Asia-Pacific leaders meeting in Sydney have agreed an "aspirational" goal to restrain the rise of greenhouse gas emissions to tackle climate change.
Saturday's deal followed wrangling at the summit
China and the US - two of the world's biggest polluters - are among the 21 nations that have signed the statement, which contains no firm commitments.
Australian Prime Minister John Howard called it "a very important milestone" towards an international deal.
Environmentalists said the declaration was symbolic rather than concrete.
"The world needs to slow, stop and then reverse the growth of global greenhouse gas emissions," said Saturday's statement by the Asia-Pacific Economic Co-operation forum.
Sydney has seen the biggest security operation ever mounted by Australia for the meeting.
Isolated scuffles broke out on Saturday between police and a few of the 5,000 protesters who marched through the heart of Sydney for a rally in Hyde Park, but the day remained peaceful on the whole.
The Apec statement included a non-binding goal of reducing "energy intensity" - the amount of energy used to produce a dollar of gross domestic product - by at least 25% by 2030.
The leaders also called for increased forest cover in the Asia-Pacific region of at least 20m hectares (50m acres) by 2020.
And they agreed greenhouse gas reduction strategies should reflect "differences in economic and social conditions" in each country.
The US has made China's involvement in moves to tackle global warming a priority, but both countries are opposed to binding targets.
Summit host Mr Howard said: "We are serious about addressing in a sensible way, compatible with our different economic needs, the great challenge of climate change."
But Greenpeace said the agreement was a "distraction" rather than a "declaration".
A spokeswoman for the organisation, Catherine Fitzpatrick, said: "Without supporting binding targets for developed countries, which is where the rubber really hits the road on climate action, it looks like a political stunt by John Howard."
The Sydney declaration also included China's and other developing nations' calls for global warming negotiations to take place under United Nations auspices.
The UN climate convention is scheduled to host talks in December on the Indonesian island of Bali.
Apec's 21 members, which also include Russia and Japan, together account for about 60% of annual greenhouse gas emissions.
Saturday's deal followed wrangling at the summit over the shape of a treaty to replace the landmark Kyoto Protocol of 1997.