In 2015, the global community came together in Paris and agreed on a CO2 emissions pathway to avoid a temperature anomaly of more than 2 °C above pre-industrial levels. A significant source of CO2 emissions, the main greenhouse gas causing climate change, is the tourism sector. From research published by the UNWTO (World Tourism Organisation) in 2008, this contribution to anthropogenic CO2 emissions was found to be significant at 4.9% in 2005 and to increase. These growing emissions contrast with the Paris Agreement goal to obtain a very substantial reduction of global CO2 emissions. This thesis examines what the main drivers for tourism’s CO2 emissions development are. It also indicates what the tourism sector should look like in terms of improved energy efficiencies and volumes of trips, guest-nights, transport distances and transport mode choice to fit a ‘climatically sustainable development’ and what policies may evoke changes toward such a tourism development. The main research question of my thesis is: ‘Which mechanisms drive the development of global tourism and its CO2 emissions, and what are potential effects and consequences of policy strategies to mitigate these emissions?