Umair Irfan, reporting for ClimateWire:
Cool roofs — created when developers use reflective paint on rooftops — do perform their intended task of reducing temperatures in urban areas while cutting building energy costs. However, they shift rainfall patterns by reducing evapotranspiration, the process by which water evaporates from the ground and enters the atmosphere. In the maximum expansion scenario, cool roofs led to a 4 percent decline in rainfall.