The fuel that goes into cars, trucks and buses is extracted from crude oil reserves deep below the surface of the Earth. The oil occurs naturally from the remains of plants and animals that died millions of years ago (fossils) and remain in the pores of the rocks and Earth's surface. This oil has been made over hundreds of millions years. Jack Edwards, professor of geology at the University of Colorado, speaks about the modern world's use of oil:

"Our children and grandchildren are going to be mad at us for burning all this oil. It took the Earth 500 million years to create the stuff we're burning in 200 years. Renewable energy sources are where we need to be headed".

When the oil is extracted from the ground it is made up of many substances which have to be separated into fractions at an oil refinery. This is done through distillation and the resulting compounds are petrol, diesel, kerosene, gas oil, lubricating oils and fuels in varying thickness. These fossil fuels contain carbon which when they burn release gases which pollute the environment. Petrol and diesel are used in vehicle engine. The fuel is burnt and transformed into movement energy then the exhaust gases, primarily carbon dioxide and condensation, are released from the cylinder and enter the atmosphere.