The increasing demand for oil products is leading to supply difficulties as the older larger fields are being replaced by smaller fields from which the oil is difficult to extract. Oil is expected to peak within 5 years and gas within 15 years.

Source: The association for the study of peak oil and gas-www.peakoil.net

Moreover rising living standards in all parts of the world and higher mobility have led to demands of fossil fuel which is not sustainable. As oil and gas supply about 60% of our energy needs, these impending peaks will affect the options for generating electricity as well as the options for heating our homes.

Nuclear energy may play a role in future energy supplies but it is not able to replace fossil fuels as sources of energy. It too suffers from resource constraints as its abundance in the earth's crust is very low. Fusion energy has yet to be demonstrated on a commercial scale and like nuclear energy cannot serve as a replacement for fossil fuels.

The only sustainable solution is to use less energy, to use that energy more efficiently and to replace fossil fuels by renewable energy sources wherever possible.

Carbon cycle	Greenhouse gas and global warming
Economics of sustainable energy use	Further advice