Transport: A roadblock to climate change mitigation?
Global emissions scenarios studies, such as those informing the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (AR5), highlight the importance of the transport sector for climate change mitigation—along with the difficulties of achieving deep reductions therein (1) [supplementary materials (SM)]. Transport is responsible for about 23% of total energy-related CO2 emissions worldwide (2). The sector is growing more rapidly than most others, with emissions projected to double by 2050. Global scenario studies, specifically those produced by integrated assessment models (IAMs), communicate aggregate mitigation potentials by sectors in IPCC reports. Yet recent evidence indicates that emissions may be reduced further than these global scenario studies suggest—if policy-makers use the full suite of policies at their disposal.