Leaders representing most of the UK's mainstream churches have today called for repentance over the prevailing 'shrug-culture' towards climate change.

The Archbishop of Canterbury Dr Rowan Williams and the Bishop of London, the Rt Revd Richard Chartres who is chair of the Church of England's national environmental campaign, Shrinking the Footprint joined other leaders to sign Operation Noah's Ash Wednesday Declaration.

A short public service of prayer and dedication to launch the Declaration will be held at St Mary-Le-Bow, Cheapside  (5pm Ash Wednesday 22 Feb), and at numerous churches around the country.

'Traditionally, Christians commit themselves to repentance and renewed faith in Jesus Christ on Ash Wednesday,' said David Atkinson, Assistant Bishop in the Diocese of Southwark. 'We must live out that faith in relation to our damaging consumer economy, over-dependence on fossil fuels and the devastation we, as a species, are inflicting on God's world. We believe that responsible care for God's creation is foundational to the Gospel and central to the church's mission.'

The Declaration, also signed by Most Rev Desmond Tutu, Archbishop Emeritus of Cape Town, is framed around seven biblical themes and argues that, to be a Christian is to accept the call to radical discipleship and to work through the implications for church life of a real change in lifestyle.

Mary Grey, Emeritus Professor of Theology at the University of Wales, believes the Declaration - subtitled 'Climate Change and the Purposes of God: a call to the Church' - comes at a key moment.

'A second Earth Summit is being prepared and the world seems apathetic towards the real threat to all planetary life,' said Professor Grey.

Bishop David, who leads Operation Noah's theological think tank, points to specific, historical confessions calling the church back to its biblical and theological foundations - notably, the Barmen Declaration of the confessing church in Nazi Germany.

'Various confessions also addressed apartheid in South Africa,' he said. 'We believe that this is a time of urgency for the church. The threat of runaway climate change is the most significant moral question facing us today.'