One of Britain’s leading climate change sceptics – former Chancellor Nigel Lawson – has admitted that humans are causing global warming.

Speaking to the House of Lords’ Economic Affairs Committee, Lord Lawson said he did not “question for a moment” that carbon dioxide was a greenhouse gas.

And he accepted there was “huge agreement” among scientists that it was having “some effect” on the atmosphere.

But the former Conservative Cabinet minister argued it would be “crazy” for the UK to try to stop burning the fossil fuels that produce carbon dioxide, claiming countries like China were simply carrying on doing so.

Lord Lawson founded the Global Warming Policy Foundation in 2009 to oppose attempts to reduce the rise in temperatures and has emerged as one of Britain’s leading sceptics.

But, unlike many “deniers” in the US, he made clear he accepted much of the basic science.

“I don’t question for a moment that carbon dioxide is a greenhouse gas and that other things being equal this will lead to a warming of the atmosphere,” he told the Lords’ committee.

“It is true that scientists differ greatly on how big the effect is, but I think there’s a huge agreement there is some effect.”

Renewable energy is making waves in Europe

However Lord Lawson argued Britain should stop trying to decarbonise the economy, claiming this would make little difference to the total global emissions and put the UK at an economic disadvantage to other parts of the world.

“We account for less than two per cent of global carbon emissions and so it’s crazy for us … we cannot do anything on our own,” he said.

He named China and India as two countries which he said had made clear they planned to continue using fossil fuels on a significant scale.

A report published earlier this year on investment in renewable energy generation found that China topped the international league table for renewables – not including large-scale hydro power – followed by the US, Japan, the UK and India.

It concluded that the developing world was now spending more than the developed world on renewables for the first time partly because the energy was “the most environmentally sound but also the cheapest option”.

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John Sauven, Greenpeace UK's executive director, said Lord Lawson’s comments demonstrated “quite a U-turn from someone who once called the scientific consensus on climate change ‘mumbo jumbo’ and extolled the virtues of pumping more carbon into the atmosphere”.

“With the impacts of climate change now playing out before our eyes, merchants of doubt like Lord Lawson are finding their dodgy wares ever harder to sell,” he said.

“Wheeling out the old argument that the UK shouldn’t go it alone on climate won’t be much help either. By ratifying the Paris climate deal, the US and China have debunked that myth too.

“Lord Lawson should now summon the courage to carry the argument through to its logical conclusion – that we need to act quickly to cut our dependence on fossil fuels and embrace clean energy.”

Richard Black, director of the Energy and Climate Intelligence Unit, suggested Lord Lawson was behind the times.

“In the last few years there’s been a massive turnaround in the seriousness with which major nations are treating climate change, stimulated both by growing evidence of impacts and the fast-changing economics of energy,” he said.

“Major economies are all reforming their energy systems, headed by China where the government has blocked new coal-fired plants in most provinces and is instead speeding ahead with wind, solar and nuclear investment.

“One result of this turnaround is that for the last two years, the global economy has grown but emissions have not – and the other is the Paris Agreement, made last December, under which every country will constrain its carbon emissions.