Why is the world running out of sand?

After water, sand is the most-exploited natural resource in the world, but its use is largely ungoverned, meaning we are consuming it faster than it can be replaced by geological processes that take hundreds of thousands of years. Making sand from ore could solve the looming crisis.GUEST: Professor Daniel Franks Director, Global Centre for Mineral Security, University of QueenslandPRODUCER: Ali Benton