Because transportation is a part of every consumer product supply chain, though, its aggregate environmental impacts are even more significant when considered as a whole. A study by the
estimated that 2800 mega-tonnes Of the world's CO2 emissions could be attributed to transportation
and logistics, representing 5.5% of the world total. Of this about half is attributable to road transport, one-third to rail, air, and sea transport, and one-sixth to logistics buildings.