Over the past three decades, Saudi Arabia has been drilling for a resource more precious than oil. Engineers and farmers have tapped hidden reserves of water to grow grains, fruits and vegetables in the desert.
The series of false-color images at left show the evolution of agricultural operations in the Wadi As-Sirhan Basin, as viewed by satellites in 1991, 2000 and 2012. The images were captured by similar sensors—the Thematic Mapper and Enhanced Thematic Mapper Plus—on three different Landsat satellites (4, 5 and 7). For scale, the agricultural fields in the images are about 1 kilometer (0.62 miles) across and use center-pivot irrigation.
The thirsty plants that rise out of the Arabian desertare quenched by water that dates back to the last Ice Age. In a more temperate past about 20,000 years ago, this “fossil” water filled aquifers that now are buried deep under the sand seas and limestone formations.