You could almost smell the aroma of the cigar smoke puffed by generations of stockmarket traders as we crossed the empty open-outcry trading floor of the old Paris bourse. The building, commissioned by Napoleon and designed in classical Greek style by Alexandre-Théodore Brongniart, has that massive—and often misleading—solidity associated with the homes of leading financial institutions.

Having been cut out of the equation by electronic trading systems that began life in 1986 and were fully airborne by 1998, the building has now morphed into an exhibition and conference centre. And the evolution has continued. The year 2000 saw Euronext emerge from the tie-up of the Amsterdam and Brussels stock exchanges with the Paris bourse, and in 2007 Euronext merged with the New York Stock Exchange Group to launch the "first global stock exchange".

Still, if we are to believe the statements of speakers at the first CRO (corporate responsibility officer) summit held in the old bourse, this is just the beginning. François-Xavier Saint-Macary, recently appointed chief executive of carbon permit trading exchange BlueNext, told the summit the ultimate aim was to create an "Earth exchange".

True, carbon markets are worryingly volatile, because they are largely created by the diktat of politicians, whose commitment continues to wobble. But the long-term trajectory is clear, Saint-Macary insisted.
The latest science shows that we are destabilising the world climate—and the ultimate trading exchange will have to be global because greenhouse gases do not respect national borders.

While the CRO summit was fascinating, future challenges were perhaps best symbolised by a new BlueNext initiative that involves co-evolving a "panda standard" with the China Beijing Environmental Exchange. This is the first voluntary standard designed specifically for the Chinese carbon marketplace, with an initial focus on agriculture and forestry. I may have been hallucinating, but I thought I detected the sweet smell of tomorrow's sustainability-focused trading environments.

John Elkington is executive chairman of Volans (www.volans.com) and non-executive director at SustainAbility (www.sustainability.com)