Decarbonization is the reducing of the use of fossil fuels in order to reduce the emission of carbon dioxide into the atmosphere and thereby slow down or halt climate change. It can be accomplished mostly by replacing fossil fuels with low-carbon energy sources for electric power generation, transportation vehicles, construction equipment and other products. Low carbon power sources include hydroelectric, solar, wind, wave, and geothermal energy.* However, these forms of alternative energy cannot, at least at present, be classified as entirely carbon-free because power from conventional fossil fuel sources is typically still required to varying extents to manufacture and install the equipment to produce and utilize this energy.
Decarbonization can also be accomplished to some extent by increasing the efficiency of use of fossil fuels as well as by reducing the processes and products that utilize fossil fuels. For example, internal combustion engines can be made more fuel-efficient. Also, their use in transportation, which is the largest application for fossil fuels in some countries such as the U.S., could be reduced by such means as discouraging automobile use by applying congestion charges and pollution fees and providing high quality alternative transportation. Houses and other buildings could be made more fuel-efficient by improving insulation and installing double-glazed windows.
In addition to reducing the emission of carbon dioxide into the atmosphere, decarbonization can also provide other direct and indirect benefits. One is a reduction in other toxic emissions, including mercury from coal-powered electricity generating plants and the mix of various pollutants from automobiles, aircraft and other transportation vehicles.
Decarbonization is probably the most important reason for greatly reducing the use of petroleum, coal and natural gas. But another important reason is the huge amount of land and water pollution resulting from the disposal of plastics and other materials made from these fossil carbon sources. Many experts believe that such pollution is contributing to the mass extinction currently occurring and could become as much of a threat to the biosphere as climate change.
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* It can be argued that nuclear energy is not a low carbon power source because of the very large amount of energy from conventional power sources that is used to construct the nuclear power plants, particularly for producing the massive amounts of concrete and steel required, and then to dismantle them after their relatively sort life spans.