The Rise, Fall, and Evolution of Africa’s Great Green Wall

The Sahara, one of the largest deserts in the world, stretching from one end of Africa to the other, covers a swathe of 3.5 million square miles. It could fit the entire United States within its borders, including Alaska.

And it’s growing.

A study by the journal Climate reported that between 1920 and 2013, the desert has expanded by 10%…