LAST weekend鈥檚 appalling carnage in Bali means airlines are once again bracing themselves for hard times. Yet if 11 September is a guide, any slump in air travel will be a blip.
Global air traffic has quadrupled since 1970 and is forecast to more than double again by 2015. Result? Air transport is the fastest growing source of greenhouse gas emissions. Though only 3.5 per cent at present, aviation鈥檚 share of emissions could exceed 10 per cent by 2050. So what are governments and international bodies doing? Precious little.
Taxing jet fuel is banned by an international treaty dating back to 1944. Emissions from international flights have yet to be included in the Kyoto Protocol. Action at the World Summit in Johannesburg was confined to consciousness-raising stunts inviting delegates to cough up voluntarily for the planting of trees to offset their planes鈥� emissions. The rest of us, meanwhile, love our cheap air tickets and seem immune to the irony of jetting off for an eco-tour on a return long-haul that produces more carbon dioxide per passenger than a few months鈥� motoring.
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True, jet engines are getting more efficient. But this will not offset the fantastic growth in passengers. And planned high-speed planes such as Boeing鈥檚 Sonic Cruiser could reverse the efficiency trend. For all these reasons, many governments, especially in Europe, now accept the need to tax jet fuel even if the industry and the powerful bodies it influences consistently block such moves.
Such intransigence looks increasingly self-serving. But in one respect the industry is right: curbing fuel consumption alone may not be the answer. In fact, to really minimise their greenhouse contributions, planes may sometimes have to do the opposite 鈥� use up more fuel by flying at lower altitude to cut out vapour trails (see 鈥淗igh flyers are scourge of the skies鈥�).
The aviation industry will no doubt pour cold water on this. And in truth, the benefits of curbing plane trails are not always easy to balance against the costs. Nevertheless, there are clearly circumstances in which flying lower could be the lesser of two environmental evils. Airlines and their customers should take the idea seriously.