FOSSIL FUELS
In 2007 the Energy Information Administration estimated that -
86.4% of all energy sources came from fossil fuels:
36.0% from oil, 27.4% from coal and 23.0% from natural gas.
Similar to wood, fossil fuels are carbon-based, however, they contain much higher concentrations of carbon due to the fact that they have been formed over millions of years under intense heat and pressure within the earth’s crust. It is because of this long formation process that they are considered non-renewable energy sources.
Fossil fuels have been plentiful and indeed have played a major role in the civilization we enjoy today. These types of fuels, however, have a major drawback: the high concentrations of carbon that they contain translates to high emissions of Carbon Dioxide (CO2) when they are burned (such as in a combustion engine). We are burning so much fossil fuel so fast that the earth cannot absorb it all, causing excess amounts of CO2 to be released into our atmosphere and contributing to Global Warming.
