By Thom Wright (2005 – 2020)
Thom Wright, as a graduate art student at Cal State University Long Beach in 2005, investigated a potential solution to Global Warming (now Climate Change), which is caused by increasing levels of green-house gases in the atmosphere due to human activity. While taking an art course in Intermedia Art, he researched one of the possible remedies that considers ways to reflect more sunlight from urban areas. He documents his findings in a student art show at the school art gallery in 2006, and in 2020 he submits his findings to the Trump Administration for recommended implementation to begin a test program in always sunny Palm Springs, CA.
In 2005 when Wright was researching Global Warming at the CSULB Library, he came across a newspaper article published in the New York Times concerning NASA research on Global Warming. One of the NASA projects noted that urban development generally increased the absorption of sunlight and raised urban temperatures about +5F versus natural areas, because of the structure rooftops and paved roads that are grey to dark grey in color. They proposed that if all the cities of the world would paint dark rooftops with white paint, that it would reflect enough sunlight to completely remove the effects of global warming due to green-house gases in the atmosphere.
Figure 1 Global average temperature versus time to the year 2000
This proposal seemed to be a rather easy solution to the future threat of Global Warming, and Wright came up with an idea to expand this solution by painting all the black asphalt streets in the world white also. This idea led him to investigate the actual aborption level of sunlight by rooftops and asphalt streets. In order to estimate the percentage of absorption of sunlight with the changing angle of sunlight during the day, he decided to build a new instrument called a solar diffuse reflectometer, and make these measurements himself, using different street materials and paints. Figure 2 shows his first instrument as it is being used to test black asphalt and white-painted asphalt.
Figure 2 The diffuse absorption reflectometer being used in an actual materials test setup using fresh asphalt and white-painted asphalt.
Wright also did experiments on roofing materials, because most colors of materials are a lighter shade of grey or brown. He started with the shingles on his own house that were a light grey color, as shown in Figure 3. Note that at this time he began wearing on his hat, white plastic coffee cup lids from Starbucks, with the letters “SGW”, indicating “Stop Global Warming”. He is shown applying a piece of aluminum foil on his roof top to make comparative measurements of the foil absorption versus the rooftop absorption. He found that as expected, the roofing shingles were about 50% more absorptive than the foil at most sun angles.
Figure 3 Wright making sunlight absorption measurements on his roof in 2005.
Wright next turned to his own street (Erwin Lane in Huntington Beach, CA) to test the levels of absorption during daylight hours. Figure 4 shows a patch of fresh asphalt applied to his own street that will compare solar reflection levels of new black asphalt versus older asphalt. Figure 5 shows Wright making a preliminary assessment of the street asphalt electrical properties.
Figure 4 SGW test patch on Erwin Lane
Wright noticed that there was some white paint lettering on his street (shown in Figure 5), and by comparing the bare asphalt with the white painted asphalt, a higher level of solar reflection was substantiated. These encouraging results led him to consider the effect of the whole street being painted white. He also began wearing white coffee cup lids on his hat to dramatize his plan to do something about Global Warming.
Figure 5 Wright making electrical properties measurements on his asphalt paved street.
In a calibration test of his instrument, Wright measures the electrical and sunlight absorption properties of the Starbucks white plastic coffee cup lid, as shown in Figure 6. It is found to be an excellent reflector.
Figure 6 Wright making electrical measurements on a white coffee cup lid to calibrate his instrument.
The following week, Wright, with his wife Linda, went to Palm Springs to make additional measurements in a desert community with lots of sunshine. Figure 7 shows one of his experiments on a major boulevard in Palm Springs, where his wife Linda has painted a section of the street with white paint to determine the darkening time for a busy street.
Figure 7 In Palm Springs at a major intersection, Mrs. Wright paints the black asphalt white.
To extrapolate his findings to the street conditions found in Palm Springs, Wright first photographed a major street intersection in Palm Springs with its normal daytime lighting as shown in Figure 8.
Figure 8 Normal daytime view of an intersection in Palm Springs
Next, working with the Maintenance Department of Palm Springs, Wright paints this intersection with a reversed pattern of white painted asphalt and with unpainted asphalt stripes indicating the crosswalk area. The simulated result is shown in Figure 9.
Figure 9 Later image of Palm Springs street intersection with white paint applied.
Although Wright’s experiments and simulations indicated promising results that could make substantial reductions in the effects of Global Warming, there were several drawbacks that emerged from the simulations for the entire city of Palm Springs. First, there is a potential concern about solar reflection off the white painted streets at sunrise and sunset. The streets of Palm Springs are mostly north/south and east/west oriented, so that near the summer solstice sunrise and sunset periods, the solar reflection off of the white-painted East/West streets would have almost 100% reflection. Drivers facing the sun at those times would experience complete whiteout of their view of the street. However, if they all wore polarized sunglasses, this effect would be reduced by 50%. Still, it was deemed insufficient in allowing visibility of traffic and possible pedestrians crossing the street, especially if the drivers were intoxicated at the time. Although this whiteout condition occurs only a few days of the year and lasts only a few hours, it does happen during rush hour. Attempts to mitigate this effect or to legislate “solar whiteout” holidays did not appear to be likely solutions. In addition, the white painting of rooftops was also brought into question, because there would be a wider range of occurrence of whiteout conditions and times of occurrence on all of the city streets with houses with varying roof angles and house facing angle.
These findings did prove useful in exposing the limits and dangers of this potential solution to climate change. Wright presented a report of his findings at a student art show at CSULB, as shown in Figure 10. And he received an “A” grade in his Intermedia course. It should also be noted that this research was paid for with his own funds. He thanks the city of Palm Springs for supporting this work.
Figure 10 Wright’s art display at CSULB in 2006 of his solar diffuse reflectometer results for white-painted asphalt streets as a potential solution to Global Warming