AS OXFORD ECONOMIST Kate Raworth so rightly puts it, economics is the ‘mother tongue’ of public policy – and it is time to reimagine it for the twenty-first century. We need a new language for public policy and debate that brings together the many different critical factors required for human beings and the planet to flourish in the new century, which go beyond the monetary alone. Such a language is emerging.

One of the most telling moments in The Big Short, the film of Michael Lewis’s tale of the subprime mortgage boom and spectacular bust of 2007, is a small note at the bottom of the screen before the credits. It reads: ‘Michael Burry is focusing all of his trading on one commodity: water.’ Burry is the genius who saw the inevitability of the collapse in 2005. He is not alone in realising that water will be the most precious commodity of the twenty-first century. The problem of water, along with carbon emissions, is driving the conception of a new category of wealth: natural capital.