On 8 February, Mr Blair made one of his occasional appearances before the House of Commons Liaison Committee, a grouping of the chairs of all Commons Select Committees. A full third of the session was devoted to climate change - a clear indication of the subject's growing political significance.
The main focus was on Mr Blair's aspirations for this year's G8 presidency on climate change (see p 17 ). The Prime Minister said he hopes to "establish a clear sense of direction of travel". The "the single most important thing" would be "a new set of international agreements with the developing countries, in particular China and India, at the heart of it."
Mr Blair said that "I think it will be very difficult, but I think the United States is ready to come back into dialogue on this question...It is not sensible at this stage of the negotiation to start talking too much about the details of it."
The Prime Minister reiterated that "we need far more" ambitious global emission reductions than will be achieved under Kyoto. However, he argued that "we should not set an over-ambitious target for ourselves."
Mr Blair warned that "the argument about Kyoto has not shifted" in the US. "The Senate voted - I think it was 100 to nothing - against Kyoto," he told the Committee. "It is very convenient sometimes for people to say it is the Bush administration, in my view whatever administration was in power Kyoto would not be passed."
Significantly, Mr Blair backed the EU's goal of limiting average global temperature rise to 2ºC above the pre-industrial level - a figure which is commanding growing significance in scientific and policy circles (see pp 17-21 ).
"We want to limit it to the two degrees because anything over that triggers a whole series of changes to climate which are immensely worrying and damaging," he said. "The more you read the science and read what is happening on the glaciers and the ice cap, the more worried you become."
MPs criticised Mr Blair for his recent speech to the World Economic Forum in which he said that the evidence on climate change "is still disputed". He maintained that his remarks "were misconstrued in certain quarters" - and that his "personal view is that there is little or no doubt about it."
The Prime Minister was also put on the defensive over the Government's controversial decision to apply to the European Commission for an increased allocation under the EU emissions trading scheme (see pp 40-41 ).
"The facts changed, so we have to submit a different proposal... because otherwise we will do unnecessary damage to our business," Mr Blair said. "I cannot have a situation where British business is going to be unfairly penalised vis-à-vis the rest of Europe when actually British business and Britain has probably done more on climate change than any other country."
The Prime Minister confirmed that it was his decision to seek an increased allocation - but denied reports of a division between the Environment Department and the Department of Trade and Industry. "It is very important...that we do not send a signal to Europe that there has been some disagreement within Government over this because there has not."
MPs tested Mr Blair's willingness to match his rhetoric on climate with hard political decisions in other areas - including aviation. Conservative MP Robert Key asked: "Do you believe the rapid growth in cheap international air travel with tax-free aviation fuel...is really sustainable?"
Mr Blair's response was blunt: "Hands up around this table how many politicians facing...a potential election at some point in time in the not too distant future would vote to end cheap air travel? Right. None." He went on to suggest that political consensus could not be reached on "slapping some huge tax on cheap air travel".
The "only way through" the problem, the Prime Minister claimed, is to "take a hard-headed look" at more fuel-efficient aircraft technology - citing the new European Airbus as an example. In fact, forecasts of aviation's climate change impact already assume significant technological improvements, but these are swamped by the growth in flights.
Surprisingly, Mr Blair omitted to mention the UK's plan to push for inclusion of aviation in the EU emissions trading scheme from 2008 - to date, the only environmental priority for the UK's EU Presidency later this year.
The Prime Minister's coyness adds weight to concerns that the plan is not making much headway in Brussels. Indeed, in February the German and French governments put forward proposals for new taxes on aviation and shipping. The scheme, which would raise funds for international development aid, will be discussed by EU Finance Ministers in the summer.