Unit 3: Natural Resources

Dr. Urvashi Sanwal

Rajdhani College
University of Delhi

1. A natural resource may be defined as any material given to us by nature lke air, water, food,
land, coal, oil crops, wood etc.

2. On basis of presence or absence of life:

i. Biotic

ii. Abiotic

3. On basis of generation:

i. Non- renewable

ii. Renewable

a) Exhaustible

b) Inexhaustible

Energy Resource
1. Renewable Resources which can be generated continuously in nature and are inexhaustible e.g.
wood, solar energy, wind energy, tidal energy, hydropower, biomass energy, bio-fuels, geo-
thermal energy and hydrogen. They are also known as non conventional sources of energy and
they can be used again and again in an endless manner.

2. Non-renewable Resources which have accumulated in nature over a long span of time and
cannot be quickly replenished when exhausted e.g. coal, petroleum, natural gas and nuclear
fuels like uranium and thorium. They are also known as conventional sources of energy.

3. Coal is the most abundant fossil fuel in the world but causes pollution and global warming on
burning.

4. It was formed 255-350 million years ago in the hot, damp regions of the earth during the
carboniferous age. The ancient plants along the banks of rivers and swamps were buried after
 death into the soil and due to the heat and pressure gradually got converted into peat and coal
over millions of years of time.

5. There are mainly three types of coal:

1. Anthracite coal (hard coal) has maximum carbon (90%)

2. Bituminous (soft coal) has 80% carbon

3. Lignite (brown coal) has 70% carbon and

4. Peat contains 60% carbon.

6. At the present rate of usage, the coal reserves are likely to last for about 200 years and if its use
increases by 2% per year, then it will last for another 65 years.

7. PETROLEUM: is lifeline of global economy and is a mineral oil formed over millions of years by
animals and plants buried between sedimentary rocks. About 1/4th of the oil reserves are in
Saudi Arabia.

8. At the present rate of usage, the world's crude oil reserves are estimated to get exhausted in
just 40 years.

9. Crude petroleum is a complex mixture so it has to be purified and refined by the process of
fractional distillation, during which process different constituents separate out at different
temperatures.

10. We get a large variety of products from this; petroleum gas, kerosene, petrol, diesel, fuel oil,
lubricating oil, paraffin wax, asphalt, plastic etc.

11. Petroleum is a cleaner fuel as compared to coal as it burns completely and leaves no residue. It
is also easier to transport and use. That is the reason why petroleum is preferred amongst all
the fossil fuels.
Liquefied petroleum gas (LPG):

1. The main component of petroleum is butane, the other being propane and ethane.

2. The petroleum gas is easily converted to liquid form under pressure as LPG.

3. It is odourless, but the LPG in our domestic gas cylinders gives a foul smell, due to ethyl
mercaptan, a foul smelling gas, added to LPG so that any leakage of LPG from the cylinder can
be detected instantaneously.

4. Oil fields in India are located at Digboi (Assam), Gujarat Plains and Bombay High, offshore areas
in deltaic coasts of Gadavari, Krishna, Kaveri and Mahanadi.

5. Global reserve: USSAR, Saudi Arabia, UAE, Iran, Qutar, USA, Kuwait.

NATURAL GAS : It is mainly composed of methane (95%) with small amounts of propane and
ethane.

1. It is a fossil fuel. Natural gas deposits mostly accompany oil deposits because it has been
formed by decomposing remains of dead animals and plants buried under the earth.

2. Natural gas is the cleanest fossil fuel and burns without any smoke
3. It can be easily transported through pipelines.

4. Russia has maximum reserves (40%), followed by Iran (14%) and USA (7%).

5. Natural gas reserves are found in association with all the oil fields in India. Some new gas fields
have been found in Tripura, Jaisalmer, Off-shore area of Mumbai and the Krishna Godavari
Delta.

6. Natural gas is used as a domestic and industrial fuel. It is used as a fuel in thermal power plants
for generating electricity. It is used as a source of hydrogen gas in fertilizer industry and as a
source of carbon in tyre industry.

Non conventional / Alternate sources of energy

1. Nuclear fission reaction, the nucleus of a heavy radioactive element like uranium, plutonium or
thorium splits up into smaller nuclei, when bombarded by low energy neutrons. A huge amount
of heat is generated in this process, which is used in nuclear power plants to generate
electricity.

2. A neutron strikes an atom of U235. It absorbs the neutron and becomes an unstable atom of U-
236
. It then undergoes fission. These neutrons can strike other U-235 atoms to initiate their
fission.
3. Uranium-235 nuclei are most commonly used in nuclear reactors.

4. Nuclear fusion reaction involves the combination or fusion of two light elements to form a
heavier element and release uncontrollable energy. Thus it cannot be used to generate
electricity, unlike fission reaction. Sun’s energy is generated by nuclear fusion reaction. The heat
and light that we get from Sun, is all due to the continuous reactions going on inside it.

5. Here two isotopes of a light element are forced together at extremely high temperatures (100
million °C) until they fuse to form a heavier nucleus releasing enormous energy in the process. It
is difficult to initiate the process but it releases more energy than nuclear fission.

6. Solar energy: Sun is the ultimate source of energy, directly or indirectly for all other forms of
energy. The nuclear fusion reactions occurring inside the sun release enormous quantities of
energy in the form of heat and light. Some important solar energy harvesting devices :
1. WIND ENERGY The high speed winds have a lot of energy in them as kinetic energy. The driving
force of the winds is the sun. The wind energy is harnessed by using wind mills. The blades of
the wind mill keep on rotating continuously due to the force of the striking wind. Which drives a
number of machines like water pumps, flour mills and electric generators.
2. A large number of wind mills are installed in clusters called wind farms, which feed power to the
utility grid and produce a large amount of electricity. These farms are ideally located in coastal
regions, open grasslands or hilly regions. The minimum wind speed required for satisfactory
working of a wind generator is 15 km/hr.

1. HYDRO POWER The water flowing in a river is collected by constructing a big dam where the
water is stored and allowed to fall from a height. The blades of the turbine located at the
bottom of the dam move with the fast moving water which in turn rotate the generator and
produces electricity.

2. Minimum height of the water falls should be 10 meters.

3. Hydropower does not cause any pollution, it is renewable and normally the hydro power
projects are multi-purpose projects helping in controlling floods, used for irrigation, navigation
etc.

4. However, big dams are often associated with a number of environmental impacts.
1. Tidal power or TIDAL ENERGY, is a form of hydropower which converts the kinetic energy of
tides into electricity. Tides are the waves caused due to gravitational pull of the moon and sun.
The high tide and low tide refer to the rise and fall of water in the oceans.

2. A difference of several meters is required between the height of high and low tide to spin the
turbines. The tidal energy can be harnessed by constructing a tidal barrage.

3. During high tide, the sea-water flows into the reservoir of the barrage and turns the turbine,
which in turn produces electricity by rotating the generators. During low tide, when the sea-
level is low, the sea water stored in the barrage reservoir flows out into the sea and again turns
the turbines.
 The energy available due to the difference in temperature of water at the surface of the
tropical oceans and at deeper levels is called Ocean Thermal Energy.

1. A difference of 20°C or more is required between surface water and deeper water of ocean for
operating OTEC (Ocean Thermal Energy Conversion) power plants.

2. The warm surface water of ocean is used to boil a liquid like ammonia. The high pressure
vapours of the liquid formed by boiling are then used to turn the turbine of a generator and
produce electricity.

3. The colder water from the deeper oceans is pumped to cool and condense the vapours into
liquid. Thus the process keeps on going continuously for 24 hours a day.
1. The energy harnessed from the hot rocks present inside the earth is called geothermal energy.
High temperature, high pressure steam fields exist below the earth's surface in many places.

2. This heat comes from the fission of radioactive material naturally present in the rocks. In some
places, the steam or the hot water comes out of the ground naturally through cracks in
the form of natural geysers as in Manikaran, Kullu and Sohana, Haryana.

BIOMASS ENERGY Energy from the sun is transferred and stored in plants in the form of chemical
energy. When the plants are cut or die, wood chips, straw and other plant matter is delivered to
biogas plant. When biomass is burnt, it releases energy in the form of heat.

1. Energy plantations

2. Petro crops

3. Agricultural and urban waste biomass

 1. Biogas is a mixture of methane, carbon dioxide, hydrogen and hydrogen sulphide, the major
constituent being methane. Biogas is produced by anaerobic degradation of animal wastes
(sometimes plant wastes) in the presence of water. Anaerobic degradation means break down
of organic matter by bacteria in the absence of oxygen.

2. Biogas is a non-polluting, clean and low cost fuel which is very useful for rural areas where a lot
of animal waste and agricultural waste are available. India has the largest cattle population in
the world (240 million) and has tremendous potential for biogas production.

3. Biogas has the following main advantages :

a) It is clean, nonpolluting and cheap.

b) There is direct supply of gas from the plant and there is no storage problem.

c) The sludge left over is a rich fertilizer containing bacterial biomass with most of the
nutrients preserved as such.

d) Air-tight digestion/degradation of the animal wastes is safe as it eliminates health

hazards which normally occur in case of direct use of dung due to direct exposure to
fecal pathogens and parasites.

BIOFEUL: Biomass can be fermented to alcohols like ethanol and methanol which can be used as fuels.
Biofuel is the fuel which is produced from organic products and wastes. The common commercially
used biofuels are bioethanol, biodiesel and biomethane.

• Bioethanol is made from sugar, algae, wheat and sugar beet.

• Biodiesel is made from vegetable oil, algal lipids, animal fats .

• Biomethane can be produced from waste organic material, sewage, agriculture waste and
domestic wastes.

Hydrogen is a clean fuel.

Hydrogen burns in air, it combines with oxygen to form water and a large amount of energy is
released.

Hydrogen can serve as an excellent fuel. It is non-polluting and can be easily produced.

Hydrogen is highly inflammable and explosive in nature. Hence, safe handling is required for using
H2 as a fuel.

It is difficult to store and transport, also being very light, it would have to be stored in bulk.

Presently, H2 is used in the form of liquid hydrogen as a fuel in spaceships.

 Land Resource
Land is a natural resource and supports each and everything. For example natural vegetation, wildlife,
human life, economic activities, transport and communication systems. India has land under a variety of
relief features, namely; mountains, plateaus, plains, islands and many more. Land is a scarce resource,
whose supply is fixed for all practical purposes. At the same time, the demand for land for various
competing purposes is continuously increasing with the increase in human population and economic
growth

The usage of land is determined by :

1. Physical factors: It is dependent on nature variants such as topography, climate, soil types

2. Human factors: It completely relies on human activities and usage such as population density,
technological capability and culture and traditions etc.

The available land is classified into two parts on the basis of its use, viz.

1. agricultural land and

2. non-agricultural land.

The change in the characteristic and quality of soil which adversely affect its fertility is called as Land
Degradation.

Land degradation means:

1. Loss of natural fertility of soil because of loss of nutrients.

2. Less vegetation cover

3. Changes in the characteristic of soil.

4. Pollution of water resources from the contamination of soil through which water sweeps into
ground or runoff to the water bodies.

Causes:

a) Deforestation
b) Overgrazing
c) Agricultural practices
d) Industrialization
e) Urbanization

Prevention and control measures

a) Strip farming
Crop rotation

b) Crop rotation
 c.

d. Construction of dams

e. Grazing
 Prevention of soil erosion
1. Conservational till farming

2. . Contour farming
3. . Terracing

4. Strip cropping:
5. Alley cropping
6. . Wind breaks or shelterbelts
Causes of Desertification: Formation of deserts may take place due to natural phenomena like
climate change or may be due to abusive use of land. Even the climate change is linked in many
ways to human activities. The major anthropogenic activities responsible for desertification are as
follows:

1. Deforestation: The process of degrading aforested land initiates a desert producing cycle that
feeds on itself. Since there is no vegetation to hold back the surface run-off, water drains off
quickly before it can soak into the soil to nourish the plants or to replenish the groundwater.
This increases soil erosion, loss of fertility and loss of water.

2. Overgrazing: The regions most seriously affected by desertification are the cattle producing
areas of the world because increasing cattle population heavily graze in grasslands or forests
and as a result denude the land area. When the earth is denuded, the microclimate near the
ground becomes inhospitable to seed germination. The dry barren land becomes loose and
more prone to soil erosion. The top fertile layer is also lost and thus plant growth is badly
hampered in such soils.

3. Mining and quarrying: Responsible for loss of vegetation cover and denudation of extensive
land areas leading to desertification.

Deserts are found to occur in the arid and semi-arid areas of all the continents . During the last 50
years about 900 million hectares of land have undergone desertification over the world. It is
further estimated that if desertification continues at the present rate, then by 2010, it will affect
such lands which are presently occupied by 20% of the human population. Amongst the most badly
affected areas are the sub Saharan Africa, the Middle East, Western Asia, parts of Central and South
America, Australia and the Western half of the United States
Water Resource
• A layer of sediment or rock that is highly permeable and contains water is called an aquifer.

• Unconfined aquifers which are overlaid by permeable earth materials and they are recharged
by water seeping down from above in the form of rainfall and snow melt.

• Confined aquifers which are sand witched between two impermeable layers of rock or
sediments and are recharged only in those areas where the aquifer intersects the land surface.

• Effects of Groundwater Usage

• Subsidence: When groundwater withdrawal is more than its recharge rate, the sediments in the
aquifer get compacted, a phenomenon known as ground subsidence. Huge economic losses may
occur due to this phenomenon because it results in the sinking of overlying land surface
causing structural damage in buildings, fracture in pipes, reversing the flow of sewers and canals
and tidal flooding.

• Lowering of water table: Mining of groundwater is done in arid and semi-arid regions for
irrigating crop fields but it is not advisable to do excessive mining as it would cause a sharp
decline in future agricultural production, due to lowering of water table.

• Water logging: When excessive irrigation is done with brackish water it raises the water table
gradually leading to water-logging and salinity problems.

Surface Water

1. The water coming through precipitation (rainfall, snow) when does not percolate down into the
ground or does not return to the atmosphere as evaporation or transpiration loss, assumes the
form of streams, lakes, ponds, wetlands or artificial reservoirs known as surface water.

2. The surface water is largely used for irrigation, industrial use, public water supply, navigation
etc.

3. A country's economy is largely dependent upon its rivers.

Due to heavy rains or sudden snow melt the quantity of water in streams exceeds their capacity and
water overflows the banks and causes inundation of the surrounding land. This situation is called
flood.

1. A flood causes a great economic loss and health related problems due to widespread
contamination.

2. Virtually anything the flood water touches gets contaminated, posing serious threat to health
due to outbreak of epidemics.

3. Human activities have been the main causes for increasing the severity and frequency of floods.
Construction of roads, parking space and buildings that cover the earth's surface hardly allows
infiltration of water into the soil and speeds up the runoff, clearing of forests for agriculture .

4. Flood plains, the low lying areas which get inundated during floods help to reduce floods.
Building up of flood control structures like flood walls or deepening of river channels have only
transferred the problems downstream. Building walls prevents spilling out the flood water over
flood plains, but it increases the velocity of water to affect the areas downstream with greater
force.

5. 5. To check the floods, efforts need to be made to restore wetlands, replace ground cover on
water-courses, build check-dams on small streams, move buildings off the flood plains etc.
Instead of raising buildings on flood plains, it should be used for wildlife habitat, parks,
recreational areas and other uses, which are not susceptible to flood damage. River-networking
in the country is also being proposed to deal with the flood problem.