant background noise gradually chips away at the peace and tranquility that a home should provide.

To manage such situations, it's wise to consult with professionals who can identify the source of the disturbance and implement effective solutions. Hiring local experts ensures that the issue is addressed promptly, providing homeowners with reassurance that their home is being taken care of.

Pests Interfering with Cleanliness

Maintaining a clean and orderly home is crucial for a sense of well-being, but pests can quickly undo this effort. Droppings, crumbs, and stains on walls and floors can make even the most diligent cleaning routines feel futile. This constant need to re-clean spaces that should remain tidy can lead to frustration and a sense of helplessness.

Addressing the root cause of the mess is just as important as regular cleaning. By eliminating pest activity, households can enjoy a more manageable and enjoyable living environment.

Allergic Reactions

Indoor comfort isn’t solely about appearance; it also involves physical well-being. Pest droppings, shed skin, and dander can trigger allergies, leading to symptoms like sneezing, coughing, and watery eyes. Many people may attribute these issues to seasonal allergies, not realizing that the problem stems from within their own homes.

Improving indoor air quality begins with tackling the source of allergens. Regular cleaning, the use of air filters, and professional assistance when needed can significantly reduce these triggers, resulting in a fresher and calmer home atmosphere.

Pets Responding to Pest Activity

Pets often detect pest activity before their human counterparts. A dog might bark at a specific corner of the room, or a cat could stare intently at a wall, sensing movement that humans miss. These behaviors are often the first indicators of a hidden problem.

When pets exhibit unusual behavior, it’s worth investigating further. Acting quickly can prevent small disturbances from becoming larger issues, ensuring a more comfortable living environment for everyone involved.

Pest Problems Starting in Kitchens

Kitchens are prime targets for pests due to the availability of food and water. Even minor spills or crumbs can attract unwanted visitors, leading to infestations that disrupt mealtime areas. Families often find it frustrating when their kitchen no longer feels clean and welcoming.

Preventing such issues involves sealing food properly, wiping surfaces regularly, and checking for leaks. When problems do arise, professional help is often necessary to address the infestation effectively.

Odors Caused by Pest Infestations

Pest infestations can also lead to unpleasant odors. Droppings, urine, and hidden nests can produce smells that linger even after thorough cleaning. These odors can make a home feel less inviting and change the perception of comfort.

Identifying and removing the source of the odor is essential for restoring a fresh and pleasant living environment. Once the issue is resolved, the air quality improves, and the home becomes more enjoyable to inhabit.

Health Risks for Families

Pests pose serious health risks to families, particularly for small children and older adults. Exposure to bacteria and allergens through droppings, bites, or contamination can lead to illness. A home meant for health and well-being can become a place of concern when pests are present.

Taking proactive steps to eliminate pest activity is crucial for maintaining a healthy living environment. Ensuring cleanliness, proper storage, and seeking professional help when needed can greatly reduce these risks.

Disrupting Rest and Sleep

Pest activity often peaks at night, directly impacting sleep quality. Scratching, squeaking, or movement during the night can wake individuals up or make it difficult to fall asleep. This lack of rest can lead to fatigue, irritability, and a general decrease in comfort throughout the day.

Addressing nighttime disturbances can restore the sense of calm needed for good sleep. Once pest activity is controlled, homeowners often notice a significant improvement in their overall well-being.

Bathrooms as Unexpected Entry Points

Bathrooms, with their moisture and plumbing, can become entry points for pests. Cracks, drains, and damp areas can serve as pathways or hiding spots. Families may notice activity in these spaces even when other parts of the house seem unaffected.

Managing moisture levels and keeping bathrooms clean can reduce the likelihood of pests using them as access points. Repairing leaks and covering drains helps maintain a fresh and functional space, which is essential for overall household comfort.

Pests can impact daily life in numerous ways, from disrupting sleep and spreading odors to causing health risks and damaging belongings. Their effects extend beyond the physical, influencing both mental and emotional well-being, and ultimately making a space feel less secure and enjoyable to live in.