Quicker cycling of water from the land and sea into the atmosphere and back down as rain has made the world’s rainfall increasingly localised, according to Paul Durack. “Arid regions have become drier, and high rainfall regions wetter, with these changes corresponding to global surface warming” the Australian researcher explains. He finds this especially worrying, given how dry his own country is.
A) Sea surface salinity changes over 1950-2000. Red areas become saltier through enhanced evaporation, and blue fresher through enhanced rainfall. B) The mean annual water transport over the ocean. Blue is where more rainfall than evaporation falls over a year, whereas orange is the opposite - the belt in which Australia is located.
At one level, anyone who’s seen a puddle dry out can understand the fact that increased temperatures might drive more water into the atmosphere. “Evaporation at the ocean surface is linked to atmospheric and ocean surface water temperatures,” Durack underlines. However, a warmer world speeds up the movement of water for a second important reason. “The more temperature increases, the more water the atmosphere can hold,” the Australian Commonwealth Scientific and Research Organization (CSIRO) scientist tells Simple Climate. This higher atmospheric water content accelerates the water cycle. Read the rest of this entry »
