US President George W Bush has begun addressing a climate change conference in Washington, under pressure to accept binding cuts on greenhouse emissions.
US President George W Bush has said clean technology is the key to solving the world's growing appetite for energy while cutting greenhouse emissions.
The two-day meeting brings together the world's top 16 polluting countries.
He was speaking at a meeting of the top 16 polluting nations in Washington.
US Secretary of State Condoleezza Rice said earlier global warming was a real problem and the US was not "above the international community on the issue".
But critics voiced concern that the US was trying to rally support for voluntary rather than binding CO2 cuts.
But critics voiced concern that the US was trying to rally support for voluntary rather than binding CO2 cuts.
They said this would dilute attempts to reach a global agreement through the UN, ahead of the expiry of the Kyoto Protocol in 2012.
They said this would dilute attempts to reach a global agreement through the UN, ahead of the expiry of the Kyoto Protocol in 2012.
Low expectations
President Bush called the Washington meeting as a precursor to UN talks in Indonesia in December, which will seek to launch a successor to the Kyoto Protocol.
All nations should tackle climate change in the ways that they deem best Condoleezza RiceUS Secretary of State Motives behind Bush's summit
Mr Bush, who shortly after taking office in 2001 said he would not submit the Kyoto Protocol to Congress for ratification, has opposed mandatory cuts.
He has championed instead voluntary approaches - echoed by China and India.
US tones on climate change this week have been more harmonious than in the past, but few participants are expecting any substantive move, the BBC's environment analyst Roger Harrabin says
Many delegates remain sceptical about the US approach on the issue, correspondents say.
'Small steps'
Speaking on Thursday, Ms Rice said that global warming was the "growing problem" should be resolved under UN auspices.
Activists want the US to take the lead in solving the climate crisis
However, Ms Rice added that "though united by common goals and collective responsibility, all nations should tackle climate change in the ways they deem best".
She challenged leaders to reduce their dependence on fossil fuels by moving toward energy sources that would reduce global warming - but without harming their economies.
However, our correspondent says they hope that perhaps some small practical steps may emerge to help share best practice between industrial sectors and they are relieved that publicly, at last, America is saying that climate change is really a problem that needs tackling.
The top UN climate official, Yvo de Boer, said he believed the discussions could feed back into the UN process.
Mr de Boer said it was crucial that industrialised nations committed to an approach that went "well beyond present efforts, given their historic responsibilities and economic capabilities".
Teams from the Australia, Brazil, Britain, Canada, the EU, France, Germany, Japan, India, Indonesia, Italy, Mexico, South Africa, South Korea, Russia and the US are taking part in the Washington forum.
