The government must impose higher taxes on gas-guzzling cars and on flights to cut carbon emissions, MPs warn today.
In a highly critical report, the environmental audit committee warns of a "dismal failure of purpose" at the Department for Transport (DfT) in its efforts to tackle climate change.
The department said tackling climate change was a "key priority", but admitted that more action could be taken.
Transport is the only sector of the UK economy in which carbon emissions have actually risen since 1990, and this is projected to continue until at least 2020.
Aviation is a particular problem, the MPs say - while this sector currently represents about five per cent of all carbon emissions, this is set to increase to 25 per cent by 2050.
They condemn the government's plans to continue allowing airports to expand, and say there is also "no excuse" for not raising air passenger duty.
The report accepts minister's efforts to include aviation in the EU emissions trading scheme, where firms would be given a certain allocation of carbon credits to buy and sell on the open market, but warns this is still "years away".
It also attacks the "scandalous" failure of European governments to properly deal with taxing aviation fuel, and although it accepts the difficulties in imposing taxes on pan-European flights, it says the government can at least introduce this on domestic flights.
Closer to home, the committee notes the government's efforts to encourage more environmentally-friendly cars and to link vehicle taxes with carbon emissions.
But it says the chancellor's creation of a new band on vehicle excise duty for gas-guzzlers is "ineffective" - they end up paying only about £40 a year more - and recommends much wider differences across various bands, of up to £300 each.
There has also been "microscopic" progress in efforts to get ten per cent of new cars emitting under 100g per kilometre by 2012 - this would be the equivalent of about 250,000 cars, but in 2004 just 481 cars fit into this category.
The committee says there must also be more effort put into taking people off the road - it says a national road pricing scheme should be introduced as soon as possible, while greater emphasis must be placed on improving bus and rail services.
Overall, it warns the DfT "seems to have a fatalistic attitude which sees carbon-intensive activities and economic growth as going hand in hand". It says this view must be addressed if the department has any chance of doing its bit to cut the UK's emissions.
Friends of the Earth described today's report as "damning", and urged the DfT to conduct a "root and branch" review of transport policy, beginning with its plans for airport expansion and road building.
"Tinkering around the edges is no longer enough to tackle the greatest threat the world faces," said director Tony Juniper.
However, a spokeswoman for the DfT insisted action had been taken to cut carbon emissions, including investing in public transport and a commitment to renewable fuels.
The department expected to cut 6.8 million tonnes worth of carbon emissions by the end of the decade, she said, adding: "We recognise the need to go further and will continue to develop policies that help reduce the impact of transport on the environment."