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Fossil fuel sources

Fossil fuels

It is only since the start of the industrial revolution (ca 1750) that there has been ever increasing use of fossil fuels as these are more concentrated that renewable energy sources. Fossil fuels such as oil, gas and coal are characterised as non-renewable because they were created over very long time periods compared with our current rate of use. In creating useful energy from the combustion of these fuels, a colourless gas called carbon dioxide is created which, being lighter than air, rises and congregates in the upper atmosphere.

Carbon dioxide is one of the six greenhouse gases whose characteristic is that they are able to absorb the heat radiated from the earth’s surface so creating global warming. The world has become very dependent upon fossil fuels as they are easy to extract, transport and utilise and are not dependent upon sunlight, directly or indirectly. However, our increasing use of energy and growing population worldwide has created another global concern which is the finite size of these resources.

Peak oil and gas

All the major models of oil production predict that the world’s oil supply will peak by 2025 and some models predict that the supply has already peaked (Figure 1).

Figure 1: Oil and gas profiles

(Source Colin Campbell)

So we need to reduce our use of fossil fuels not only to limit impacts of climate change, but also to conserve resources for succeeding generations.

Switching from oil to gas will only be a short term option as the world’s supply of gas is likely to peak within 20 years. What is of greatest concern is not when the oil or gas peaks occur, but how the world will manage with ever decreasing amounts of liquid or gaseous hydrocarbons. In the accompanying figure, it can be seen that the decline is predicted to vary from between 2% and 7% per year.

Even at the lowest rate of decline, the mismatch between demand and supply is such that it is important to start now to switch from oil to other energy sources preferably renewable as soon as possible. Such a change in energy source will help to limit climate change.

Figure 2 below shows the predictions of the various oil production models. These are summarised in the graph which shows not only the predicted date of the oil peak but the subsequent rate of decline in millions of barrels of oil per day.

Figure 2: Summary of various oil production models

(Source ERC, UK)

Further reading Global oil depletion – an assessment of the evidence for a near-term peak in global oil production, UK Energy Research Centre report August 2009

Activity Age range
  Use of fossil fuels   
  Science, geography
 11 – 18  


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