• However, these gases rapidly spread all over the globe, so their effect is detected everywhere, particularly in highly vulnerable regions - for example in a number of poor countries in the South that are affected by a harsh and changeable climate.

• Fossil fuels, which we burn to provide power and transport, are a particular culprit, releasing into the atmosphere gases such as carbon dioxide (CO2) which warm the Earth's surface.

• The contribution of a species to radiative forcing of climate change depends on the molecular radiative properties of the gas, the size of the increase in atmospheric concentration, and the residence time of the species in the atmosphere, once emitted.

• The main petroleum liquids used in road transport are gasoline and diesel through internal combustion engines; gasoline is mainly used in passenger cars, light duty vehicles and passenger two wheelers whereas diesel is used in all forms of road transport, except passenger two wheelers.

• Today attention is increasingly turning toward PHEVs, which use both grid electricity and gasoline as fuels.

• In general, the more energy the battery is capable of delivering, the greater the gasoline fuel savings.