The production, distribution and use of energy create pressures on the environment in the household, workplace and city, and at the national, regional and global levels. Therefore, energy indicators are useful for evaluating impacts of energy systems in all these areas. Environmental ISED measure the impact of energy systems on the overall environment, and in particular the determination of positive or negative trends in land, water (fresh and marine), and air quality. Such environmental impacts vary depending upon how energy is produced and used, and on related energy regulatory actions and pricing structures. Gaseous emissions and particulates from the burning of fossil fuels pollute the atmosphere and cause poor local air quality and regional acidification. Large hydropower dams flood land and may cause silting of rivers. Both the fossil and nuclear fuel cycles, as well as geothermal production, emit some radiation and generate wastes of different levels of toxicity. Wind turbines can spoil a pristine countryside. And gathering firewood may lead to deforestation and desertification. Principal issues related to the environmental dimension include global climate change, air pollution, water pollution, wastes, land degradation and deforestation.