Energy intensity refers to the amount of energy used to produce a unit of one dollar of gross domestic product (GDP).
The declaration also calls for increasing forest cover in the region by at least 20 million hectares by 2020. Forests help absorb greenhouse gases that warm the earth's atmosphere.
"This demonstrates the relevance of Apec. It demonstrates that Apec is very much alive and kicking," John Howard, Australia's prime minister, said.
Prayers for Greenland icecap
|Farmers speak out on |
Some analysts say the measures are not enough to combat the problem of global warming.
Mark Diesendorf, senior lecturer at the Institute of Environmental Studies at Australia's University of New South Wales, said: "Real goals and real targets are really needed and you cannot reduce energy intensity by raising emissions and lowering energy consumption."
Catherine Fitzpatrick, a campaigner for Greenpeace, said the Sydney Declaration was a distraction from greater effort needed to combat climate change.
"The failure of Apec to produce meaningful progress on climate change confirms that the place to do this is at the Kyoto negotiations in Bali in December," she said.
The Sydney Declaration was signed before George Bush, the US president, returns to Washington on Saturday night ahead of a key report on the Iraq war.
Security is tight at the summit, with police drawing a five-kilometre cordon of steel and concrete fences across parts of Sydney.
|Protests during the summit have |
been largely non-violent [AFP]
Police obtained special legislation giving them extra powers against protesters throughout the summit.
Demonstrators who gathered about one kilometre from the opera house where the leaders were meeting faced a heavy police presence.
One protester, Cynthia Morgan, said: "We are here to tell Apec that we don't like what they've got to say."
Senior police officers had said they feared a repeat of violent demonstrations seen in Melbourne during the World Economic Forum in 2000 and at last November's G20 economic leaders meeting.
So far, the protests have been largely non-violent, with only a few people arrested.
Bush has met other leaders on his four-day visit to Sydney, including Hu Jintao, Chinese president, Vladimir Putin, Russian president, and Shinzo Abe, Japan's prime minister.
On Saturday, Bush met Abe and Howard for a trilateral summit that had been expected to urge China to be more transparent about its military programme.
Mitsuo Sakaba, a Japanese foreign ministry spokesman, said. "As far as China is concerned, the three leaders shared the same recognition that it's important to have a positive engagement with China."
"They reached a consensus that it is important to be constructively involved in China," Sakaba said.
The talks come amid Chinese concerns that the three countries are aiming to form an agreement on containing China.
There was little progress at the Apec summit on re-starting the stalled Doha round of World Trade Organisation talks, which have focussed on liberalising world trade.
Pascal Lamy, WTO director-general, said at a security conference on Saturday that a global trade deal was possible, but negotiations needed support from political leaders.
"A deal is now do-able but we need a final push, which needs leaders' constant attention and mobilisation," Lamy said.