China's great northern plain, home to more than 200 million people, is generally subhumid or arid and depends on unsustainable pumping of underground aquifers for irrigation. The Yellow River has been diverted to the point that it no longer flows to the sea. Meanwhile the water tables of Beijing and other large northern cities are falling dramatically as a result of pumping of groundwater.
The challenge of securing safe and plentiful water for all areas of the world is one of our most daunting tasks.
In numerous parts of the world we have exceeded sustainable limits on the withdrawals of water from groundwater aquifers and from rivers.