As UN climate negotiations rumbled on in Warsaw, big business came together with conservation groups in Edinburgh last week at the inaugural World Forum on Natural Capital to put a price on nature.

The idea goes back to the Rio+20 conference in 2012, when a group of investors drafted the natural capital declaration. It argues that if we price everything nature gives us (wildlife, plants, forests, waterways, pollination, you name it), companies would think twice before destroying them.

Like advocates of the market for more than 200 years, the drafter of the declaration cannot abide the idea of "the commons" – commonly held resources whose reproduction and use is not subject to the laws of finance. The English enclosures, starting around the 15th century, and the Scottish clearances, from the 18th century, turned most common land in our country into private property, generating the profits that fed the Industrial Revolution.

In its quest for new markets today, finance is again intent on privatising the "global commons". The first step, as is clearly expressed in the natural capital declaration, is to start thinking of the environment as if it were capital, and to price it accordingly.