Despite the Mediterranean weather we've been enjoying, the annual exodus to even sunnier climates - much of it by plane - is almost upon us. Our love affair with flying is fuelling phenomenal growth in the airlines' activities: flight numbers are projected to double by 2020 and triple by 2030. But it is also driving phenomenal growth in the airlines' greenhouse gas emissions, and therefore their contribution to devastating climate change.
According to scientists at the Tyndall Centre, one of the UK's foremost climate change institutes, aviation's emissions are growing so fast that they will gobble up all reductions from every other sector if they are left unchecked.
Yes, think about that again. Unless the airlines cut their emissions significantly in coming decades, we won't be able to emit any other CO2s; not from manufacturing, travelling by other means, heating our homes, building - nothing - if we want to meet our targets and stabilize atmospheric CO2 levels.
So, given that we know technological advances alone cannot possibly counteract this level of growth, we face a clear choice: reduce aviation's expansion, or give up on tackling climate change altogether.
Though progress has been poor, the UK and EU are publicly committed to tackling what Tony Blair has called "the greatest environmental threat we face" - and, like it or not, that means reversing the projected growth in the amount of flying we do.
The UK is far from accepting this (publicly, at least, it still backs the "predict and provide" approach, and has authorized a national program of runway building to accommodate all those extra flights), but the EU is proposing measures to tackle flying's environmental impact, focusing in the short term on bringing airlines into its Emissions Trading Scheme (ETS).
Many airlines have been quietly lobbying for this for months, aware that they will be forced to do something, and that, of the options, incorporation into the existing ETS would do least to hamper their continued growth.
Why? Because the principle of giving airlines unrestrained access to the ETS would mean they will be able to buy the right to emit CO2 from other industries. And why would this matter? For a start, aircraft emissions are between two and four times more damaging to the climate than those from other industries (due partly to the altitude at which they are emitted, and to the effects of non-CO2 emissions such as condensation trails and nitrogen oxides), this will actually worsen climate change, as ground-level emissions are replaced by emissions with at least twice the climatic impact - even when the scheme is working properly.
Second, the airlines will perversely, like other polluting sectors, receive a massive windfall from the taxpayer if they are simply given their initial allocations free of charge (grandfathering), rather than being made to pay a market price, through auctioning, for what is, after all, a tradable, valuable commodity.
Third, aviation's high demand for emission permits is likely to put significant strain on the existing system, with the very real risk that current members will lobby aggressively for a loosening of the overall cap - thereby reducing the effectiveness of the entire scheme.
Fourth, and most damningly, it just won't work. The European Commission has admitted that the increase in ticket prices from bringing airlines into the ETS could be as little as €0.2 per return flight, and would be unlikely to exceed €9. This price rise would have little effect on reducing demand for flying.
Emissions trading can play a role, but only if it is genuinely designed to cut the aviation sector's emissions year on year - rather than providing it with the means to continue growing - and as long as it is the polluter and not the taxpayer who pays.In other words, it must be a "closed" system so thatairlines must compete among themselves for limited rights to emit. The total initial cap must be rigorous, with strict annual reductions in allocations, and it must be paid for rather than simply given away. And the scheme would need to be backed up with other measures, such as emissions charges, to tackle the non-CO2 emissions.
Until the airlines are made to pay their way, meeting the social and environmental clean-up costs of their operations, we can't expect many to give up their personal freedom to travel the globe in the blink of an eye. Unless the airlines' right to pollute at will is stopped, climate change is never going to be halted.
Caroline Lucas MEP (Green) is EU Rapporteur on aviation and climate change
Email to: carolinelucas@ greenmeps.org.uk
© 2006 Independent News and Media Limited