The UK will miss its "carbon budget" targets to cut emissions over the next decade if it relies on existing policies, analysts warn.
Cambridge Econometrics's latest analysis confirmed the UK has missed its long-standing target to cut carbon by 20% by 2010, despite a large fall in emissions in 2008-09 as a result of the recession.
The rise in emissions during 2010, which officials attributed to heating by households in the face of cold winters, is a warning signal to ministers striving to be the "greenest government ever", the analysts said.
The forecast suggests UK emissions will fall by around 0.5% to 0.75% every year this decade, increasing to around 1% a year in 2020-25 as power generation moves towards more low-carbon supplies.
But on existing policies, including those inherited from the last government and those soon to be put in place by the coalition, the UK will narrowly miss its first two five-year carbon budgets and fail to meet the third which runs from 2018 to 2022 by a wider margin.
Professor Paul Ekins, of University College London, a senior consultant to Cambridge Econometrics, insisted that failing to reach the 20% target by 2010 showed how difficult it was to put in policies that would achieve effective reductions.
He said the official estimate of growth in emissions in 2010 showed that "this Government's aspiration for green growth has yet to be realised".
He said: "The historical link between economic growth and increased emissions has clearly not yet been definitively broken, which must be deeply worrying for a government that is seeking both strong economic growth and ever deeper emission reductions. In this context it is clear that stronger policies will be required to meet the carbon budgets for the 2020s and beyond."
He said much was riding on the impact of a carbon floor price, energy market reforms and the success of the Green Deal which aims to improve the energy efficiency of buildings.
A spokeswoman for the Department of Energy and Climate Change (Decc) said: "The UK is expected to meet the first three carbon budgets according to Decc's central emissions projections. We are not relying on the recession to help us reduce emissions, which is why we are radically reforming the electricity market, increasing home energy efficiency under the Green Deal and creating a Green Investment Bank."