Over the course of millions of years, high pressure and high temperature transformed ancient organisms into what is known as fossil fuels. Coal, natural gas, and petroleum are all fossil fuels that formed under similar conditions.

World's largest oil exporters

1. Saudi Arabia: US$113.7 billion (17.2% of exported crude oil)
2. Russia: $72.6 billion (11%)
3. Iraq: $50.8 billion (7.7%)
4. United States: $50.3 billion (7.6%)
5. United Arab Emirates: $47.9 billion (7.2%)
6. Canada: $47.6 billion (7.2%)
7. Kuwait: $28.3 billion (4.3%)
8. Nigeria: $25.2 billion (3.8%)
9. Kazakhstan: $23.7 billion (3.6%)
10. Norway: $22.7 billion (3.4%)
11. Angola: $20.2 billion (3.1%)
12. Brazil: $19.6 billion (3%)
13. United Kingdom: $16.1 billion (2.4%)
14. Oman: $15 billion (2.3%)
15. Mexico: $14.9 billion (2.2%)

Petroleum is non-renewable, and will soon be completely extractred. Experts predict peak oil production as soon as 2050, meaning finding alternative energy resources is paramount. Many industries are currently developing energies to replace oil definitely.