New satellite data from NASA paint an unpleasant picture of the planet, with sprawl creating more mega-cities that are getting hotter and hotter. NASA found that the temperature in Atlanta, Ga., sometimes rose to 12 degrees Fahrenheit more than the surrounding countryside, an effect attributed to more pavement and fewer trees. Between 1973 and 1992, the Atlanta area lost 380,000 acres of trees. Atlanta’s heat was found to be so intense that it could trigger thunderstorms. The satellite data point to similar problems in cities around the world, such as Shenzhen, China, which was transformed between 1988 and 1996 from a small city to a sprawling metropolis with almost no vegetation. NASA advises cities to combat the heat effect by planting trees and other vegetation and resurfacing roads, roofs, and parking lots so that they are lighter in color.