Churches are being encouraged to commit to effective action ahead of the United Nations COP26 summit taking place in Glasgow in November.
They are also being asked to hold a 'Climate Sunday' to put pressure on the government to issue domestic policies addressing climate change and carbon emissions before the start of the 12-day summit on 1 November.
The call comes from a coalition of Christian organisations including A Rocha, CAFOD and Churches Together in Britain and Ireland who say that recent cuts to overseas aid and a lack of commitment on emissions reductions have undermined the UK's credibility as a leader on climate action.
They want the government, in its role as chair of COP26, to "seek faster and deeper global emissions cuts", and deliver on its promise of financial assistance to help poorer countries adapt to the climate disruption they are already experiencing.
Over 1,500 churches across the UK have signed up to host a Climate Sunday service, with a national Climate Sunday event to take place in Glasgow Cathedral on Sunday 5 September. But the coalition is encouraging more to get involved.
In addition to hosting a Climate Sunday service, churches are being asked to sign the Time is Now joint call to the government to "unleash a clean energy revolution", protect green and wild spaces, and support those most vulnerable to the effects of climate change.
Andy Atkins, Chair of the Climate Sunday Coalition and CEO A Rocha UK CEO, said: "The climate crisis is accelerating alarmingly; but we have the unique opportunity in rich countries to accelerate the solutions by directing Covid recovery funds towards building a new, green economy.
"At present the government is in danger of 'building back worse'. So, there has never been a more crucial time for UK churches to come together to pray, act locally and speak up nationally on the climate crisis and on the need to 'build back greener'."
Christine Allen, Director of CAFOD said: "It's becoming a matter of integrity for churches to put their own house in order on this threat to people and nature.
"Local church communities across Britain and Ireland are also signalling loud and clear that they expect the Westminster government to show integrity too, and get the UK firmly on track to meet its own emissions targets before chairing the UN climate negotiations in November."
Hannah Eves, a member of the Young Christian Climate Network, which is also in the coalition, said: "It's five to midnight on the ticking clock to avoid catastrophic climate change. We're thrilled to see churches now acting on the concerns of my generation. But the grand statements we hear from the government are so often undermined by contradictory actions.
"Boris Johnson says 'We're committed to Net zero,' then launches a massive new road-building programme, for example.
"The whole world is watching. Our government needs to put it's own house in order fast, to have a fighting chance of delivering a successful COP for the world and my generation."