In 2003, Dexter Dunphy and his colleagues published The Phase Model, which mapped an organisation’s response to issues of corporate sustainability. Rejection and non-responsiveness progressed through compliance and efficiency to strategic proactivity and ultimately to the sustaining corporation. It is a journey from denial to acceptance.

The journey can also be tracked, broadly, over time. Before 2000, the educational challenge was to make managers aware of the significance of environmental concerns. In curricular terms, this meant an elective for the converted, with many others rejecting the “tree huggers”. For the next five years, as awareness increased, compliance and efficiency were the order of the day. Corporate sustainability officers appeared, low-wattage light bulbs were installed and corporate social responsibility reports were issued. The tipping point came in 2006 with Al Gore’s An Inconvenient Truth.