Chapter 1: Environment

Environment:
A place around us includes people, children, benches, ground, grass, trees, insects, birds, sunlight,
air, land, water, mountain etc.
Biotic components constantly interact and exchange things with each other as well as with the
Abiotic components for their survival and existence.
The major areas in which the role of environmental scientists are of vital importance are natural
resources, ecosystems, biodiversity and its conservation, environmental pollution, social issues
and environment human population and environment.

Need of Environmental Studies:

➢ Environment Issues Being of International Importance.
➢ Problems Cropped in The Wake of Development.
➢ Explosively Increase in Pollution.
➢ Need for An Alternative Solution.

Environment: Environment means the surrounding external conditions influencing development

or growth of people, animal or plants; living or working conditions etc.
Biotic Components means living organism surrounding us like trees, birds, insects, animals,
humans, grass etc.
A-Biotic Components means non living things around us like air, water, land, sunlight, mountain,
river, ocean.

Various types of environment:

Environment

Atmosphere Biosphere

Lithosphere Hydrosphere

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Segments of Environment:
Atmosphere: The atmosphere implies the protective blanket of gases, surrounding the earth.
(a) It sustains life on the earth.
(b) It saves it from the hostile environment of outer space.
(c) It absorbs most of the cosmic rays from outer space and a major portion of the electromagnetic
radiation from the sun.
(d) It transmits only here ultraviolet, visible, near infrared radiation (300 to 2500 nm) and radio
waves. (0.14 to 40 m) while filtering out tissue-damaging ultra violate waves below about 300
nm.

Hydrosphere: The Hydrosphere comprises all types of water resources oceans, seas, lakes, rivers,
streams, reservoir, polar icecaps, glaciers, and ground water.
(i) Nature 97% of the earth’s water supply is in the oceans,
(ii) About 2% of the water resources is locked in the polar icecaps and glaciers.
(iii) Only about 1% is available as fresh surface water-rivers, lakes streams, and ground water fit
to be used for human consumption and other uses.

Lithosphere: Lithosphere is the outer mantle of the solid earth. It consists of minerals occurring
in the earth’s crusts and the soil e.g. minerals, organic matter, air and water.

Biosphere: Biosphere indicates the realm of living organisms and their interactions with
environment, viz atmosphere, hydrosphere and lithosphere. The atmosphere forms a protective
shell over the earth. The lowest layer, the troposphere, the only part warm enough for us to survive
in,is only 12 kilometres thick. The stratosphere is 50 kilometres thick and contains a layer of
sulphates which is important for the formation of rain. It also contains a layer of ozone,
which absorbs ultra-violet light known to cause cancer and without which, no life could exist
on earth. The atmosphere is not uniformly warmed by the sun. This leads to air flows and
variations in climate, temperature and rainfall in different parts of the earth.
The lithosphere began as a hot ball of matter which formed the earth about 4.6 billion years
ago. About 3.2 billion years ago, the earth cooled down considerably and a very special event took
place - life began on our planet. The crust of the earth is 6 or 7 kilometres thick and lies under the
continents.
The Biosphere is the relatively thin layer on the earth in which life can exist. Within it the air,
water, rocks and soil and the living creatures, form structural and functional ecological units, which
together can be considered as one giant global living system, that of our Earth itself.

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Key Definitions/ Formulas:

1. Natural (Physical Environment) :

The environment in its original form without the interference of human beings is known as
natural environment. Natural environment includes all living and nonliving things occurring
naturally on earth. It operates through self regulating mechanism called homeostasis i.e, any
change in the natural ecosystem brought about by natural processes is counter balanced by
changes in other components of environment. Natural environment often used as a synonym of
habitat.
Examples- Ecosystem and Biodiversity.
2. Man made or Anthropogenic Environment (Built Environment) :
The environment changed or modified by the interference of human beings is called man made
environment. Man is the most evolved creature on this earth. He is modifying the environment
according to his requirements without bothering for its consequences. Industrialization,
urbanization and population explosion are deteriorating the environment more and more
Examples- Infrastructure, Utilities, Institutions, housing, industries , parks, buildings, energy
networks, transportations, etc
3. Social Environment :
Social Environment includes an individual’s social, economic and political condition wherein
he lives. The moral, cultural and emotional forces influence the life and nature of individual
behaviour. (Customs, Traditions, ethics, Language, Culture, Professions, Living conditions etc).
The social environment refers to the immediate physical and social settings in which people live
and or in which something happens or develop. It includes the culture that the individual was
educated or lives in, and the people and institutions with whom they interact.
4. Psychological Environment:
Although physical and social environment are common to the individual in a specific situation.
Yet every individual has his own psychological environment, in which he lives. Kurt Lewin has
used the term ‘life space’ for explaining psychological environment. The Psychological
environment enables us to understand the personality of an individual. Both the person and his
goal form psychological environment.

Structure of Environment
Environment consists both physical and biological. It includes both living and non-living
components.
Physical Environment:
(i) Solid - The lithosphere (solid earth) - Mountain Environment
(ii) Liquid - The hydrosphere (water component) - Glacier Environment
(iii) Gas - The atmosphere - Plateau Environnent & Costal Environnent.

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Biological Environment :
(i) Plants (flora)
(ii) Animals (fauna)

Concept of 4Rs

► Reduce: Prevent generation of waste in the first place; by eliminating waste at source through
better planning and design. Don’t use a resource if there is an alternative. (Donate old things;
Take good care of your things; choose walking / cycling than driving; Use glassware than paper
wares).

► Reuse: Use a resource again and again without changing it or reprocessing it for different
functions than what they are intended. (Old news papers used for packing; Plastic and steel
containers used for plantation etc).

► Recycle: Reproduce / remanufacture the new material by using recyclable waste as raw
material in its parent industry. (Paper, Glass, Plastic, Metal, Rubber etc).

► Recover: Producing usable products or energy by processing / treating the waste. (biogas,
fertilizer, Waste to energy etc).

► Benefits of 4R’s – Reduce waste, Reduce pollution, Save energy, Save resources,
Improve economy, Create employment.

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Environmental Issues

GreenHouse Effect: Greenhouse effect is the process by which radiations from the sun are
absorbed by the greenhouse gases and not reflected back into space. This insulates the surface of
the earth and prevents it from freezing.
What is the Greenhouse Effect?
➢ A greenhouse is a house made of glass that can be used to grow plants. The sun’s radiations
warm the plants and the air inside the greenhouse. The heat trapped inside can’t escape out and
warms the greenhouse which is essential for the growth of the plants. Same is the case in the
earth’s atmosphere.
➢ During the day the sun heats up the earth’s atmosphere. At night, when the earth cools down
the heat is radiated back into the atmosphere. During this process, the heat is absorbed by the
greenhouse gases in the earth’s atmosphere. This is what makes the surface of the earth
warmer, that makes the survival of living beings on earth possible.
➢ However, due to the increased levels of greenhouse gases, the temperature of the earth has
increased considerably. This has led to several drastic effects.

Effects on animals:
It helps spread different types of diseases like malaria, filariasis, cholera, and diarrhea etc due to
rise in temperature.
It helps increase the number of vectors like insects transmitting diseases.
Effects on plants:
It affects water cycle, soil moisture and soil composition. As a result, there is a change in
cultivation and harvesting periods of crops.
Due to the effect of global warming, tropical plants are seen at the temperate region.
It also affects breeding, growth and development of disease causing insects.
Effects on climate:
It increases the temperature of earth.
It brings about the melting of ice in the Polar Regions, which increases the sea level due to which
the low land coastal areas may sink and go underwater.
It also changes the pattern of rainfall and weather conditions.
Global Warming is the warming of the earth through carbon dioxide (CO2) being pumped into
the atmosphere from tailpipes and smokestacks.
Then the gases trap heat like the glass in a greenhouse. This is where the term the “greenhouse
effect” came from.
Effects :
➢ Temperature increases
➢ Glaciers melt
➢ Rising ocean levels.
➢ Alter forests, crop yields.
➢ Affect human health.
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➢ Affect ecosystems.
➢ Season changes.
➢ The phenomenon of increasing the temperature of the earth as in artificial greenhouse gases is
called green house effect.

Environmental
Issues

Green House Effect Climate Change

Global Warming Acid rain

Ozone Layer Nuclear Accidents

Depletion
➢ The gases which are responsible for the greenhouse effect are called greenhouse gases.
➢ Environmental scientists estimated that the green house effect of carbon dioxide was 57%,
chlorofluorocarbon was 25%, methane was 12% and that of the oxides of nitrogen was 6%.

• GWP is the global warming impact that a GHG would have over a 10-year timeframe

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• By definition, CO2 is used as the reference benchmark.

Climate Change
➢ Climate is the average weather at a given point and time of year, over a long period (typically
30 years).
➢ We expect the weather to change a lot from day to day, but we expect the climate to remain
relatively constant.
➢ If the climate doesn’t remain constant, we call it climate change.

Acid Rains
Acid rain is basically rain that has a low pH.
➢ When fossil fuels such as coal, oil and natural gas are burned, chemicals like sulphur dioxide
and nitrogen oxides are produced.
➢ These chemicals react with water and other chemicals in the air to form sulfuric acid, nitric
acid and other harmful pollutants like sulfates and nitrates. These acid pollutants spread
upwards into the atmosphere, and finally return to the ground in the form of acid rain.
➢ Acid rain results when sulfur dioxide (SO2) and nitrogen oxides (NOX) are emitted into the
atmosphere and transported by wind and air currents. The SO2 and NOX react with water,
oxygen and other chemicals to form sulfuric and nitric acids. These then mix with water
and other materials before falling to the ground.

2SO2 (gas) + O2 (gas) + 2H2O (l) → 2H2SO4 (aqueous) - rain

4NO2 (gas) + O2 (gas) + 2H2O (l) → 4HNO3 (aqueous) - rain

Effects of acid rain

Acid rain is an extremely destructive form of pollution, and the environment suffers from its
effects. Buildings, Forests, trees, lakes, aquatic life, animals, and plants suffer from acid rain.

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Depletion of Ozone Layer

Troposphere:
➢ The lowest layer (about 15 km from the ground)
➢ Contains normal air composed of N2, O2, water vapour, CO2, etc.
➢ Temperature decreases with altitude.

Stratosphere:
➢ Above the troposphere
➢ Temperature increases with altitude
➢ Contains a lot of ozone (ozone layer):
➢ Found in the stratosphere between 10 - 50km above the ground .
➢ Protects us from the harmful effects of UV of certain wavelengths.
➢ Decrease in ozone concentration → Increase in UV-B radiation reaching the earth surface.

Chemical Reaction:
O2 + sunlight → O + O
O + O2 → O3
Impacts of ozone layer depletion
Destruction of ozone Layer:
Chlorine atoms from CFCs attack the ozone, taking away ozone and forming chlorine monoxide
(ClO).
O3 + Cl → O2 + ClO
Chlorine monoxide then combines with another oxygen atom to form a new oxygen molecule
and a chlorine atom.
ClO + O → Cl + O2
The chlorine atom is free to destroy up to 100,000 ozone molecules.
➢ Sunburn, eye diseases (cataract),
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➢ Reduce our immune system
➢ Skin Cancer
➢ Cataracts and Other Eye Damages
➢ Suppression of Immunity
➢ Reduce photosynthesis - crops affected.
➢ Reduce crop yield.
➢ Reduces plankton population
➢ Reduces penguin population
➢ Reduces the percentage of hatching of frog eggs
➢ Forming photochemical smog
➢ Degrades building materials

Nuclear Accidents
When safety measures and principles are ignored or are not properly observed by nuclear plant
operators, a nuclear accident can occurred with serious consequences for the environment, human
health and public opinion.
Impacts of Nuclear Accidents
► develop cancer
► deaths
► Species extinction
► DNA alter
► Residual radioactivity in environment (environmental pollution)
► High fever, diarrhoea, fatigue, mortality, infection bleeding etc.
► Skin diseases
► Disturb aquatic life

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