When severe weather strikes, people are in a heightened state of alert and tuned to their radios for the latest information. Blockbuster movies portray the awesome destructiveness of twisters and perfect storms. Set next to such powerful natural events, paving materials and rooftop surfaces are unlikely to arouse strong emotional reactions, yet they can be even more deadly.

"Over the past twenty years, there have been more deaths related to increased urban heating than all major storms during that time. . . Cool roofs save lives," Hashem Akbari, staff scientist from the Leader Heat Island group, said.

Urban heat islands--the higher temperatures in cities compared with surrounding rural areas--contribute to a growing number of medical and environmental problems, in addition to increasing the amount of energy spent on cooling.

According to the Centers for Disease Control and Prevention, there are an average of 381 heat-related deaths per year in the United States. Urban heating has also contributed to an increase in asthmatic conditions and other respiratory illnesses. This is due in large part to an increase in ground-level ozone air pollution caused by heat islands.

The regrettable thing about heat islands is that, unlike major storms, they can be easily mitigated. Just a small reduction in temperature, says David Hitchcock of the Houston Area Research Center, is enough to have a dramatic affect on the environment. "Houston can reduce peak summertime temperatures by two degrees or more. While this might not sound like much, it could reduce ozone (more) than many of our current air pollution measures. Many of the actions needed will pay for themselves."

HARC has developed the Cool Houston Plan, which focuses on three simple elements: rooftops, roads, and trees. A new approach to these elements can greatly reduce the discrepancy between urban and rural temperatures, which can be as high as ten degrees on summer days in Houston. Changing the color of the surface material on rooftops, and of paved areas such as roads and parking lots, greatly increases their reflectivity, directing the sun's rays away from the city and reducing the temperature. Typical pavement temperatures on a July day in Houston average around 133 degrees. Change the color of some of the paving materials and the temperature is reduced to 88 degrees. In Houston, HARC hopes the city will implement this suggestion by using new, porous material in pavements and, where possible, painting surfaces white. Even something as simple as laying down grass parking lots, as at Reliant stadium, contributes to heat reduction.

Reflective roofing material or lighter colored roofing also makes a big difference in temperature, which Hitchcock states will pay for itself in reduced energy costs. Currently, HARC is working with the city of Houston to explore the use of reflective roofing on city buildings.

Planting more trees helps mitigate the urban heat island by providing shade and by reducing some forms of air pollution.

Hitchcock said that the city has been generally receptive to their Cooler Comunities proposals. “There has been support of heat island concepts and involvement by the city of Houston over the past few years. . . Mayor White is knowledgeable about the benefits and issues. We hope the city will serve as a champion for heat island actions. (However) heat island mitigation is really a regional challenge, so we also need strategies that involve Harris County and the outlying counties."

Because changing governmental policies and practices as they relate to surface materials and tree plantings involve many debates and decisions, HARC is also focusing on other factors that contribute to the urban heat island. They are encouraging city residents to do their part to cool the city. "One cool roof on a residential street can affect that block's temperature," says Akbari. Homeowners can help by planting trees where they will shade their homes, particularly on the western side and around their air-conditioning units. They also can reduce the area they have to mow by using other types of shade planting, including trees. If they need to replace a roof, they can use reflective roofing, and driveways can be surfaced using lighter colored chip seals or coating products.

Hitchcock states that the next step for the Cool Communities Plan will be to continue informing the public, city officials, and developers that taking simple steps can have a huge environmental impact.

In addition, HARC is trying to determine "what changes (they) can make in the thermal characteristics of cities that will provide the greatest benefit." In Houston, for example, planting more trees might be especially desirable because trees reduce flooding and increase property values, as well as reducing urban heating.