By Christopher Landau
BBC religious affairs correspondent
Muslims, Jews and Christians are among the attendants
Leaders from the world's religious traditions have signed a manifesto urging tough action on climate change.
Around 1,000 delegates are meeting at the Interfaith Climate Summit in Uppsala, Sweden, at the invitation of the Swedish church.
The manifesto, signed by 30 religious leaders, calls for "rapid and large emission cuts in the rich world".
It argues in favour of a reduction in carbon emissions of at least 40% by the year 2020.
Leaders are also calling on individual followers of religious traditions to recognise the importance of caring for the environment.
They also place an emphasis on the world's more prosperous nations shouldering the burden of responsibility over the issue.
Rich countries, the manifesto states, "should pay for international cuts in addition to their own domestic initiatives. These payments should be obligatory."
The signatories also urge the sharing of technological expertise to mitigate the effects of climate change.
Some have questioned what role religious leaders have in an issue that already preoccupies scientists and politicians.
The Archbishop of Sweden said that the hope offered by religious traditions should be recognised alongside the fear some people justifiably feel about the impact of climate change.
"I am convinced that the issue of climate change is not an issue best left only to politics, natural science or the market," he told delegates.
"Our faith traditions provide a basis for hope and reasons for not giving up... despite our shortcomings."
Delegates have also conceded that some religious traditions have been slow to recognise the importance of climate change.
One prominent participant is the Anglican Bishop of London. He says that religious communities must learn to speak out on the issue.
"Here is a major human emergency," he said. "Have the faiths of humankind got anything to say about this challenge?"
"Many of our constituencies regard this still as a peripheral second-order issue - it's got to be moved up the agenda."
What is undeniably unique about this gathering is the breadth of cultures and backgrounds represented.
Delegates were welcomed by HRH Crown Princess Victoria of Sweden.
During the opening ceremony in Uppsala's cathedral, a packed congregation listened to a performance of "Bridge over troubled water", before singing the Christian hymn, "All things bright and beautiful".
Afterwards, a Taiwanese Buddhist nun rubbed shoulders with an American Indian; a Palestinian Christian chatted with a Muslim from Wales.
Political leaders were also present, including Vice-President of the European Commission Margot Wallstrom.
She said that it made sense to hear the views of religious leaders, given the influence they can have over their communities.
The inter-faith summit would "bring another perspective to the climate change debate, an ethical and moral perspective, and a debate that many politicians might not be willing to engage in", she said.
The religious leaders who have travelled to Sweden believe that their ethical contribution to the climate change debate is vital.
The lasting question is whether their contribution will make a real impact - both on their own religious communities and the wider world.