Renewability and sustainability are two critical factors that will decide the future course of the world. We have to learn from Nature how sun is able to sustain life on earth for millions of years without the slightest hitch. The sun provides light energy for the photosynthesis to generate Carbohydrate using carbon dioxide from the atmosphere and water. The green pigment in the leaves of the plant ‘Chlorophyll’ catalalyses the photosynthesis. The plant grows and serves as food for animals. After certain period both the plant and animal dies and becomes carbon. New plants and animals are produced and the cycle continues. The dead plant decays and serves as manure for the new plant. A sequence of combinations of atmosphere, photosynthesis, micronutrients in the soil, absorption of carbon dioxide from air and release of Oxygen into the atmosphere, food production, life sustainenace, death and decay play like a symphony in an orchestra. Microorganisms too play their role in this cycle.
It is obvious from the above process that life cycle is based on ‘Renewability’.The death and decay of the old plant gives way to the birth of new plant and new cycle. There is nothing static .It is a dynamic and cyclic process, where ‘Renewability’ is the key. Only with renewability the process can ‘sustain’. Without a cyclic nature, the process will end abruptly. In fact ‘renewability’ and ‘sustainability’ are closely linked.
When we try to develop a new source of energy it is absolutely critical that such a source is renewable and available directly from Nature. Sun is the prime source of such energy, though it is also available in other forms such as wind, wave, ocean thermal etc. Such renewability can come only from Nature because human life in intricately linked with Nature such as earth, sun and wind. Everything that happens in Nature is to support life on earth and not to destroy. This is a fundamental issue.
When we dig out Carbon from the earth that was deeply buried by Nature and burn them, we release Carbon dioxide as well as Oxide of Nirtogen.Though our primary interest is only heat, we also create by-products such as greenhouse gases that upset the natural equilibrium. Nature can make some adjustments in order to maintain equilibrium; but when this limit exceeds, the equilibrium is upset creating a new environment, which may be alien to human life. This is unsustainable. Nature does not burn organic matter indiscriminately to generate Carbon dioxide to promote photosynthesis. It judiciously and delicately uses atmospheric Carbon dioxide without the slightest disturbance to the equilibrium. Many chemical reactions are irreversible and can cause irreversible damages, similar to ‘radiation’ from a nuclear reaction.
Whatever we do in the name of science, we will have to face their consequences, if we fail to understand the process of Nature completely and thoroughly. Fossil fuel sources are limited and burning them away to meet our energy demands is neither prudent nor sustainable. Human greed has no limit. We live in a finite world with finite resources and there is no place for infinite greed and destruction. There is no solution in Science for human greed.