Professor of Landscape Architecture and Urban Planning at Texas A&M & Best Practices Panel Member for the SWMD transformation project
In terms of medicine and climate, there are a lot of innovative changes that have (or are) coming that is student led, curriculum development (like the national climate report card, etc.). On your website, you profile a student organization that you spearhead specific to Evidence-Based Design (EBD), please tell us about it.
About six years ago I joined A&M. Some of my students wanted to study how environments could make them safer and healthier, so we formed the ‘Microclimatic Design Research Group’. It was mostly made up of PhD students and a few masters students. We met regularly until Covid happened. We found that meeting online wasn’t as effective and decided to expand. Now we have 35 members from all over the world: from Japan, New Zealand, etc. In some cases, its faculty, and some are PhD students. Every week we get together for one hour, share ideas, presentations; it has become a very vibrant group. Much of it has to do with urban heat, and a lot of it has to with vulnerable populations, the elderly and young kids. We discuss how design can make environments safer.
I was recently listening to a segment on the local radio her in DFW, and it discussed how people just aren’t aware of how heat levels are becoming more drastic, and the heat waves are lasting longer. Where they may have been fine before are now experiencing negative impacts before they realize it hit them.
One study I worked on in Toronto looked at not only how neighborhoods are designed to resist heat impacts, but we also analyzed hospital records during heat waves. We found that neighborhoods with more trees and less hard surfaces had fewer emergency medical calls, versus those with less trees and more hard surfaces. It’s not cause and effect, but there is a relationship. Some of my research even looks at red-lined districts in Texas and those populations are vulnerable due to the fact that those areas are now hotter places and more dangerous. We also have been looking at subsidized housing, where people may not have air conditioning or even heat, and how they’re affected during heat waves and cold spells.
What motivated you to create the student group? What exactly do they do? Are there any innovations that have they come up with? What do you think the future holds for design students?
When I was in Canada, I was at a very good university, but with little to no access to PhD students and had to rely on other departments, but what I wanted was a whole lab of students. Taking my research to a new level, I wanted to focus my last years on making a difference. I have had a lot of good students working with me. I toiled in obscurity for the first 20 years, nobody cared about cities and what they were doing for climate change. Now there is a great deal of interest. There are not many people in urban design, architecture, or landscape architecture doing much with microclimatic data. I wanted to look at how we can study these questions, but also communicate them to the designers and to the public. Also, I just wanted to do some good science. I have a few books on the subject and have been told they are easy to read; ultimately hoping to have an impact on how cities are designed.
I was fortunate enough to supervise students and interns through academia and in an office setting. I miss that energy and passion young minds have for the future; it certainly can revive some of that hope you lose when you get out into the professional world after college.
Students are exciting. They have such different perspectives, and I’ve learned so much from them. It can be pretty discouraging, how little control we have as an individual, but with microclimatic urban design, students find that they can have a huge amount of control over local communities; though they may not influence the global scale, locally they can.
We both have academic trainings in Geography, so I think we both also appreciate the importance of interdisciplinary research.
It is so important to have people from many different backgrounds and disciplines.
Given the historic extreme heat this summer, what do you think the top priorities are to address the threatening effects of climate change. Locally? Globally?
Locally, you can’t really change the air temperature or humidity, these are low. Radiation is what should be changed. I have the students use high quality air sensors while they stand in full sun and take the temperature. Then I have them stand in the shade and take the temperature. Though the variation is only a few degrees, they can feel how significant the difference is, even with just few degrees change, how much cooler it is in shade, because the solar radiation isn’t being absorbed as heavily on your body. Also, there is quite a lot that diffuses from the sky.
I taught an Environmental Science lab while I was in graduate school. Using barometers to observe the weather for one lab, I wish I had thought to make that connection with them.
My PhD advisor, Terry Gillespie and I actually developed a model called the COMFA model. [He passed away recently, my colleague and I wrote an ‘In Memoriam’ to celebrate his incredible accomplishments]. We have even developed this model for kids. It can look at the amount of energy a person is losing to wind or getting from sun or the environment. On a hot day in Texas, usually solar radiation is the biggest energy drainer. If you can shield this, it helps a lot. Also, when radiation falls on surfaces, like a lighter surface, the radiation will reflect onto you. Asphalt will absorb most of it but still it emits the terrestrial or long-wind radiation, which will also heat you up. However, there are four even five variables to consider, all must be individually observed.
Can you tell me about another research endeavor involving extreme heat mitigation?
When the Olympics were to be held in Tokyo, they called on me to design their race route. We traveled to the city and put instruments on cars and bikes, then traveled at the rate of a runner, analyzing second by second for about two hours. We were able to identify hot spots along the route and modeled different scenarios on how to cool those spots. However, Covid happened, and the Olympic committee started to put things on the back burner. After my pleas for their consideration of safety for the participants, even for spectators, I think they were finally so tired of listening to me they moved it 300 miles north to a cooler climate. They said they didn’t want to impede the view of the imperial palace. Sometimes, even when you have good evidence, stakeholders may have different interests.
I can tell you firsthand, the varying interests of the diverse number of stakeholders in the SWMD park and streetscape transformation project is something we must take into consideration at each step of the planning process.
As an organization that has also published research on urban heat islands (UHIs), where do you think the literature is lacking?
A lot of the work is on air temperature, sometimes they find a reasonable difference, but most of the time there is too much time spent on air temperature, and not radiation. A lot of the research is misguided. The focus needs to be on radiation. People are now looking at ‘surface heat islands’, finding that places with few trees and more surface area are causing humans to absorb more heat, and that can carry into the night, when night temperatures don’t cool down; think of sleeping near a wood stove just after its been put out. And it’s not just surfaces, its all of the things that effect the energy budget of the person; the amount of terrestrial radiation from surfaces, if wind is there that can cool, etc. We need to move to a more comprehensive approach. Also, a lot of things in a city reduce the wind flow.
You would be happy to hear, we started working with DART, in hopes of using the microclimatic data we gather at bus stops in the District to influence the design of new bus shelters throughout the city.
It’s interesting, even food is impacted in unique ways. Many immigrants desire food from other countries that are difficult to grow properly here due to sold and climate. Bitter melon for instance, is a popular item for many Canadian immigrants of Asian and African descent. It has many medicinal benefits and a distinct flavor. Thought it can technically be grown in the U.S., due to the different conditions, it lacks the same flavor, and shipping it long distances has similar negative impacts. So, people are studying the phenomenon of ‘plant heat islands’. Since grapes are widely used in winemaking, we found a great deal of research on how different grape species are grown in a variety of conditions.
I worked on a research project for my thesis, investigating placemaking techniques utilized by refugees in an urban community garden setting. It was exciting to discover their different gardening techniques; how they accommodated the dense, clay soil of Texas, and of course the heat; a very different set of conditions than what they were used to in the fertile lands of Bhutan. The group I worked with had a similar affinity for a unique food item. It is called ‘Gandrunk’, or okra that they dry on their back porches or window seals to eat as a snack throughout the day.
Of the many projects you have worked on throughout your career, which are you most proud of and why?
I think it would be the energy budget model, COMFA that I created with my advisor, Terry Gillespie. It was started as far back as 1979 if you can believe it. There were no microcomputers, and they were just coming out with the IBM PC. The idea of modeling was still new, you could do long-hand equations, but that was it. So, I invented this model, then connected it with urban design. It was almost dumb luck in the beginning when Terry and I put this together. I wanted to find out how to see what the most important issue was; is it better to have a dark surface or light? To reflect or not? It wasn’t clear. As it turned out, it relates directly to things you do on the landscape, like density of tree species. We’re able to see which species works best, and can try different interventions then test them against the model. I keep thinking in the next year or two, we’ll develop a tool for anyone to be able to use the model and analyze their environment to make an area cooler or warmer.
I heard recently that it is humidity that really has the impact on how we feel heat in our environment. However, ‘relative’ humidity is typically what is provided in weather reports to the public and that this is the humidity in the shade only and can be misleading and dangerous to vulnerable populations assessing whether or not they can work outside.
Relative humidity is the same in the sun and the shade. Relative humidity is confusing. When the air temperature is higher, it can hold more water. They should be using absolute humidity. Most mornings, dewpoint is at 100% relative humidity. This strongly influences a person’s thermal comfort, and abatement strategies would need to change as humidity changes.
I read the abstract for ‘An in-depth analysis of the effect of trees on human energy fluxes’. I read that an even-distribution of trees was found to be overall most effective and that taller trees with low branches and dense crowns had the largest effect on solar radiation reduction, did you find any other best practices?
Still depends. There is not one definitive answer. In that study we found some of those relationships, but in Dallas the sun angle could be different. We need to take each issue as a unique condition.
Aside from the use of trees and other cooling mechanisms, what if you are in a situation where you are trying to mitigate heat without the use of water? How can you cool without water? Is this anything you’re familiar with?
I come up against this all the time. In a lot of studies, we find that bodies of still water have little impact. Ponds in particular have almost no effect on microclimate, and often will even reflect heat onto people at low sun angles. Water from a fountain could cool the air but mixes so quickly with the hot air that it’s hard to measure; therefore, even a fountain would have little effect. Misters would have a greater effect, taking heat out of the air, and heat away from bodies. Its also important to think about how water can impact surface temperatures. When the sun falls on a building, you can spray water on the building to emit less terrestrial radiation; or put plants on the building like vines, this will have the same positive cooling effect; putting something green on the surface will cause evapotranspiration providing a similar effect.
Urban Design Associate