Tourism as a sector accounts for a considerable share of global passenger transport, and is thus of interest in studying global mobility trends and emissions associated with transport. In 2005, tourism accounted for about 5% of global CO2 emissions, three quarters of this caused by passenger transport. Given the rapid growth in tourism, with 1.6 billion international tourist arrivals predicted by 2020 (up from 903 million in 2007), it is clear that the sector will contribute to rapidly growing emissions, and thus increasingly interfere with global climate policy. This is especially true under climate stabilisation and “avoiding dangerous climate change” objectives, implying global emission reductions in the order of -50% to -80% by 2050, compared to 2000. Based on three backcasting scenarios, and using techniques integrating quantitative and qualitative elements, the paper discusses the options for emission reductions in the tourism sector and the consequences of mitigation for global tourism-related mobility by 2050. The paper ends with a discussion of the policy implications of the results.