Task Force 4: Refuelling Growth: Clean Energy and Green Transitions 1. The Challenge The transport sector accounts for nearly 25 percent of global CO2 emissions. Further, emissions from the transport sector in the G20 are attributable to more than two-thirds of this share (Vorholz, 2018). In particular, road transport contributes the highest share (87 percent) in sectoral greenhouse gas (GHG) emissions (Paladugula et al., 2018). The G20 countries continue to rely heavily on oil in the sector.