Tech Topics - Summer 2008 - (Page 21) TheHill URBAN WARMING By Kimberly Link-Wills Study indicates temperatures climbing faster in major cities homeowners could help increase surface reflectivity by using lighter colors of asphalt and roofing materials, said Stone, who pointed to the black shingles typical in North America. “A lot of it is driven by cultural preference,” he said. “It makes very little sense to do that in a place like Atlanta.” Atlanta is rapidly losing trees to asphalt, Stone said, asserting that the region should follow Los Angeles’ lead and adopt its campaign to plant a million trees throughout the city. “You could significantly cool down cities by planting trees and using highly reflective materials,” he said. Stone also recommends reducing lot sizes in the suburbs. “The displacement of forested areas by the expansive lawns and large houses of low-density development serves to increase surface heat production. Lawns are better than driveways and streets in reducing temperatures, but they’re not as effective as the naturally forested areas they displace.” GT A re large cities warming at a faster rate than the rest of the planet? Brian Stone, an associate professor in city and regional planning in Tech’s College of Architecture, says they are. Stone’s research points to “an increase in the rate of urban warming more than 30 percent greater than the rate of rural warming.” He shared the findings in April as part of the Tuesday Talks series hosted by the Georgia Tech Library and Information Center. “Most of our attention today is focused exclusively on greenhouse gases. Very little attention is given to land surface changes,” said Stone, who earned his doctorate in city and regional planning at Tech in 2001. “Carbon dioxide is very slow to be removed from the atmosphere,” Stone pointed out. “If you want to cool down cities, the places where the majority of the global population now resides, reducing greenhouse gas emissions is a long-term strategy. Strategies focused Associate professor Brian Stone’s research shows that an average July day in Atlanta in 2100 could be as high as 112 degrees. on revegetation and surface reflectivity are likely to cool cities much faster than greenhouse gas controls.” Typically, temperature data is garnered from rural weather stations, said Stone, who drew from records in large urban areas, including HartsfieldJackson International Airport in Atlanta. He used weather data from 1950 to 2000 in 50 of the 60 most populous U.S. regions. According to Stone’s documentation, “The actual magnitude of warming in urban areas is likely to be much greater than that forecast by the Intergovernmental Panel on Climate Change, greatly elevating the need for climate-responsive design strategies to counteract the impact.” Currently, an average July day in Atlanta is 89 degrees, Stone said. His calculations project the temperature on that same day in Atlanta in 2100 could be as high 112 degrees Fahrenheit, assuming trends continue. “This presents a serious planning challenge, serious public health issues,” said Stone, who asserted that annually more fatalities on average are attributable to heat waves than to hurricanes or tornadoes. City planners, builders and TECHTOPICS | SUMMER 2008 21 http://gtalumni.org
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