As nations are spelling out their bargaining positions for the negotiations on a new international climate deal to take place in Copenhagen next month, churches around the world are trying to ring home the message that climate protection is an ethical and spiritual issue.

The 7-18 December United Nations summit in the Danish capital Copenhagen will set the agenda for the next stage of the fight against climate change. "This is the last chance the world has to keep global temperature increases below 2 degrees Celsius," says Alexi Barnett, campaign officer for Scottish Catholic International Aid Fund, explaining the importance of churches' support for a successful outcome in Copenhagen.

That is why her organisation has teamed up with Christian Aid and the Church of Scotland to get congregations in the northern part of the United Kingdom to heed a call by the World Council of Churches (WCC) and ring their bells on Sunday, 13 December.

On that Sunday, midway through the UN summit, the WCC invites churches around the world to use their bells, drums, gongs or whatever their tradition offers to call people to prayer and action in the face of climate change.

By sounding their bells or other instruments 350 times, participating churches will symbolize the 350 parts per million that mark the safe upper limit for CO2 in the atmosphere according to many scientists.

Groups ranging from the Open Sanctuary at Holy Trinity Anglican Church in Tilba Tilba, Australia, to the Lutheran congregation in Sibiu, Romania, have already pledged their participation. Some link the climate action with their traditional advent celebrations, such as the Evangelical Lutheran Epiphany Church in Hamburg, Germany, that will invite children to draw stars of hope while the bells will be rung and 350 drum beats will be sounded ahead of the congregation's advent concert.

As each group starts their own observation of the 13 December event at 3 p.m. local time, a chain of chimes and prayers will be stretching in a time-line from the South Pacific – where the day first begins and where the effects of climate change are already felt today – to Denmark and across the globe.

The politics of bells: controversy on the role of church in society

Even before the bells have started ringing, they have managed to stir a debate about the special perspective Christians bring to the climate debate. "In some countries, the question has been raised whether churches have the right to use their bells for what may be considered to be a political campaign," says Dr Guillermo Kerber, WCC programme executive on climate change.

"Those who support the campaign see the care of creation and of people's lives and livelihoods threatened by climate change more as an ethical and spiritual issue that, of course, has political implications, not in a partisan sense but referring to the common good," Kerber adds.

"We pray that decision makers everywhere take seriously the responsibility implicit in God giving humankind dominion over His creatures upon the earth," says Dr Mogens Lemvig Hansen, explaining why the Danish Lutheran Church of Vancouver, Canada, of which he is president, will ring its bells.

"Churches have a special role to play – and church bells have a role to play" in this debate, says Bill McKibben, a well-known writer and a Sunday school teacher in the United Methodist Church, in a video message on youtube.

"Where I live, in the United States, before we had radio when somebody's house caught on fire we rang the church bells so that everybody would know and come out to do something about it. Well, something's on fire now," adds McKibben, whose book The End of Nature was one of the first to explain global warming to a mainstream audience when it came out in 1989.

The Conference of European Churches (CEC) and the Council of European Bishops’ Conferences (CCEE) have endorsed the campaign in a joint letter to the churches in Europe.

Also on 13 December, participants at the UN conference are invited to pray alongside the Danish Queen and church leaders from around the world in an ecumenical celebration at Copenhagen's Lutheran Cathedral.

The Archbishop of Canterbury, spiritual leader of the Anglican Communion comprising some 80 million Christians worldwide, will preach the sermon. The celebration will be broadcast live on Danish television and on the website of the Danish Broadcasting Corporation.