Water is becoming a scarce resource in many parts of the world. Water tables have been falling in many regions for decades, particularly in areas with intensive agriculture. Wells are going dry and there are few long-term solutions available — a common stopgap has been to drill deeper wells.
The top 2 inches of topsoil on all of Earth’s landmasses contains an infinitesimal fraction of the planet’s water — less than one-thousandth of a percent. Yet because of its position at the interface between the land and the atmosphere, that tiny amount plays a crucial role in everything from agriculture to weather and climate, and even the spread of disease.