Addressing the Harmful Effects of Climate Change on Extreme Heat and Human Health

Addressing the Harmful Effects of Climate Change on Extreme Heat and Human Health

Oct 20, 2022
On this episode, Don Berwick of the National Academy of Medicine’s Climate Collaborative, Tom DiLiberto of the National Oceanic and Atmospheric Administration, and Aparna Keshaviah of Mathematica explore the risks that climate change and extreme heat pose to human health and how data can help inform solutions.

On this episode, Don Berwick of the National Academy of Medicine’s Climate Collaborative, Tom DiLiberto of the National Oceanic and Atmospheric Administration, and Aparna Keshaviah of Mathematica explore the risks that climate change and extreme heat pose to human health and how data can help inform solutions.

Climate change is making heat waves more intense and frequent, which takes a toll on human health. Although extreme heat is less conspicuous than a tornado or hurricane, it is responsible for the highest number of annual deaths among all weather-related hazards. Even when extreme heat doesn’t prove deadly, it can increase the risk of heart and respiratory problems, and it is especially dangerous for children, seniors, and people with underlying health conditions.

This episode of Mathematica’s On the Evidence podcast explores the risks that extreme heat poses to human health and how climate change is exacerbating those risks. We discuss the ways that people are using data and evidence to develop solutions to climate change and extreme heat.

The guests for this episode are Don Berwick, Tom DiLiberto, and Aparna Keshaviah.

Berwick is president emeritus and a senior fellow at the Institute for Healthcare Improvement and a former administrator of the Centers for Medicare & Medicaid Services. And, of particular relevance for this conversation, he is now involved in the National Academy of Medicine’s Action Collaborative on Decarbonizing the U.S. Health Sector (known as the Climate Collaborative for short). The Climate Collaborative is a public–private partnership of leaders from across the health system committed to addressing the health care sector’s environmental impact and strengthening the sector’s sustainability and resilience.

DiLiberto is a climate scientist and science communicator at the National Oceanic and Atmospheric Administration, where he is working with more than 65 communities to map urban heat islands and use data-driven insights to mitigate the harmful and inequitable effects of extreme heat.

Keshaviah is a principal researcher at Mathematica who helped develop ClimaWATCH, an interactive online tool that can support communities that seek to understand and adapt to the local effects of heat waves on their residents’ health.

Listen to the full episode.

View transcript


When we have these unprecedented temperatures, vulnerable populations are especially at risk of course – people who are already frail, whose bodies because of chronic disease or compromised organs are at risk – and especially issues around equity because there will be people of lower income who don't have resilience, who don't have the air conditioning or access to the kind of supports that wealthier people may have. So the extreme heat hits vulnerable people hard. It can kill them.


I'm J.B. Wogan from Mathematica, and welcome back to On the Evidence, a show that examines what we know about today's most urgent challenges and how we can make progress in addressing them.

On this episode, we're going to talk about the risks that extreme heat poses to human health and how climate change is making things worse. We'll also learn about a few ways that people are using data and evidence to develop solutions to climate change and extreme heat.

Generally speaking, extreme heat is weather that is much hotter than usual, and sometimes more humid, for at least a few days. Depending on the location, the precise combination of high temperatures and relative humidity that cause extreme heat conditions can vary. But under those conditions, your body works harder to maintain a normal temperature, which can lead to death. In fact, extreme heat is responsible for the highest number of annual deaths among all weather-related hazards.

I have three terrific guests to guide this conversation -- Don Berwick, Tom Di Liberto, and Aparna Keshaviah.

Don is President Emeritus and a Senior Fellow at the Institute for Healthcare Improvement and a former administrator of the Centers for Medicare and Medicaid Services. Of particular importance for this conversation, he is now involved in the National Academy of Medicine's Action Collaborative on Decarbonizing the U.S. Health Sector, known as the Climate Collaborative for short. The Climate Collaborative is a public/private partnership of leaders from across the health system committed to addressing the healthcare sector's environmental impact while strengthening the sector's sustainability and resilience.

Tom is a Climate Scientist and Science Communicator at the National Oceanic and Atmospheric Administration, otherwise known as NOAA. Tom is involved in NOAA's work over the past five years with more than 65 communities to map urban heat islands and use data-driven insights to mitigate the harmful and inequitable effects of extreme heat.

Aparna is Principal Researcher at Mathematica who helped develop ClimaWATCH, an interactive online tool that can inform communities about the local effects of heat waves on their residents' health.

After the interview, if you want to learn more about Don, Tom, and Aparna's work, please take a look at the Mathematica blog post that accompanies this episode. It includes a list of related resources as well as a full transcript of the episode. I hope you find our conversation useful.

Tom, I want to start with you. In my intro, I explained what extreme heat is. Previous generations have experienced hot days and hot summers before. What is different now, and does the data suggest extreme heat is more of a problem today?


Extreme heat is very different now, and it will continue to be different more into the future as well. Those hot days that happened in the past, those record-breaking days, will happen more often into the future. They're happening more often now. Because when you raise the average temperature of the planet, what you're actually doing is raising the odds not only of you experiencing slightly warmer average temperatures on a day-to-day basis, but you also greatly increase the chance of you seeing those extreme heat events happening on the far side of the statistical distribution.

So we've already seen heat waves get stronger and last longer. We're expecting to see that continue even more into the future. We've seen more and more heat records being broken in the last 20 years or so than we've seen previous to that, and that's also expected to continue as well.


It seems like my e-mail inbox is more frequently flooded with news headlines about hot days. Particularly, I used to live in Seattle; and I still subscribe to e-mail news alerts from the Seattle Times. It seems like – it's almost like they're in a different climate now just from reading the news from when I lived there. Actually, I remember living there in the summer of – I think it was 2009; and it was a record hot summer day or summer at that point. But it seems like they've had more records broken since then.


Yeah, we've had several just incredibly strong heat waves that have happened across the globe. One happened in the Pacific Northwest last year, where it wasn't that the records were being broken but completely smashed. Canada set its all-time hottest-day records the same place three days in a row. Then this year, we've seen unbelievable heat waves happening across Europe as well as across Asia as well.

So the common question we often get, "Well, if we're just saying the average temperature is increased by two degrees Fahrenheit, what difference does that make?"

Well, it's not the shift in the average temperature. It's a shift in the entire statistical distribution towards hotter temperatures. That is what the big concern is because it means that record-breaking temperatures in the past are more likely to happen now, and now there are better chances of seeing events that we frankly have never seen before. The Pacific Northwest heat wave is a really good example of that.


Don, I want to talk now about the relationship between extreme heat and people's health. How does the heat affect people's health; and if we're seeing higher temperatures more often, what does that mean for health outcomes and for the health sector as a whole?


Quite dramatically, the World Health Organization last year said that climate change is the number one threat to human health on the planet, which is a really powerful statement from the leader of standard setting in the world.

Part of it is the extreme heat events that Tom was talking about. Remember that when we have these unprecedented temperatures, vulnerable populations are especially at risk of course -- people who are already frail, whose bodies because of chronic disease or compromised organs are at risk, and especially issues around equity because there will be people of lower income who don't have resilience, who don't have the air conditioning or access to the kind of supports that wealthier people may have. That applies within the country; and it applies globally. You can see the effects of these extreme heat events on populations in poorer countries in their extreme.

There is the distributional issue Tom was talking about. So the extreme heat hits vulnerable people hard. It can kill them. But remember that shift that Tom's talking about also has a burden that echoes in health a lot, in which the extreme heat event is kind of like – it's just a signal of what's going on in the underlying distribution. For example, water security is a massive problem both in the center of the United States but also in entire nations around the world. When nations become water insecure, people become ill. You need access to water.

Same for food insecurity – agricultural effects of not just extreme heat events but the heat shift are severe. This all leads to instability and migration issues because it's hard to think immediately about population migration and health, but let's think about the refugee crises we're dealing with. The amount of refugee crises and the attendant problems of health can go up by an order of magnitude easily under the circumstances we're seeing right now.

So that's only some of the connections. I haven't yet talked about disease factors, zoonoses, new forms of disease that appear in places that they've never appeared before.


I wanted to ask about the health sector too though because the healthcare sector, I imagine, will be strained by all of the worsening health conditions of their patients. Is that a fair assumption?


Absolutely, already we're seeing some serious supply/demand mismatches in healthcare – partly due to COVID, partly due to the great resignation. Hospitals are really currently operating at the edge of their capacity, sometimes beyond their capacity, in the sense of care unit beds or your price of conditions can be insufficient and at that time the tragic choices. So, yeah, extreme heat events can plug the resources of the hospital systems locally. I think we saw that in the Northwest during this extreme heat event.

The other thing to keep in mind is all this is about cascade effects. If people subject to an extreme event – like COVID or like an extreme heat event – have to get into hospitals, there are people waiting to get into the hospitals for other reasons – for surgeries or for elective electives. If for some reason you can't get in, there's a knock-on effect on access and presumably health (inaudible) for people who need care but aren't part of that epidemic.


Wow, that's interesting.

Aparna, I want to turn to you now. When announcing efforts to address extreme heat this past summer, the White House mentioned that extreme heat was more likely to affect certain people -- like black, indigenous, and other people of color, as well as people with low incomes. So I'm wondering what do we know about the geography of extreme heat and how the locations where this is occurring dovetails with concern the White House has raised about some communities being more vulnerable?


So first, it's important to keep in mind that actually one in three Americans are already living in counties regularly exposed to extreme heat. So daily summer highs average 100 to 120 degrees in much of the country where people are concentrated. We're also seeing that extreme heat is migrating northward.

So we talked about the unprecedented deadly heat waves in the Pacific Northwest, and it's not just poorer populations that are vulnerable. A lot of people in the North don't have air conditioning, and so they can't cool their indoor environments. In the North, bodies are less physiologically adapted to heat; so their sweating mechanisms, for example, aren't as effective compared to acclimatized populations in the South.

Then third, climate change is resulting in kind of these shifting weather patterns and shifting disease burdens, as Don mentioned. So people and clinicians aren't able to recognize always these tropical diseases that are being introduced. Heat stress – you just don't know that you're kind of experiencing the effects of extreme heat if you're in the North because you've never experienced something like this before.

So I mention these heat waves in the North to illustrate that there's actually many dimensions of vulnerability; but that said, poorer residents and communities of color have been disproportionality impacted. That's in part because of long-lasting effects of redlining, which is a discriminatory lending practice from the 1930s that was race-based. It ended up kind of geographically concentrating African Americans and immigrant communities into areas where there are now fewer trees, more pavement, and more heat.

So today what we see is that in the hottest counties across the country, more than one in three residents are minorities – 35% -- compared to an average of just 14% in other counties where there's less heat.


One way that I've been thinking about the problem of extreme heat – and this is admittedly a very kind of niche slice of the world, but I'm a lifelong tennis player. Recently, I've noticed that extreme heat is really affecting the ability of professional tennis to sort of have tournaments in these traditional places that are very hot. The top American man this summer, Taylor Fritz, he actually retired in the middle of a match – I think here in D.C. – because he was dizzy and had blurry vision. This is not somebody who's like older and would be categorized as vulnerable. This is somebody who's in peak condition with the elite athletes in the world. If he can't handle the heat in D.C., then what does that mean for the rest of us ordinary, not-super-human people?


Exactly, yeah, there's just going to be these huge shifts in where conditions are livable day-to-day and then as well as when you're talking about kind of peak extreme athletic performance. It just changes things.

I live near Asheville in the mountains, where we're lucky that night time temperatures dip even when it does get hot. So we actually, I think, are seeing increased tennis tournaments in our area perhaps for that reason. It's much more habitable because of the elevation.


This podcast – we try to look at both problems and solutions, and all of you are in some way working on solutions to this issue. So I want to talk about some of the work that you all are doing to address extreme heat and its negative health effects.

Tom, in my intro I mentioned that you're part of NOAA's community-led urban heat island mapping campaign. I'm hoping you can talk a little bit more about that campaign, and I'll give you some questions here. What are its overall goals? What kinds of data or insights are being generated by the campaign? If you don't mind, could you point us to some examples of communities that are translating those data-driven insights into action?


Yeah, sure, I think Aparna really covered the really good reasons and goals of this – is that urban heat islands for a long time were people who are just kind of learning. I mean, heat islands kind of see it as city hot/rural areas cooler as kind of this monolith of that. But what's actually true is that even within a city, there is drastic differences in temperatures neighborhood by neighborhood, depending on the development practices. As Aparna mentioned, some of these practices – the reason for them are due to a variety of discriminatory practices like redlining.

So a study came out that was one of the lead scientists and one of the scientists that we actually work with at NOAA, basically found that redline communities on average across the country are hotter than non-redlined communities within cities, basically saying that the literal temperature people are experiencing the moment they step outside their house is affected by development practices from the early 20th Century that were discriminatory in practice.

One of the goals of these urban and heat element mapping campaigns is to help cities understand what parts of their communities are hotter than other parts of their communities, specifically so they would know when there are heat waves, when there are hotter temperatures, where there might be issues or where they might need to put their resources now to help mitigate some of these extremes.

Oftentimes, not surprisingly, I imagine the people on this podcast and also probably people listening is that oftentimes when you see, again, these hottest areas, these are not just the hottest areas. They tend to be the most polluted areas, and they tend to be areas that are full of communities of color and vulnerable communities. It's one of those things where it's not one sort of negative impact; it's almost a compound sort of impact.

So the goal of these urban island mapping campaigns is, one, to allow cities and communities to understand what areas of their cities are hotter than other areas; but it's also to build community-led, bottom-up interest and passion about this topic so that solutions can be implemented. We've worked with these campaigns themselves that not only include city officials, but they include community groups. In fact, they're pretty much required to include community groups. These are people from their own communities measuring their own temperatures. It's their own data. It's their own lived experience.

Oftentimes when we go back years later and we talk to the folks who are doing this, one of the reasons they say they love this information is not just for the data that it collects and gathers and the maps it produces, but it's this galvanizing community impact that they've found even more important because we know that this is not the last step for this. It's just a lot of times, it's one of the first steps; and it's a long process from just collecting the data to implementing solutions. In order to implement solutions in a lot of places, you need to have community involvement and community buy-in; and this is one way of creating that community buy-in because they're actively measuring their own communities.

And we're listening to them. It's a dialog for each of these communities, which is one of the reasons why this has become such a really popular program within NOAA. It started with just one or two cities in 2017; and we've monitored or measured over 20 this year, including our first two international cities. Oftentimes the reason why we choose the number of cities is not because of a lack of interest, but it's because of a lack of funding. There's only so much money to go-around to measuring these things.

The other big thing with the goal of this is that we can now create a community of practice amongst cities across the country and across the world, where they can share the solutions that they're developing with each other so that folks don't have to start from ground zero. They can build on what's worked in other communities and implement them in their own cities.


If I remember correctly, one of the ways that you're gathering that more kind of neighborhood-level data is sensors on people's bikes that are being driven around by (inaudible) and scientists. Is that right?


Yeah, that's right. . So the way it works is that we have these sensors that get put on the people's cars or bikes or even occasionally we try them on backpacks, and they drive transects through the city three times a day – the meaning, the peak heating in the afternoon, and then the evening – basically to see how heat develops and how it dissipates throughout a city. Those paths are determined by the community members by saying, "This is an area that tends to be hotter. This is an area that we're more concerned about. This is an area that goes through a known vulnerable community."

We want to know information from this community, so we develop those transects with the community involvement; and we use a machine-learning algorithm. All that data comes back; we basically apply that across the entire city, and we get these urban heat island maps.

One city if you're looking for a really good example – the first city that we really did this for was Richmond, Virginia. They've taken this data and they've really used it to implement solutions across the city as well as looking at this from other angles, especially as it relates to health. They've compared these urban heat island maps to emergency room visits, to 911 calls, and other sorts of metrics – socioeconomic metrics as well in their city. They really get a better idea of the vulnerabilities within their own city.


That's interesting. So there was – I think it was just last week I noticed there was a story from City Lab that was talking about a convening of chief heat officers, which is an increasingly common position at the city level. When they were talking about solutions, one of the things they brought up was some of the cities were focusing on tree canopies in some of the hottest parts of the city; and everything was cooled roofs. I was wondering, is that the kind of thing? I don't know if any of the communities you're working with have done that, but it seemed to be the kind of targeted place-based solution you could implement after identifying where you have some kind of heat islands.


Right, so increasing the tree canopy is one way – cool roofs, cool pavements. In fact, urban shade -- you can actually even include that tall buildings actually provide shade, although there's some other heat effects from the urban canopy. If you have these really tall buildings next to each other, it kind of reduces the air flow. But buildings can provide shade. You can create shade areas. It's also just knowing where resources need to go.

Another benefit of these sort of campaigns and community involvement is that there's been studies that basically show that when a City comes in without talking to community and just plants trees, and you don't have the community buy-in, there can oftentimes be mistrust between a community that's been under invested for a very long period of time and a City that in part has done a lot of that not investing in that community. So by having this involvement of the community as well as the officials, you're more likely to see a positive sort of reaction or build a joint sort of solution as opposed to what's seen oftentimes as someone helicoptering in saying, "Here, we're going to plant some trees." Then, they helicopter out.

So tree canopies is really also an important one. Oftentimes, blogs -- just kind of knowledge building and creating the spaces for dialog, which can often be pretty important in terms of solutions-based when it comes to urban heat islands.


Don, I want to turn to you now. I mentioned in my intro that you're on the Steering Committee for that National Academy of Medicine's Action Collaborative on Decarbonizing the U.S. Healthcare Sector, which is known as the Climate Collaborative for short. You're also on the Policy Financing and Metrics working group for that collaborative. Give us a little more background about the collaborative and the purpose of that specific working group.


Let me say first thank goodness for Tom's work and for the idea of localizing the efforts that he's talking about. I deeply believe that of my own wife. We do have the wrong Berwick on this podcast. My wife Ann is Sustainability Director for the City of Newton. She works every day all day, with very strong support from the mayor, on solar energy, on decarbonizing homes, on greenhouse gas emissions, electrification. So I want to really endorse what, Tom, you were just talking about – about local action. It's absolutely key.

Yes, so the National Academy of Medicine, which is the Medical Division of the National Academy of Sciences, Engineering, and Medicine, two years ago had its chief executive, Dr Victor Dzau, outline three priorities for the Academy in the next few years; and he put climate change on that list. It was equity and pandemic preparedness were his other two. The initial run at it is what you referred to – the Action Collaborative on Decarbonizing Health Care. Healthcare's footprint is about 8.5% of all greenhouse gas emissions in the country.

In fact, we have now federal leadership on this. President Biden and the Assistant Secretary for HEW, Rachael Levine, have now declared an aim of a 50% reduction in that footprint by 2030 and 100% by 2050. This is an implementation side of that in which we've drawn together dozens, soon hundreds, of health organizations committed to achieving that decarbonization.

The road map for that is very well-developed. Just last week, the National Academy issued preliminary road map guidance for how to do that. Before that Health Care Without Harm, which is a 30-year-old organization that's also worked on this, has also put a road map on decarbonization.

So our collaborative is working hard on that now. It's a tough job because it's not just the greenhouse gases that hospitals emit, let's say, by burning fossil fuels for their energy. There's what's called scope 3 emissions, which have to do with the supply chain – where they get their supplies and equipment and the sources. We have to work highly collaboratively. So in the collaborative, we're not just healthcare systems but also suppliers – like people that make medications, that make medical equipment, that do medical transport, and so on. It's been going really well, and a lot of high-level attention is being devoted to it. I'm optimistic, although it does involve change in the way people address what they do.

Part of that change is regulatory; and, yes, I co-chair the sub working group on policy, finance, and metrics. We're trying to develop recommendations to federal, state, and municipal governments on what they can change by the regulatory environment to actually encourage decarbonization in healthcare. We have a policy working group right now that's going to be, by the end of the year I think, issuing a whole bunch of recommendations about policy changes that would make it, I guess, more interesting, more possible, for healthcare organizations to get rid of fossil fuels. That's rather more long-term than what Tom was talking about, but I think we have to walk and chew gum at the same time here.

The stuff I'm involved in, I wish we started 20 years ago because we wouldn't be having the rest of this conversation now if we did it globally. But we've got to both deal with the mitigation of the effects that Tom was talking about and get ahead of the game by starting to decarbonize the fossil fuels out of our economy.

I'll say one other thing. You didn't ask quite about this, but we hear a lot about it – which is remember the globe because a lot of what we're talking about is going to play out not in the U.S. It's going to play out in Bangladesh, India, and parts of the world which are just on the edge and have very insecure supports for dealing with this warming. Unless the U.S. gets deeply involved in global policies and is very supportive to these vulnerable environments, we're going to pay a big price downstream – not to mention the moral imperative.

One last piece is preparedness. We've kind of referred to that. We actually are not well-prepared for this or a lot of other 21st Century threats. I chaired a National Academy of Medicine effort to understand what preparedness of the 21st Century threats, which are pandemics, global migration, climate wars, and extreme heat events. So we're working hard now to begin to come up with a national plan for much better preparedness in our healthcare system, and we're on our heels right now to get ahead of that.


I wanted to ask about health equity, and I think this ties back to some of the earlier parts of the conversation where we were talking about how vulnerable populations may be at higher risk of being exposed to extreme heat or may already have health conditions that would be exacerbated by extreme heat. But then you just brought up a different way of thinking about health equity too in terms of making sure that the U.S. is doing right by other countries that maybe are more vulnerable at the national level.

What is the collaborative doing in the space of equity? I believe I remember that being a priority in sort of the background materials about the collaborative. How is the collaborative trying to seek to advance health equity?


Well, this has to do with what Aparna was talking about earlier. The collaborative is not at the moment involved in global climate mitigation, although we're learning from other countries. For example, the National Health Service in the UK has committed now to decarbonizing an entire health service; and we're learning from what they're doing and how they're approaching it.

But I think that you can't look at the effects of climate change without noticing the asymmetry of effect that Aparna was talking about. So the Department of Health and Human Services has established now an Office of Climate Change and Health Equity. So we're uniting the efforts, looking especially at the vulnerable populations that are most affected by climate change.

By the way, may be least able to participate in the mitigation of this. When you want to decarbonize your home, you've got to think about insulation and air source heat pumps instead of furnaces. Well, where's the capital and the investment going to come from for health people of lower income with that kind of migration?

The same for hospitals – a massive, rich academic medical center may well have the resources to decarbonize. There, it's primarily a matter of will. But small community hospitals or hospitals that serve more vulnerable populations, hospitals more on the edge, they may need some help to be able to get involved in this.

One of the things we're doing for example – actually this month and last month we've been running what we call Carbon Clinics. These are free access to very high-level consultations for members of the collaborative to learn how to decarbonize. They don't have the threshold to cross of hiring consultants or paying a lot to get into the game. We'll help them do that.


That's interesting – carbon clinics, so kind of a medical terminology there as well.


It's been really interesting. The other thing is experts are showing up very generously. The Carbon Clinics are actually run virtually by our top experts in the country on decarbonization. So suddenly, we can offer 5,000 American hospitals to the absolute best thinking on this at zero cost; and I'm pretty excited about it.


I also read that the collaborative is aligning goals and actions based on evidence. As the host of a podcast called On the Evidence, that caught my eye. It sounds to me like an aera where organizations like Mathematica might be able to contribute to solutions. So I was wondering what kinds of evidence are needed. Is it a matter of new evidence, or is it a matter of following the evidence that already exists?


Both, and the third level is data. So there's local evidence. Like how does a hospital know where its emissions are coming from? There are accounting systems for that very well-developed, greenhouse gas protocols. They have to learn how to use that because they want their efforts to be data-based, not just based on guesses or myths.

With respect to evidence, of course the biggest evidence is that we have a climate change problem – so just to dot that I. Let's get beyond this now – this continuing debate about whether this is an issue or whether it's man-made is – come on. It's time to end that. So that's a will-building, and I think healthcare needs to be out in front of that saying, "Yes, there is climate change; and it's community-caused, and we need to mitigate it."

In terms of steps to take, this is hard. Yes, we need to grow continuing evidence. For example, the scope 3 emissions – which is these upstream sources – how do you trace them? How do you find them? What actually is causing it? And then, what are the changes that really matter?

The National Academies are committed by DNA to using evidence to do what they do, and his collaborative is very much committed to that.


Aparna, I want to turn to you now. You helped develop the ClimaWATCH tool for Mathematica. Tell us a little bit about the tool. What's its purpose, who can use it, who did you envision using it and how? Maybe give us a few examples of how the tool crystalizes these overlapping problems of extreme heat, health, and inequity?


ClimaWATCH brings together data on heat, humidity, social vulnerability, and health care claims. The goal is essentially to help communities explore how heat waves are impacting health. It essentially facilitates the type of investigations that Tom mentioned are happening in Richmond, Virginia. It shows where heat waves are concentrating, who lives in those regions, how different types of health issues accumulate around a heat wave, and then the financial toll that these illnesses take among one of the most vulnerable groups in the U.S. – which are Medicaid beneficiaries.

With maps and comparative statistics, we break out information by geography, social vulnerability dimensions, demographics, and even care settings. So the tool kind of helps paint this picture to see what are the potential group causes of climate-induced health issues.

There's a lot of ways communities can use this. It wasn't meant to answer a single question. It was really meant to kind of facilitate exploration. So public health agencies, for example, can use the tool for municipal vulnerability planning, like to see who's most susceptible to heat-related health issues and then to measure kind of the extent of climate-related health inequity.

The health care providers can use the tool. They can anticipate surges in hospitalizations after a heat wave to determine how to adjust local staffing or resources. So ultimately, it kind of gives national, regional, and local statistics and maps. That's meant to help communities develop adaptation strategies that are really tailored to their population's needs. We want to kind of give people data maps, tools, to help them rebound more quickly from the effects of heat waves.

ClimaWATCH stands for climate, weather, analytics, trends in community health – is the acronym there.


That is something that is free and available on the Mathematica website where people can explore and play with it if they want, yeah?


That's right. It is out there publicly. We are still making refinements in the tool. There's some nuances in how you define a heat wave. To Tom's work – it's not so simple, and so there's improvements that we're trying to make to really kind of tailor this and provide information that people can act on. The initial prototype is out there.



All right, so I wanted to wrap up by asking a couple questions that anyone can answer or maybe we'll get multiple answers for. I know it can be difficult to measure the effects of extreme heat on health. What are the current challenges with data, and what needs to change to help inform effective action against extreme heat and its impact on people?


So unlike hurricanes, wildfires, acute weather events, heat is invisible. So one of the key challenges is attributing health issues to heat, ruling out other risk factors. For things like heat stroke, heat exhaustion – I mean, "heat" is literally in the name. We know they're caused by heat. But what about heart attacks? What about kidney failure or respiratory conditions? They are indirect, downstream events; so it's harder to attribute those to heat.

That challenge is made worse by the fact that during patient intake processes, clinicians don't routinely ask about environmental or climate-related exposures. So those types of triggers for health issues often go unrecognized. We tried to kind of help get around this with ClimaWATCH. We used kind of this county-level comparative analysis to quantify how many extra health care visits, how much excess Medicaid spending occurs because of heat waves. So there are ways you can kind of get creative and measure that, but attribution is kind of one key challenge.

Then the second key challenge I'll mention is just that it's hard to factor in personal susceptibility into community preparedness and response. So two people who live in the same county can have very different risks for heat stroke because one lives in an urban heat island or lacks AC or is taking a medication that makes it harder to regulate their body temperature. It's hard to take into account all of these factors and create nuanced health messaging that's easy to understand and motivates people to act.


Tom, I saw you nodding as Aparna was talking. What was it that she said that really resonated with you?


All of it – I realize I wish I'd went first because that's what I was going to say. I mean, it's a difficult problem when it comes to heat. Heat is an invisible sort of issue. There's a classic photo example that a scientist may often use -- climate scientists tend to use when we will show a photo of a damaged area due to a hurricane. We'll show tornado damage. Then for heat, we'll just show a photo; and it's sunny outside. That's what it looks like. So in terms of getting people to understand or deal with the risk of extreme heat, the problem is that oftentimes things that get really large in the media or it can be really arresting images don't really exist as well for heat.

Another thing is that when you take a look at when people cover heat in the media, it's not photos of people being hurt or fainting due to heat exhaustion. It's usually a photo of a kid running through a sprinkler, or it's a photo of somebody eating a rapidly-melting ice cream cone – which are not, I would say, on the level of the risk of extreme heat for a lot of these areas. But those oftentimes, if you look at stock images of extreme heat, it's a fire hydrant with a hose of water coming out and kids running through it. It's a very positive look in something that is very dangerous.

From my perspective, one of the challenges is with these campaigns that we're running at NOAA, it's a one-day snapshot. We know that that's not necessarily true the entirety of the year. So there is still a data issue when it comes to just understanding how urban heat islands, for instance, change throughout the year. How do they change when there is winds or a slight wind is coming out of different directions or different atmospheric patterns? Does that affect the way heat dissipates or moves out of cities?

There's still a lot of questions about that. From an early warning standpoint for these events and from a forecasting standpoint, I feel like there is a lot of information that it can still be tied to, as well as just learning whether we can tie in extreme heat with air quality at the same time and see if those sorts of issues coalesce or basically how they can interact on different levels throughout a given city.

So I was just nodding my head a lot. My neck hurts now just because I was agreeing so much with what Aparna was saying.


Not to bring up tennis too much, but I do remember one year the Australian Open, the way that they visualized how hot it was. I think they had the heat rule in effect. The players have to leave if it gets too hot. So they cracked an egg – the commentators – they cracked an egg and dropped it on the tennis court. And it cooked on the court. You got a very quick sense of exactly how hot it was and why you could not be exercising.

Don, is there more to say about how you show the relationship between health and heat here?


I was going to go back to barriers question. You asked about in health care what's in the way right now. Tom and Aparna nailed some of it, but a couple of other thoughts. One is if you think about extreme heat as an example of a regional trauma, a regional crisis, proper regional response requires high levels of cooperation among institutions that are used to competing with each other. So whenever we have a regional threat – mass trauma or pandemic or extreme heat – we've got to build some vehicles for a regional response.

I think there's good news there. There are some excellent examples around the country, but it's been a barrier that Hospice, for example. They usually wouldn't share information on their current bed occupancy. That would be their competitive advantage. Now they have to learn to.

A second is executive priorities. In order to get ahead of this problem we need boards, trustees, and executives in healthcare to be attending this; but they're really busy. They're dealing with equity issues. They're dealing with payment problems. They're dealing with the pandemic. They're dealing with patient safety threats. To knock on the door really loud and say, "Hey, everybody, wake up; this is a threat," is a problem. And how to get this on the table for boards and executives in medical institutions to think about has been a bit of a problem.

The last I'll say again is the politicization of climate policy. It's costing this country immensely. The climate has now entered this period of organization, and it makes it harder to take collective action. Somehow we've got to find a way to get beyond it before our egg cooks, (inaudible) we're headed for trouble.


In that same CityLab article, one of the chief heat officers was complaining that even just within her own city, the number of bureaucracies that she had to – the cats that she had to herd – was a barrier to actually effecting change in her community. I imagine it just gets harder at the county or regional level.


Decarbonization is a collective good. I mean, any one person can say, "Well, not me; I don't make that much difference," or "I'm special, so don't bug me with it." It's not going to work. Everyone's got to be in; and that ethos, that sense of solidarity about tackling this, is elusive in the American political climate. We've got to overcome it. It's all of us in, or we're not going to win.


Don, I think in our planning call I think you referenced one other thing that I thought it would be bringing up, which was there are different kinds of health that could be affected. Behavioral health is maybe something people wouldn't have top of mind. Is that another challenge – sort of measuring the effect of extreme heat on behavior and behavioral health?


Definitely, my colleague Nikki Lurie who was the Secretary for Preparedness and Response used to say that every crisis, every threat, always has two threats. There's the threat itself and the mental health component effects of that. So, yes, there's a lot of psychological morbidity associated with this. There is a behavioral side of this that can be a really serious problem.

We've seen in the pandemic, by the way, also the psychological impact of the pandemic is a form of morbidity that's not as serious as the disease itself; but it is serious.


I'd love to end on a hopeful note. I'm wondering if you all have any hope that you can supply. Where do you find hope in current efforts to address the effects of extreme heat on human health?

Maybe, Tom, do you want to start us off?


Sure, so one thing that – I like people. That's always my thing when it comes to climate change. I find people the best. I like positive people. One thing that gives me hope is in all of these campaigns, I love interacting with and getting to know the community members doing – the volunteers actually measuring their urban heat islands. They come. They're of all ages. They're all everything, and it's amazing to be able to see just how passionate people are about their home communities and how they want to make change and how oftentimes they know they want to make this positive change.

Their passion behind what they're doing and the passion behind the change they want to see gives me a lot of hope in terms of making sure that such vulnerable communities will be able to deal with some of the impacts of climate change now and in extreme heat too.

Also, there's a lot of really amazing community-level groups out there at the grassroots level in every city across this country that I never knew about before doing these campaigns. It's remarkable, and that's what gives me hope.


I wondered about – so you mentioned that this work started with just a couple of communities. The ones that have been doing this for years, are you seeing any progress there? Do you feel like they're more sophisticated in their measurements or that they've actually been able to implement some solutions to this issue?


Yeah, so the early communities that were involved in these campaigns are now leaders when it comes to helping other communities be able to find solutions. They've been doing their own solutions in their own city, but it's also been really hopeful and great to see how they see this as something that's not just a Richmond thing, for instance. They see this as an everywhere thing, so they're trying to help other communities do this.

That's another reason that gives me hope is that even in the last five years or so since this started in 2017, employees have a team. It's just been unbelievable how many cities and communities big and small – we're talking tiny communities in Indiana to the biggest cities in this country to international cities – that are now really looking at heat as this major problem and looking to implement changes and solutions to both not only mitigate urban heat islands but also adapt to some of the issues that we're currently seeing and will continue to see going forward in the future.


Okay, awesome.

Aparna, where do you find hope?


We have more data than ever before to measure these health effects, and we have more technology even to deliver interventions to people. So if we could figure out a way to, say, target heat alerts with the precision and the speed that Amazon that targets ads or Netflix targets show recommendations, I mean we could actually make a dent in this.

So the tools are there; and with people like Tom helping to put those tools into the hands of people with more and more people being directly impacted and seeing and feeling the effects of climate change, I'm hoping that the collective will to act will increase. I think we have the foundation. It's really kind of a matter of working with what we already have.


All right, Don, I'll give you the final word. Where do you find hope in this very serious problem?


Well first, listening to Aparna and Tom, the data that Aparna is talking about – the ability to know where the problems are localized – we're really getting ahead of that. And Tom's passion for localities, that feels right to me; and I have a lot of confidence in local action. A lot of it comes from, as I said, my wife's work in our city over the past few years – solar panels everywhere now. The City Council holds almost unanimous support – really strong support to electrifying homes and getting greenhouse gases out of homes. So I know that's more longer term than what Tom is talking about, but it matters to get ahead of this; and I sense at least the community levels that will.

The other thing I take a lot of hope from is examples of success. In healthcare, again, the decarbonization effort – we cannot assert that it's impossible because we have examples of hospitals and health systems that have already decarbonized. Kaiser Permanente – a massive program helped their system in the West. They have, over the past five or six years, decreased the greenhouse gas footprint phenomenally.

Gundersen Health System across Wisconsin, zero – they're now carbon neutral. So we have proof of concept now, and so we're beyond the "Can it be done?" Now we're at, "Will it be done," and I think that's always a better place to be. The collaborative that we mentioned, National Academy, our job is generate a platform in which it becomes conventional behavior to get ahead of this problem of greenhouse gases.


I think that's a great place to end. I really appreciate everybody taking the time to talk today and being willing to have this conversation.


You've made it a pleasure, thank you.


Enjoyed it.


Thank you.


Thanks to my guests – Don Berwick, Tom Di Liberto, and Aparna Keshaviah. And thank you for listening to another episode of On the Evidence, the Mathematica podcast. This episode was produced by the inimitable Rick Stoddard. In our show notes, we include a full transcript of the episode. We also include links with more information about the Climate Collaborative, NOAA's community-led campaign to address urban heat islands, and Mathematica's ClimaWATCH tool.

There are a few ways you can keep up-to-date on future episodes. You can subscribe wherever you listen to podcasts, or you can follow us on Twitter. I'm @JBWogan. Mathematica is @MathematicaNow.

Show notes

Learn more about ClimaWATCH, an interactive online tool that can support communities seeking to understand and adapt to the local effects of heat waves on their residents’ health.

Learn more about Mathematica’s interdisciplinary climate change practice.

Learn more about the National Oceanic and Atmospheric Administration’s work over the past five years with more than 65 communities to map urban heat islands and use data-driven insights to mitigate the harmful and inequitable effects of extreme heat.

Learn more about the National Academy of Medicine’s Action Collaborative on Decarbonizing the U.S. Health Sector.

About the Author

J.B. Wogan

J.B. Wogan

Senior Strategic Communications Specialist
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