A top British climate change official backed an embattled European Union scheme Friday to tax industrial carbon emissions, but also allowed for exceptions in highly competitive sectors.

Adair Turner, the newly-appointed head of Britain's Climate Change Committee, also expressed skepticism toward the reliance on industry-wide agreements and new technology favoured by the United States for reducing the greenhouse gases that drive global warning.

"My commission and the British government are in favour of moving quite fast in auctioning the permits [to emit CO2] rather than giving them away for free," as is currently done, he told business leaders and journalists in Paris.

Several major multinationals, including Shell France and cement giant Lafarge, threatened this week to stop investing within Europe or to move operations outside the EU unless the plan to sell emission permits was scrapped.

Some industries such as steel and aluminum, Turner acknowledged, face high energy costs and stiff competition from abroad, and should thus receive some form of relief.

"But it most industries the issue of international competitiveness does not arise," he said.

Lord Turner, a former vice-chairman of Merrill Lynch Europe, heads a committee that will advise the Britain on climate change policy and setting targets for slashing greenhouse gases.

It will also monitor the government's progress in adhering to its own goals.

Britain has pledged to introduce the world's first legally-binding targets to cut carbon output by at least 60 percent before 2050, using 1990 levels as a benchmark.

The Climate Change Committee may recommend, by year's end, that reductions be as high as 80 percent, and that other greenhouse gases be included in the legislation, he said.

While underlining the urgency for an aggressive climate change policy, Turner said he was skeptical of two main axes in the US approach to slowing global CO2 emissions.

"I am very worried that the world is simply assuming that carbon capture and storage (CSS) is going to be available as a technology and at a reasonable cost by 2015," he said.

CSS is an as-yet unproven technique for diverting carbon emissions -- from coal-fired energy plants, for example -- and storing them deep underground so that they do not escape into the atmosphere.

"Almost every plan that I see has simply penciled that in" as if it were a given, he said. "If we don't have it, we will have a major problem."

The International Energy Agency has forecast a double of coal use over the next 20 years, especially to fuel new power stations in China and India.

The administration of George W. Bush has touted CSS as a key technology for reducing emissions.

Turner also expressed caution on the efficacy of industry-based agreements on curbing CO2 output.

Unless government steps in -- at the national and international level -- companies that invest in energy efficiency and carbon-reducing measures will be penalised by competitors who shun such measures, he said.

"At the end of the day, because this is a collective public problem it ultimately does require governments to require that all the players come in to a level playing field," Turner said.

While there is general agreement on the need to keep global temperatures from rising above two or three degrees Celsius compared to pre-industrial levels to avoid catastrophic climate change, the world "has not quite woken up to the fact that it will require very, very radical action," he said.

But even if the needed measures cost one-to-two percent of world GDP over the next several decades, the cost is a relative small price to pay.

"The great wars of the 20th century cost 30 or 40 percent of GDP and millions of lives. Compared to the sacrifices previous generations made, this is trivial," he said.

Turner's comments come ahead of a "Major Economies Meeting" in Paris next week, a US-led gathering -- grouping G8 nations, the EU and major developing economies such as China and India -- of the world's major carbon-emitting nations.