Fossil fuels

There are quite a few problems with fossil fuels, but they all centre around future availability and the difficulties of disposing of their combustion products. There are three principal fossil fuels:

Coal: there's not as much left as you might think.
Natural Gas: being squandered?
Oil: peak oil may be past

Fossil fuels produce a lot of carbon dioxide when burnt, with coal as the worst offender. Burning any fossil fuel causes global warming because all produce carbon dioxide when they are burnt. Oil and natural gas also produce water vapour as a combustion product. This is not bad in itself, but unfortunately its often produced in places where we really do not want it. Here are the numbers:

Fuel Composition CO₂ H₂O

Natural gas CH₄ 2.75 2.25

Petrol C₈H₁₈ 3.09 1.42

Jet Fuel A C₁₂H₂₆ 3.11 1.38

Fuel oil C₂₄H₅₀ 3.12 1.33

Coal Carbon 3.67 0

This table shows the tonnes of carbon dioxide (CO₂) and water (H₂O) produced when one tonne of fossil fuel is burnt.

The combustion products pose problems when it comes to disposing of them:

Carbon reuse: carbon dioxide can be used and recycled if uses can be found.
Carbon sequestration: maybe carbon can be buried for long-term disposal - but not cheaply.
Water vapour: putting in it the wrong place can cause problems.