Environmental Science
By Subroto Kumar Saha
Reviewed by Shishir Reza
Global environmental and climatic insurgencies are uprising day by day where people and nature are innocent victims. On the basis of the global and national environmental thoughts, Subroto Kumar Saha published a book on Environmental Science from Bangla Academy in 2007.
The book deals with elements of environment, importance of nature, elements of earth, structure of biosphere, lithosphere and hydrosphere; life and genesis and growth; ecology, food chain and carbon cycles; energy and environment, human ecology, population-environment nexus; soil erosion, natural disasters, environmental pollution, global environmental movements, green house impacts, environmental laws and policies, as well as population-development nexus.
The author analyses the elements of atmosphere nitrogen (78.08 percent), oxygen (20.94 percent), argon (0.93 percent), carbon dioxide (0.03 percent) and water (0.025 percent). This environmental philosophy based work also sheds light on the theory of special creation, theory of spontaneous generation, theory of catastrophism, cosmozoa theory and biological origin of life.
In general, economic pursuits of human beings are dependent on the natural environment, as nature is the provider of raw materials for the production of different goods. Nature provides us with two types of resources: material resources _ mineral and fossilized energy which is extracted from the natural state at some cost to the economic agent who is involved in the extraction; and environmental resources _ clean air, water, rivers, natural beauty, oceans _ the use of which does not involve any payment as there is no market for them.
Besides, nature works as a waste assimilator as wastes are discharged into the environment without anybody having to pay for it. On the other hand, modern technology increases the use of resources and also enables us to affect the environment in many ways. Before the invention of CFCs (chlorofluorocarbons), used as propellants in spray cans and as coolants in refrigerators and air conditions, we were not causing depletion of the atmosphere.
Let us consider the use of energy resources, such as coal, in the generation of power. The combustion of coal produces heat that generates power, while wastes such as carbon dioxide is released into the atmosphere and solid wastes are disposed off on land. The environment has the capability of transforming some of these wastes into useful products, for example, trees convert carbon dioxide into carbohydrates through photosynthesis. The wastes can also be rendered harmless through biogeochemical processes. These reflect the waste assimilative capacity of the environment. As a result, economic activities do not overload the assimilative capacity of the environment. However, when too many wastes are discharged into a specific environment, it cannot assimilate all of it and there is environmental pollution. Pollution induces the negative externality, which is unsustainable to society, economy and the environment.
In his book, Saha clarifies climatic factors heat, light, water, air, carbon dioxide, gaseous elements; biotic factors animals, micro-organisms, plants; edaphic factors water in soil, air in soil, temperature; and topographic factors height, light, sun, air.
Besides, the author mentions that environmental resources depend on utility, functionability, demand, accessibility, obsolescence and eco-friendliness.
This book is useful for modern times as we are going through environment and development conflicts. People need better understanding of nature-based philosophy, environmental sustainability and forest ecosystems. As we want to create a green and economic equity based society, we have to realize the nexus between development and the environment.
This book would be helpful for students of environmental science, teachers and researchers, as well as activists who want to shape a sustainable world. n
The writer is an environmental analyst.
