2. What is Environmental Science?
The study of how humans interact with their environment.
Our environment is everything that surrounds us, both
natural and man-made.
Environmental science is an interdisciplinary field that
includes both scientific and social aspects of human
impact on the world.
3. Environment: the total of our
• All the things around us with which we interact:
• Living things
Animals, plants, forests, fungi, etc.
• Nonliving things
Continents, oceans, clouds, soil, rocks
• Our built environment
Buildings, human-created living centers
• Social relationships and institutions
4. Components of Environment
The two major Components of environment are :
Biotic components: All living organisms around us viz. plants,
animals, and microorganisms
Abiotic components : Air, Water, and Land etc.
5. Natural resources: vital to human survival
• Renewable resources:
Perpetually available: sunlight, wind, wave energy
Renew themselves over short periods: timber, water, soil
These can be destroyed
• Nonrenewable resources: can be depleted
Oil, coal, minerals
6. Objectives of Environmental science:
According to UNESCO (1971), the objectives of environmental studies are:
(a) Creating the awareness about environmental problems among people.
(b) Imparting basic knowledge about the environment and its allied
(c) Developing an attitude of concern for the environment.
(d) Motivating public to participate in environment protection and
(e) Acquiring skills to help the concerned individuals in identifying and
solving environmental problems.
(f) Striving to attain harmony with Nature.
7. Scope of Environmental Studies:
Environmental Science: Environmental Engineering:
scientific study of environmental system
(air, water, soil and land), the inherent or
induced changes on organisms and the
environmental damages incurred as a
result of human interaction with the
the study of technical processes
involved in the protection of
environment from the potentially
deleterious effects of human
activity and improving the
environmental quality for the
health and well beings of
promotes due regard for
physical, social and economic
environment of the enterprise
or projects. It encourages
planned investment at the
start of the production chain
rather than forced investment
in cleaning up at the end
Environment impact assessment, economics of pollution,
prevention, environmental management standards
8. What are the challenges we face?
What are the environmental issues we are facing today?
12. We face challenges in agriculture
• Expanded food production led to
increased population and
• It’s one of humanity’s greatest
achievements, but at an enormous
• Nearly half of the planet’s land
surface is used for agriculture
• Chemical fertilizers
• Changed natural systems
13. We face challenges in climate
• Scientists have firmly concluded that humans are changing the composition of
• The Earth’s surface is warming
• Melting glaciers
• Rising sea levels
• Impacted wildlife and crops
• Increasingly destructive weather
Since the Industrial Revolution, atmospheric carbon dioxide
concentrations have risen by 37%, to the highest level in
15. We face challenges in biodiversity
• Human actions have driven many species extinct, and biodiversity is declining
Biodiversity loss may be our biggest environmental
problem; once a species is extinct, it is gone forever
18. Our energy choices will affect our future
• The lives we live today are due to fossil fuels
• Fossil fuels are a one-time bonanza;
supplies will certainly decline
We have used up ½ of the world’s oil
supplies; how will we handle this
imminent fossil fuel shortage?
19. Effect of agriculture on Environment
Grazing and agriculture: Oldest economic activities by
New methods of agriculture, new seed, new fertilizers–
Bring changes in natural environment
ILL EFFECTS OF FARMING:
Multiple cropping makes soil less productive
Over watering makes soil saline
Fertilizers usage: makes soil and water polluted
Pesticides usage: kills microorganisms in the soil
Extension in agriculture may cause deforestation
20. Housing and its impacts on Environment
1) Rural housing
No system for waste management
Poor sanitation facilities
Domestic animals (cows, buffalows) create unhealthy conditions
Drinking water often contaminated
2) Urban housing
Over crowding: puts pressure on land and natural resources
Slums(unauthorized settlements): disease-prone
More pollution because of industries
Dumping of solid waste a problem
21. Impact of Science and technology on
Invention of Engines and Automobiles
Efficient machines were made on the cost of environment
Cutting down the trees
Invention of concrete building of dams, and diversion of
rivers water for agriculture and power production
Chemical fertilizer and pesticides
Huge amount of ground water is extracted with pumps
22. Importance of Environmental Studies
Solving the issues related to environment
Over exploitation of non-renewable sources
Maintain the ecological balance
Eco friendly product
Conservation of natural sources
Understand the food chain
Inculcating attitude and value
Encouraging Environment protection
23. Components of Environment
Earth’s environment can be further subdivided into the
following four segments:
It is the gaseous envelope surrounding the earth and extends upto
500 kms above the earth’s surface.
Constituent Volume %
Water vapour 0.1–5
Carbon dioxide 0.03
Trace constituents* Balance
*The trace constituents include Helium, Neon, Krypton, xenon, SO2, NO2,
Ammonia, Ozone, and
Carbon monoxide etc.
The atmosphere, which is a gaseous cover, protects the earth
from cosmic radiations and provides life sustaining
Oxygen, the macronutrient Nitrogen and Carbon
dioxide needed for photosynthesis.
The atmosphere screens the dangerous UV radiations from the sun
and allows only radiations in the range of 300 nm – 2500 nm (near
UV to near IR) and radio waves.
The atmosphere plays a major role in maintaining the heat balance
of the earth by absorbing there-emitted radiation from the earth.
25. Five Layers of the Atmosphere
Troposphere : lowest layer – extends up to 10km; contains 99% of the water vapor and 75% of
the atmospheric gases
• The troposphere is the first layer above the surface and contains most clouds and half of the
• Weather occurs in this layer
Stratosphere – directly above troposphere, extending from 10 km to about 50 km above Earth’s
• Portion of the upper layer contains high levels of a gas called ozone
• Many jet aircrafts fly in the stratosphere because it is very stable. Also, the ozone layer absorbs
harmful rays from the Sun
Mesosphere – extends from the top of the stratosphere to about 85 km above Earth
• Coldest layer with little ozone
• Meteors or rock fragments burn up in the mesosphere.
• Ionosphere here – layer of charged particles
Thermosphere – thickest atmospheric layer found between 85 km and 500 km above Earth’s
• The thermosphere is a layer with auroras, known for its high temperatures.
Warms as it filters out X-rays and gamma rays from the Sun
Ionosphere here, too – help carry radio waves
Exosphere - The atmosphere merges into space in the extremely thin exosphere. This is the
upper limit of our atmosphere.
• Outer layer where space shuttle orbits.
The lithosphere is the solid, outer part of the Earth.
The lithosphere includes the brittle upper portion of the
mantle and the crust, the outermost layers of Earth's
A hydrosphere is the total amount of water on a
planet. The hydrosphere includes water that is
on the surface of the planet, underground, and in
the air. A planet's hydrosphere can be liquid,
vapor, or ice.
The biosphere is a global ecosystem composed of living
organisms (biota) and the abiotic (nonliving) factors from
which they derive energy and nutrients. Earth's
32. Environmental disasters : Case studies
1. Bhopal Gas Tragedy
A poisonous gas cloud escaped from the Union Carbide India Limited (UCIL) pesticide factory. The cloud
contained 15 metric tons of methyl isocyanate (MIC), covering an area of more than 30 square miles. This event
is now known as the worst industrial environmental disaster to ever have occurred.
Research showed that factory personnel neglected a number of safety procedures. There were no valves to
prevent water from entering the storage tanks.
33. On April 26, 1986 tests were conducted in nuclear reactor 4 of the Chernobyl nuclear power plant in
Ukraine. Errors in the reactor design and errors in judgment of the personnel of the power plant caused
cooling water to start boiling. This caused reactor stress, resulting in energy production increased to ten
times the normal level. Temperatures reached more than 2000 °C, causing fuel rod melting and further
cooling water boiling.
Radioactive particles released: plutonium, cesium, iodine, strontium
2.Chernobyl: Russian nuclear power plant explosion
34. 3. Oil spills
Many times occurred.
During Gulf War 1991,
Mumbai : In Arabic sea 2010
The gas leak killed at least 4.000 local residents instantly and caused health problems such as oedema for at least 50.000 to perhaps 500.000 people. These health problems killed around 15.000 more victims in the years that followed. Approximately 100.000 people still suffer from chronic disease consequential to gas exposure, today. Research conducted by the BBC in 2004 pointed out that this pollution still causes people to fall ill, and ten more die every year.