Matt has been studying eco-towns, since the UK government is planning(? pondering?) planting 10 such. As an engineer, he doesn't think it sound. And it got me thinking: what does the gospel say on this?
In brief, I think the gospel leads us not to abandon forlorn cities (whether to move to Cambridge, or to build new eco-towns, or to move to the nice suburbs!). From a gospel perspective, nothing is irredeemable. While ultimately we recognise that all human efforts at regeneration will be subject to frustration, it is in hope that the One who so punished us will one day set it free from its bondage to decay (Rom 8). God hasn't pulled out of this world. He hasn't carried out his sentence of condemnation on it completely, and whisked people off to live elsewhere. No - he sent his Son into the world to redeem it, and sends his people into it, cursed as it is. The devil won't have the final word on the world: the final word is Jesus. God will renew his world, uniting all things under Jesus as head. So as God works in grace in the world, even as many people continue hell-bent on destruction, so we must work in grace in the world, not abandoning what is rotten, but seeking to redeem. We must engage in the renewal of the messed-up rather than trying for the new and untainted.
Which brings me to this: in fact, to try to build perfect eco-towns suggests a rather-too-positive view of human nature and ability. "The old is a mess: but we'll try new and untainted." This neglects to address the main problem: we can't build a new and untainted system, because we ourselves are tainted with the problems of the old! At heart, we don't want to manage God's earth and society well under him, because we are selfish. Rather than using what we've got to serve other people to God's glory, we seek to use other people to get what we want, to our own glory. We're only interested in environmental issues when our own nest is snug. Trying to build new eco-towns is like trying to retreat away from sin to a monastery: it doesn't change our hearts. Building the right structures will not change our hearts to live in a non-selfish way to steward the earth, love other people and worship our Creator. It'll just make Pharisees: "Lord, I thank you that I am not like other men. I recycle every week, I use renewable power sources, and I'm certainly not like that inner-city yob over there!" To imagine that eco-cities are the answer is an unrealistically optimistic view of human nature.
So, it's the now & not yet of the gospel again. God is set on redemption, and works in grace in the world: so must we. Yet we live awaiting that final redemption of the earth so live in hope rather than thinking we can accomplish everything now.
An interesting conundrum is posed in Isaiah: how can the utterly faithless, condemned city become a glorious city of righteousness? There's no hope in her! But there is hope in the faithful servant, sent by God. And so at the end of the Day, the only perfect City is not built by human hands, but comes down out of heaven to earth, from God. A faithful city and a restored Eden, a people whose hearts have been changed. Come, Lord Jesus!