Can the aviation industry rise to the challenge of global warming? Mark MacKenzie reports

In last month's damning report on the likely consequences of rising carbon emissions, Sir Nicholas Stern cited civil aviation as a significant contributor to climate change. Aviation, according to Sir Nicholas, accounts for around 1.6 per cent of global emissions, a figure expected to treble by 2050. The findings made such grim reading that many would have expected an instant rethink of the way airlines deal with their carbon footprints.

The aviation industry, however, seemed less than exercised by Sir Nicholas's call to arms. Not unpredictably, Michael O'Leary, chief executive of the budget carrier Ryanair, dismissed the warnings as the "usual horseshit", citing the fact that EU-wide aviation accounts for only 3 per cent of total emissions, compared with the 25 per cent produced by road transport. One of the more surprising sideshows to the report, however, was the spate of stories that seemed to suggest that a viable alternative to reducing the volume of aviation traffic might be a range of new technologies set to take to the skies in the coming decades.

Earlier this month, engineers from Cambridge University and the Massachusetts Institute of Technology unveiled plans to produce the world's first silent airliner, the SAX-40. The result of the three-year Silent Aircraft Initiative (SAI), when the plane comes into service some time around 2030 it will, claim designers, be barely audible outside airports. It is dubbed "the flying wing" for its futuristic blend of wings and fuselage; advocates boast it will be up to 25 per cent more fuel-efficient than current aircraft.

At about the same time the SAX-40 was being introduced, another report, The Future of Travel, was sounding an optimistic note. Attempting to second-guess travel innovations for the coming century, among its claims was that, by 2050, a new breed of "hypersonic" plane will significantly reduce long-haul flight times. With the capability to quadruple current average cruising speeds from 550mph to 2,100mph, journey times from London to Sydney, for example, might be cut from around 20 hours to five. On the subject of emissions, however, the press release was vague, suggesting only that as hypersonic planes will fly higher than conventional airliners, "the effect from emissions is likely to be quite small".

Those outside the industry are less confident. "The problem with most of this new technology is that it was conceived long before we realised the immediacy of the [emissions] crisis," says Mike Mason, founder of the environmental charity Climate Care. "The SAI, for example, started three years ago; even then, global warming wasn't such a big issue and the emissions components haven't been optimised." The bottom line, says Mr Mason, is that changes in technology will come too late to make a significant difference. "The lifespan of an airliner is about 40 years, so while an airliner produced today may be incrementally better [in terms of emissions], the fleet we're relying on is the one we've already got."

Mr Mason, who regularly lobbies the world's major carriers to reduce emissions, is frustrated by what he sees as an industry-wide denial of the Stern report. "Not one [carrier] has a business plan for a carbon-constrained world," he says. But if the Government presses ahead with a proposed series of airport expansion plans, they may not need to. The Independent recently carried statistics that seem to contradict any green noises emanating from Downing Street.

With massive expansion programmes planned for 15 UK airports, annual passenger numbers are expected to rise from 200 million to 470 million by 2030. This would see carbon emissions from UK aviation rise from their 2000 level of 8.8 million tons annually, to somewhere around 18.8 million tons a year, accounting for between 18 and 23 per cent of all UK emissions. Mike Mason is one of a number of commentators who believe that, if the planet is to have any chance at all, emissions reductions of 90 per cent are needed as soon as 2030 - roughly the time the SAX-40 could be taking off.