Wind Slowing Down?

Around the world, surface winds are slowing down, a new study says. Strangely enough, the alleged culprits aren't new buildings but new trees.

The easing breezes—if also detected higher up—could affect movements of air pollution but may not necessarily give the wind power industry a case of the doldrums, experts say.

For the new study, published Sunday by the journal Nature Geoscience, scientists analyzed nearly 30 years' worth of wind speed data collected from more than 800 land-based weather stations, mostly in the Northern Hemisphere, where long-term wind-data collection has been most reliable.