this temperature difference can be very problematic when heat waves hit big cities for a number of reasons. for example, increased temperatures can increase energy consumption and increase the amount of air pollutants and greenhouse gases that are emitted. 

but these heat islands (uhis) also are problematic for individuals experiencing heat stress — which can cause heat injuries that sometimes lead to death — and can exacerbate global temperatures.

it’s a rising concern that’s being met with research on the subject — with the hope that the research can inform solutions and result in action. here are some solutions that can help reduce the impacts of the urban heat island effect.

increase the green 

shading

preserving and increasing the green space and canopy cover in urban areas can have a significant impact on how warm a city is. with increased canopy cover, the potential for more shade exists and consequently more cooling effects. most of the time this means planting more trees to increase tree canopy cover. but deciding where to plant trees in a city is crucial to the success of the trees and the cooling that they provide, as well as crucial to making sure that the urban canopy is distributed fairly.

aaron ramirez, an assistant professor at reed college, and hannah prather, a postdoc in ramirez’s lab, employ translational science when conducting their research, where they incorporate managers and other stakeholders into the process of research so that conversations can be started right away about how to act upon the research.

they are working with the city of portland to reduce the canopy disparities and make sure that less wealthy communities are not more adversely affected by the urban heat island effect. 

“our research interests in this area are focused on how uhis drive increased tree stress in urban forests,” ramirez said. “this is an important potential feedback loop whereby communities already underserved could experience higher rates of tree stress and mortality, which would strengthen the urban heat island effect.

“in our work, we are developing new methods for measuring tree stress in the urban landscape and working with managers to explore ways to prevent these dangerous feedbacks between increased tree mortality risk and human health risks.”

management decisions, informed by their research, could be anything from updating approved planting lists to including more drought-tolerant trees to changing how the city manages irrigation of city parks. this is especially important for portland and other cities that have some of the highest urban heat island effects around the country. portland, ranked no. 4 in the difference between rural and urban temperatures, is up to 19 degrees hotter in urban areas, while no. 1-ranked las vegas has a difference of up to 24 degrees. 

green roofs 

increasing the amount of green spaces in cities can happen in seemingly unlikely places. green roofs have the ability to help combat the urban heat island effect by providing shade, reducing rooftop temperatures, and increasing insulation in buildings, which reduces energy consumption. green roofs can even remove greenhouse gas emissions and other pollutants from the air via sequestration and storage. 

solar 

the use of solar energy can have many of the same effects as increasing green spaces in cities in addition to acting as a mitigator of climate change and the heat island effect. in using solar panels, the need for non-renewable energy is reduced and fewer amounts of detrimental emissions are put into the atmosphere in the first place, which can help reduce temperatures by not contributing to the greenhouse effect.

depending on the type of solar array installed, it can provide shading and cooling similar to that of vegetation.

additionally, when installed on rooftops, solar panels are able to insulate buildings. in the summer months this can create a cooling effect during the day, while in the winter months it can help prevent heat loss at night. this means less cooling energy and costs in the summer and less heating energy and costs in the winter.

city management

vegetation is a great way to adapt to urban heat islands, but how we manage man-made materials is also very important in how we react to rising temperatures. 

cooling materials

the materials that buildings, cars, pavements and other surfaces are made of and what color they are affect how much heat is retained in those objects and how much heat stays in urban spaces.

lighter colors have high albedo — a measure of how much light that hits a surface is reflected without being absorbed — and trap less heat than darker colors. cool roofs and cool pavement can help lower temperatures, but there are more areas that can also be evaluated.

the heat island group at berkeley labs is looking at cars, pavements, roofs, and walls to evaluate what materials and colors can help create cooler cities. often this means lighter colors and more reflective materials will provide the most benefits.  

city planning 

the urban heat island effect is a complex network of many factors, such as those discussed above. researchers like vivek shandas at portland state university point out that there are other factors to consider as well in addition to the ones already discussed. designing our cities so that there are varied building heights, varied canopy cover, and varied street widths can immensely help reduce the heat island effect by increasing air flow that can then cool down the city environment. the hope is that research like shandas’ can help inform city planners and managers so they can adapt to the detrimental urban heat island effect. 

so: what do we do?

whether mitigating it in the first place or adapting to the urban heat island effect, there are many ways in which researchers have the potential to work with bureaucracy to bring about much needed change. this can be accomplished by increasing urban green spaces and cover, choosing better materials to build with, planning cities in better ways by being informed by research, and reducing our reliance on energy from fossil fuels.

these ideas — along with reducing our footprints in other ways including eating more plant-based foods, reducing fuel consumption for travel, using less single-use packaging, and interacting with our legislators to let them know how we feel about a changing climate — have the potential to reduce the urban heat island phenomena and make cities safer for residents in the years to come. the research has and will continue to guide us to solutions. now is the time to act upon it.

civil engineering has been practiced as early as the ancient roman times, and has been a relatively static field, in regards to its materials and methodology. now with the new discoveries concerning climate change and global health, policies put forth by entities such as the u.s. green building council have been a catalyst for change in the industry.

as a construction management intern for clark construction, i was able to have a hands-on understanding of the roles of an engineer on a structural project. on a field site, there are a dozen moving parts which are constantly working to build and bring to life the work of the designs.

my assignment was the closeout phase of the 7th and 8th floors of gwu science and engineering hall. the clark office was set up on the penthouse level, giving me the unique chance to work both in the office and “in the field.”

in the office, i was able to communicate with the project managers and the architect for proper documentation of submittals, requests-for-information (rfis), and leed documentation. since the building was designed as a leed gold structure, i was given the task of ensuring the project’s construction phase had met the leed requirements. this entailed contacting subcontractors for exact information of the source and contents of their materials, which included having non-voc paints, fsc wood products, and fluorescent bulbs.

since this was a summer internship and the project was nearing substantial completion, time was of the essence. every day, sometimes even twice a day, i would call each of the subcontractors in order to get the proper documents. as i waited for this information, i would have to photograph the job site every other day to ensure that the project was within the leed guidelines of source control and interior standards. pictures of the safety net and of the construction crew working in a secluded area were recorded. this aspect was crucial since the project was a completion of the top two floors, therefore little evidence of construction was to be seen from the lower floors.

during the course of the data collection, i did receive some advice from my supervisors and occasional assistance from the clark leed fellow. although each of the members of my team had specific priorities to complete. i came to learn that typically, the leed documentation was sent weeks after the clark construction team would leave the project site. it left me with the impression that the leed certification was not a pressing matter. the leed aspects of the project (the chilled beams, the green roof, and interior air quality control) were outlined years before excavation. while the last stages of accreditation could be finalized after the project site was completed, which was an acceptable practice for contractors.

after four weeks of collecting the data in various different forms and after meetings with a clark leed fellow, it was ready to be uploaded to the usgbc website. this process should have been just several clicks of the mouse and keyboard, however since the website was down, i had to upload each item individually. it was painstakingly long, although i was able to finish the leed certification for the project before i left for the end of the summer.

the construction industry is not the most glamorous and not the most thrilling. however, structures of all kinds – bridges, skyscrapers, and dams – are ubiquitous and unavoidable. as a first-hand witness to the leed process, i have endured the long processes of waiting, photo-taking, and paperwork. it made me feel more like a secretary than an engineer, more of a scorekeeper than a construction management intern.

despite all of that, my internship gave me a glimpse of the growing green standards in the construction industry. these structures will be around for at least the next 50 years. i am pleased to have had the opportunity to observe sustainability at its core, which is to develop and build an entity which meets the needs of the present without compromising the needs of future generations. 

they also provide a habitat for diverse organisms such as butterflies, slugs, snails, and birds. the green roof utilizes native, flood tolerant plants, that have a high capacity for water absorption and storage. they are economical and have provide great benefits for any building establishment containing a green roof. i believe that every college, university or home should have a green roof to increase habitat for organisms that have lost their habitat from buildings, and reduce runoff. i love the green roof garden, because it’s simple, easy and fun.

the miliken institute school of public health is the fourth building at the george washington university to include a green roof. a green roof is exactly what it sounds like: a rooftop covered with special absorbent soil and seedum plants. green roofs keep urban areas cool by reflecting sunlight that would otherwise by absorbed into the traditional black tar roof. this prevents urban heat islands, which is what we call a metropolitan area that is warmer than the surrounding communities. they also keep water sources clean by absorbing rainwater that would otherwise become stormwater runoff, potentially causing sewage overflows.

why does this matter? while green roofs alone probably won’t change washington’s climate or put a stop to all pollution, they certainly help. just one acre of green roof can absorb 630,000 gallons of rainwater each year. there are 6,200 acres of rooftop in dc; if every roof was green, we could prevent 3.9 billion gallons of stormwater runoff every year.

erica halvorson is a senior at the george washington university majoring in journalism and mass communication.

by: samantha hoilett and kelsey bobeck