Water Cycle Pushed to Limit In Southern Hemisphere As Planet Warms

Soils in large areas of the Southern Hemisphere have been drying up in the past decade as temperatures have risen in Australia, Africa, and South America, according to the first major study of evapotranspiration on a global basis. The study found that from 1982 to 1998, the evaporation of water from the soil and plants to the atmosphere increased steadily in the Southern Hemisphere as temperatures climbed. But beginning in 1998, the rates of evaporation slowed dramatically in many parts of the Southern Hemisphere as soils became increasingly dry, an indication that the planet’s water cycle is being pushed to the limit, according to the study by U.S. scientists, which was published in the journal Nature. In some regions, rising temperatures have simply removed all of the available moisture from the ground, said Steve Running, an ecologist at the University of Montana in Missoula and one of the researchers involved in the study. While the moisture returns to the land in the form of rainfall, it often falls in different regions of the planet, leaving some regions increasingly dry, he said.