Questions have been raised about President George W Bush's commitment to addressing climate change before leaves office.
Sunita Narain
Despite refusing to sign up to the Kyoto Protocol, Mr Bush has been vocal recently about the need for a new strategy to curb Earth-warming emissions.
He has announced plans to develop a strategy building on a 1992 UN agreement by the end of 2008. Critics, though, were quick to point out the date is less than a month before his final term of office ends.
The White House announcement on Friday that a gathering of the world's biggest greenhouse-gas emitters on September 27th and 28th in Washington was part of the strategy to involve developing countries in the move to cut pollutants.
But even before the announcement, participants in the first full-scale UN session on climate change last week questioned Washington's motives.
"The constant excuse that the United States has given for not participating in a climate regime, by blaming India and China ... is not just unfortunate but I think is very far from the truth," Sunita Narain, director of India's Centre for Science and Environment, told reporters at the UN session.
While Washington has avoided committing to Kyoto, it is a party to the United Nations Framework Treaty on Climate Change signed by Mr Bush's father, president George HW Bush, in 1992.
By agreeing to dovetail with the UN treaty, the Bush administration has raised cautious hopes for US action among environmentalists.
The White House assertion that the September meeting is the start of a process likely to end by late 2008 "could leave other nations with the perception that the administration is trying to run out the clock," said Annie Petsonk, international counsel for the group Environmental Defence.
But the Bush team could play a useful role if it re-engages other nations within the context of the UN treaty, Ms Petsonk added.
The UN treaty framework is where the international community is working out a way forward after the Kyoto pact expires. The UN treaty countries are to meet later this month in Vienna, Austria, and again in Bali, Indonesia, in December.
Because the United States is a long-time greenhouse gas emitter, Ms Petsonk said "the administration has to overcome a pretty major credibility problem with other countries if it wants to make that useful contribution."
Mr Bush has rejected mandatory limits on greenhouse gas emissions in favour of voluntary caps - the main divergence between the US stance and countries in the Kyoto Protocol.
The September summit will discuss emissions targets that will replace the Kyoto Protocol when it expires in 2012.
The Washington gathering, to be led by Secretary of State Condoleezza Rice and addressed by Mr Bush, is set for the same week world leaders convene at the United Nations, including a one-day session dedicated to climate change on September 24th.
The attendees due at the Washington meeting includes some of the world's heaviest contributors to global warming: Britain, France, Germany, Italy, Japan, China, Canada, India, Brazil, South Korea, Mexico, Russia, Australia, Indonesia and South Africa.