He’s not the only one. As a member of the United Church of Chapel Hill, he helped start the Sustainable Households Challenge, a six-month program encouraging families to monitor and record various aspects of their daily lives with a view to improving their environmental footprints.

The results, says Demby, have been impressive, with families making significant progress, for example, in reducing their home energy use, or buying local produce. Transport has also proved to be a big issue for challenge participants -- Demby and his wife, who regularly carpool together, have recently taken to spending more days at home:

“One of the things my wife and I were able to do was we designated two days at home where we don’t go anywhere per month. That meant no car travel. If we could just increase that to three days, then we’d already be reducing our car travel by 10 percent!”

When it comes to advice for others, Demby says it is important for people not to be too hard on themselves. Even if a household tries a particular action, like cutting its car use by 25 percent, but fails, the effort in itself will have made a difference in making people more aware of their impact. The success of the Sustainable Households Challenge has spurred the congregation to even greater ambitions.

Not only are members launching a second round of the challenge, with original participants guiding new families, but they are also hoping to present the challenge to the church’s general synod in the spring, with a view to rolling out the initiative to other congregations.

For Demby, sustainability is as much about cultural, personal and spiritual change as it is about politics:

“What we have to work towards is not legislation or a bunch of rules. We need a paradigm shift -- people need to take this on board and understand that sustainability is a good thing. The energy crisis of the Seventies taught us that folks would change when they had to, but as soon as it cleared up they went back to their old ways. We need a cultural shift that ingrains sustainability into people’s way of thinking.“