Media Briefings

Urban Heat: How rising temperatures affect U.S. cities

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Daytime temperatures in cities can be as much as 1 to 7 degrees Fahrenheit higher than in nearby rural areas. This “heat island” effect, caused by the absorption and re-emission of heat from buildings, roads, and other urban infrastructure, is worsened by climate change and affects the health of city dwellers. SciLine’s latest media briefing covered the basics of urban heat and related weather patterns, the effects of extreme heat on human health and wellbeing—including disproportionate impacts on low-income populations—and strategies for designing more heat-resilient cities. Three scientific experts briefed reporters, and then took questions on the record. 

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RICK WEISS: And hello, everyone. Welcome to SciLine’s media briefing on urban heat islands, climate change and health. For those not familiar with SciLine, we are a philanthropically funded, editorially independent, free service for journalists and scientists based at the nonprofit American Association for the Advancement of Science. Our mission is pretty simple. It’s just to help reporters like you get more scientifically validated evidence into your news stories. And that means not just stories about science, but any story that can be strengthened with some science, which, frankly, in our view, is almost any story you can think of. We know that many of you are not specialty science reporters, but even those who are have less time than ever to do your reporting. We’re here to lessen that load. Among other things, we offer a free matching service that helps connect you to scientists who are both deeply knowledgeable in their field and are excellent communicators on deadline or as needed. Just go to, and click on I Need an Expert.

And for those of you, I just want to say as an aside, who are looking for fresh city-based story ideas, I encourage you to visit the experts on camera page on our website to sign up for a one-on-one video interview opportunity with a city planning researcher we’ve lined up to be available next week who can discuss what’s next for once-bustling downtowns that are now languishing because of the pandemic – a really interesting story and some great expertise there. Check it out at, and look for Experts on Camera.

Today’s feature – today’s briefing will feature three experts on a topic that could hardly be more timely as many U.S. cities have been roasting in record-breaking temperatures. They’re going to help you untangle some of what you’ve heard or read or felt if you don’t have air conditioning so you can include some essential science in your extreme weather stories, not only weather and climate science, but also social science because many of the factors that are contributing to our cities’ increasingly disastrous thermal realities are the result of people and their behaviors and policies.

I’m not going to take the time now to give full introductions for today’s experts. Their bios are on the website. I’ll just say that we will hear first from Dr. Chandana Mitra, who is an associate professor in geosciences at Auburn University, who’s going to provide an overview of urban heat island science and how the heat-absorbing and heat-generating aspects of cities are exacerbating climate change-related temperature increases. Second, we’re going to hear from Dr. Jaime Madrigano, an epidemiologist and researcher at RAND Corporation, who will speak about direct and indirect health impacts of heat stress and why some communities are more impacted by urban heat than others. And then finally, third, we’re going to hear from Dr. Vivek Shandas, a professor in urban studies at Portland State University, who will expand on some of the historical disparities that are today contributing to the inequitable impacts of heat stress on different communities. And we’ll talk some about solutions, the kinds of things that communities can do to mitigate against current urban heat island trends. And with that, we’ll get started. Over to you, Dr. Mitra.


Overview of urban heat island formations in cities


CHANDANA MITRA: OK. Thank you. Sorry. I was muted for that. Thank you, Rick. So I will begin with – let me click on this. I will begin with explaining to you why cities have a different climate than the surrounding rural environment. So what happens is when we replace the natural surfaces – the meadows, the forests and the fields – with stone and concrete, they are – they do nothing but trap and store all of the heat which is emitted from all these surfaces. And that’s a reason why urban areas or cities are a few degrees hotter than the surrounding vegetated rural area. To give you a better perspective, say, for example, we were not having this online, this particular meeting, and we were all cramped up into a room. And say, now I know it’s a 120, but say 100 people and 300 watts is the minimum around what we emit, each one of us. And so around 30,000 watts of heat just because of us being in a room. So if you translate that knowledge and talk about cities, think of, say, thousands of people, in some cases millions of people in cities doing their job, going around – cars, buildings and the amount of heat the city generates. So that’s a reason why, over the city, a bubble, a heat bubble occurs, which is different from what the surrounding environment is. And this phenomena of a heat bubble is also referred to as a heat island, urban heat island. Now, in a very simple way if I explain to you what heat islands are, so it is just the difference between the temperature of downtown city area with the rural neighboring outside of the urban areas. That’s what urban heat islands are, urban heat in density is – the difference between temperature of downtown and the rural areas. So generally, an average is between three to five degrees Fahrenheit. But of course in cities like Phoenix, on any given summer day, it could go up to 15 to 22 degrees.

So urban heat islands depend very much on where the city is located, the background climate, the time of the season – of the year, the time of the day, all of those factors – if it’s near the sea or it’s inland – all of those factors actually influence the urban heat island in density. Now, the bottom here, I have a video from National Weather Services, which later on you can watch little more details on what urban heat island is. Now, moving on from this, a very important message which I want to pass on to all of you is that it’s not only the big cities. It’s not only Los Angeles, and New York and Atlanta and Beijing, New York – sorry – New Delhi and Lagos are having urban heat islands. It’s also the medium and the small-size cities. So around a city, which is a million or so population, they would have anything between a two to six degrees Fahrenheit temperature differences between the core of the city and the rural areas. So very important not just to look at big cities, but also smaller and medium-sized cities because when a natural disaster hits on any extreme weather even, be it heat waves, urban flooding, hurricanes, tornadoes, we cannot just ignore the small and medium-sized cities because people live in them. So the brunt of climate change, the brunt of all these extreme weather events are also felt by people who live in these small and medium-sized cities, the communities.

Having said that, I could not share one of these iconic dramatic pictures of Hotlanta. And this is a satellite image which kind of gives you the surface urban heat island. And you can see how red it is. It’s all red. And the redness kind of a little bit becomes yellowish as you move away from the core of the city. But the dark blue patches there are not all the vegetated parts. They are actually the shadows of these tall buildings. So they are still concrete. So that’s really a very important message from this particular image.

Now, moving on from big city, which I also want to emphasize, as mentioned earlier, is the small and medium-sized cities. So this is my research with one of my students. Birmingham and Auburn-Opelika, both in Alabama. So Auburn is where I am now located there, doing this talk from. So Birmingham has 212,000 population, and Auburn-Opelika together have 160,000. So pretty small as compared to the big cities. But even small cities like this, they have anything between four to five to six degrees Fahrenheit temperature differences between the core of these cities and the surrounding rural areas. So it exists in all cities, every size, everywhere.

Now moving on to heat waves, because we are hearing a lot about heat waves that happened in Europe earlier on and then, of course, Siberia, now northwest British Columbia, everywhere. So talking about how heat waves are connecting with this urban heat island which exist for every city. First, I just want to draw attention to these definitions of heat waves, which is the numerous definitions. I just had, like 15 and above, but they are 20, 25. Lot of definitions coming from different institutions and from different scholarly groups. But I would think that the National Weather Service is one which kind of says that if you have three consecutive days with a maximum temperature of over 90 degree Fahrenheit, then they will declare that to be a heat wave. And that’s where the cities and the people communities start preparing what to do next if you have a heat wave.

Now, a very important thing as we’re seeing more and more happen, especially what happened last two weeks in northwest U.S., is this – how the top of the atmosphere is connected with what’s there on the surface. So we understand that there is phenomena which is high pressure blocking, which happens over the region and sits for days and sometimes for weeks over a certain region. And that creates these heat waves. In sum, they create heat waves. So what happens is – so heat waves are something which is more of a top-down approach kind of affecting what’s there on the surface. And what’s there on the surface, there are cities, which have their own urban heat island, right?

So in this particular study, which me and my colleagues have done – this is again for Birmingham, Ala. What we saw – this was a unique case in 2007 where there was a regional drought, extreme drought event. There was an atmospheric high blocking event, which created the heat wave. And then, of course, we had urban heat island for Birmingham city itself. What we found is because of all this, you know, the cooking of this soup between the different layers of the atmosphere and the bottom, what happened is there was the urban heat island of Birmingham got enhanced by around two or three degrees Fahrenheit. And now if you say, oh, well, two and three degrees is not enough. What’s the big deal with that? Say, if you’re running a fever of two degrees, how would you feel? So imagine the city is constantly running fever, and the people living in those cities are constantly getting hammered by this discomfort, the thermal discomfort, which is created because of this heat waves and the urban heat island.

Now, last, what I want to just point out is that urban heat island doesn’t just impact humans and just create the, you know, the discomfort, but it also impacts the other weather phenomena, like precipitation. It influences the amount of rainfall. The rainfall is sometimes higher in the downwind of the city because of the impact of urban heat island. It also impacts – connected with air pollution, it impacts the amount of lightning falling in cities. It also impacts how dry your city will be. So I’m not going to go into any more details in the interest of time, but I’m going to leave these slides. And if you have any questions, please, you can ask me in the Q&A session. So I think that’s end of my presentation. And thank you for listening.


RICK WEISS: Thank you for that great introduction, Chandana. And a reminder to reporters, all these slides and a transcript of these presentations will be available on our website after the presentations today. We’ll move on next to Dr. Madrigano.

Effects of Urban Heat on Health


JAIME MADRIGANO: OK. Thank you, Rick, and thank you for the opportunity to be here today. It’s a pleasure to be on this esteemed panel and to discuss this topic of utmost importance – the effect of urban heat on health. So I want to start out by broadly covering the health impacts of heat, and I’ll start by saying that these are not limited to just urban areas. In fact, there are many populations outside of urban areas that are particularly at risk for health impacts from heat, especially outdoor workers like agricultural workers. But as Chandana so nicely covered how heat can get trapped in urban areas and that can really exacerbate the effects in urban populations, that’s our focus today.

So during extreme heat events, we see a rise in emergency department visits, hospitalizations and death in the general population. And these types of health encounters also increase with moderate rises in temperatures, too. So it’s not just extreme heat waves or heat events, particularly for vulnerable populations. Classic signs of heat exposure include heat cramps, which are muscle spasms during vigorous activity in hot environments, heat exhaustion and heat stroke, which is potentially fatal. And these are all related to body overheating. But it’s important to note that these conditions, which people most often associate with heat exposure, are just a small portion of the health impacts that we see when we carefully look at data from an extreme heat event.

So physiologically cooling is achieved through increased blood flow to the skin and sweating, and these mechanisms rely heavily on the cardiovascular and endocrine systems. Kidney disease can also impact the body’s ability to cool itself. So we often see increases in cardiovascular disease and kidney disease during extreme heat. Respiratory disease is also linked to heat exposure. And one thing to keep in mind is that high temperatures can also contribute to harmful buildups of pollutants in the air. And there have also been studies that have shown that extreme heat exposure is associated with poor reproductive outcomes like preterm birth and even mood and anxiety disorders.

So heat is sometimes known as a silent killer, and that’s because unlike other natural disasters, like hurricanes, there isn’t obvious damage, big physical destruction that people associate with injuries, illness and death. But according to the National Weather Service, on average over the last three decades, heat has been associated with more fatalities than any other type of weather event. That includes hurricanes, floods, tornadoes. But it’s interesting to note that when the National Weather Service estimates the number of heat-related deaths each year, their totals are based on deaths that are directly attributable to heat. And these estimates usually come from codes on death certificates that specifically identify excessive heat exposure as the cause of death. However, as I mentioned on my previous slide – oops, sorry. As I mentioned on my previous side, there are many other types of illnesses that increase during extreme heat events, things like cardiovascular disease and respiratory diseases as well. And often, these are the things that are noted on the death certificate. So that’s why it’s really important for researchers to take statistical approaches to really quantify the health impacts of exposure to heat. And that – the way that usually works is for a given urban location or city, researchers may look at the number of deaths or hospitalizations that have occurred during the time period of the extreme heat event or when the temperature rose and compare that to long-term daily average death rates for the same time of year for that particular city. So in that way, researchers can estimate the number of excess deaths or excess hospitalizations that are associated with that heat wave event. And recent studies indicate that in the U.S., there may be as many as five to even 12,000 excess deaths due to extreme heat each year.

So a really important point to note is that he is not an equal-opportunity killer. And so while everyone can be at risk during a heat wave event, when temperatures get very hot, certain populations are more susceptible than others and are more frequently impacted. There are three factors that we think about when we think about heat vulnerability, and that is exposure, sensitivity and adaptive capacity. And as we’ve been talking about today, certain areas have higher heat exposure than others, and that’s because of things like lack of tree cover, more asphalt and concrete. And people that live in these areas have higher heat exposure on any given day. People can also be exposed to more heat because of their occupation – so, for example, outdoor construction workers. And people can be more sensitive to heat because of their age or underlying health conditions and the medications that they take for those conditions, which can affect the body’s ability to cool itself. And finally, adaptive capacity relates to a person or population’s ability to mitigate the effects of extreme heat. So low-income populations have less capacity to adapt because they may have financial constraints which may limit their ability to access air conditioning. They may have poorer housing conditions which retain more heat, and those residences may also be in parts of the city that are hotter. And similarly, studies have shown that communities of color have been more impacted by extreme heat. And this may relate to other health and socioeconomic factors that affect exposure, sensitivity and adaptive capacity.

But interestingly, even in work that I have done in New York City, we found that access to air conditioning was lower for Black New Yorkers than other race/ethnic groups, even after adjusting for income. So we think that this actually points to the pernicious effects of systemic racism. For example, traditional measures of socioeconomics are not equivalent across races. So Black individuals may have lower purchasing power than white individuals due to the fact that costs of goods and services are higher in many Black communities. People of color may also be more likely to live in buildings that are not conducive to AC installation because of the older wiring. And furthermore, it’s important to point out that the way our cities have developed over time reflect a host of systemic discriminatory practices. For example, historical redlining, which I’m sure Vivek is going to cover much more thoroughly, has resulted in communities of color, low-income and immigrant populations living in parts of the cities that retain much more heat due to lower tree canopy and other aspects of urban form.

So this is why when we think about infrastructure, it’s really important to consider the growing burden of urban heat and its inequitable consequences because there are aspects of city design, energy infrastructure and housing conditions that are all very relevant to heat and health. And then finally, I wanted to end by making the point that extreme heat is a significant public health burden. And we often say that climate change is expected to worsen it. But what I wanted to point out is that climate change has already made it worse.

So I’m sure you’ve heard reports about the recent devastating heat wave in the Pacific Northwest and that would have been virtually impossible without climate change. But beyond that, a study published earlier this year looking at data from over 40 countries over the last few decades estimated that 37% of warm season heat-related deaths can be attributed to anthropogenic climate change. And while different populations have varying degrees of risk perception when it comes to heat, depending on their age or social vulnerability or the general climate in which they live, several studies have shown that communicating the health risks can be an important motivator when talking about climate change. So it’s important to make these connections when reporting on this topic. Heat is an exposure that is important and a growing public health burden. It has already been affected by climate change and is expected to continue to worsen. So thanks very much and look forward to questions.


RICK WEISS: Thanks, Jaime. Super interesting. A lot of factors there that maybe we don’t think about every day, including I think it’s so interesting to think about places where the wiring just can’t handle an air conditioner. I know several outlets in my house if I put my air conditioner in, I blow a circuit. At least I have a few that will work. Let’s move on to Dr. Vivek Shandas.

Converging Heat Vulnerability: Our Atmosphere, Our Policies, Our Response


VIVEK SHANDAS: Hello. I hope you can hear me. Well, I am delighted to be here on a pretty somber topic around converging factors that affect heat vulnerability. I think this builds really well on what Chandana and Jaime have just set up. And I just want to talk a little bit about history before getting into a little bit of the direction forward that we’re really embarking upon here, really thinking about this from a science policy and solutions perspective. And that’s really where we’ve been spending a lot of time in this heat work.

I want to start with what Jaime just mentioned in passing around the historic trauma that many communities face when it comes to policies that were promulgated in the 1930s during the Roosevelt administration that Congress quickly passed and that really segregated our neighborhoods into four distinct categories of risk. And so that’s what we generally refer to as redlining. And those areas that were considered – that were drawn with red lines were considered the most risky for home mortgages. So one might be asking, why would home mortgages have anything to do with heat? And it turns out we did a – what I would consider a groundbreaking study that was published last year. You may have seen some press about this in relation to how these redlined areas were consistently facing – and the communities living in them were consistently facing hotter environments. And that really comes down to a set of policies that were put in place that amplified temperatures. These were four grades, A being, quote, “the best” or the least risky, if you will, from a home mortgage point of view and D being, quote, “hazardous” from that perspective. And what we saw was about a almost a five-degree difference in terms of the areas that were highly invested. So those were the A areas versus the D areas that were highly disinvested over time. And that really translated out to regardless of whether we looked in the Northeast, Southeast, Midwest, inner mountain range or even West Coast, this pattern was really consistent across the 108 cities we looked at in the United States – in the continuous United States. And when we looked a little more closely, we found that the amount of impervious surface – that’s the asphalt, the concrete, the materials that really amplify – they absorb that shortwave radiation coming in from the sun and readmit it as longwave radiation – really kind of is already baked into many of these neighborhoods in terms of the amount of tree canopy and impervious surface that Jaime was just referencing.

And this plays out on an intra-urban scale. And what we have seen now, as we looked more closely at many of these neighborhoods that were redlined or greenlined, is that we found that this was a conscious and deliberate planning effort at the local planning – through local planning agencies, where greater amounts of asphalt was put in these locations with big box stores, a variety of other large, asphalt-ridden landscape features, highway projects in the 1950s. As we were moving lots of concrete and material, those were often put into the C- and D-grade neighborhoods. Large-scale housing projects were also cited in those – has continued, actually, through to this day is these large-scale housing projects also find themselves in C and D neighborhoods. Industrial facilities were often cited in these places. And then lack of parks and green spaces – with the disinvestment that was happening, there was not money being put towards the green areas. We created a little online link – which I’m happy to share these slides and – that you can go to and look to see if your city is actually one of these places where we had examined for this particular redlining study.

The story kind of continues into what we’re talking about, what we do today as a result. So part of the solutions or the direction that we really think we need to be moving towards is engaging communities in their place, developing the analytical tools that are necessary for examining different scenarios of how – as a place changes, what can we do to adapt and mitigate some of that heat? And then what can we do to continue to build capacity for community groups as well as decision-makers? And we call this the heat watch model, where we essentially engage local communities. We collect hundreds of thousands of individual temperature and measurement points in a location, and then we work with the communities to actually interpret those – the meaning of that particular distribution of what we have, what we see in those locations. These are really fun exercises to engage communities, to go out, collect real science data and – as a civic science activity. And we’re then able to run some really fancy mapping algorithms to create these surfaces that describe air temperature in these locations throughout a city. And so we put this together in a report. In this case, we were – we’re looking at a place in Texas, Houston, in Harris County, where we collected over 232 individual measurements with community groups and saw a temperature differential of about 17 degrees across one particular city. And of course, there are web maps that you can go in. This is Miami. You can go in and kind of hone in on specific neighborhoods, put in addresses and see what the heat is in those locations as well. So this is an attempt to try to not just identify historic patterns of what is it that we need to do – though also to think about how can we engage communities in identifying the solutions at the very local level?

And I’ll come around the corner and close up here for some promising directions that this work is offering. I had the good fortune just yesterday testifying in front of Congress around this particular issue. And one of the things that’s really getting some attention is bills that are attempting to put money in the hands of local communities to be able to start mitigating the risks of extreme heat. For all the reasons that Chandana and Jaime have identified this, these are bills that are attempting to really focus the attention, the nation’s attention on the discriminating killer that heat is, often affecting communities that are low-income, marginalized communities, as well as those who have pre-existing health conditions or are older. And so these are very promising directions. And I’m really looking forward to seeing if this gets some traction as we move forward.

I want to leave some references for you of some of the work that I presented today. And I’m, again, happy to share these slides and turn it over to our discussion. And here’s some contact information related to – if you have questions about climate equity or infrastructure, I’m glad to engage. Thank you.


What are some science-backed tips and pitfalls-to-avoid for reporters covering urban heat and rising temperatures?


RICK WEISS: Fantastic. Thank you, Vivek. It’s – you know, climate change and warming is so often seen as a national, global problem. And it’s hard to get your arms around thinking about solutions. It’s great to see the attention being brought down that this is truly a local story that reporters can cover as local news and aim towards solutions. We’re going to start our Q&A now. I want to remind reporters you can click on the Q&A icon at the bottom to send in your questions. And just before we start that, I want to make a quick note that some of you may be interested in that a group called Climate Central, which is a research group some of you may be familiar with, just this week released a report on urban heat islands called Hot Zones. And it offers some really nice city-specific heat graphics that may be of interest to some of you who are covering this for your local outlets. So you may want to check it out after this briefing at

And we will move into the Q&A right now. And I want to start just with one question that we always pose to our experts at the beginning of the Q&A session, which is just to ask you each to make a quick remark about what you’ve seen in terms of the media coverage of this topic to date and any advice you’d like to share in terms of something that you’ve seen getting done in the media on this topic that you think is admirable, that you want to encourage, or things that you see that are a little bit problematic or not what you wish they would be to help reporters continue this work in as high quality a way as possible. And I will start with you, Chandana.


CHANDANA MITRA: Yeah, thank you. That’s a great question. So first, I would like to say that the media is doing a great job. So what we saw 10 years back, climate change and, you know, different aspects of climate change were not that discussed or printed out or in news media. But I think everyone is doing a great job on that for the past few years.

One thing, which I personally – being in academia, I feel that we are doing enough for our community. But where I think the press could really reach out is K-12 because what I think is the K-12, the students, the kids who are in schools, especially the ones who are, like, 6th to 8th grades where they really have the formative years, they are going to be the activists of tomorrow. So we are doing what we are doing. But they are the ones whom we have to train to be much more vigilant, much more aware of what the problems they will face. So I think if there’s a way in which media can write at their level and probably send out some newsletters, something off to superintendent of schools or different other ways in which students K-12 can be engaged, I would suggest that would be a very good way of involving more, you know, students and parents and grandparents into the stock of climate change.


RICK WEISS: Great. Thank you. Jaime.


JAIME MADRIGANO: Sure. Thanks. Well, I think there has been a lot of great media attention to this topic, as Chandana said. And I think, you know, in particular in the middle of summer at this moment and right now, we see a lot of attention to it and a lot of media attention to it. And I think that’s great. And there’s growing, I think, recognition of the health impacts, which I think – you know, some years ago there was less attention or less recognition of those health impacts and more just around physical discomfort or people exercising. So I think that’s been a great direction.

I guess I would say that, you know, we’ve all talked about some of these really, like, long-term decisions and planning and things that really go into how heat affects people. So things like energy infrastructure, housing infrastructure, all kinds of infrastructure that we’re thinking about now. So I would say it would be great to hear more holistic media attention to these long-term thinking, not just when we’re in a crisis moment in the middle of July when a heat event has occurred or is about to occur, but tying it to the other discussions around long-term thinking and resilience and those ultimate health impacts. And with that, I think there’s a lot of solutions, as Vivek mentioned, that are being driven at the community level. So that’s a great place to look to for those that kind of thinking.


RICK WEISS: Great. And Vivek.


VIVEK SHANDAS: Yeah. I just build on these great comments already made. I think the media is really doing an excellent job with individual stories of heat exposure. Like, what is it about this particular person living in this trailer park, for example, that died recently during the Pacific Northwest heat dome? Like, what were the conditions there? What was that person experiencing? Did they talk to their neighbors? Like, those stories have been very compelling to help folks like me get a better understanding of the pathways through which heat can affect individuals and amplify vulnerability. And that, I think, is just a big kudos, big thumbs-up on those stories.

A couple of places where I think it might be helpful to dig a little bit deeper is to think about what I was just framing this up in terms of convergence of the social characteristics and the built environment characteristics of a individual place or an individual neighborhoods and the way in which heat actually affects that almost coming together of a perfect storm to create this excess mortality or morbidity that we see from heat waves. And so heat waves don’t just kill people by coincidence. There’s really a set of conditions that are in place. And fleshing that out a bit more, I think, would be really helpful. While the numbers of the almost thousand people who died in the Pacific Northwest heat wave – heat dome recently is helpful, those individual stories, I think, are only coming out now and very helpful.

And just one other quick plug for graphics – trying to – the reason we were able to get traction with some of the heat equity work and the redlining work is because we were able to get down to very detailed descriptions of where heat was higher and lower in terms of a specific region. So whether that’s a state, whether it’s a metro area, whether that’s a county, et cetera, getting a bit more on the graphics, which our colleagues and our practitioners say speak for themselves, that would be really wonderful to see as well.

In rural areas, where there is less concrete and asphalt, what happens to heat?


RICK WEISS: Cool. Great idea. Thank you. All right. We’re going to move into some of the questions you all have been submitting. And I’m going to start with a question directed to Chandana. It’s virtually a physics question but I think one we can handle here from Mark Victoria (ph), a freelance video producer, who mentions that you said cities with all the concrete and stone absorb more heat than grasslands and tree-covered areas. So in those more natural areas, where does the heat go if it’s not getting trapped by concrete and asphalt?


CHANDANA MITRA: Thank you for the question, Victoria. So to answer to you, I would say. And I think Jaime once referred to it as that it’s when heat wave or heat excess heat up, it’s all for cities as well as for rural areas. So having said that, it’s not that the rural areas don’t get heated up. The thing is all what’s above the rural area, above the surface and above the city. So we have – if you think of natural surfaces, then when it heats up, you know, when the sun sets, it kind of escapes back into the atmosphere, right? But when you have a city, what happens is you have air pollution. You have more pollutants there. You have more, how would I say, more buildings and more – less trees, again, and several factors are not matching up to what you see in a rural area. So when the same amount of insulation from the sun comes down on the surface, if one is city and one is natural, the natural one equally heats up and releases the heat as the sun sets. But in case of cities, the absorption is more. The retention is more. And when the sun sets, there’s, of course, release of heat. But it – because of all the things in the air, the pollutants and water vapor, whatever it is, everything kind of traps more heat and, thus, forms the bubble, which doesn’t happen over a rural area. So that’s a basic physical side of differences between the environment above a city and that – what’s happening with the heat in a rural area.

As eviction protections end, how do heat and climate factor into what could be an influx of people losing their housing?


RICK WEISS: The ability to radiate out. Interesting. Great. OK. A question here from Scott Morgan at South Carolina Public Radio. Vivek, this may be for you or Jaime. The CDC’s eviction protections will be ending next week. How does heat and climate play into what could be an influx of people who might be evicted? Jaime, I see you nodding. Do you want to take a first shot at that? Oh, you’re on mute.


JAIME MADRIGANO: Oh. Sure. Yeah, sure. Yeah, I would say, you know, as mentioned, you know, indoor housing conditions play a large role in how people are affected in terms of health. We spend most of our time indoors. And so, you know, a lot of people that die from heat events are dying in their home. So obviously, proper housing conditions and the ability to stay cool indoors is very important. So I think, you know, we should probably be thinking of heat as a disaster and crisis like we thought of COVID, like we think of hurricanes. You know, people do need shelter that can protect them from this. And so I think, you know, it is unfortunate to think about those safety measures ending. And I think, you know, there is evidence that, for example, homeless populations are more susceptible to heat waves. And so this is something we need to be thinking about in terms of preparedness and planning and especially, you know, in the – with the idea of overlapping disasters as well. So, you know, in the summer, you may not just be affected by a heat wave, you may be affected by a heat wave and a wildfire or a hurricane event as well. And so these are all the types of things that we need to be planning for.

As heat rises in many places, how can we address the fact that air conditioning also contributes to greenhouse gas emissions that, in turn, drive climate change?


RICK WEISS: Question here from Ivan Amato, freelance reporter, mentions that air conditioning and cooling technology generally is one of the biggest contributors to energy use and associated CO2 emissions, as well as leakage of greenhouse gases into the atmosphere, so more AC without dramatic improvements in the technology is going to actually worsen the conditions for heat distress. Does the panel have any thoughts about policy, land use, city planning, or other categories of action that could help address this only-to-grow problem? Vivek, is that something in your domain?


VIVEK SHANDAS: Sure, yeah. I mean, this is one of these questions that are – that’s really about multi-solving. If planners and public health officials are looking just at heat, it often is very – I’ve just observed, it’s very difficult to get a lot of political traction, per se, at least maybe in the past. It may be different now. But what we really need to be thinking about is multi-solving for heat and other things simultaneously. And so part of that, at least what we’ve been seeing is it comes from a point of there are no cities that I know of in the U.S. that have integrated heat into their land-use planning processes. And so that is likely going to change. And I hope that’s going to change in the coming years. But the idea of AC being the means to do it – I think AC in the short term will prevent heat related deaths more than anything else, period. Like, that is the most effective approach that we’ve seen move forward. And I think Ivan already knows that. But to get a little bit deeper is, how can we get geometries, orientation? How can we actually be thinking about building materials in addition to – how can we think about in addition to social programs that can actually connect people in and around a neighborhood so that there’s options for cooling in and around a city? So that’s really what we’re talking about is this multi-solving and really coming up with several different – connecting the dots on several different parts of a development process that currently doesn’t include heat.

How reliable are the reports being issued by local and state health departments about heat-related deaths?


RICK WEISS: I have a related question here that might have your name on it, Jaime. It relates to something you mentioned earlier. It’s from Thomas Frank, from E&E News based in Washington, D.C. How reliable or significant are the reports being issued by local and state health departments about heat-related deaths this year in the northwest? You mentioned some of the methodology for these things, which sounds a little bit indirect. Are they trustworthy?


JAIME MADRIGANO: Yeah. Thank you, Thomas. That’s a great question. And I think, you know, I always caution people not to really think of – in terms of necessarily reliability in this very near term because I think it is – what’s being reported is accurate to the extent that it’s known at this time. So as I mentioned, you know, what can be known right now usually are those directly attributable deaths. And often it’s – it takes a longer time to tease out those indirectly attributable deaths because it involves a review of many years of data and comparing that data to this current event. And so I have no doubt that those numbers will increase over time. And, you know, I think it is significant that we’re already seeing pretty large numbers.

What are some of the most efficient ways local governments can prepare cities for heat waves?


RICK WEISS: Question here from Claire Caulfield from the Honolulu Civil Beat in Hawaii. Chandana, this might be a good one for you. What are some of the most efficient ways governments can prepare their cities for heat waves? Honolulu seems to be going all-in on tree planting. How does that compare to other mitigation options?


CHANDANA MITRA: So thanks for the question, Claire. So, of course, tree planting is a no-brainer. I mean, that’s something which we all have to do, and we have seen already lots of research has been done trying to show how these cool islands are created within the heat island, which kind of helps in ameliorating the urban heat island in density. Other than that, we have some research going on in New York and other places on cool roofs, like painting roofs white. And that could be a low-cost mitigation technique. And I think the – of course, we have – one of the most important things, which I think every city can do is awareness, creating awareness, which is sometimes we think we’re doing enough, but we do not do enough. And most of the people, like I’m in the South, I can see people don’t even know what heat waves are or what they can do when they are hit by a heat wave – where to go, what to do. So awareness is a big thing, which every single city office or mayor’s office should be doing for their community.

What specific policies can help address the disproportionate impacts of urban heat?


RICK WEISS: Great. And a great responsibility for journalism to help raise that awareness as well. So, Vivek, let me throw this one your way. This is from Kate Gavaghan from Sci In The Tri based in North Carolina. She says that my area of Raleigh-Durham is conducting an urban heat island temperature mapping campaign tomorrow, one of 13 U.S. cities participating this summer. And what specific policies do the panelists think would be most helpful to address the dangerous disparities raised today?


VIVEK SHANDAS: I think we’ve already started in on that. I think both Jaime and Chandana were getting into some of the policies that might work. I’m really a fan of just two fundamental things. One is kind of the social infrastructure that needs to be put in place. Like, what are the ways in which communities can get to know each other a little bit more? What would it be like to have a policy where we provide incentives for block parties in urban areas where people can come out and actually re-acclimate to a non – to an outside time where we could actually talk to each other and get to know each other? Because often one can under-assess where people might be potentially vulnerable to heat waves and potentially looking for ways to support communities that may not have cooling options.

That’s not necessarily a policy at the city scale. But that’s where the second option is, is where can we think about infrastructure options, both gray blue and green – gray blue and green infrastructure, kind of rainbow-colored infrastructure as I like to think about it, where you have – you know, the gray infrastructure, the electrical grid is one of the key pieces with this. And if you have a rolling brownout or a blackout during a heat wave, even those communities that are well-off and able to run their AC, et cetera, are going to be hit really hard. And we might see a spike in the number of deaths that emerge. And then the green infrastructure, as Chandana was describing, no-brainer in terms of the medium- to longer-term approach of how do we actually think about ways to be able to implement even green walls, green roofs, street trees, yard trees, et cetera? And how do we use wintertime water to be able to feed into that during hotter, drier summer seasons? And so there’s that kind of industrial ecology system that one can think about. And then, of course, the blue infrastructure. What can we do with our cities that have quickly gotten water out of the cities as quick as possible? When can we use that as a reliable resource and actually think about storing that over time and rebuilding the watersheds that we’ve all paved over in almost all of our cities across the world?

Does the current influx of wildfire smoke exacerbate or contribute to the heat island effect?


RICK WEISS: That’s a very interesting idea. You know, we’ve heard a lot with climate change about the idea of increasing our storm sewer systems to get all those heavy torrential rains out of here. That’s a resource that I guess people are going to be wanting to preserve if possible. Here’s a question from Andrew Hazzard from the Sahan Journal, based in St. Paul, Minn. How does the current influx of wildfire smoke being experienced in cities across the nation exacerbate or contribute to the heat island effect? Jaime, we’ll start with you on that.


JAIME MADRIGANO: Sure. Yeah. It is definitely quite concerning to think about, again, these two kinds of compound or overlapping disasters. And I think, you know, if you think in particular about some of the health outcomes that I mentioned earlier in the briefing – cardiovascular disease, respiratory disease – both of these exposures, heat and wildfires in particular or soot and air pollution, affect those outcomes. And there’s been a few studies that have looked at that synergy between those exposures and showed an even greater effect on health when people are exposed to both simultaneously. So it’s definitely a cause for concern and, you know, something to be thinking about as, you know, just sort of as the other panelists have been saying, too, just thinking about all of these factors coming together and the multi-solving that we need to be doing.

How can cities incorporate heat risk into their planning, including in historically red-lined neighborhoods?


RICK WEISS: A question here for Chandana from Neela Banerjee at NPR. What would it look like – or Vivek – what would it look like for a city to incorporate heat risk to planning? How would the look of and the systems in a historically redlined neighborhood actually change?


CHANDANA MITRA: OK. So I’ll take this first, and Vivek can follow the discussion. So the – I – again, I would like to again say that it’s all about talking to people. So communication and awareness is key. If you’re really thinking of the people whose first priority is not thinking about, oh, there’s going to be a heat wave and what will I do? That’s not their priority. Their priority is what comes to the table? So it’s very important to make people understand how these big events are actually impacting even the food which comes in front of you. So first is education, communication and, like Vivek said, it’s bring people over in front and talk to each other. Kind of solve their problems as a – as – together, like connecting the dots and trying to solve issues which are more near and dear to their daily lives.

One other thing which I think from the policy point is that cities can actually – most of the cities do not have climate action plans. We think many have, but many of them don’t have. So I think that kind of gives a perspective of what’s going to happen to your locality. Like here, I was mentioning Birmingham a number of times in my research. So in the state of Alabama, Birmingham is the only one in the past two or three years which has a climate action plan. But believe me, when a heat wave or any of these disasters happen, equal attention should be paid to cities like Auburn or Montgomery or even, you know, all the newer cities of any size. So one is awareness, communication, making people talk to each other, then – and the top-down approach would be climate action plans and also planning in such a way where, which Hong Kong does – has done a very good job is, trying to have these air corridors or getting into sort of replication, which is called biomimicry, where you have more windows. You kind of see how the ventilation happens in between the houses, in between, you know, different angles of a house. It’s more on the planning side, though. But these things also should be taken care of if, really, the city governments and planners can do something for the community.


RICK WEISS: Great. Vivek, did you want to add anything to that?


VIVEK SHANDAS: Just really briefly I’ll add to that – I – just to build on what Chandana was saying. And I’ve really been impressed by places that have been hit really hard by heat waves and some folks who have been taking it seriously by creating these ideas of resiliency hubs and the – or even climate kiosks that can be a mechanism by which information, awareness and engagement can actually be happening. And these are scalable at the neighborhood scale or even at the regional scale, trying to be at the place where we actually understand what are the stressors that are our region is experiencing at this time? And where is trusted information that we can go to to be able to look for potential solutions? So that’s one immediate thought. The other is, really, fundamentally, we know that climate change is affecting historically marginalized populations harder than those that have had a lot of privilege. And so part of centering historically marginalized populations is really trying to think about a co-governance and collaborative process where communities that are going to be hardest hit will get that attention when, for example, land-use siting decision is made of where to put the new post office or where to put the new big box store. These things will amplify temperatures in historically marginalized communities. So can we have a planning system that brings those considerations into the review – designed review process as well as the siting process? Those are some thoughts.


RICK WEISS: Can you describe a climate kiosk? What is that? Is that a physical information post of some kind or a meeting place?


VIVEK SHANDAS: Well, part of this is based on a lot of the literature. We put a resiliency reader together for my climate – my graduate level climate adaptation class. And one of the things that the literature keeps coming back to is, how do we circulate information? Similar to what Chandana was describing, like how do we get information that communities can immediately access? A lot of the people here, at least in the Pacific Northwest, who faced grave health concerns during the heat dome, we’re learning now that they didn’t really know what options they had about where to go, what to do. Public health wasn’t prepared. Planning wasn’t prepared. The community-based organizations weren’t prepared. And so really trying to think about how do we centralize a weather-based, extreme-weather based systems, whether they’re physical systems, which I would really think might pose some challenges but also could potentially move forward for allowing communities to quickly access them for getting immediate attention around. What options are in this neighborhood for cooling resources? That’s the – that’s at least the concept I’ve been playing around with recently.


RICK WEISS: That’s neat. And I think that addresses a few of the questions we’ve been saving here. But go ahead.


JAIME MADRIGANO: Oh. I just wanted to add one thing really quickly to add onto what both Vivek and Chandana said is that talking to the people most affected is such an important part of thinking of solutions because one thing we’re seeing in some of the research I’m doing is when we talk about, you know, increasing street tree cover and tree canopy, a lot of communities are very concerned about potential displacement and this idea of green gentrification. And so it’s really, you know, of course trees are a great solution, but we need to be thinking holistically and involving the communities that are most affected and could potentially be affected by unintended consequences.

Are there any proven ways to prevent deaths during heatwaves that have not yet been adopted inside the United States?


RICK WEISS: So maybe a penultimate question here – and it asks to go a little bit beyond some of these ideas that you’ve just been talking about that I guess are at least being talked about being implemented. But if we look a little more blue skies, this is a question from Tony Barboza at the LA Times. Can you point to any proven or effective ways of preventing people from dying during heat waves that are not being used now and are not being adopted in the United States, something to look even further afield – anything that we haven’t touched on already?


CHANDANA MITRA: Yeah. If I can go first, I mean, this is an example from a city in India – Ahmedabad. What they have done is – and as we know, for the past few years, there have been heat waves, which is not expected from a tropical country like India or Saudi or any of the countries in South Asia. But that particular city, they have prevented some of the deaths by – again, awareness is what they’re trying to do is they use cellphones to send out group messages through WhatsApp and through other text messaging systems they have and also huge hoardings – again, getting to what Jaime was telling is awareness – and even Vivek – is using native language. So, I mean, this is not a direct way of really saving lives, but indirect and very effective, very effective, which I think we don’t do it that much in communities and in cities in the U.S. And that could something be learned from, I said, Hong Kong and many other cities in other parts of the world.

What is one key take-home message for reporters covering urban heat and rising temperatures?


RICK WEISS: It’s a great point, considering how segregated different language media are, for example, even in this country, to get those messages out in a variety of ways.

So I want to start to bring this around to conclusion. We’re close to the top of the hour. And I’d like to just go around the horn one last time and ask each of you to – just if there’s one take-home message, something that, you know, if nothing else, reporters on the line here today walk away with an understanding of, can you each just say briefly what that most important take-home point would be? And I will start with you, Chandana.


CHANDANA MITRA: Thanks, Rick. So what I think is – and I think Vivek mentioned not exactly the word I’m going to say – but around that is coal production. So co-production is the – for me, the most important term which should be used and sort of hammered into everyone’s heads, be it – because the federal government, the state government, local government, NGOs, media, faith groups, even the baseline people walking out. No one can do it alone. So it has to be a co-production and very much integration of services available. All of that have to play a role in trying to reduce whatever the effects of climate change near and in the future can be achieved. And so joining hands, working together is one of the key messages I would like to pass on from my end.


RICK WEISS: Great. Thank you. And Jaime.


JAIME MADRIGANO: Sure. I’ll just – I’ll kind of tag team onto that. I think it goes along with it, which is that I think a lot of the solutions are very local. So they may be common across cities – tree plantings or reflective coatings for roofs or things like that. But, you know, I think what we’re learning is that there are just different pockets of vulnerability. There are also temperature thresholds that are often used for heat warnings, may not actually meet the needs of different pockets of the city because they get hot – much more hotter. So it really means all of those stakeholders, from planners and policymakers to grassroots organizers to researchers, just to the general public, really kind of being involved in trying to get together and look at local data, understand what’s happening, get information from residents and really try to tailor the solutions to the local environment.


RICK WEISS: So we have a lot of votes for cooperation here. Vivek.


VIVEK SHANDAS: Yeah. I – 100% with those. Maybe I add a complementary side to that is – and that’s around the idea of climate – the existential threat of climate change is still something we’re still – we’re trying to wrap our minds around. And this heat dome was a wake-up call for many of us in the Pacific Northwest about how ill-prepared and, in some case, maladapted we are. And so what I think is going to be a really central theme here is continuous learning. Like, how do we maintain – how do we engage the media in identifying the things that we’re learning are emerging as a result of these anomalous events that are going to be increasing in intensity, frequency and maybe duration as well.

And so how can we engage in a – robust data collection campaigns to describe the distribution might be like in different heat – in different geographic regions as well as different community capacities? How do we understand the pathways through which exposure are going – people are exposed to heat and experience vulnerability? How do we then develop data and understanding and learning around the effectiveness of solutions? So I really want to think about this as a – we’re still really as a community of heat scholars trying to wrap our minds around this. And we’re really dependent on the media to try to identify those key places where we are learning something about this phenomenon and what is working and what’s not working.


RICK WEISS: Fantastic. I want to thank all of our panelists today. I want to mention to the reporters on the line, as you get ready to log off, you will see a short, three-question questionnaire pop up as you leave. I would like to strongly encourage you, even though we all hate these questionnaires, to just take the 30 seconds it takes to answer those three questions. It really helps us keep these briefings on target and serving you in the best way possible. I encourage everyone to also visit the SciLine website, Follow us on Twitter @RealSciLine. And we’ll see you soon, I hope, at our next sideline media briefing. Thank you all for your work on this panel and for attending. So long for now.

Dr. Jaime Madrigano

RAND Corporation

Dr. Jaime Madrigano is a policy researcher at the RAND Corporation. Her research focuses on environmental and social determinants of health, including environmental pollution, extreme weather and disasters, and the built environment, with an emphasis on environmental justice. Dr. Madrigano has expertise in using epidemiologic methods to inform policy, and her research has been cited in multi-agency climate and health preparedness efforts in New York City. She has also worked with local health departments and community-based stakeholders to conduct health and environmental needs assessments. Dr. Madrigano is currently leading research to examine the relationship between systemic discriminatory practices and inequitable environmental burdens in the U.S., as well as work funded by the National Institutes of Health to examine heat vulnerability in New Orleans. (Read full bio.)

Dr. Chandana Mitra

Auburn University

Dr. Chandana Mitra is a physical geographer and climatologist at Auburn University, where her research is focused on characterizing the impacts of urban growth on local climate, especially in the area of heat and precipitation variability. Her research also involves urban sustainability, testing and evaluating the various adaptation and mitigation techniques in a warming cities. She has extensively used GIS/remote sensing techniques and urban growth models to better understand the dynamics of human-environmental interaction, working in various parts of the United States as well as in India. (Read full bio.)

Dr. Vivek Shandas

Portland State University

Dr. Vivek Shandas is a professor in urban studies and planning at Portland State University, where he specializes in developing strategies for addressing the implications of climate change on cities. His teaching and research examine the intersection of exposure to climate-induced events, governance processes, and planning mechanisms. As the founder and director of the Sustaining Urban Places Research Lab, he brings a policy-relevant approach to research, including the evaluation of environmental stressors on human health, the development of indicators and tools to improve decision making, and the construction of frameworks to guide the growth of urban regions. (Read full bio.)

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