INTRODUCTION TO ENVIRONMENTAL STUDIES IMPORTANT NOTES

 

1. Components of Environment

Planet earth is the only known planet in the universe having diversity of life. As earlier mentioned, life could have been possible on the planet only because of the healthy interactions between biotic and abiotic components in such a manner where the flow of energy and biogeochemical cycle follow a well-defined path. The planet earth is categorized into different spheres which represent solid (rock/soil), liquid (water) and gaseous (air) phases. The overlapping zone of the three spheres, where life is available, is called the biosphere.

 

Lithosphere: Earth’s structure can be stratified into outer crust, middle mantle and inner core regions. Lithosphere is the outermost layer of the crust which represents the land mass of the planet. It consists of rocks, soil, sediments and minerals. Various geological structures or landforms like high mountains, plateau, deep valleys and sea beds make the surface of lithosphere uneven. Mount Everest is the highest point on the lithosphere. Various geological processes like weathering & erosion, volcanic eruptions, biogeochemical cycles take place at the lithosphere. Different terrestrial ecosystems like forests, grasslands, deserts etc. are found on the lithosphere.

 

 

Hydrosphere: Hydrosphere represents water masses on the planet present in solid (ice cover, glaciers etc.), liquid (water bodies) and gaseous (water vapours) phases. Hydrosphere covers almost three-fourth of the total surface area of the earth. Oceans and seas represent marine ecosystem which contains 97 percent of the total water content (having very high concentration of salts) of the planet. Remaining 3 percent of the water resources are freshwater present in the form of glaciers, rivers, lakes, ponds etc.

 

 

Atmosphere: The thin sheet of gaseous mixture which envelops the planet earth is called atmosphere. Content of water vapor, density of the air mass and atmospheric pressure decreases rapidly with the increase in altitude.

 Brief description of atmospheric layers is as follows

 

Troposphere: the altitude of this layer varies from 16 km at equator to 8 km at poles. Largest percentage of the air mass found in this region. The upper layer is called tropopause. Temperature decreases with increase in altitude (-6.4 C per km) in this layer and varies from 15 C (ground Level) to – 56 C (tropopause).

 

Stratosphere: Temperature starts rising in this layer from tropopause (-56 C) to stratopause (-2 C) as ozone (O3) layer in the upper stratosphere absorbs solar radiation and temperature rises. Ozone layer in this region absorbs harmful UV radiation, particularly UV-B radiation (280 nm to 315 nm), because of which life is possible on earth’s surface. However, the ozone layer is depleting at a fast pace due to the presence of ozone depleting substances (like chlorofluorocarbons- CFCs). Ozone holes are the places in the upper stratosphere where the concentration of ozone has depleted drastically.

 

Mesosphere: temperature starts decreasing again and reaches at -96 C at the upper boundary of the layer i.e., mesopause. Density of air is very low and important chemical species found in this region are O2 + and NO+ which do not absorb much solar radiation. This causes the decline in ambient temperature in this region.

 

Thermosphere: ionic oxygen atoms and other ions in this layer absorb short wave solar radiation which increases the temperature in this layer rapidly from -96 C (lower boundary) to 1200 C (upper layer).

 

Biosphere: This is the self-regulating overlapping region of atmosphere, lithosphere and hydrosphere in the environment where life sustainably exists, nourished and flourished by the healthy interaction between biotic (autotrophs and heterotrophs) and abiotic components (air, water, sunlight, soil, rock etc.) of the nature.

 

Environmental Education in India: India also started taking significant steps to propagate environmental education. At post-graduation level, the environmental education was started by many central and state universities in India during 1985-2000. In 1991, Hon. Supreme Court of India gave historical ruling to implement environmental education at all the levels and gave directions to make Environmental Studies a compulsory paper for all the streams at under-graduate levels in Indian universities. At present, various short-term and regular courses on environment and its various dimensions are being run in various universities in India.

 

Concept of Sustainability and Sustainable Development

 

It was the global perception that the environmental conservation and economic development cannot be pursued together. With the onset of 1980s, the world started finding the middle path so that the long-term economic development may be pursued without harming the environment. With this aim, the United Nations established World Commission on Environment and Development (WCED), under the chairmanship of Geo Harlem Brundtland (Former Prime Minister of Norway) in December 1983. Hence, this commission is commonly known as the Brundtland Commission. The task of the commission was to formulate “A global agenda for change”. Brundtland Commission submitted its report entitled “Our Common Future” in 1987 which gave the concept of Sustainable Development to the world. Report defines Sustainable Development as “development that meets the needs of the present without compromising the ability of future generations to meet their own needs.” Sustainable Development Goals (SDGs): these are the seventeen goals set as the ‘2030 agenda for sustainable development’. It was adopted by the United Nations state members in 2015 as ‘a blueprint for peace and prosperity for people and planet, now and into the future.’ All the developed and developing countries have been called to achieve the goals by global partnership.

 A brief description of the three pillars is given below:


Environmental Sustainability: it means that we should consume the environmental goods and services in a sustainable manner. Mahatma Gandhi, once rightly said “Earth provides enough to satisfy every man’s need but not everyone’s greed”. The present rate of over-exploitation of natural resources exceeds manifolds the rate of replenishment of the same, which is causing environmental degradation at an exponential rate. Therefore, the natural resources should be utilized sustainably. Sustainable Development Goals 6 (Clean Water and Sanitation), 7 (Affordable and Clean Energy), 13 (Climate Action), 14 (Life below Water) and 15 (Life on Land) indicates environmental sustainability.

 

Social Sustainability: it defines a society having fair and equal opportunities for its population with gender equality, good health and education facilities and people’s participation in nation building. Sustainable Development Goals 3 (Good Health and Well-Being), 4 (Quality Education), 5 (Gender Equality), 7 (Affordable and Clean Energy), 16 (Peace, Justice and strong Institutions) and 17 (Partnerships for the Goals) indicates social sustainability.

 

Economic Sustainability: economic sustainability means the equitable distribution of the resources. No one should be deprived of the basic needs to sustain a healthy life. Benefits should be earned from the resources but not at the cost of irreversible loss to the environment. Sustainable Development Goals 1( No Poverty), 2 ( Zero Hunger),7( Affordable and Clean Energy ), 8( Descent work and Economic Growth ).


Important Questions

1. Describe the various components of atmosphere.

2. Discuss Sustainable Development. Write a short note on Sustainable Development Goals.


Whatever subjects notes you want, please inform me in the comment box.

Post a Comment

0 Comments