How important are shipping’s emissions compared with aviation’s?

13th June, 2008

There have been claims in the past couple of years from the aviation industry and its supporters that aviation has been unfairly singled out as a contributor to climate change.  In particular, it has been stated that shipping is growing faster than aviation. 

The AEF has carried out a study which compares the growth of emissions from UK international shipping and aviation in order to investigate these claims.

Only official data has been used, compiled by the UK government for UNFCCC and placed on the DEFRA web site.

The ratio of CO2 emissions between aviation and shipping has increased greatly since 1970 when it was less than one. However, there is some indication that it is no longer increasing.  The annual international aviation/shipping ratio is very variable, but has remained in the 4 to 6 band since 2000. There is no evidence of a reducing ratio. If domestic aviation and shipping are included, the ratios are somewhat lower, in the band 3 to 4 since 2000. But again, there is no evidence of a reducing ratio.

From these figures, it is concluded that the UK emissions from aviation are a great deal more important than those from shipping and there is no evidence of a change in that position. It should also be noted that if the effect of non-CO2 emissions are taken into account, the impact of aviation relative to shipping is probably much greater.

See AEF paper for analysis and graphs (Word doc, 6 pages).

The situtation is rather different for the EU as a whole – shipping emissions still exceed aviation. See AEF paper – EU.