But that’s just the point. There’s so much shipping that the amount of CO2 pumped into the atmosphere is nearly twice that of aviation, worldwide, despite the fact that shipping might seem more efficient.

“Flying, on the other hand, is essentially frivolous…”

I think there’s plenty of business people who would argue that their physical presence in other countries is what keeps trade going, secures new business and otherwise adds to economic growth and keeps people employed. There’s only so much you can do with video conferencing.

Similarly, why should holidaymakers, travellers, musicians or anyone visiting friends and family abroad curtail their flying when there’s plenty of other ways of reducing CO2 emissions?

Besides, what is cruising on the latest 5,000 passenger cruise ship then if not the frivolous leisure activity of those who can afford it?

Aviation accounts for so little of the CO2 output compared to other sources that the energy and money invested in campaigns against it would be better spent elsewhere.

For example, instead of protesting outside airports against aviation, campaign vociferously outside Parliament for more high speed rail links to Europe, and the renewal of old and improvement of existing rail links to get more cars, coaches and lorries off the road.

Aviation receives a disproportionate amount of protest considering it’s supposed contribution to global warming, and they’d enlist more support putting positive suggestions forward rather being a rent a mob outside an airfield.

“So why aren’t climate change protesters chaining themselves to cruise ships, or demonstrating outside dock expansion projects and shipyards?”

Well, I think that is because shipping is about 20 times as carbon efficient as aviation over a given distance. So whilst there might be a vast amount of shipping out there, it is at least a pretty efficient means of transportation.

Flying, on the other hand, is essentially frivolous (in general), because it merely carries stuff faster. So it reflects an inefficient use of the world’s resources in order to accelerate activities for the rich few, be they business travellers, holidaymakers or people who like fresh fish from the other side of the world. That is bound to drive a somewhat emotional response from the public, because it really feels like a direct, conscious choice by the minority that sticks two fingers up at the majority.

That is why, in my opinion, people take on aviation as a climate change issue. Tackling shipping becomes a far more open argument about the nature of capitalism and globalised markets, which is frankly unwinnable. Flying less is somewhat more achievable.

It is also worth noting that although aircraft are remarkably efficient considering what they do, they are still only as efficient (per passenger kilometre) as driving a fairly inefficient car. Improvements in efficiency do not seem to be coming too readily any more, either: http://www.theicct.org/information/reports/efficiency_trends_for_new_commercial_jet_aircraft_1960_to_2008

http://www.timesonline.co.uk/tol/news/environment/article6936289.ece

I hope.