Hot Enough For You? Cooling The Worsening Urban Heat Island

33:54 minutes

a stylized version of the earth with cloudsThis story is part of Degrees Of Change, a series that explores the problem of climate change and how we as a planet are adapting to it. Tell us how you or your community are responding to climate change here.

The Urban Heat Island

a city skyline under a hazy yellow, brown sunset
Phoenix, Arizona, the hottest city in the U.S. Credit: Shutterstock

We’ve known for more than 200 years that cities are hotter than surrounding rural areas. All that concrete and brick soaks up the sun’s rays, then re-emits them as heat long after night has fallen. On top of that, waste heat from the energy we use to power our buildings, vehicle emissions, and even air conditioning units can cause some cities to be as many as 20 degrees Fahrenheit warmer than their rural surroundings—creating “urban heat islands.” Between the toll that heat takes on the body and the concurrent air quality problems that heat exacerbates, heat waves kill more Americans per year than any other weather-related event. And if enough city residents are using air conditioning to beat the heat, power outages from overworked grids can add to the risk of mortality.

As the globe warms, urban heat islands are projected to become more pronounced, with even hotter temperatures and a more stark urban-rural divide. But scientists and engineers have been working on solutions to reflect the sun before it can raise temperatures, such as cooler roofing materials and heat-reflecting pigments, cool pavements, green roofs, and neighborhood green space. Ronnen Levinson of the Lawrence Berkeley National Laboratory joins Ira to describe what we know about cool infrastructure, while Global Cool Cities Alliance executive director Kurt Shickman explains how cities around the world are implementing solutions—and why it may take something as bureaucratic as building codes to see mass adoption of cooling strategies.

Los Angeles: Cool Roofs And Fitting The Solution To Landscapes

The city of Los Angeles passed the first mandate for residential buildings to have high-reflectivity roofs, a step up from the past requirements, which only applied to flat, commercial roofs. Los Angeles is also pouring cool pavements to test their effectiveness in lowering temperatures.

But how do researchers know these interventions are actually working? And how do you pick the right intervention for any given neighborhood in a city with as big and varied a landscape as Los Angeles? USC scientist George Ban-Weiss talks about his work tailoring cool solutions to individual neighborhoods, and the data that’s still missing as communities weigh the costs and benefits of planting trees versus painting pavement or roofs white.

New York City: Green Roofs And Community Activists

four kids run and play in a large fountain. there is a french architectural arch in the background
Summer in NYC’s Washington Square Park. Credit: Shutterstock

While heat waves are projected to kill thousands of New Yorkers per year by 2080, that pain is not likely to be distributed evenly. Some of New York City’s hottest pockets—near highways and heavy industry, with fewer green spaces—are communities with the most vulnerable populations. And research has found these hotter urban heat islands are home to higher percentages of poor people and people of color. Meanwhile, while New York City alerts residents of heat events and offers cooling shelters for them to go to, the shelters can be difficult for people to access, or even hear about.

But community groups in the Bronx, Harlem, and other parts of the city are working both to cool down their neighborhoods, and connect residents to life-saving cooling. Justine Calma, a reporter for Grist, details the environmental justice problem of the urban heat island, and how New York City is responding.

Phoenix: The Hottest City In The U.S. Is Trying Everything

Phoenix, Arizona, experiences temperatures over 100 degrees in the summer, and researchers are only expecting summers to get hotter and longer. Hot season durations are projected to increase by several weeks on both ends, while the likelihood of temperatures that exceed 115 degrees is only expected to grow. In 2017, an estimated 155 people died of heat-related causes in the Phoenix area.

But the city has been taking the heat seriously. Phoenix has been painting municipal building roofs white since 2006. The city also has ambitious goals to establish shade trees, shelters along public transit routes, and a HeatReady program that would put heat planning on par with disaster preparedness—all with help from scientists like Arizona State University researcher David Hondula. Hondula joins Ira to describe the challenges of getting cities invested in heat preparedness, both short-term and long-term, and what’s next for Phoenix.

How You Are Responding To Urban Heat Islands

How is your county, city, or neighborhood responding to extreme heat? Let us know in the comments below.

Jeremy Hoffman, climate scientist for the Science Museum of Virginia, called in to tell us how his community in Richmond, Virginia developed a method to map urban heat islands. Listen below.

 Transcript: In the summer of 2017, the Science Museum of Virginia hosted a citizen science campaign to measure our city’s temperature during a heat wave. We sent teams of volunteer scientists all over the city with thermometers and GPS units to measure temperatures across various land use types in the city’s metro area. We found a 15 degree Fahrenheit difference between the warmest and coolest place in the same city, on the same day, at the same time. Now, we’re working with the city health department to understand thresholds for issuing heat warnings as we identified higher heat-related illness rates in those warmest zip codes. 

We’re also coordinating with local non-profits to focus tree plantings and greening projects in the most heat-striken areas, which also tends to be areas of extreme poverty and health inequity. We call a team program we developed with a local education non-profit, “Throwing Shade in RVA,” which advances health and climate equity education for local teens. I have many more stories to tell you about heat enrichment, but we’ve since also recreated the same type of study in Washington, D.C. and Baltimore, Maryland, with this summer campaigns happening all over the country.

Citizen science is the best way for us to empower our communities to understand urban heat and then fight back against it. 

Something You Can Do!

a white house with a white roof
Credit: Shutterstock

How can you help your city cool down a bit? Make your roof a cool roof, whether your material is white paint or heat-reflecting shingles. The Cool Roof Rating Council has recommendations for materials you can choose, and a directory of rated products. The CRRC also keeps an updated list of rebates and building codes to help you identify what the requirements for cool roofs are in your city and whether you can save any money on the update.

If you don’t own your home or can’t convince your landlord to make the change, then think on a neighborhood level. Plant a tree (and care for it), or contact your local government about creating green spaces and parks in either your neighborhood, or those that don’t have them. Find out how efforts by South Bronx residents led to the creation of Hunts Point Riverside Park in 2004.

Further Reading

  • Learn about albedo and creating cooler playgrounds with this activity from Science Friday’s education team!
  • Read about how this week major metro areas in the West, including Las Vegas, Phoenix, Sacramento, and San Francisco, were experiencing heat waves with temperatures as high as 120 degrees Fahrenheit in USA Today.
  • Find out more about Phoenix’s HeatReady program for heat readiness in Scientific American.
  • Learn more about the Urban Climate Research Center’s studies at Arizona State University.
  • Learn about Los Angeles’ initiative to pour cooler pavement materials in the Los Angeles Times.
  • Read more on New York City’s bill requiring new buildings to establish green roofs in Dwell.
  • Read Justine Calma’s reporting on how climate action could avert hundreds of heat-related deaths in the U.S. and how heat waves are impacting communities of color in Grist. 

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Segment Guests

Kurt Shickman

Kurt Shickman is executive director of the Global Cool Cities Alliance in Washington, D.C.

George Ban-Weiss

George Ban-Weiss is a professor of civil and environmental engineering at the University of Southern California, in Los Angeles, California.

Ronnen Levinson

Ronnen Levinson is a staff scientist and leader of the Heat Island Group at Lawrence Berkeley National Laboratory in Berkeley, California.

Justine Calma

Justine Calma is a staff writer at Grist. She is based in New York, New York. 

David Hondula

David Hondula is an assistant professor at the School of Geographical Sciences and Urban Planning and is a senior sustainablity scientist at Julie Ann Wrigley Global Institute of Sustainability at Arizona State University. He is based in Phoenix, Arizona.

Segment Transcript

IRA FLATOW: This is Science Friday. I’m Ira Flatow broadcasting today from KUNC in Greeley, Colorado. 


If you live in the Western United States, including the San Francisco Bay Area, where temperatures this week surpassed 100 degrees– can you believe that– breaking 100-year-old records, you can feel there is something different about the climate now. And in big cities, concrete jungles, oh, they only amplify that heat. Since 1810, we have known that urban centers are warmer than their rural surroundings. 

Our building material, it turns out, absorbs more of the sun’s heat. They hold it longer, closer to the ground than vegetation and soil. And sometimes, the difference is as much as 15 or 20 degrees Fahrenheit. This urban heat island effect is the poster child for regional climate change. And it’s projected to worsen under global climate change. 

History shows that heat kills, costing more lives per year than any other weather-related disaster we see in the United States. Heat, as we have seen from numerous heat waves, is deadly. But just as we’ve known about the heat island for centuries, scientists and engineers have been working on technologies to cool our cities for decades. Remember when the Department of Energy was pushing for white roofs? Yeah. Well, the science of cool roofs, cool pigments, cool pavements, and the use of greenery to cool our streets, well, that science is still evolving. 

And cities are buying in. For example, the state of California requires cool roofs on commercial buildings. Philadelphia has a cool roof mandate for a low slope commercial roofs. Louisville offers people rebates for installing cool roofs. LA took that up a notch a few years ago and required more. They require more residential cool roofs. And we’ve been looking to you, our listeners, to help direct our coverage. We’ve asked you to tell us what your community is doing to tackle climate change head on or to adapt. Well, like this project from Jeremy Hoffman in Richmond, Virginia. 

JEREMY HOFFMAN: In the summer of 2017, the Science Museum of Virginia hosted a Citizen Science Campaign to measure our city’s temperature during a heatwave. We sent teams of volunteer scientists all over the city with thermometers and GPS units to measure temperatures across various land use types in the city’s metro area. We found a 15-degree Fahrenheit difference between the warmest and coolest place in the same city on the same day at the same time. 

Now, we’re working with the city health department to understand thresholds for issuing heat warnings, as we identified higher heat-related illness rates in those warmest zip codes. We’re also coordinating with local nonprofits to focus tree plantings and greening projects in the most heat-stricken areas, which also tend to be areas of extreme poverty and health inequity. We call a teen program we developed with a local education nonprofit, Throwing Shade in RVA, which advances health and climate equity education for local teens. 

We’ve since also recreated this same type of study in Washington DC and Baltimore, Maryland with this summer campaigns happening all over the country. Citizen Science is the best way for us to empower our communities to understand urban heat and then fight back against it. 

IRA FLATOW: That was Jeremy Hoffman from Richmond, Virginia. And we would like you please to add your voice. Tell us how you are responding to climate change. In what ways is your community resilient to heat or other aspects of climate change? You need to become part of the story. 

Please visit us at sciencefriday.com/degressofchange and let us know. Or give us a call to tell us now how your city is dealing with the heat. That’s what we’re going to be talking about for the rest of the hour– 844-724-8255, 844-SCI-TALK. Or you can tweet us @scifri. How does your city deal with the heat? Let me introduce my guest to talk about that. Kurt Shickman is Executive Director of the Global Cool Cities Alliance. He’s in Washington DC. Welcome to Science Friday. 

KURT SHICKMAN: Thank you, Ira. Great to be here. 

IRA FLATOW: Nice to have you. George Ban-Weiss is professor of civil and environmental engineering at the University of Southern California in Los Angeles. Nice to have you. 

GEORGE BAN-WEISS: Thanks for being here. 

IRA FLATOW: You’re welcome. And Ronnen Levinson, staff scientist and head of the Heat Island Group at the Lawrence Berkeley National Lab in Berkeley. Ronnen, thanks for being with us. Nice to have you. 

RONNEN LEVINSON: Thanks for having us here. 

IRA FLATOW: Well George, let me ask you first. I gave a colloquial definition of what a urban heat island is. From a scientific point of view, how would you define it? 

GEORGE BAN-WEISS: Well, the urban heat island is typically defined as the temperature difference between the urban area and the rural surroundings. And it’s a way of thinking about the climate effect that the process of urbanization has had on the region. So basically, the process of paving over and putting buildings on natural vegetative cover. 

IRA FLATOW: You pave paradise and put up a parking lot, so to speak. 

GEORGE BAN-WEISS: Yeah, exactly. 

IRA FLATOW: And it’s going to get worse, you’re saying, under climate change? 

GEORGE BAN-WEISS: Well, temperatures are increasing under climate change. So it’s important to understand the distinction between the local impacts of global climate change versus the urban heat island effect. Global climate change is occurring due to increases in greenhouse gases, and those have local impacts on cities. The urban heat island effect is something that happens as land cover changes in a city. Now there’s actually interesting research that looks into how those two things interact. And the research suggests that urban heat islands will actually get stronger with global climate change because of the ways that cities warm differently than rural surroundings. 

IRA FLATOW: I mentioned how hot it’s been over 100 degrees in the Bay Area and a heat wave throughout the Western US. Are these heat waves part of the urban heat island also? 

GEORGE BAN-WEISS: Well, the heat waves are caused by large-scale weather systems, so they’re really not caused by the urban heat islands per se. But the urban heat island sort of layer’s on top of heat waves to make them even stronger. 

IRA FLATOW: Ronnen Levinson, overall, how does a cool roof work? Is it as simple as painting everything white? 

RONNEN LEVINSON: The technology’s a little bit different, but the idea is to reflect as much sunlight as you can away from the building. You don’t want to just paint your roof white because the paint that’s meant to go on a wall won’t adhere very well to a roof. Instead, if you wanted to resurface your roof, your best option is to pick a cool version of a roofing material when it’s time to replace your roof. But if you have a roof that still has a lot of service left, you could look at applying a elastomeric roof coating, which is the analog of a white paint, but it’s designed to work on a roof. 

IRA FLATOW: I’ve seen some roofs now– I was in New York the other day. I was looking at the big Javits Center, the center they have down there. And the roof has grass on it. It’s green. Is that one of the ways of cooling your roof off? 

RONNEN LEVINSON: It’s a different strategy. That’s a garden roof, also called a green roof sometimes. And a garden roof can be a very pleasant place to be. But if you’re going to put a garden on your roof, first your roof has to be strong enough to hold all of that soil and vegetation. And you have to be able to make sure that the plants stay alive. And if you’re in a climate that’s very dry much of the year, that means you have to irrigate them. So a garden roof is an excellent way to stabilize the temperature and to keep things cool, but it does require love and care. 

IRA FLATOW: Yeah, well, Kurt Shickman, you’re executive director of the Global Cool Cities Alliance. Why do we need a global alliance for city cooling? 

KURT SHICKMAN: Well, it really grew out of the work at the Lawrence Berkeley National Lab and specifically, a scientist named Arthur Rosenfeld who was the grandfather of energy efficiency. And what really drove him and what was an observation that the science for cool roofs and cool walls, for example, and the benefits around them for buildings, for communities, for cities, and even for global cooling was very strong and that the products that were available had been available on the market for quite a while and were generally comparable in price. 

And the weak link was actually taking those two pieces and then looking at the idea that we aren’t seeing as fast in implementation as those two other factors would imply. So they established our organization, and we’ve been active for about eight years to really work with cities to drive down into what the actual implementation challenges are in implementing urban cooling strategies, both here in the US and globally. 

IRA FLATOW: And your group just finished taking applications for something called The Million Cool Roofs Challenge. Tell us what that’s all about. 

KURT SHICKMAN: Sure. So The Million Cool Roofs Challenge is a $2 million initiative to bring cool roofs to scale in places that need them the most. And what we’re doing there is really trying to support, with the first million, support some boost grants we’re calling them to generate the good practices that we’ve seen work elsewhere in terms of implementation so things like encouraging broad engagement from government and the public industry, technical experts and academics, like the gentleman that called in from Richmond, Virginia, and also to develop pilots of the technologies in local contexts so people can see and feel it, and also generate local information about the performance that can then drive greater action. 

And then while the team’s there, one will get to scale, which we’re defining as applying one million square meters of cool roofs by the end of 2020, and they’ll win the second million dollar prize. And this is really driven by the issue of access to cooling. So it’s a little less of an issue in the US. But in developing countries, we’ve got about 1.1 billion people who don’t have physical or economic access to what we would consider to be space cooling so like electrical, mechanical cooling. And so cool roofs and improving the thermal comfort of buildings and communities is really how they’re going to stay cool in a warming world. 

IRA FLATOW: George Ban-Weiss, you’re based in Los Angeles. Most people when they think of heat islands and concrete jungles and cities, they’re talking about the pavement getting hot. You see during a hot day, people talk about it. It’s so hot out, I could fry an egg on the pavement. We’re talking about roofs. Is there anything we can do for the pavement to cool it off? 

GEORGE BAN-WEISS: Yeah, so in the same way that you can make a roof reflective, you can also make pavement reflective. And whereas there’ve been requirements for cool roofs for a few years to 10 years, depending on what type of requirement we’re discussing, and it’s also been researched quite a bit over time looking into the climate impacts and other impacts of cool roofs, cool pavements are a little bit younger. And they’re currently in development by a bunch of companies. 

The city of Los Angeles has a sustainability plan they’re calling The Green New Deal. Well, it includes a lot of different things, including 100% renewable energy by mid-century. But it also includes a heat island reduction target where they have the goal of reducing the urban-rural differential by almost 2 degrees Fahrenheit by 2025 and 3 degrees Fahrenheit by 2035. And so they call out using cool roofs and tree cover but also cool pavements. 

The cool roof, as you mentioned, policy has been in place for a few years now. And I think the last I heard is they’re around 20,000 new residential cool roofs installed. Cool pavements are currently being piloted by the city. So it started with a pilot project around a year ago I think where they converted 14, I think it was, city blocks to cool pavements with new coatings. And they were looking mostly for pavement engineering types of things. There were some kind of rough temperature measurements done. 

But now they’re going to do a somewhat larger scale pilot program where they’re going to pave with cool pavements neighborhoods. And so we’re hoping to use that as sort of a living laboratory to be able to measure how adoption of these cool pavements is affecting surface temperature, air temperature, and other things. 

IRA FLATOW: Cool. I’m Ira Flatow. This is Science Friday from WNYC Studios. Let’s go to the phones. Lots of people would like to talk about it. Let’s go to Portland, Oregon for Casey. Hi, Casey. 

CASEY: Hi there. How’s it going? 

IRA FLATOW: Hi there. Go ahead. 

CASEY: Yeah. So I’m an urban forester for the city of Portland, Oregon. And what we’re really focusing on and what we’re trying to do to manage the urban heat island effect, even in a wet place like Portland, is really focus on increasing the canopy cover of the city, especially in low income areas where historically trees have been removed or not been planted. So by far, from the research that I’ve seen regarding urban canopy cover, that the canopy cover is the biggest thing that affects the urban heat island effect in two ways, mainly that the trees actually grow over the top of the roads. 

And the buildings by shade them but also act as an air conditioner and they pull up water through the stems of the trees and actually or through transpiration or evapotranspiration, put it out into the air. And by that effect, basically air condition the city, especially in the urban areas where you have any amount of water in the ground can get pulled up into the air. So mainly what I’d like to sort of make more of a comment is or mainly as a comment to say that I think cities should really be focusing on making spaces for large canopy trees that can grow over and shade the areas around any impervious or hot services like pavement and buildings. 

IRA FLATOW: Good point. Ronnen, George, Kurt– any reaction to that? 


GEORGE BAN-WEISS: Well, I can respond to that. I think that that’s a really important point. If you’re thinking about not just temperature but actually thermal comfort of pedestrians, having shade is really the most important thing, even for the same air temperature. So adding tree canopy is a really important way to improve thermal comfort of people. The other thing that’s interesting too is that even in a place like LA, you would think that, OK, if we want more trees, we need to get the water to irrigate those trees from somewhere. And that’s, of course, true. 

But there is actually research that suggests that if you place the tree in places that that makes sense, for example, around lawns that overall, the amount of evapotranspiration, meaning basically water loss from the soil, goes down because of the way that the tree can shade the lawn. And so you can actually water your lawn less by adding a tree that shades the lawn. 

IRA FLATOW: Gentlemen, anybody else have a comment. 


RONNEN LEVINSON: Go ahead Kurt. 

KURT SHICKMAN: I would just add that these are, in every city, it’s going to be a basket of solutions that gets to the end goal of urban cooling. And tree canopy is a critical piece of that. And these are not just mutually non-exclusive, but they’re actually self-reinforcing as George just pointed out. And there’s also some benefits when you are changing the color of your roof to a lighter color, which is 20% to 30% of a city’s areas is the roof, which may not always be covered by tree canopy. There could be some benefits when you get to that large scale air cooling with reduced evaporation that provide some of the same benefits that George was just mentioning in terms of groundwater. 

Ronnen, quick jump in? 

RONNEN LEVINSON: Yeah. I’ll just add that if you’re going to green your city, you’re better off using trees than grass because trees draw much less water. And if you’re in a dry climate, that makes a big difference. 

IRA FLATOW: That is interesting. And it’s something that I don’t think most people think about. They walk through the concrete of this city, and they don’t think about, hey, a tree could be here and provide cooling and shade and all kinds of stuff. Kurt, are there gaps between technology and policy? What cities, urban, federal need to do between we just talk about it and what steps they need to take. 

KURT SHICKMAN: Sure. So I would say yes. There is a pretty big gap because the technology’s been around a very long time, and we haven’t seen the action we want to see. And I think there’s a couple of reasons for that. I guess the first and easiest one is that heat is a pretty hidden disaster for us. You mentioned it in the top of the show. It kills more people than any other natural disaster in an average year, but we rarely hear about it unless it’s a major, major heatwave. And that actually translates into how it’s implemented in cities. 

You won’t find any city or any government anywhere that has a Department of Heat. And yet, if you look at what each individual department within a city’s mission is, heat is going to impact it in some major way. And so when we see policies in cities, the ones that are effective are those that gather these different departments together and really start to look at the problem of heat within their own activities, within their own budgets, and so on. And that’s great, but that’s also a very challenging thing to do city by city. So that’s why we see slower implementation than we’d like. 

IRA FLATOW: I want to thank my guests, George Ban-Weiss, professor of civil and environmental engineering at USC, and Ronnen Levinson, staff scientist, head of the Heat Island Group at the Lawrence Berkeley National Laboratory. Ronnen and George, I thank you for taking time to be with us today. 

GEORGE BAN-WEISS: Thank you so much. 

RONNEN LEVINSON: Thanks for having us on. 


IRA FLATOW: Continuing with our degrees of change episode this week. Not far from Los Angeles, the city of Phoenix, Arizona has the distinction of being the hottest in the nation. Starting in May, daily highs surpass 100 degrees and stay there until September. Remember that heatwave I was mentioning in the San Francisco Bay area? Well, the high in Phoenix yesterday was 110 degrees. 

And when it gets that hot, it’s not just uncomfortable, we’re talking about health and safety, people without air conditioning, especially the very young and the elderly. They are at the highest risk of health problems or even death. So how do you help them get through this summer? Well, cities can open cooling centers. But you also have to make sure people go to them, which doesn’t always happen for various reasons. We’re going to take a look at efforts to understand and safeguard health in the urban heat island. 

We’re still talking to Kurt Shickman, Executive Director of the Global Cool Cities Alliance. But I also want to turn to Dr. David Hodula, an assistant professor– Hondula– I’m sorry, last time you were on, I got it wrong also– assistant professor of geographical science and urban planning at Arizona State University in Phoenix. Welcome to Science Friday Dr. Hondula. 

DAVID HONDULA: Good morning, Ira, from beautiful Phoenix. 

IRA FLATOW: How hot is it today there? 

DAVID HONDULA: Well, we’re only heading into the low 100 degrees today, not as bad as it’s been in the past couple of days but still warm and still a threat for public health, as you mentioned. 

IRA FLATOW: And we want to get to that. Let me also bring on Justine Calma, a staff writer for Grist who has been reporting on New York City’s disproportionately hotter neighborhoods and the community groups working to both cool down the neighborhood and connect residents to life-saving coolness. Welcome, Justine. 

JUSTINE CALMA: Hi, Ira. Thanks so much for having me. 

IRA FLATOW: It’s great to have you. David, I want to zoom in on this idea that the urban heat islands are bad for human health. And it’s not just about being hot and being uncomfortable. People are actually dying there. 600 people have died in the US from heat. 

DAVID HONDULA: Yeah. Well, that’s a good point you raised, Ira. And in fact, there’s quite a bit of discussion amongst researchers and public health officials about exactly what the burden of heat is. There are different accounting systems for measuring how many people get sick from or die from heat. In Phoenix and in Maricopa County, we’re fortunate to have one of the most sophisticated of those systems anywhere in the world. The numbers here locally suggest that in our county alone, more than 150 people have died as a consequence of heat in the past three years. And that’s a significant problem that we’re working to address. 

IRA FLATOW: And you can’t blame that solely on climate change, can you? It’s not the sole reason why people are dying from the heat? 

DAVID HONDULA: No, absolutely not. Of course, heat is a major factor in the story for heat-related illness and deaths. And more heat in the future suggests higher risk. But in addition to the strategies we’re hearing about from the previous speakers about cooling the cities, as you said yourself, we also want to think about cooling the people. What resources do people have access to to stay cool? 

And some of our data suggests that some of those social programs and those social factors could be just as or more important of a part of the story in what future risk will be compared to temperature. So not only do we need to keep an eye on the thermometer, but we also need to keep an eye on the budgets for homeless shelters and other social service programs that are helping to keep people out of harm’s way. 

IRA FLATOW: Kurt Shickman, I remember that big heat wave in Europe in 2005 where tens of thousands of people died of heat-related causes. How did they respond to that knowing how terrible that was? 

KURT SHICKMAN: Well, Europe has really been an interesting test case for using technology to do a better job of communicating with the public during heat disasters. There’s a program called Extrema, which is a satellite program that is now in place in Athens and Paris and Barcelona where the city tracks its air temperatures based on a translation from a surface temperature every five minutes. And people that have signed up for the program will be alerted when they’ve entered into a community that’s highly heat vulnerable or when one of their loved ones who’s sign up for the program has and will prompt them to call them or to check in on them. 

And that’s also tied in with a broader look of inventorying the spaces that cities already have and guiding folks to those that are cooler, that provide a respite. So, for example, in Paris, they don’t talk about heat islands anymore. They talk about cool islands and creating these spaces. And so the first thing they did was they looked and inventoried the space they had and found over 800 different locations that could serve as a cool respite for people during heatwaves. And they’ve added signage and road mapping to make people aware of that. And they’re looking to add an additional 300 over the next 10 years or so. So this is a really comprehensive look at how we make people safer and more resilient during the worst heat events. 

IRA FLATOW: Justine Calma, is it tough to get people to take advantage of whatever facilities, cooling facilities that a city offers them to just go out there? 

JUSTINE CALMA: Well, there has to be cultural competency. And so here in New York City, what the city has been trying to do is making sure that they’re partnering with grassroots groups on the ground in the neighborhoods that are the most heat vulnerable. They’re generally neighbors that have higher percentages of residents of color, many immigrant neighborhoods, places where there tends to be less green space, historic disinvestment that’s led to neighborhoods with more heat trapping surfaces and families that may not have as much access to air conditioning. 

Now if this city is relying on making announcements online or tweeting updates, that’s not necessarily going to reach our seniors, or there may be language barriers. It’s really important to just have a beat on how people are actually getting their news. And so that’s why you’re seeing these partnerships like the Be a Buddy Program that was piloted in the neighborhood of Hunt’s Point in the Bronx. They’re working with The Point CDC, which is a local organization. 

And they’re building this network of volunteers and health professionals that they’re training to be able to check in on residents who are the most vulnerable and really build up that social cohesion. Folks can go to their website to sign up to have their grandmother, grandfather, whoever, make sure that someone is checking in on them in the middle of a heat emergency. 

IRA FLATOW: And David Hondula, when you have heat and you have that kind of pressure on people, there’s also additional factors that the heat may exacerbate like air quality, right? 

DAVID HONDULA: Absolutely. Yeah. The heat can absolutely be a compounding issue, a cascading issue, if you will. One of the possible cascades that we’ve been talking about ties into this term we’ve heard Kurt using– heat disaster. We know that the heat and the power systems are closely coupled. 

And we see one of the most significant risks facing health in Phoenix is the possibility of a coupled heatwave and power failure in the summer months in the future. And we know that heat can trigger power failures because of the way that the infrastructure interacts with the weather. So we’re really trying to think about with our public health partners and city officials, how do we handle these interesting interdependencies that you bring up? 

IRA FLATOW: And how does Phoenix, as you say Phoenix 110, how is Phoenix hoping to tackle all of this? 

DAVID HONDULA: I love the point that Kurt made earlier when he raised the concept of the Department of Heat, and that’s absolutely been our experience here as well. One of my colleagues says that heat is everyone’s concern but no one’s responsibility. And although that’s a bit of a tongue in cheek thing, it really resonates with our experience working with cities. 

There is a lot of concern about this topic in the various city halls in this region. But it is not entirely clear who’s in charge, whose decision will it be to make a certain investment, to make a certain priority. And the city of Phoenix as spurred by some funding that it received from the Bloomberg Philanthropies out of New York City last summer is really trying to think about what the governance model will be, what the organizational model should be. 

How do we ensure that heat and thermal comfort and related considerations are part of decision making criteria across the organization, which we think is as absolutely essential? As we’ve heard other speakers say, heat can be a part of the story of every action that every department is taking. And the city of Phoenix and others around here are looking to build that glue to ensure that heat is in the conversation explicitly. 

IRA FLATOW: Justine, you’ve been were reporting on New York City’s work with grassroots organizers to fix some of the flaws you talked about in the system. How’s that been working out? 

JUSTINE CALMA: So what I heard from The Point CDC, one of the city’s first partners, is that it’s been successful so far there. They’re growing their network. They’re better able to get folks to cooling centers in the neighborhood versus relying on posters or signs to get people there. They’re actually bringing people in. But it’s really, it’s a two-prong approach. On one end, they’re trying to improve and overhaul the communications and emergency response system, build up that social cohesion. 

And then on the other hand, they’re also making sure that they’re greening these neighborhoods so changing the actual physical environment, like planting green roofs and making sure there are more trees like one of at your callers said, and green space. And particularly low income neighborhoods are places that have more industrial development. So there’s a lot of promise and excitement there. 

IRA FLATOW: I’m Ira Flatow. This is Science Friday from WNYC Studios coming to you from Greeley, Colorado KUNC with my guest Kurt Shickman, Justine Calma, and David Hondula. We’re talking about heat islands and what happens. And now we’ve moved on to talk about how do you rescue– how do you help people who are most vulnerable? We hear about the elderly. Why are the very young so at risk when it’s so hot out? 

IRA FLATOW: Justine, do you look into that also? 

JUSTINE CALMA: Yeah. One of the things that I look into– I also look at air quality and heat vulnerability, particularly in neighborhoods where children have higher rates of asthma. That can be triggered by heat. People with respiratory illnesses are also among the vulnerable. And so you can see that impacting young people as well. And so that’s another way that some of these neighborhoods that have more industry, pollution, and higher temperatures kind of get a triple whammy of these effects. 

IRA FLATOW: Let me see if I get a phone call or two in before we have to go. Let’s go to Fred in Fort Collins, Colorado. Hi, Fred. 

FRED: Ira, thank you for having me on the show. I’m a big fan. 

IRA FLATOW: All right, go ahead. 

FRED: So I’m grassroots organizer with a local citizen group here, The Community for Sustainable Energy. And we’re working to get our municipal utility, police parking lot, and rooftop space with utility and solar panels. And I’ve read that in the natural environment, solar panels can increase the local temperature. I’m curious if they have the same impact on the built environment that impacts the urban heat island effect, especially if they’re shading parking lots. Does that increase or decrease temperature? 

IRA FLATOW: Kurt, would you know that? 

KURT SHICKMAN: Yeah, so it’s a bit of a mixed bag. So when you’ve got solar panels on your roof or over a paved space, you’re certainly creating a more comfortable space underneath and reducing the thermal load that’s on the building itself. And in many cases, you can pair solar with some of these other interventions we’ve been talking about like vegetation and more reflective or lighter color surfaces and have positive reactions for both. So you’re cooling off the panels, for example. So it’s not a definitive answer to say it makes things hotter. I think generally what we say is we want to pair the panels with other interventions, so we’re getting the benefits of the multiple different ways you can attack this problem. 

IRA FLATOW: My last question is, we want to leave our listeners with an action they can take. What can we do about heat islands? Kurt, first you. 

KURT SHICKMAN: Sure. So I guess I’d start with, on the homeowner side, we don’t like to think about our roofs that much. But when you are replacing your roof or doing any work on your roof, for every type of roof that’s out there now, there’s a cool option and asking about that and making that decision when the time comes, would be great. I’d also note there’s opportunities to be involved in volunteer organizations that plant trees and maintain trees with the cities. That’s a huge benefit. 

And then finally, just going back to the caller at the beginning, Jeremy Hoffman from Richmond, there are growing movements around Citizen Science. And volunteering to help those is immeasurably valuable for cities as they’re trying to understand this problem and tackle it and target their intervention sites, So those are the three that I’d mentioned. 

IRA FLATOW: David, give me your best. 

DAVID HONDULA: Playing off of the theme that Kurt raised there, I’d advocate for joining the public dialogue on this topic. There are zoning meetings, city council meetings, planning commission meetings where decisions are being made that are going to affect heat and quality of life in our cities. And the more participation we can have in those meetings and advocacy for heat shade, cooling amenities, the better. And if joining those meetings doesn’t work for you, doesn’t fit into your schedule, ask city representatives and staff to meet with you and your organizations and your family. I think there is eagerness to hear more perspectives about how we can cool our cities. 

IRA FLATOW: I want to thank all of you for joining us today– Dr. David Hondula, assistant professor of geographical science and urban planning at Arizona State, Justine Calma, staff writer for Grist in New York, and Kurt Shickman, Executive Director of the Global Cool Cities Alliance. Thank you all for joining us today. And our Degrees of Change Series needs your voice from our listeners. Tell us how you are responding to climate change. In what ways is your community increasing its resilience to climate change? We want you to become part of this story. 

So visit us at sciencefriday.com/degressofchange. Let us know. sciencefriday.com/degressofchange. Charles Bergquist is our director, senior producer, Christopher Intagliata. Our producers are Alexa Lynn, Christie Taylor, Katie Feather. And we had great technical and engineering help today from Rich Kim, Sarah Fishman, and Kevin Wolfe. 

Also saying thanks to Ryan Thompson, Robert [INAUDIBLE], Neil Best, and all the great folks here at KUNC in Greeley, Colorado who welcomed us into their studios today. And as every week we tell you, we’re active on Facebook, Twitter, Instagram, all the social media. You can even ask a speaker to play Science Friday. So every day now is Science Friday. In Greeley, Colorado, I’m Ira Flatow.

Copyright © 2019 Science Friday Initiative. All rights reserved. Science Friday transcripts are produced on a tight deadline by 3Play Media. Fidelity to the original aired/published audio or video file might vary, and text might be updated or amended in the future. For the authoritative record of Science Friday’s programming, please visit the original aired/published recording. For terms of use and more information, visit our policies pages at http://www.sciencefriday.com/about/policies/

Meet the Producers and Host

About Christie Taylor

Christie Taylor was a producer for Science Friday. Her days involved diligent research, too many phone calls for an introvert, and asking scientists if they have any audio of that narwhal heartbeat.

About Lauren J. Young

Lauren J. Young was Science Friday’s digital producer. When she’s not shelving books as a library assistant, she’s adding to her impressive Pez dispenser collection.

About Ira Flatow

Ira Flatow is the host and executive producer of Science FridayHis green thumb has revived many an office plant at death’s door.

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