With modernization and industrialization our use of non-renewable resources has increased. Industrialization is not only at the point of exhausting the resources which are non renewable but has also added pollution to the system with the use of these resources. But once these non-renewable resources are exhausted we will not be left with any more.
What is Non-Renewable Resource?
A non-renewable resource is a natural resource that cannot replenish itself on any time scale relevant to us. It is available in a limited quantity and we are using it up faster than nature can replenish. As these resources are not renewable they are not sustainable. They are also environmentally damaging. Yet right now, our entire society and economy are based on nonrenewable resources, particularly fossil fuels.
Fossil fuels are primarily used for fuel though virtually every product in our day-to-day use is made from substances derived from fossil fuels or utilizes fossil fuels in its manufacture or transportation. Some of the common items made from fossil fuels are detergents, synthetic fibers (nylon, polyester, acrylic), plastics, paints, garden hoses, food additives, cleaning products, pesticides, nail polish, lipstick, shampoo etc.
Metals are also non-renewable and with use it is also getting depleted. If this continues, soon it may neither be economically viable nor environmentally feasible to mine the lowest grade ores. Mining these ores requires more fossil fuels and creates more waste in mining. Mining, by its nature is a highly complicated, expensive, extremely energy-intensive, and highly technical task.
Fossil fuels were formed from prehistoric plants and animals that lived hundreds of millions of years ago. When they died they decomposed and remained buried under several layers of mud, rock, and sand. In some areas, the ancient seas which covered them later dried up and receded.
The dead plants and animals decomposed into organic materials over millions of years and formed fossil fuels. There are different types of fossil fuels and their formation depends on the nature of combination of animal and plant debris, duration of burial, and the conditions of temperature and pressure under which they decomposed. Visit here for details on the Geological Age  which created the fossil fuels
Oil and natural gas
Oil and natural gas are formed from tiny decayed plants, algae, and bacteria. Millions of years ago microscopic plants and animals which died in the sea slowly sank and got covered by layers of mud. With increased pressure from the mud the organic matter got cooked. In most areas, thick liquid called oil formed first, but in deeper, hot regions underground, the cooking process continued until natural gas was formed. Over time, some of this oil and natural gas began working its way upward through the earth's crust until they ran into dense rock formations which prevented them from seeping to the surface. It is from under these formations that most oil and natural gas is produced today.
When gas and oil burn they produce mainly carbon dioxide and water, releasing the energy they contain. Crude oil is a mixture of different chemicals and is usually separated out into fuels such as petrol, paraffin, kerosene and heavy fuel oils. Natural gas produces carbon dioxide, which is a greenhouse gas.
These sources of energy are relatively cheap and most are easy to get and can be used to generate electricity. The oil-based fuels provide less energy per kilogram than natural gas. See an animation. How a Combined Cycle Gas Turbine (CCGT) power station works  . Click on the tabs to find out more
Coal is formed from 300 to 400 million-year old dead remains of trees, ferns and other plants called peats. Over the years layers and layers of peat were formed. Once the seas dried up and receded, heat and pressure from the rocks converted peat into coal. Carbon is the most important element in the plant material. This gives coal most of its energy. In some areas coal was formed from swamps covered by sea water. The sea water contained a large quantity of sulfur, and as the seas dried up, the sulfur was left behind in the coal. Efforts are on today to remove sulfur from coal because sulfur can cause air pollution. There is, however very little sulfur content in coal deposits formed from freshwater swamps. See an animation How a coal-fired power station works  . Click on the tabs to find out more about coal energy
Coal is black solid and is soft enough to be carved into shapes. There are different types of coal. Some contain impurities, such as sulfur, that pollute the atmosphere further when they burn, contributing to acid rain. Coal can be found in parts of the world that were once covered with swampy forests, such as the UK about 250 million years ago. There are large deposits in China, USA, Europe and Russia. South Africa also has relatively large deposits.
When coal burns it produces mainly carbon dioxide, some carbon monoxide and soot (which are unburned carbon). Many coals when burned produce smoky flames. Their energy content weight for weight is not as great as oil. When coal burns it produces more carbon dioxide than oil.