The transportation sector is a significant contributor to greenhouse gas emissions globally. According to the International Energy Agency, the transportation sector was responsible for around 14% of global greenhouse gas emissions in 2019. Within the transportation sector, the road transportation subsector (which includes passenger and freight vehicles) is the largest contributor, followed by the aviation and marine subsectors.
It's worth noting that the percentage of greenhouse gas emissions from the transportation sector may vary depending on the specific data sources and methods used to calculate the emissions. Some estimates put the transportation sector's share of global emissions at a higher percentage, while others put it at a lower percentage.