Division of Energy
Global Climate Change: Role of Fossil Fuels
Primary sources of greenhouse gases in Missouri are carbon dioxide from the combustion of fossil fuels and methane from agricultural activities and solid waste landfills.
A large percentage of the energy we use comes from fossil fuels. Energy from oil, coal and natural gas is expended in automobiles, heating, electric power plants and major industrial processes.
One of the reasons we rely so heavily on fossil fuels is that they are relatively cheap. However, all of the environmental costs of providing and using fossil fuels are not included in the price paid by the consumers. Use of fossil fuels is increasing the release of the greenhouse gases carbon dioxide and methane, as well as sulfur oxides to the atmosphere. Other costs of burning fossil fuels include the costs to human health and the environment from acid rain and smog.
When fossil fuels are burned, essentially all of the carbon in the fuel chemically combines with the oxygen in the air to form carbon dioxide. About 1.5 percent of the carbon in fossil fuels is emitted in the form of carbon monoxide. Typical hydrocarbon fuels contain 75 to 90 percent carbon by weight. Thus, for every ton of fossil fuel burned, at least three-quarters of a ton of carbon enter the atmosphere in the form of carbon dioxide. (Energy Information Administration, 1993)
Since 1860, global annual emissions of fossil fuel carbon dioxide have increased from 0.1 billion metric tons to approximately 5.9 billion metric tons of carbon per year in 1988. The United States is the world's largest source of energy-related carbon dioxide emissions, emitting 1.3 billion metric tons in 1990.
Also, 20 percent of the methane emissions and more than half of all sulfur emissions on an annual basis are derived from the production, distribution or use of fossil fuels.
Mobile sources are a major contributor not only to greenhouse gas emissions, but also to air quality problems. When fossil fuels are burned to power an automotive engine, some of the fuel remains unburned or is partially burned and leaves the engine as hydrocarbon and oxygenated compounds. Also a portion of the fuel can escape from the vehicle through evaporation.
Substantial reductions in vehicle tailpipe emissions were achieved during the '70s and '80s largely through catalytic converters and improvements in fuel efficiency. The reduced emissions yielded less of a net impact due to the increases in vehicle trips and vehicle miles traveled. Changes in demographics and employment patterns during the '70s and '80s resulted in increases in vehicle ownership and vehicle miles traveled that are higher that the growth rates in population. As a result, net emissions reduction from mobile sources generally have been lower than originally anticipated despite significant technological advances. (EPA Transportation Control Measures Information Documents, March 1992).