The Kyoto protocol on climate change cannot work in its current form, Prime Minister Tony Blair has said.
Tony Blair said new technology must be used to cut greenhouse gases
Most of the developed world - except the US - has signed up to the agreement.
But Mr Blair, writing in the Observer, said cuts in greenhouse gas emissions can only be achieved by establishing an initiative that includes the US.
His comments come ahead of a conference on climate change in London on Tuesday, chaired by Mr Blair.
Any new agreement after the Kyoto protocol expires in 2012 would not be able to work either if, as with Kyoto, the US is not part of it, Mr Blair said.
He blamed the problems surrounding the climate change debate as the "trouble with so much international politics: a reluctance to face up to reality and the practical action needed to tackle problems".
Mr Blair argued that the problem of global warming cannot be dealt with unless any new agreement includes India and China - exempted from the current protocol because they are classed as developing countries.
It must also include the US - the world's biggest polluter.
President Bush refused to ratify the Kyoto treaty when 141 countries signed up to it this year because he said it would be too costly to the American economy, and the fact that the fast-growing developing countries were not part of it.
All those countries outside the current agreement will be at the conference this week - a week Mr Blair described as "crucial" in the fight against climate change.
The G8 industrialised nations will meet China, India, Brazil, Mexico and South Africa in London.
Mr Blair said there were "huge opportunities" in technology.
"We need to see how the existing energy technologies we have such as wind, solar and - yes - nuclear, together with new technologies such as fuel cells and carbon capture and storage, can generate the low carbon power the world needs."
The government will be taking action soon to achieve its domestic goal of reducing carbon dioxide emissions by 20% by 2010, said Mr Blair.
One policy being considered was increasing the use of eco-friendly biofuels - made from plant oils.
"If we can achieve just 5% of fuel from renewable sources by 2010 that has the potential to take more than one megatonne of carbon," he wrote.
Lack of action
Environmental group Friends of the Earth criticised the government's lack of action.
Executive director Tony Juniper said: "It is very good that Tony Blair is using Tuesday's inter-governmental meeting to encourage countries to work together to tackle climate change, but surely the first step is to put our own house in order.
"Sadly our government is failing to do this.
"It is essential that we keep and meet the manifesto target, which has now been repeated three times, to cut emissions by 20% by 2010 compared with 1990 levels."