The Sahara desert creeps up on a palm field. The Sahara desert is expanding , and has been for at least a century. It’s a phenomenon that seems impossible to stop. But it hasn’t stopped at least one group of scientists from dreaming of a way to do it. And their proposed solution , a grand scheme that involves covering vast areas of desert with solar panels and windmills, just got published in the prestigious journal Science. Eugenia Kalnay , a prominent atmospheric scientist at the University of Maryland, has been thinking about this idea for a decade. Kalnay is small in stature, soft-spoken. But she’s made her name with big and bold ideas. And what could be bigger and bolder than reversing the course of the world’s biggest desert? Her academic adviser at MIT, Jule Charney , was among the first to describe the vicious cycle that can lead to desertification. With drought, green vegetation disappears, and the light-colored dirt that remains reflects more of the sun. This cools the land surface, which in turn means that there’s less heat driving air upward into higher and cooler levels of the atmosphere – the process that normally produces precipitation. […]