The Group of Eight powers meeting in Scotland have agreed the text of a communique on combating global warming, a German negotiator told reporters.
He said they had agreed to try to reduce greenhouse gases by promoting cleaner technology and energy efficiency, but also made reference in their text to the Kyoto Protocol - which the United States, alone among G8 members, has not signed.
No specific targets were mentioned in the text.
“The document was accepted and you can be sure that there won't be any more changes,” he said.
“The Kyoto accord will be mentioned but the document won't contain any concrete figures."
The United States is the only G8 country to have refused to ratify the Kyoto protocol and has been isolated on the issue. President Bush has been slow to accept the world is getting warmer and that mankind is at least partly to blame.
Environmentalists have urged the other seven G8 nations to isolate Mr Bush and, if necessary, issue a split communiqué rather than accept a watered-down deal.
Earlier Italian diplomat Cesare Ragaglini said:"The final communiqué will give a clear indication of various actions to be taken that could lead to a reduction of greenhouse gas emissions".
One G8 source even went so far as to say the wording of the final communiqué had been fully agreed, although it is unlikely to satisfy environmental campaigners.
"There is no way we are going to resolve the historic disagreement on Kyoto," said Mr Blair, who has made climate change - along with the alleviation of poverty in Africa - central to Britain's year-long G8 presidency. "Nor is the G8 the place to negotiate a new treaty."
The world economy will also dominate today's talks at this plush Gleneagles golf resort, with record oil prices the main concern.
Oil prices hovered near record levels yesterday despite expectations the leaders are set to make an official appeal for more stable prices and more freedom for oil companies to invest in oil-rich countries.
G8 leaders will discuss foreign policy issues, particularly the Middle East, although they are not expected to make any major announcements.
Following five days of pop concerts, demonstrations and sporadic violent protests on Scotland's streets, there are no anti-G8 protests planned on Thursday.
Much of the demonstrators' anger stems from the failure of the world's rich countries to alleviate poverty in the developing world, particularly in Africa.
That will be the focus of Friday's talks, when anti-poverty campaigners will urge the G8 to double aid to Africa to $50 billion (€41.9 billion) a year, open markets to African goods and cancel debt.
In a speech in London on Wednesday, U.N. Secretary-General Kofi Annan urged G8 leaders to make bold steps towards meeting the Millennium Development Goals, which include halving extreme poverty and hunger by 2015.