Planes, car, buses and trucks...
All are pollutants means of transport that contributes to the "greenhouse effect".
However, leaked UN report says that ships pollution is three times higher than previously thought, and represent 1.12 billion tonnes of CO2 per year, while global air travel is responsible for around 650 million tonnes of CO2 each year.
That means that ships are responsible for 4% of CO2 emissions, and must be included in Kyoto targets.
- True scale of CO2 emissions from shipping revealed (The guardian)
- Ships' greenhouse emissions revealed (Nature)