Ships, not planes, new warming risk

Carbon dioxide emissions from shipping are double those of aviation and increasing at an alarming rate, which will have a serious impact on global warming, according to industry and European academics.

Separate studies suggest that maritime carbon dioxide emissions are not only higher than previously thought but could rise by as much as 75 per cent in the next 15 to 20 years if world trade continues to grow and no action is taken. The figures from the oil giant BP, which owns 50 tankers, and researchers at the Institute for Physics and Atmosphere in Germany reveal that annual emissions from shipping range between 600 and 800 million tonnes of carbon dioxide, or up to 5 per cent of the global total. This is nearly double Britain's total emissions and more than all African countries combined.

Carbon dioxide emissions from ships do not come under the Kyoto agreement or any proposed European legislation and few studies have been made of them, even though they are set to increase.

Aviation carbon dioxide emissions, estimated to be about 2 per cent of the global total, have been at the forefront of the climate change debate because of the sharp increase in cheap flights. Shipping emissions, which have risen nearly as fast in the past 20 years, have been ignored by governments and environmental groups. Shipping is responsible for transporting 90 per cent of world trade, which has doubled in 25 years.

Donald Gregory, director of environment at BP Marine, said last week that BP estimates that the global fleet of 70,000 ships uses about 200 million tonnes of fuel a year and this is expected to grow to 350 million tonnes by 2020. "We estimate carbon dioxide emissions from shipping to be 4 per cent of the global total. Ships are getting bigger and every shipyard in the world has a full order book. There are about 20,000 new ships on order," Mr Gregory said.



http://www.theage.com.au/news/world/ships-not-planes-new-warming-risk/2007/03/03/1172868811080.html

What's the emission per payload ton-mile of ships compared to aircraft? I would venture that it's a LOT lower, by at least an order of magnitude. Of course, each has its particular downside: aircraft spew their exhaust at high altitude where the greenhouse and ozone-reducing effects are greater, while ships emit more SOx and particulate pollution due to the less refined nature of their fuel.

If we really need to knit together a global industrial civilization, on balance I'm more in favour of doing it with ships than planes. Of course, re-localizing production to decrease the overall amount of transportation the world requires is the best idea. As well as reducing emissions, that would help increase the resilience and sustainability of our civilization.