NASA heat-mapping helps cities find cooler solutions

The Associated Press
Monday October 23, 2000

Trees around school playgrounds do more than shade kids after a fast-round of keep-away. If enough playgrounds and parking lots are shaded, the whole city will stay cooler. 

Changing black roofs and parking lots to white also can help, federal scientists say. 

Those nice, cool colors, green and white, are the keys to using information which NASA provided two years ago in infrared photographs pinpointing the hottest spots in Louisiana’s capital of Baton Rouge. 

Sacramento, Atlanta, Baton Rouge and Salt Lake City were pilot cities in a NASA-Environmental Protection Agency project that has since spread to Houston, Los Angeles, Chicago and Phoenix. 

The object: reducing urban heat islands where asphalt, concrete and steel hold and intensify heat. Cities can be 2 to 8 degrees hotter than the area around them. That, in turn, intensifies pollution. 

The first flights were over Atlanta in May 1997. NASA researchers reported this year that Atlanta’s heat creates nighttime thunderstorms when the sky outside the metro area is clear. 

Baton Rouge, Salt Lake City and Sacramento were heat-mapped two years ago. 

Baton Rouge architect Coleman D. Brown is already convinced that white roofs are best for the commercial buildings he designs. Helping the city is a bonus. 

He replaced the coal tar roof at Brown & Brown Architects five years ago with an insulated white roof. His air conditioning bills fell from about $2,500 a month to $1,800 to $2,000 a month. 

“Here’s the kicker,” he says: the roof cost much less than a coal tar roof. It won’t last as long, but the air conditioning more than makes up the difference. 

Fran Stewart, an environmental scientist at the Department of Environmental Quality, reports to NASA and EPA this week on what the city-parish is doing to get out of the blacktop. A committee is rewriting the landscaping ordinance. 

“I’d like to see pretty much all shade covering all parking areas,” said Peggy Davis, education director for Baton Rouge Green, a group dedicated to planting trees in the city. “I’m hoping for 60 percent.” 

Sacramento already requires new parking lots to include enough trees to shade at least half of the parking lot after 15 years. 

In January, the Sacramento Municipal Utility District plans to offer the nation’s first incentive for white roofs on both homes and commercial buildings, said Ray Tretheway, executive director of the Sacramento Tree Foundation. 

“They’re projecting they’ll rebate 20 cents a square foot if you go to a cool roof,” he said. 

The Lawrence Berkley National Laboratory has said that doubling the space shaded by trees and adding several square miles of light surfaces would cut Sacramento’s smoggy days in half, he said. 

In Baton Rouge, turning every roof and every street and parking lot in the city from black to white would get the city halfway to its total air quality goal, said Hashem Akbari, head of the Lawrence Berkley National Laboratory’s urban heat project. 

It’s a long-term goal. 

“A lot of roofs are being changed every 10 years. And pavements also need to be resurfaced every seven to eight years. So we are hoping within 10 to 15 years, we would get to that objective,” he said. 



Salt Lake City isn’t changing its landscape ordinance, said Meryl Redisch, Executive Director of TreeUtah. 

She said she thinks it’s more important to work directly with developers and councils to get them to include cool community strategies. In the Highland community, she said, one of the architectural and landscape architecture firms is adding more trees in parking lots and more landscaping in general. 

Baton Rouge Green isn’t just working outside the schools, but teaching the children inside them. 

Both its tree planting and education programs were started well before the EPA’s urban heat initiative. Baton Rouge Green has been planting trees at 10 schools a year since 1992. 

The NASA data shows which schools need them most, Morris said. 

Architects in the city also began using white roofs before the project began, Brown said. A survey of the city’s biggest contractors found that they had installed 3.1 million square feet of white roofing — enough to cover the Superdome more than six times — over the past three years. The figure probably can be doubled to include all contractors, he said. 

A new roof isn’t always needed. Brown said one of his friends cut the temperature in his Houma boathouse by about 10 degrees just by painting the metal roof true white instead of off-white. 


On the Net: 

NASA: http://www.ghcc.msfc.nasa.gov/urban/ 

Lawrence Berkley National Laboratory: http://EandE.LBL.gov/HeatIslands/ 

EPA: http://www.livablecommunities.gov/toolsandresources/sg—heat.htm 

Lawrence Berkley National Laboratory: http://eetd.lbl.gov/HeatIsland/ 

Baton Rouge: http://www.batonrougegreen.com/ 

Sacramento: http://www.energy.ca.gov/coolcommunity/index.html 

Salt Lake City: http://www.treelink.org/treeutah/flyover.html