Tanzina Vega: 2020 is on track to be one of the hottest years on record. The exposure to this extreme heat depends on where you live. The temperature of one neighborhood could be as much as 20 degrees hotter than another. Much like with COVID-19, communities of color are disproportionately bearing the brunt of this temperature disparity. One recent study indicates that this might be by design. Earlier this year, researchers at Portland State University and the Science Museum of Virginia linked the temperature disparities we're seeing today to racist housing policies from decades past.

Now we turn to the authors, one of the authors of that study, Vivek Shandas, is a professor of urban studies and planning at Portland State University.

Vivek, thanks for joining.

Vivek Shandas: Thanks for having me.

Tanzina: In the study, you looked at more than 100 cities in the US. What's the degree of difference in terms of temperature between Black neighborhoods and white neighborhoods.

Vivek: Across the country, we surveyed about 108 cities. Systematically, we were finding that there was a pattern of about five degrees of difference in terms of Fahrenheit that's averaged across the entire country. In some cities, that difference was upwards of 13 degrees Fahrenheit. What we're seeing is a real disparity in terms of who's getting exposed to this extreme heat.

Tanzina: Are there differences that are more pronounced depending on which cities we're talking about? Where are certain disparities more striking from a geographic standpoint?

Vivek: This is something we're still digging into. This is one of these correlative studies where we're just looking for really broad patterns. One of the things that emerged for us immediately was that 94% of the cities that we looked at had this pattern where historically redline areas were always hotter than their non-redline counterparts. This history of disinvestment that had occurred in these redline neighborhoods was very stark and very easy to pick up in this broad survey of the cities.

Geographically, we're finding that there are several cities that really ranked in the top. Completely coincidentally, the city that I live in, Portland, Oregon, which is needless to say, been on the news a lot lately, ranked number one on that list. That's where we saw the temperature difference of 13 degrees Fahrenheit. That really got us thinking. The next city was Denver, Colorado, then came Minneapolis. Then came the usual suspects that we've heard a lot about in the news in terms of Baltimore and Jacksonville and Orlando and Chicago, as well as Philadelphia. There are these set of cities that just follow the top three. We're really starting now to look into those specific cities, why they're ranking so high, what happened historically? What were some of the local policies that occurred that created this massive disparity in terms of heat?

Tanzina: You're talking about disparities within the same city. These are neighborhoods within the same city. These aren't from city to city even.

Vivek: Correct. Even within the city, we have certain areas that have had massive freeways go through, that have had large public housing complexes, that have had all the permissive and undesirable land uses go to these neighborhoods that were historically redlined over the '30s, '40s, '50s, and '60s. All those things that the wealthier often wider neighborhoods didn't want ended up in these neighborhoods. That's where we're seeing a lot of this disparity,

Tanzina: Vivek, are there other-- I want to get back to how this happened, what explains the heat disparities. You mentioned things like freeways, but what about things like trees?

Vivek: We've been conducting these campaigns where we go around and work with community organizations to go and collect temperature and humidity measurements throughout the country. One of the things we started seeing, as we were going about engaging these vast cadres of volunteers to collect these temperature and humidity measurements at very fine resolution, very really granular stuff, we started seeing that the neighborhoods and the volunteers would comment to us that the neighborhoods they were driving through just had, many of them had fewer trees, had very different land uses. We started looking at this in relation to socio-demographics, who was living there.

We noticed that there was a very clear pattern of lack of tree cover in these locations. What happens is, when you put a freeway down, you put a big box store down with all that asphalt parking lot, that really seals up the ground, and there's much less space for anything else that can go. You're squeezing out trees in the sense of putting down all of this asphalt, these big box stores, these freeways. What now communities have to do in order to be able to cool their neighborhoods with trees, is work even harder to now tear up that old asphalt, tear up that concrete. I'm in touch with so many planners and urban foresters that are talking about how do we expand canopy in places that have so much surface ceiling of asphalt. That's one of the biggest conundrums that we're faced with now, is that these historical planning and design policies went in place in such a way that they really make it even harder now to be able to cool those areas as opposed to the non-redline counterparts where we can get trees in much easier today. We have a lot of work ahead of us.

Tanzina: Vivek, I want to make sure we get this in. We've got about two minutes left here. I'm curious about the health effects of heat, particularly in the communities that you're talking about. I grew up in a community such as this. I'm wondering, is there physical or mental health issues that happen as a result of extreme heat for people who live in these communities?

Vivek: Oh, absolutely. It's one of the silent and most discriminating killers that we know of at this point. Outside of COVID, it's been one of the largest killers in terms of natural hazards that the US and many places around the world face. What happens is, it's often a heat wave comes through, which are growing also intensity duration and frequency around the country. It essentially affects the body through physical response. This is your ability to thermoregulate. Once you reach that 37 Celsius or a 98.6 Fahrenheit threshold, and your body's not able to sweat and get that heat out, certain organs start to fail. What you start seeing is those that are most vulnerable, especially those that have preexisting health conditions, which COVID and many other health conditions would challenge them to be able to come through a heatwave well, if you have a preexisting condition, if you have a lack of AC or ability to run the AC, those are really pernicious experiences and conditions that would expand and deepen the likelihood of mortality or morbidity. It is a very intense killer that way.

Tanzina: Viveck Shandas is a professor of urban studies and planning at Portland State University. Vivek, thanks for being with me.

Vivek: Appreciate that. Thanks, take care.

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