"It is indeed important to recognise, among the causes of the current ecological crisis, the historic responsibility of the industrialised countries," the pope said.

"Less developed countries, and especially emerging nations, are not however exonerated from their responsibility... because the duty of gradually adopting effective environmental measures and policies belongs to all," he added.

The pope's appeal came as crucial UN climate talks in Copenhagen were bogged down by procedural wrangles and divisions between rich and developing nations.

World leaders were converging on the Danish capital ahead of the climax of the negotiations on Friday.

The conference's goal is to agree an outline deal of national pledges to curb carbon emissions and set up a mechanism to provide billions of dollars in help for poor countries in the firing line of climate change.

The appeal by the pope, who has spoken out frequently on environmental issues, was part of his message for the Roman Catholic Church's World Peace Day.

The Vatican releases the message well in advance of the actual day, January 1.

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