"As far as climate change is concerned, [the growth in air travel] is an utter, unparalleled disaster. It's not just that aviation represents the world's fastest growing source of carbon dioxide emissions. The burning of aircraft fuel has a 'radiative forcing ratio' of around 2.7. What this means is that the total warming effect of aircraft emissions is 2.7 times as great as the effect of the carbon dioxide alone.
The water vapor they produce forms ice crystals in the upper troposphere (vapor trails and cirrus clouds) which trap the earth's heat. According to calculations by the Tyndall Centre for Climate Change Research, if you added the two effects together...aviation's emissions alone would exceed the [British] government's target for the country's entire output of greenhouse gases in 2050 by around 134 percent. The government has an effective means of dealing with this. It excludes international aircraft emissions from the target.
It won't engage in honest debate because there is simply no means of reconciling its plans with its claims about sustainability. In researching my book about how we might achieve a 90 percent cut in carbon emissions by 2030, I have been discovering, greatly to my surprise, that every other source of global warming can be reduced or replaced to that degree without a serious reduction in our freedoms. But there is no means of sustaining long-distance, high-speed travel."