The leaders say that developed countries have a moral responsibility to take the lead in countering global warming since much of their wealth was brought about by activities that produce high levels of carbon emissions.
They are pressing for a deal that will help developing countries mitigate the worst effects of climate change on the poor and vulnerable and support economic development.
The leaders admitted, however, that they were sceptical a deal would be reached to replace the Kyoto agreement, which expires in 2012.
The Rev John Marsh, moderator of the General Assembly of the United Reformed Church, said: "We share the anger and frustration of the world's poorest countries with the intransigent positions adopted by negotiators of some of the richest countries ahead of the Copenhagen summit which has rendered a binding agreement unlikely. The time for talking is over."
He said wealthy countries had a "moral obligation" to make decisions at the UN summit towards a treaty that binds them to cuts in their carbon emission levels of at least 40 per cent by 2020.
"We call on the government to do everything in their power to persuade their American counterparts to commit to this timeframe and target at Copenhagen," he said.
Thousands of people are expected to for a giant blue wave in front of the Houses of Parliament on Saturday to put pressure on the Government ahead of the summit from December 7 to 18.
The Archbishop of Canterbury Dr Rowan Williams and the head of the Roman Catholic Church in England and Wales Archbishop Vincent Nichols will join around 3,000 Christians at a church service in Westminster ahead of the protest.