The green of the fossil water of the desert

The Wadi As-Sirhan basin in Saudi Arabia has been green and green for the past 25 years. These images are false-color satellite images taken in the infrared. What you see in green is the vegetation. The green circles that proliferate in the middle of the desert are agricultural lands, fields with a diameter of kilometers; this aspect is due to the irrigation system. And the water comes from the subsoil. It is the ‘fossil’ water contained in the underground aquifers that were filled during the last glaciation. twenty thousand years later, the Arabs are extracting this water from a depth that can reach a kilometer. No one knows how much water there is, but hydrologists have estimated that it will be profitable to pump this water for about 50 years.