The UK must cut its greenhouse gas emissions by at least 34 per cent by 2020, the committee set up to advise the government on climate change has recommended.

The Committee on Climate Change, chaired by Adair Turner, also said emissions should be cut by even more if an international deal on reducing greenhouse gases is agreed.

If the current UN negotiations lead to a new deal on climate change in Copenhagen next December, the UK’s greenhouse gases should be cut by 42 per cent on 1990 levels by the end of the next decade.

The significant reductions can be achieved at a cost of less than one per cent of GDP in 2020 and using existing green technologies, a report from the committee said.

But stronger government policies will be needed to move the UK to a low-carbon economy.

The cuts can be achieved by cleaner power generation from sources such as wind, which could make up 30 per cent of the UK’s electricity by 2020 and measures including energy-efficiency improvements in homes and offices and developing more efficient electric and hydrogen-powered cars.

The report said nuclear power could play a role in low-carbon electricity generation and did not rule out new conventional coal-fired power stations in the next decade.

It recommended the government should make clear that fossil-fuelled power plants which do not have technology to trap and permanently store carbon emissions should not be allowed to generate electricity beyond the early 2020s.

New coal-fired power stations should only be built with the “clear expectation and certainty” that they should be retrofitted with carbon capture and storage (CCS) by the early 2020s, Lord Turner said.

The climate change committee, set up under the Climate Change Act, has already recommended a cut of 80 per cent on 1990 levels by 2050 – advice which has been accepted by the government.

The report set out the first three five-year “carbon budgets” needed to meet the interim and long-term reductions in emissions.

The committee said the budgets should include all greenhouse gases, not just carbon, but should not include aviation and shipping because of difficulties in deciding how much the UK is responsible for. “Clear strategies” should be in place to cut emissions in those areas, the report recommended.

The report also said the 34 per cent target should be achieved by emissions cuts domestically and within Europe, and not through “offsetting” by paying poor countries to reduce their greenhouse gases.

Lord Turner said: “Climate change poses a grave threat to human welfare, the environment and the economy.

“We need to act now, in the UK and as part of a global agreement, to significantly reduce our emissions.

“It is not too late to tackle climate change, but it will be unless the world takes action soon, and the developed countries need to lead the way with strong commitments and strong delivery against the budgets.

“The reductions required can be achieved at a very low cost to our economy: the cost of not achieving the reductions, at national and global level, will be far greater.”

He acknowledged that higher electricity and gas prices created by investment in renewables could push a further 1.7million households into fuel poverty – but said 400,000 could be lifted out by energy efficiency measures in their homes.

Tim Jackson, economics commissioner at the Sustainable Development Commission, warned the goverment’s commitment to building a low-carbon Britain was woefully inadequate.

“The only appropriate response to both the current economic crisis and the impending crisis of climate change is a comprehensive programme of investment in low-carbon technologies and upgrading Britain’s buildings,” he said.

“What we need is a wholehearted political and economic commitment to achieving a sustainable Britain.”