In total, aviation emissions represent around 6% of UK greenhouse gas emssions.
In 2013 aviation emissions fell 0.6%; this is in line with the trend in recent years where emissions fell 0.7% on an average annual basis from 2009 to 2013.
In 2013 passenger numbers increased by 4%, suggesting the reduction in emissions was likely to be due to changes on the supply side (e.g. from increased passenger loading or improved fuel efficiency).
In future, aviation emissions are projected to rise without further reduction measures. They can be reduced through a combination of fuel efficiency improvement, use of biofuels and a moderation of demand growth.
Policy approaches to aviation emissions should be at the global or EU level, given the international nature of the industry. Until these are agreed, our recommendation is that an appropriate long-term planning assumption for aviation is for emissions to be around 2005 levels in 2050.
An increase in demand of around 60% would be consistent with this, and should be used by the government when assessing related policies (e.g. airport capacity).