LONDON, May 6 (Reuters) - Carbon trading and increased regulation could hinder efforts to reduce airplane greenhouse gas emissions through innovation and increased use of biofuels, airline industry leaders said on Wednesday.

Airplanes account for an estimated 2-4 percent of global carbon dioxide (CO2) emissions, which scientists say could cause global temperatures to rise, triggering widespread disease, famine, flooding and drought.

'It's is a small part of the problem but it's a very visible part of the problem, and therefore it's vulnerable to the wrong sort of policies being made,' Paul Steele, executive director of the Air Transport Action Group, told an aviation and climate change conference hosted by the British Airports Authority.

Governments will meet later this year in Copenhagen to carve out a new treaty on climate change to succeed the Kyoto Protocol after it expires in 2012.

Many say that although aviation makes up a relatively small part of global emissions, it has the potential to grow if unaddressed.

'If left unchecked, global aviation emissions could reach 2.4 billion tonnes of in 2050, which would be 15-20 percent of all CO2 permitted under a global agreement,' said Ben Combes of the UK's Committee on Climate Change, adding that this would be a nearly four-fold increase on current levels.

As a result, the European Union approved the inclusion of aviation under its Emissions Trading Scheme from 2012.

The problem, they say, is that they have not managed to clearly communicate this to the public.

'We have a story to tell and we need to get out there and tell it even more clearly and succinctly than we have in the past,' said Roger Bone, UK president of Boeing ( BA - news - people ).

'Technologies already on the drawing board show potential by 2020 to reduce CO2 by 30 percent ... a single aircraft powered by this engine saves the equivalent to planting 250,000 trees,' said Robert Nuttall of engine-makers Rolls Royce.

TRADING LOOMS

Under the European plan, all airlines flying into and out of EU airports will have emissions capped at 97 percent of their 2004-2006 average, and carriers will be forced to buy carbon permits to cover any excess.

With global air traffic set to double by 2020, the EU is keen to apply the 'polluter pays' principle, though some worry that its plans could clash with climate legislation proposed in other countries including the United States, Canada, Australia and New Zealand.

'We're not against emissions trading per se ... (but) what we're seeing right now is that multiple overlapping trading schemes are going to create problems for industry,' Steele said.

'Aviation is not trying to shirk its responsibility. It should be accountable for its emissions, but it should pay for them once, the same as any other industry does.'

(Reporting by Michael Szabo; Editing by William Hardy) Keywords: AVIATION/CLIMATE

(michael.szabo@reuters.com; +44 207 542 9242; Reuters Messaging: michael.szabo.reuters.com@reuters.net)

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