What is the climate crisis doing to our bodies and brains?

This episode delves into the intersection of the climate crisis and public health, with a particular emphasis on how the former is impacting on our bodies and our brains. Conversations with both featured guests explore how climate change exacerbates traditional health issues and introduces new risks, such as the increasing range of vector-borne diseases and what that means for the future of healthcare in cities. Our brains are also at risk, with extreme weather and rising temperatures impacting our behaviour and the neurological development of our children - even before they are born. It is crucial for academia and science to push for interdisciplinary collaboration and actionable research to inform urban climate policy if we are to meet these new challenges and safeguard public health, particularly the most vulnerable populations.

Image Credit: Photo by Jesse Orrico on Unsplash.

Featured guests:
Clayton Page Aldern is an advisor, data scientist, author and journalist at Grist (but who has also been widely published elsewhere) whose work is focused on homelessness policy, climate change, and neuroscience. His book, The Weight of Nature: How a Changing Climate Changes our Brains, examines how the climate crisis impacts brain health, covering topics like extreme weather effects on prenatal development, PTSD in first responders, and neurological changes linked to the climate crisis.

Quinn Adams is the Scholar in Residence at the C40 Centre for City Climate Policy & Economy and a PhD candidate at Boston University School of Public Health. Her research focuses on the health risks from climate change and extreme weather events. She is particularly interested in action-oriented research and identifying strategies to reduce health impacts, with her dissertation focusing on the growing risks of the climate crisis altering the ranges of vector-borne diseases.

Links
Climate Change and the Health of Socially Vulnerable People - United States Environmental Protection Agency
Pregnancy during Hurricane Sandy linked to kids’ psychiatric disorders, study says - Washington Post
More jobs, better heal

If you want to learn more about the Journal of City Climate Policy and Economy, please visit our website: https://jccpe.utpjournals.press/

Cities 1.5 is produced by the University of Toronto Press and Cities 1.5 is supported by C40 Cities and the C40 Centre for City Climate Policy and Economy. You can sign up to the Centre newsletter here. https://thecentre.substack.com/

Our executive producers are Calli Elipoulos and Peggy Whitfield.

Produced by Jess Schmidt: https://jessdoespodcasting.com/

Edited by Morgane Chambrin: https://www.morganechambrin.com/

Music is by Lorna Gilfedder: https://origamipodcastservices.com/

Transcript

[Cities 1.5 main theme music] I'm David Millerfolde and you're listening to Cities 1.5, a podcast exploring how cities are leading global change through local climate action. 

[urgent music] Eco-anxiety, climate stress, eco-rage, planetary depression – most of us working in the climate sector are familiar with these terms, and maybe even suffer from them, ourselves. Sometimes, the burden of what the science is telling us can weigh heavily on our shoulders. But, aside from these negative psychological effects, what is neuroscience telling us about the impact the climate crisis is having on us?

Why might city residents be disproportionately affected? And what about the growing risk from vector-borne diseases like those spread by mosquitoes, fleas and ticks, such as Lyme disease, which are increasingly shifting and expanding their geographic range as the planet boils? When we delve into the intersection of climate and public health, we already know a great amount. [music fades out]

[energetic, upbeat music] As we have heard in previous episodes of Cities, 1.5 extreme heat increases the risk of pregnant women being hospitalized, premature labour, and stillbirth, and air pollution can lead to higher rates of cardiovascular and lung disease and elevated rates of asthma in children. These are all health impacts caused by the climate crisis, which are particularly felt in our cities by city residents. But what about our brains?

Until very recently, the neurological effects and impacts on brain health from the climate crisis have been understudied and poorly understood. But a new field of study is emerging to map and explore how the changes we are seeing in the climate and our ecosystems are also shaping alarming transformations in our brains, provisionally called climatological neuroepidemiology—not a term that trips off the tongue—this emerging area of research is trying to bridge the divide between climate change and our brain health.

Scientists and researchers in this field are already exploring how the neurological effects of extreme heat may lead to spikes in violent crime in cities. The prevalence of post-traumatic stress disorder in survivors of extreme weather events such as wildfires, storms, and floods are already well known, but now studies are emerging, which show increased rates of anxiety, depression, and ADHD in children who were still in the womb when such weather events took place.

Potential correlation between blue-green algal blooms and the devastating and incurable neurological condition ALS are being investigated. Outbreaks of infectious diseases such as malaria or dengue fever are being seen in geographies where they were previously unknown. Vulnerable populations, such as homeless communities, people with disabilities, children, and the elderly are most at risk from these effects on public health. And, as scientists and public health experts keep warning us, this is just the beginning. [music fades out] 

[light, rhythmic music] Today, we'll be hearing from two guests who are experts on the emerging public health risks associated with the climate crisis, from the neurological impacts of global heating and extreme weather to the challenges of vector-borne disease expansion into cities that have never previously experienced them.

But, before we take a deep dive into what the climate crisis can do to our brains, let's get an overview of the changing landscapes of climate and public health from one of our leading experts at the C40 Centre for City Climate Policy and Economy. [music ends] 

Quinn Adams 04:14 

[rotary dial telephone rings] [clicks] My name is Quinn Adams. I am a doctoral candidate at Boston University School of Public Health, and Scholar in Residence for C40 Centre for City Climate Policy and Economy, and I'm calling in from Salt Lake City, Utah. [receiver chimes, replaced in cradle]

David 04:29

Quinn, thanks so much for your ongoing work and for being willing to speak to us on the podcast. 

Quinn Adams 04:36 

Thanks for having me. 

David 04:36

Can you just introduce yourself and tell our listeners a bit more about your research work at the Boston University School of Public Health and what you do for the C40 Centre for Climate Policy and Economy? 

Quinn Adams 04:49 

Absolutely. I am a doctoral candidate in Environmental Health at Boston University. I conduct research mainly on the health threats from climate change and extreme weather events. My work spans several aspects of this connection, but I spent quite a bit of time understanding the health implications of extreme heat in cities and really understanding the effectiveness of various interventions to reduce heat-related health outcomes.

And then, separately, the majority of my work actually is focused on how climate change and extreme weather events impact the distribution of vector-borne infectious diseases and how we can leverage things like climate-based early warning systems to anticipate and prepare for infectious disease outbreaks in advance.

I'm Scholar in Residence for the C40 Centre and something that I'm really passionate about is bringing an action-oriented lens to research, and so a big majority of my role is thinking about ways to push academic researchers in climate and health to ask the right questions and produce relevant and timely research that can be directly used to inform city climate policies.

And another part of this role really includes providing mayors and other city policymakers with the scientific evidence around climate and health in a way that's useful for them, to inform both their communications but also, you know, their decision making. 

David 06:05

So let's talk about the last couple of points, first, and then we'll get into the details of your research and work because, from my perspective, the idea that we should give prominence to the impacts of the climate crisis from a public health perspective is relatively new. Do you have any insights as to why there is this emergence of interest in, and action on, public health impacts arising from the climate crisis?

Quinn Adams 06:36 

You know, I think the first thing is really that, over the past few decades, there's been this huge increase in scientific research, and also academic programs that allow students to train in the field of climate and health, and this research really brings this broader awareness to the interconnectedness between things like climate change, public health, but also sustainable development. And, I think also, one thing that kind of brings more awareness to this, but also more interest in it from a multidisciplinary lens, is that the impacts of climate change are really becoming unavoidable, and billions of people already are experiencing and being impacted by extreme weather events. 

So, not only are we, you know, observing these effects in real life, but the science on this is so abundantly clear in showing us that climate change is not only exacerbating or, you know, worsening the existing health problems, but it's also posing new risks. I'll give a few kind of broader examples because these connections are very intricate, and the first one is really this increase in frequency and intensity of extreme weather events which can directly cause things like, you know, more injuries and fatalities, but also can lead to cut offs of needed medical equipment or, in the longer term, mental health issues or respiratory problems. 

Another big thing, especially for cities is heat-related illness and rising temperatures and the increasing urban heat island effect is causing higher rates of heat exhaustion, dehydration, heat stroke, and deaths, as well, particularly among the vulnerable populations. One thing, like I mentioned, that's particularly of interest to me is this increase in vector-borne diseases, so things like warming temperatures, changes in precipitation patterns, they're allowing disease vectors, which are things like mosquitoes and ticks that spread diseases like malaria, dengue, and Lyme disease, for example, to survive in new places and bring infectious diseases kind of outside the previously endemic areas and into populations in areas that have little or no immunity acquired.

For example, 2023 had, you know, the highest historical record of dengue cases ever, with upwards of 4 million infections. Another one is waterborne infectious diseases. Climate change, prolonged drought, flooding events, these all impact the quality and quantity of available water. It can also lead to infectious disease spread like cholera and typhoid, and other pathogens that enter the water sources.

[driving music] I think an understudied kind of aspect of this is malnutrition and how, you know, prolonged drought, variable rainfall patterns can influence crop failures, food shortages, and malnutrition is also something that increases someone's susceptibility to infectious diseases, which kind of makes this vicious cycle between the three things.

David 09:27

So, let's segment those a bit. Your own research for your doctorate is about vector-borne diseases. Can just talk a bit more about what you just highlighted, about things like dengue, or can you give the listeners a bit more of an insight into where you're going with this research and what you've learned so far? [music fades out] 

Quinn Adams 09:47 

Yeah, definitely. So, my specific research for my dissertation is looking at one specific disease in Brazil which is visceral leishmaniasis. It's an important public health concern, but a lot of people haven't ever heard of it because it is a neglected tropical disease, which means that it doesn't get as much attention as it should, and it largely affects those living in poverty, with limited resources. And this disease is vector borne. It's also zoonotic, making the relationships with humans and the environment and climate really quite complex.

And so, what I'm studying with it, is how weather and climate change, more long term, impacts its distribution around Brazil, and then also the connection with, you know, sociodemographic characteristics – how poverty and sanitation and urbanicity all influence these relationships, as well. 

David 10:40

Well, as you said, it's an understudied and less well-known disease. I'm certainly one of the people who don't know much about it, and this is vector borne, so does that mean by mosquitoes or some other similar kind of insect?

Quinn Adams 10:54 

It's spread by a sandfly. It, generally, is in a reservoir of-- actually, it lives in the domestic dog. It's picked up by a sandfly vector and then transmitted to humans by biting the human. 

David 11:10

And, generally prevalent amongst lower-income people.

Quinn Adams 11:14 

That's right.

David 11:14

So, a variety of challenges come together in that which I think, from the perspective of mayors and cities, can be both daunting but also interesting because there is poverty, climate, health. You've spoken a bit about the impact of extreme weather, and one of the impacts that you noted, that probably is not as often spoken about as it should be, is malnutrition. Can you speak about that a bit more? 

Quinn Adams 11:41 

So, in terms of malnutrition, specifically, I think there's a lot of kind of complex things coming into play, and one of the big ones is this just variable rainfall patterns that is coming with climate change, it's really hard to predict and, oftentimes, we're seeing these really prolonged droughts, followed by extreme rainfall or periods of intermittent rainfall that's just hard to predict, and that kind of leads to a lot of disruption in agricultural systems. So, I think one of the main things that this leads to is really just food insecurity, which exacerbates undernutrition, and also micronutrient deficiencies, which is a big one.

We've also seen that rises in CO2 leads to less nutrient-dense foods and, yeah, this is a really big one among children, pregnant women, marginalized communities, as well. So, it's kind of this linkage between longer-term climate change and these events like drought and intermittent rainfall that are contributing to this. 

David 12:41

I know there's a local example of the very worrying consequences, indeed, from climate change and other environmental challenges. Can you speak about that and what we see in Utah? 

Quinn Adams 12:53 

Yeah, absolutely. I think one of the big things that we see here in Utah—which is largely desert—is a lot of drought, and something that's coming out of that is the drying up of the Great Salt Lake, which is not only producing things like worsening levels of dust pollution, which also tends to sit right above the city because we're in this big valley, but also releasing toxic gases, things like arsenic into the air that are also kind of moving over the city, as well. 

David 13:24

Arsenic's not very good to be breathing in. That's a layman's way of looking at it, but I trust I'm right. 

Quinn Adams 13:29 

You are correct. That's for sure. 

David 13:33

What about the particulates, as well? Is that a public health issue, or is it just something unpleasant? 

Quinn Adams 13:38 

[gentle music] That's a public health issue, for sure. Yeah. I think Salt Lake City, especially in the wintertime, we get an air quality inversion due to the valley that we sit in, and it's a combination of particulate matter from things like vehicle emissions, but also from things like the drawing up of the Salt Lake that produces a lot of respiratory health issues and cardiovascular issues, as well. And, something that we've been seeing a lot out west, and largely increasingly, I guess, across the United States and beyond, is this increase in allergy season from longer summers. It produces more and more emissions, I guess, of pollen and other allergens that cause respiratory issues, as well. [music fades out]

David 14:23

How's the city handling that, Quinn? It sounds like there's multiple problems here. There's arsenic and other toxic compounds. There's particulate matter. There's the automobile exhaust. Is the city coping with this, or how are they acting? 

Quinn Adams 14:37 

Yeah. You know, I think one of the biggest things that Salt Lake City is doing right now to try and combat this is to increase their water supply and that is, you know, diverting water from various streams and rivers and also reducing or conserving water more effectively. 

David 14:55

Yeah, they've had a couple of progressive mayors. It's quite an interesting place.

We discussed a whole range of important and quite complicated public health issues. Is there anything in the literature that you've seen or anything that you've experienced at C40 that suggests actions that mayors and their policymakers should take to both mitigate against these risks, and to adapt to them?

Quinn Adams 15:23 

Yeah, I think the most obvious thing and straightforward thing that I can say right now is our need to reduce our reliance on fossil fuels, and that's kind of the underlying cause for all of these issues that I've talked about today. But, I also want to emphasize that, like I said, people are already experiencing these really negative impacts of climate change and extreme weather events, and so adaptation is going to be an increasingly important avenue for city policymakers.

And, I think there's definitely a few that are interesting and emerging that I can talk about. One of them is, you know, the development of heat action plans, which has been done all over the world in a various number of ways. These things can include things like early warning systems to prepare people in advance of forecast heat, things like opening cooling centres or public outreach campaigns, increasing awareness from the public.

David 16:14

Can you talk about any examples you've seen of how urban planning and urban infrastructure can contribute to both mitigation and public health protection? 

Quinn Adams 16:24 

Yeah. You know, the first thing that I can think of that really ties into this question is building cities that incorporate things like blocked-off bike lanes or sidewalks, or promoting green space, making it really enticing for people to spend time outside and spend time walking or biking instead of driving. And, you know, these are policies that can be implemented at the city level that not only promote a reduction in transportation emissions, but also in health actions such as, you know, biking or walking. And so, I think that's a pretty big one, and also access to green spaces has been known to improve mental health among urban residents, so that's just another benefit that can come from that.

David 17:11

A couple of times you've mentioned under-studied areas, you know, the emerging work in mental health, under-studied or neglected diseases, and there does seem to be some space between what the best scientists in the cutting-edge academics know about the public health threats of the climate crisis and action being taken in response to this. Given your dual role as a scholar in residence with C40 Cities and as a PhD candidate at Boston University School of Public Health, do you have any thoughts about how to bridge that gap between emerging academic knowledge of public health threats and the action needed to mitigate against them and adapt to them? 

Quinn Adams 17:57 

Yes, this is exactly what I spent a lot of my time thinking about, and I think the biggest thing here is interdisciplinary collaboration and also ongoing communication. So, climate and health, and climate change more broadly, is inherently interdisciplinary. We need actors from research, from policy, from practice, all working together to make improvements to our planet. And, without this interdisciplinary collaboration, we need to understand how to talk to each other in the same language, and ongoing communications is another really, really important one.  If we are trying to get academics to ask the right questions in a way that is useful for policymakers, we need to have an understanding of what policymakers need and at what timeline.

Another really important aspect of this is knowledge sharing and that's both across borders, but also among different sectors.

And then, the final one that I would bring up is education. So, I'm in a program at Boston University called the Urban Program. It's this multi-disciplinary kind of training program that allows doctoral students to get training in how to make their research more action oriented, and how governments work and how they use those types of research. So, education programs like this, that bring up the next generation of researchers and giving them training in how to make these connections and how to make the research more actionable is going to be even more and more critical as we try to bridge this gap. 

David 19:32

I hope that many of the world's great universities are listening to that comment, Quinn, and will start crafting programs that provide that opportunity, as you said, to bridge where academics want to research and what cities and other policymakers need. 

A lot of this news is kind of grim. Disease is spreading because of climate change and patterns of where insects are have changed dramatically. Malnutrition – having less-nutritious crops because there is increasing heat and paradoxically, increasing rain and single events. [driving, pensive music] It's all really worrying. Do you have hope? And, if so, what gives you hope for the future in terms of safeguarding public health in view of all these climate-related trends?

Quinn Adams 20:24 

Yeah. You know, I think, in this field, like you said, it's very easy to get caught up in all the things that are going wrong every day, but I think I find the most hope in really just recognizing that there are so many people working hard every day to make this world a better place, and I recently read this inspiring article from the New York Times that talked about how, you know, society won't really be inclined to act on climate change until we believe that our actions are useful and urgent, so that's the kind of things that I try to focus on. And, the collaborations that are going on, this increased focus on health and social justice and just, you know, the increase in urgency around these topics, I think that creates a space where people are more and more willing to act. 

David 21:09

Extremely well said. Thank you so much for your time today and your insights into this really important but still emerging connection between climate change and public health. 

Quinn Adams 21:20 

Thanks for having me. [music ends] 

David 21:23

[light, driving music] This episode of Cities 1.5 is produced by University of Toronto Press with generous support from C40 Cities. Want more access to current research on how city leaders are approaching climate action? We also publish the Journal of City Climate Policy and Economy. Our mission is to publish timely, evidence-based research that contributes to the urban climate agenda and supports governmental policy toward an equitable and resilient world. The Journal serves as a platform for dynamic content that highlights ambitious, near-term climate action, with a particular focus on human-centred solutions to today's most pressing climate challenges. To read the latest issue, visit JCCPE.utpjournals.press or click on our link in the show notes.

Clayton Page Aldern 22:23 

[rotary dial telephone rings] [clicks]  It's Clayton Page Aldern. I'm a senior data reporter at Grist, and I'm calling in from Seattle. [receiver chimes, replaced in cradle]

David 22:32

[light, rhythmic music] Clayton is the author of the recently published book, The Weight of Nature: How a Changing Climate Changes our Brains. In it, he explores evidence and stories which underpin the newly-emerging and alarming field of climatological neuroepidemiology which encompasses research and personal testimonies from city residents across the world. [music ends] 

Clayton, I'd like to say thanks so much for coming on Cities 1.5 today. 

Clayton Page Aldern 23:03 

Hey, thanks so much for having me, David.

David 23:06

So, before we start talking about the book, can you maybe speak a bit about how you've made this connection between neuroscience and climate change? 

Clayton Page Aldern 23:18 

Sure, happily. So, my day job is as a data reporter at Grist, and that has not always been the case, right? Winding up as a quantitative journalist working on climate change wasn't necessarily the goal from day one. I was in grad school for neuroscience and finished this graduate program and thought I'd kind of landed my dream job, which was effectively sitting in a windowless lab, looking at a computer screen all day, and modelling brain networks. I mean, this is the stuff in which I was interested. I was a computational neuroscientist, so it looked a lot like data science as a job, and also it felt a little bit disconnected from reality.

Ultimately, the long story short here is I pulled the plug on the lab with an aim toward taking the science in which I was interested out of the lab and into the world. And, for me, that transition looked like moving into public policy. I worked in housing and homelessness, and by way of a series of happy coincidences, ended up finding a staff job in journalism at Grist. This is about five years ago, and it was over the course of this transition that I was introduced to an editor who looked at my neuroscience background and said, "Hey, you know, you know about things that some other environmental journalists might not. Might you be able to take this background in neuroscience and give us some kind of series on the relationships between climate change and the brain?" Right? "This is your brain on climate change. Give us that."

And, I'm glad I did because the threads at which I began to pull, which at the time were on the relationships between extreme heat and aggression, extreme heat and cognition, mountaintop removal mining and major depressive symptomatology in residents of towns at the foot of these mountains. These felt like threads worthy of further investigation, and the long story short there is that this initial series for Grist eventually became a book proposal, and you're looking at the results of the six-or-so-year research timeline that followed. 

David 25:26

Can you tell us a bit more about how you went from having the task of writing a series about these issues to the book? Was there some kind of moment during this writing that you realized you wanted to write a book? How did that come about? 

Clayton Page Aldern 25:43 

It really was a function of a kind of unravelling. I mean, when I say "pull at threads," I saw some of these disparate fields of research in my mind kind of start to converge in terms of the point I felt they were making about climate change and neuroscience, with that central point being that brains are, by definition, enmeshed in environments. They're always reaching out; brains seek to model the world around them, and so, as a function of that prerogative, they're always taking in information about the world. [driving music] They're always seeking to get a sense of the statistical regularities of one's environment and present it to your felt experience, so you, as a person, you, as a thinking, conscious self, have access to information about the world. But the brain has this job of modelling the world around it and the world is changing, right?

So, as I began to pull at these threads of, again, aggression, cognition, after a certain time, I began working on brain disease – zoological diseases that are a result of expanding habitable ranges of disease vectors. I started looking at language loss, the extent to which a degrading environment may bear on something like vocabulary and the degree to which that vocabulary loss ultimately reflects a certain construction of reality on behalf of speakers of a given language. All of these threads, for me, began to point at this notion of brain as modeller, brain as embedded in the world around it, and therefore subject to the world's whims, subject to the manners in which that world was changing.

So, I don't know if there was a moment, per se, at which this necessarily became a book project, but I think as some of these central themes began to emerge for me, it at least became clear that there was an investigative and long-form treatment that warranted some kind of exploration. [music ends] 

David 27:48

Because the brain models the world around it as the world changes, that's also having an impact on the brain. Is that a layman's way to take what you were starting to see in your work? 

Clayton Page Aldern 28:00 

Yeah, I think that's exactly right. And, we see this in so many manners. The fact that the goal of the brain is effectively to capture regularities of the world and store them, such that we're not surprised by those regularities. If you were surprised by the fact that you had two hands, or that the sky was blue, you'd never get anything done because you would be in this constant state of shock and awe that the world looked the way it does.

But, you don't do that, right? You navigate the world, accordingly. And, the reason that's true is because your brain is kind of stashing those statistical regularities away and, instead, only really offering you new information effectively when it encounters something that doesn't necessarily match your expectations about the world. The brain seeks, effectively, to compare the expectations that you hold about what you're about to experience with what is actually happening on the ground, to the extent that it can estimate it, using things like eyes and ears and noses. And so, you're always taking in the sensory information about the world and comparing it to your expectations, and what provides the brain with sensory information is the environment.

And, again, the environment is changing, and so we should expect this organ that samples it regularly to change, in kind. That's kind of the theoretical neuroscience underlying this project. 

David 29:30

Can you talk about that, in the context of this change in the environment that, you know, perhaps the brain isn't used to, why that has an impact, how it has an impact, and what your research showed as some of the consequences? 

Clayton Page Aldern 29:46 

Yeah, some of this research has almost nothing to do with neuroscience per se, and instead comes from, you know, very careful observation on behalf of folks like behavioural economists who have been studying environmental effects on productivity, for example, or the likelihood of violence or civil riots as a function of these environmental determinants, for years.

And, you are probably familiar with some of these feelings that economists describe in aggregate, because you have felt more ornery in the heat, or maybe a little slower in terms of your thinking. It's harder to solve problems when it's very hot. It's a little easier to respond impulsively to various interactions that one might have in the world when it's hot, and those poor psychological experiences, these kind of universal shared truths, in terms of the human experience, that behavioural experience of being in the world, they do indeed have neuroscientific correlates. 

What do we know? We know that, as the heat marches on, as temperatures rise, we know from these behavioural economic studies, for example, that immigration judges are more likely to reject asylum applications on hotter days. We know that baseball pitchers are more likely to hit batters intentionally with their pitches on hotter days. The US Postal Service receives, you know, more racial discrimination and sexual harassment claims and union grievances on hotter days, right? We have all this evidence of these tendrils of heat reaching in, and the book seeks to think about this behaviour, think about the behavioural effects of extreme heat and other environmental vectors and environmental determinants, and then ask, "Why might these effects be manifesting?" And, it uses neuroscience as a lens to try to answer the why. 

David 31:52

The police chief in Toronto once told me that he had to have more officers on duty in really hot weather. 

Clayton Page Aldern 32:00 

We see this all over the world, right? It's not just Toronto. It's not just New York City. You know, effectively, anywhere you look, you see some kind of relationship, both at the individual level and the neighbourhood level and the level of the city and inter-city comparison, you see this relationship between something like heat and violence and something like heat and cognition, you know?

So, if we zoom the lens in on New York City for a moment, it's almost de facto true at this point that, indeed, as temperatures rise, you do see upticks in cases, for example, of domestic violence, you see upticks in aggravated assault. [gentle music] In New York City, for example, there is this fabulous study, conducted by an economist named Jisung Park, who compared students taking exams on the same day to both one another, but also to themselves over time. And, when you compare a student to his or herself, over time, you have this really nice, statistically valid comparison wherein you'll be able to isolate the effect of external variables in a way that simply comparing people to one another might not, and what Dr Park found is that, effectively, extreme heat, in addition to, and limiting the degree to which students are able to perform on these tests, you know, it also, by extension, limits the likelihood that they're going to graduate on time. There's this reliable effect that basically says something like for every extra degree Fahrenheit that students experience in New York City on exam time, the likelihood of graduating on time drops by 1% or something like that. [music fades out] 

The neuroscience appears to be, in both cases, a function of impulsivity, and the reason that we can say as much is because we've, as neuroscientists, effectively tossed people into brain scanners and asked what's happening from this FMRI perspective when heat influences the brain when people are exposed to heat. And, what we see is the swaths of cortex, they're really, really evolutionarily new stuff at the front of your brain, and in fact, the newest part of the new stuff, what's known as the dorsolateral prefrontal cortex, it looks overworked in the heat, and your rational decision-making centres, they're effectively becoming less coordinated with the rest of your brain. The relationships between those centres and other brain areas starts to look more randomized.

And, in turn, the influence of more emotional centres like the amygdala, for example, which is sending projections up to the front of the brain, as well, they tend to take on undue influence, effectively, so you have this situation in which the rational deciders of your brain are almost malfunctioning. What they're actually doing is worrying about keeping you alive, and so the energy that would otherwise go into rational decision-making is basically going into survival, and what's left is you have an outsized influence of these limbic structures, these emotional structures like the amygdala on other parts of your prefrontal cortex. And so, you see, effectively, impulsive decision-making arise in time. 

David 35:26

We're seeing lots of extreme weather events. Last summer, Canada was essentially on fire and it was so bad that, you know, the smoke was a public health hazard along the East Coast, the United States. The mayors all made a statement about it and connected it to climate. It's a climate-related event. Can you speak a bit about the impact of storms on mental health and our brain activity, and specifically, I know there's been research done on children who were in utero during Hurricane Sandy, Superstorm Sandy in New York City and I think people will be interested to hear what that research shows?

Clayton Page Aldern 36:03 

Yeah, happy to. So, when we think about extreme weather and natural disasters, and I will indeed include wildfires in that conversation, as well, we're thinking about a couple of different modes by which these extreme weather patterns influence neurocognitive health and mental health and, indeed, the cellular health of neurons. 

You mentioned smoke exposure, for example. Particulate matter is really bad for the brain. This is something that we've known for a very long time and, you know, are effectively at, you know, kind of “smoking causes lung cancer" levels of evidence. Particulate matter exposure is highly predictive of neurodegeneration – various dementias, Alzheimer's, Parkinson's, that kind of stuff. Small particulates can effectively cross the blood brain barrier, so they hitch a ride, you know, up on your nasal nerve and then get into the brain where they cause this low-level inflammation chronically.

And so, what happens when you experience chronic inflammation in brain tissue? The argument that researchers are furthering is that this is one additional step along the way to neurodegeneration. So, that's one example of how do we experience this stuff in the present? 

But, as you suggest, it's not just the presence that we need to be concerned about because, in some cases, the imprint of extreme weather on our brains, it occurs before we've even had a chance to be born. You mentioned this Hurricane Sandy study, and it stems from the lab of this scientist named Yoko Nomura at CUNY, and Nomura's work was kind of—how do I put this?—serendipitously well timed in terms of the fact that she had gathered a cohort of 400 or so expecting mothers—this is around 2009, 2010—as part of a study called the Stress in Pregnancy Study, and she was interested in cataloguing the various environmental and socioeconomic stressors to which pregnant women were exposed, and then she wanted to track the maternal child health outcomes in question over the first, you know, decade of the children's lives.

And then, Hurricane Sandy waltzed into town in in 2012, you know, a couple of years into her study, and it was this moment in which she was able to effectively isolate the effect of one environmental stressor because there were children in the study who had been born before the storm, there were those who were in utero during the storm, and then there were those who were conceived after Sandy. And so, she had this cohort of children that she was then able to effectively follow for the first decade of their lives and ask questions about neurocognitive outcomes and neuropsychiatric health.

And, ultimately, what she found is that the children who were exposed to Sandy in utero had, by preschool, developed a drastically increased risk of various neuropsychiatric conditions like anxiety and depression and ADHD and various conduct disorders.

[driving music] So again, some of these changes that we're talking about, some of these brain changes, the neuroscience in question, it manifests very early in life and indeed, sometimes before one is even born. [music fades out]

David 39:30

It's fascinating the impact that this can have on babies, in utero. It's also very worrying and it's worrying, the cognitive impacts, if I understand from a layman's perspective, could be leading to deterioration, dementia, that kind of direction in adults. You also talk about potential health impacts from zoonotic diseases, and you have this wonderful phrase, "Vampire bats are climate refugees, too". Can you just speak a bit about that impact, as well, because, if we've got, on the one hand, severe impacts or concerning, let's say, impacts on children and adults from various climate-related matters, and then for another side, zoonotic diseases, that's extremely concerning. 

Clayton Page Aldern 40:23 

It is concerning, and the zoonotic story is very easy to tell, because people don't need to do anything different to experience an increased risk of some of the brain diseases in question that are carried by these types of vectors. For example, ticks, mosquitoes, indeed, vampire bats, some of these vectors of brain disease, they're increasing their habitable ranges as a function of a changing climate. So, even if you, David, don't do anything different, you may be experiencing an increased risk of contracting one of the diseases in question, and this is stuff like yellow fever and cerebral malaria, all that fun stuff, just because the zoonotic vectors of those diseases may be more likely to run into you, because their habitable range is increasing.

And this is to say nothing of the fact that people are modifying their behaviour, insofar as urbanization and deforestation are very frequently putting people into closer proximity to the disease vectors in question. And so, as we encroach on these natural habitats and as the range of these habitats tends to broaden, there's this kind of twofold storm wherein we're, almost by definition, as a matter of billiard balls bouncing off of one another, more likely to experience some kind of zoonotic brain disease. 

David 41:49

The work you're doing is in a new field that's provisionally called climatological neuroepidemiology. Can you just talk about what the most interesting areas of research are that you are seeing at the moment in that area? 

Clayton Page Aldern 42:04 

I actually think some of the most compelling research in this field that indeed I've provisionally called climatological neuroepidemiology, some of the most interesting research in this field is happening at the intra-city level, which is to say we're not just looking at brain cells, we're not just looking at organisms – we're looking at the relationships between organisms, which is to say, people and the built environment around them and the manners in which we interact with one another inside cities.

I live in Seattle. There's a huge life expectancy difference between people who live in North Seattle and live in South Seattle, and one of the reasons that's true is because in South Seattle, you have a drastically increased exposure rate in terms of things like noise pollution and diesel exhaust. There's less green space, and so people are exposed to more heat, because I think the micro scale is the level of the person in this conversation and the macro scale would be the global conversation. But, at this mesoscale, at the level of the city, I think we're finding some really compelling epidemiological evidence suggesting that the changes in question are real, right? The effects of these changes are real, and I think, to the extent that researchers can make these effects known to people, as opposed to offering them up as somewhat theoretical, we're able to track said outcomes in real cities, I think that kind of evidence is going to be extremely useful for policymaking. 

And, you know, what are the outcomes in terms of that public policy work that I find to be most useful? I think it's when folks take a look at that research and make smart decisions about the built environment, based on them. The decisions that we make about density, about green space, about clean air and water within the built environment, these have real neurocognitive outcomes and being able to demonstrate as much really matters to me.

I'm interested in looking at evidence of scalable solutions. At the level of the city, that might look like, you know, an investment that a given urban area has made in green space and the corresponding health outcomes that one does indeed observe when those investments are made. I like to look at those types of empirical outcomes and say, "Okay, let's think about the manners in which this solution is scalable." I think, when you start to think about the question of scale, we can move beyond the complacency that I fear hope can inspire, and instead toward an action and an action that is motivated by desire.

[driving, pensive music] I want more cities to look like the one that has the equitable distribution of green space that leads to good health outcomes. So, that's kind of the picture of the future in which I'm interested, and I think there's a lot of really important work to be done on that front. 

David 45:15

It's a fascinating picture of the future, very aligned with C40's vision of cities and, you know, one of the things you said today that really struck me is the impact of particulate matter on brain health. Our Co-Chair, Sadiq Khan, has worked very hard to lower emissions in London, because of the impact on breathing, and there's going to be a benefit on brain health, and that gives me hope because it's a real action that makes a real difference for hundreds of thousands of people.

And, you know, Clayton, you give me hope. What you've said today is daunting and worrying, but if we know the facts, at least then, we can try to take the actions to change them. You've been incredibly generous with your time and I wish you continued success with your work. 

Clayton Page Aldern 46:04 

Hey, thanks so much for having me, and I'm with you. I think awareness is a really, really important first step here. [music ends] 

David 46:15

[energetic, upbeat music] The idea is that the climate crisis is literally changing our brains, and that global cities face new threats in the form of expanding disease regions is terrifying, but it's the reality we have to face if we're to fully understand the folly of continuing to burn fossil fuels.

These emerging fields are yet another front at the intersection of public health and the impacts of global heating. Cities will bear the brunt of many of these alarming impacts on public health, which we will be increasingly facing as climate impacts worsen. It's critical that all orders of government and policymakers use this research when building urban climate and public health policies, especially if our most vulnerable city residents are to be protected. [music fades out] 

[Cities 1.5 main theme music] Next time on Cities 1.5, we revisit a topic that is so crucial to climate justice, we've dedicated an episode to it every season – wellbeing economics. This time, we speak with two experts who are helping to put these fundamental principles into practice a hemisphere apart from each other.

Thobile Chittenden works at the Wellbeing Economy Alliance as Network Co-Lead in Johannesburg, South Africa, and is also the CEO of the Makers Valley Partnership. Hollie Irvine is the Love Letham Project Lead with the Perth, Scotland, arm of WEAll. Far apart and drastically different as the communities they serve may be, we'll see how the values they share and the foundations they're building are creating good lives for all now, and into the future too.

[Cities 1.5 main theme music continues] This has been Cities 1.5, leading global change through local climate action. I'm David Miller. I was the Mayor of Toronto, Canada, and I know, firsthand, the role cities can play in solving the climate crisis. Currently, I'm the Editor in Chief of the Journal of City Climate Policy and Economy, published by the University of Toronto Press in collaboration with the C40 Centre for City Climate Policy and Economy, where I'm also the Managing Director. C40's mission is to use the voices and the actions of its member mayors to help the world avoid climate breakdown.

[music continues] Cities 1.5 is produced by University of Toronto Press in association with the Journal of City Climate Policy and Economy and C40 Cities. This podcast is produced by Jessica Schmidt, and edited by Morgane Chambrin. Our executive producers are Peggy Whitfield and Calli Eliopoulos. Our music is by Lorna Gilfedder.

The fight for a healthier world is closer than you think. To learn more, visit the show's website, linked in the episode notes. See you next time. [main theme music continues then ends]