World energy consumption has been rising at a concerning rate since the mid 1970s. The reliance on oil presents a problem as this form of fuel runs out, the energy crisis worsens. Although rates of increase in energy use have been declining, the industrialization, agricultural development and rapidly growing populations of developing countries will need much more energy. However to bring the developing countries' energy use up to that of industrialized countries by the year 2025 would require an increase in the current global energy use by a factor of five. The planetary ecosystem could not stand this, especially if the increases were based on non-renewable fossil fuels. The current threats of global warming and acidification of the environment also tend to preclude even a doubling of energy use based on the present pattern of energy supply.