IT is estimated that if everyone in the world lived like the average American - consumed as much, drove gas-guzzling cars and used as much fuel for heating and air-conditioning - we’d need five whole Earths to support us.

Before you get too smug, it has also been estimated that if everyone lived like the average European, we’d need three Earths. We’re consuming far too many of the world’s precious resources, in other words: more than the planet can stand.

The One Planet initiative, to which the city council has signed up, seeks ways we can live more sustainably.

It’s a noble aim. Putting it into practice isn’t easy, and sometimes the proposed solutions - such as York council’s plans for an eco-friendly, communal heating system for new houses at York Central - don’t seem very sexy. But it is precisely schemes such as this which, repeated again and again, could make a difference.