Fossil fuels include coal, oil, and natural gas. They occur naturally in the Earth, and can be burned for energy. They currently provide over 80% of the world's energy, but at a heavy environmental cost: pollution and climate change. Over 75% of all greenhouse gas emissions are due to burning fossil fuels.
How much is there
Globally, per person, there is about 31 tonnes of oil (recoverable) somewhere in the Earth. oil.reserves(tonnes per capita)(world.population). Average production is about 1.5 kg/day per person oil.production(lbs/day per capita)(world.population). Rich countries consume a lot more, poor countries use a lot less.
Fossil fuel molecules are mainly hydrocarbons.
Burning fossil fuels perfectly, produces carbon dioxide and water vapor.
- Example: Methane (natural gas):
- CH4 + 2 O2 -> CO2 + 2 H2O (exothermic: 890290 J/mol)
Imperfect combustion produces other substances such as carbon monoxide.
Fossil fuels can also be used to make hydrogen gas.
Fossil fuels are also used in making plastic, some of which is disposable. Other uses include making thousands of different chemicals, but together they add up to only a small fraction of fossil fuel consumption. [quantification needed]
Coal and oil are formed from organic material (mostly plants, sometimes dead animals) that got buried in the Earth millions of years ago.