The Sahara Desert is the third-largest desert on Earth, and the biggest hot desert. But at one time, it wasn’t covered by the sand dunes we see in photos today.
In fact, many, many years ago, there was a time scientists call the “Green Sahara” period.
A new paper looks at just how rainy the Sahara was and whether the causes of that desert turning brown could apply to others.
Jessica Tierney is an associate professor of Geoscience at the University of Arizona and lead author of that paper, which was published in the journal Science Advances.