Predicting plant water needs in a warmer, drier world. Plants drink up much of the water that falls to Earth. They take what they need before releasing it through tiny holes on the underside of their leaves, just as people release water vapor with every exhale. For agricultural crops, this means the best available estimates of future water needs, growth and vulnerability are “likely to be incorrect” during periods when the atmosphere is very dry, said another of the study’s authors, Mukesh Kumar, who is an associate professor of civil, construction and environmental engineering at University of Alabama.