Weatherwatch: why cooling white roofs cause neighbours to swelter

Climate hack used to reflect heat results in less rain and higher temperatures in surrounding regions, study finds

Painting roofs white and creating lighter coloured pavements and roads are recognised as ways to reflect heat in urban areas and help combat global heating. However, a new study shows that this geoengineering technique unexpectedly causes temperatures to rise in the surrounding region.

Scientists have previously used large-scale climate models to assess the climate impacts of increasing albedo (reflectivity) on land, but these do not pick up changes in small-scale atmospheric circulation. Yu Cheng and Kaighin McColl from Harvard University simulated the localised changes and found that increasing albedo resulted in increased convection at the boundary of the high-albedo area – similar to the breezes found where sea meets land.