How much does transport contribute to global warming?

The transport sector contributes over 25% of the global warming potential caused by GHG emissions. Road transport alone is responsible for around 17% of global CO2 emissions (which is around 80% of emissions from all types of transportation). This means that 4,064.7 MtCO2 was released by road transport in 1999 (WRI, 2002). These emissions are caused by the combustion of petrol (gasoline) and diesel.

The average emissions for one person travelling by car in the UK are 3.96 tCO2 per year.

Additional emissions are attributable to vehicle manufacture or the "embodied" emissions. These are, for example, around 18 gCO2/km for a default "Toyota Camry-style" car with a vehicle lifespan of 300,000 km over 15 years (a total of 5.4 tonnes of CO2), assuming 95% of metals and 50% of plastic will be recycled (Weiss et al, 2000). Alternative technologies, particularly increased use of lightweight aluminium may result in higher emissions due to the greater energy needed to produce it. Using recycled materials can more than halve embodied energy. Honda's environmental report states they have reduced emissions per car by 65% since 1995.