Ahead of Mr Blair's big September speech on climate change - the world's biggest collective challenge, he will say - a minister admitted the time has come for the government "to move from words to delivery" at home. Abroad it must also press Washington "to be more ambitious", he said.
That amounts to confirmation that Labour has not done enough, despite brave words since 1997, and that ahead of likely British elections in the spring it must improve its record and distance itself from the White House.
In a speech to an environmental conference in London, Lord Whitty, Labour's former general secretary, now an environment minister, told delegates, "we plan to use our position in every way we can to push this agenda at a senior level" in the EU and the G8, makingwhat he called "a clear case for concerted action" by the world community.
With Mr Blair returning from holiday this week to start preparing his speech, and the environment featuring as a sensitive issue in the Bush-Kerry presidential race, Lord Whitty had to tread a diplomatic course yesterday and was careful to praise US research.
He continued: "But research and development is not a substitute for taking concerted action to reduce emissions now. We know enough about climate change to know that if we do not act now, we will need to make more drastic changes later."
In answer to questions about aircraft pollution he admitted he personally favours a pan-European, preferably, a global tax to tackle a fast-growing problem. Aviation fuel is untaxed.
That is no more likely to appeal to the US aviation lobby than Lord Whitty's confirmation that Mr Blair's chairmanship will press for the start of an EU emissions trading scheme and tackle EU aviation emissions.
He claimed that UK air pollution is much less dangerous than in the 50s, when winter smog killed 4,000 Londoners, but admitted a new hazard - summer smog - had caused the premature death of 769 people in England and Wales in August last year.
Lord Whitty also endorsed the views of a German academic at the conference that aerosol emissions, widely condemned, may actually be helping to cool the planet, acting as a temporary cover for the ozone hole. If aerosol use is stopped, as environmentalists want, it could bring unwanted side-effects, the conference heard.
Lord Whitty praised the UN environmental programme, now headed by the respected former German minister, Klaus Topfer. He also warned Moscow - whose long-pledged support for Kyoto has still not materialised - that hopes that climate change "would be good for Russia" are wrong.
But ministers know that they are failing to meet Labour's 1997 target to cut by 20% carbon dioxide emissions by 2010, well ahead of the Kyoto target of 12.5% for all greenhouse gases. The target has been scaled down to a "goal" which may be missed by 5% or more.
Ministers have also been slower than most EU members to embrace renewable energy sources - notably wind power - in line with well-aired hostility within the Bush administration. A 10% UK reliance on renewables by 2010 is another target the government will miss.
Mr Blair wants climate change and Africa to be the main themes of his
international roles in the G8 and EU next year.