Climate change & carbon budgets: the contribution of international transport emissions

For global mean temperatures to remain below the 2C threshold, annual emission reductions of an unprecedented scale are required over the coming decades. Yet, even within industrialising nations, two sectors in particular, international aviation and shipping, anticipate a medium-term continuation of emissions growth. At the scale of analysis, it is unimportant which sectors reduce their emissions, as long as the relevant carbon budget is not exceeded. In this regard, those sectors with the lowest abatement costs are likely to compensate for sectors with significant technological and socio-economic barriers to emission reduction. Yet the scale of growth anticipated within aviation and shipping, without technological step changes in the short-term, places significant additional pressure on other sectors to mitigate. Given the overarching climate change challenge, this paper explores the available space for growth for international aviation and shipping given the likely managerial and technological efficiency and carbon intensity improvements to international transport and anticipated growth rates. The results illustrate the necessity for urgent and effective policies on emission mitigation for international aviation and shipping, if the 2C target is to remain an achievable goal.