Travelism was responsible for some 5 per cent of global manmade emissions in 2005, of which air transport contributed two-fifths, that is 2 per cent of world-wide emissions (UNWTO et al. 2008.) If we were to include radiative forcing, aviation’s contribution to global warming is significantly more – in the range of 3.5-4.9 per cent (Gossling et al. 2008: 873; Lee et al. 2009). Roughly 40 per cent of commercial aviation emissions are from domestic travel and 60 per cent from international travel (OECD 2011; UNWTO et al. 2008).