Nearly 86% of the world’s energy is supplied by the combustion of fossil fuel. While the processes by which the energy of this fuel is made available for human use in the form of heat or mechanical power are circumscribed by the principles of thermodynamics.
Among fossil energy resources, coal appears to be available in abundance for at least two to three centuries, while the fluid fossil fuels, petroleum and natural gas, may last for less than a century. The availability of fluid fuel resources can be extended by manufacturing them from coal by coal gasification and liquefaction. (The manufactured fluid fuels are called synfuels.) Fluid fuels can also be obtained from unconventional resources, such as oil shale, tar sands, geopressurized methane, coal seam methane, and methane hydrates lying on the bottom of the oceans and under the
icecaps. The manufacture of synfuels and the exploitation of unconventional fossil fuel resources will be more expensive than the exploitation of proven reserves, and the manufacturing and recovery processes will entail more severe environmental effects than those associated with exploitation of conventional reserves
Mitigating the adverse environmental effects of energy use has been a chronic problem afflicting nations worldwide, because national economies do not automatically respond to limit environmental degradation.
The reduction of emissions of carbon dioxide is a problem of a different kind and magnitude than reducing emissions of the other GHG pollutants. Eighty-eight percent of the world’s primary energy sources and 63% of electricity generation comes from fossil fuels. Reducing CO2 emissions to the atmosphere simply means lowering the rate of consumption of fossil fuels. Burning less fossil fuels or replacing them by other energy sources would involve a radical change in our energy supply structure.
In conclusion, while urban and regional environmental pollution is still a major problem, especially in developing nations, the experience in industrialized nations has shown that it is technically and economically solvable and politically manageable on the time scale of several decades. It remains to be seen whether the much greater problem of global warming can be solved with comparable measures sustained over the next centuries.
