Environmental impact of the energy industry to virtually all aspects of present society, especially for transportation and heating for both homes and for commercial activities. Natural gas is often described as the cleanest fossil fuel, producing less carbon dioxide per joule delivered than either coal or oil., and far fewer pollutants than other fossil fuels. However, in absolute terms it does contribute substantially to global carbon emissions, and this contribution is projected to grow. According to the IPCC Fourth Assessment Report, in 2004 natural gas produced about 5,300 Mt/yr of CO emissions, while coal and oil produced 10,600 and 10,200 respectively (Figure 4.4); but by 2030,
Unconventional oil about some of the chemicals mixing with ground water (either as runoff or through seeping). There are processes either in use or under development to help mitigate some of these environmental concerns. The conversion of coal or natural gas into oil generates large amounts of carbon dioxide in addition to all the impacts of gaining these resources to begin with. However, placing plants in key areas can reduce the effective emissions due to pumping the carbon dioxide into oil beds or coal beds to enhance the recovery of oil and methane. Carbon dioxide is a greenhouse gas, so the increased