
The meeting also agreed that deforestation must be addressed to stop the planet heating up.
"It's a very important milestone in the march towards a sensible international agreement on climate change which recognizes the need to make progress but also recognizes that different economies bring different perspectives to addressing the challenge of climate change," APEC host Prime Minister John Howard said.
US President George W Bush, Chinese Premier Hu Jintao, Japanese Prime Minister Shinzo Abe, Russian President Vladimir Putin and 17 other leaders agreed to the Sydney Declaration.
"It's a very important milestone in the march towards a sensible international agreement on climate change which recognizes the need to make progress but also recognizes that different economies bring different perspectives to addressing the challenge of climate change," Howard said on the steps of the Sydney Opera House on the harbour foreshore.
He said the APEC meeting would "add to the momentum which will be continued at the meeting being convened by President Bush in Washington at the end of this month of major economies to deal with climate change issues and also the very important United Nations to take place in Bali in December which will be hosted by Indonesia."
Howard had hoped to get a grouping that represents 40 per cent of the world's population to agree on a specific "long-term aspirational global emissions-reduction goal" but resistance from China and other developing country members meant he had to settle for agreement that a "long-term aspirational goal" was something that ought to be fixed in the future.
Both Australia and the US have refused to be part of the UN-sponsored Kyoto Protocol thrashed out in Japan in 1997 and which commits 35 industrialized countries to legally binding emissions-reductions targets. Developing countries were to join at a later date.
Bush and Howard argued that meeting Kyoto-style targets would hurt their economies and that it was wrong for only rich countries to bear the cost of addressing climate change.
The US is the single biggest polluter and Australia, the world's biggest coal exporter, leads the emissions rankings on a per capita basis because of its reliance on coal for power generation.
Environmental campaigner Abigail Jabines from international lobby group Greenpeace accused Bush and Howard of trying to wriggle out of their climate obligations by aspiring to nothing more than "aspirational goals"
"If John Howard and George Bush are sincere in addressing climate change, they should ratify Kyoto Protocol and embrace real solutions such as renewable energy and energy efficiency and set legally binding targets to reduce greenhouse gas emissions," she said. "To John Howard and George Bush - don't run away from Kyoto Protocol, just do it."
The declaration was thrashed out against the backdrop of "Fortress Sydney" with the streets cleared of people, train stations closed and the Opera House and other APEC venues barricaded by a five-kilometre steel fence. A security presence of 3,500 police and 1,500 troops threw a cordon around the conference venues.
Huge anti-war protests against Bush did not materialize. Around 4,000 marched against an organizers' promise that a phalanx 20,000-strong would take to the streets.
Deutsche Presse-Agentur