Natural Resources

NATURAL RESOURCES

NATURAL RESOURCES

Renewable Resources Inexhaustible Can be regeneratede.g., Forests,

Wildlife,Wind Energy,Bio-mass

Energy,Tidal Energy,Hydro Power…

Non-renewable Resources Limited Cannot be regeneratede.g., Fossil Fuels like

Coal, Petroleum…Minerals…

Rate of Consumption > Rate of Regeneration

MAJOR NATURAL RESOURCES

Forest Resources Water Resources Mineral Resources Food Resources Energy Resources Land Resources

FOREST RESOURCES

FOREST RESOURCES

Covers earth like a green blanket… Produce innumerable goods… Provides several environmental services… 1/3rd of the world’s land area is forested. Former USSR – 1/5th

Brazil – 1/7th

Canada – 6-7%

USA – 6-7%

USES OF FORESTSCommercial Uses

Timber Fire wood Pulp Wood Food items Gum Resins Non-edible Oils

Rubber Fibers Lac Bamboo Canes Fodder Medicines…

–––

USES OF FORESTS

Ecological Uses Production of Oxygen Reducing of Global Warming Wild Life Habitat Regulation of Hydrological Cycle Soil Conservation Pollution Moderators

OVER EXPLOITATION OF FORESTS & DEFORESTATION Increased Population Increased

requirements. Total forest area in 1900 – 7000 mha

1970 – 2890 mha

2000 – 2000 mha Deforestation rate is less in temperate

countries compared to tropical countries (40-50%).

CAUSES OF DEFORESTATION Shifting Cultivation

300 million people living as shifting cultivators. 5 lakh ha of forests cleared annually.

Fuel Requirements Increase in fuel wood requirement

o 1945 – 65 million tonso 2001 – 300-500 million tons

Raw Materials for Industrial Use wood for making boxes, furniture, railway sleepers, plywood… Pulp for paper industry.

Development Projects Hydroelectric power projects, Big dams, Roads, Mining…

Growing Food Needs Creation of agricultural land and settlements by clearing forests.

Overgrazing

CONSEQUENCES OF DEFORESTATION It threatens the existence of many wild

life species due to destruction of their natural habitat.

Biodiversity is lost and along with that genetic diversity is eroded.

Hydrological cycle gets affected, thereby influencing rainfalls.

Problems of soil erosion and loss of soil fertility increases.

In hilly areas it often leads to landslides.

CASE STUDY 1 Desertification of Hilly regions of the

iHimalayasDeforestation in Himalayas, involving clearance of

natural forests and plantations of monocultures like Pinus Roxbhurgi, Eucalyptus Camadulenses etc. have upset the ecosystem by changing the various soil and biological properties. Nutrient cycling has become poor, original germplasm is lost and the area is invaded by exotic weeds. These areas are not able to recover and are losing their fertility. The entire west Khasi hill district of Meghalaya in North-East Himalayas, Ladakh and Parts of Kumaon and Garhwal are now facing the serious problem of desertification.

CASE STUDY 2 Disappearing Tea gardens in Chhota Nagpur

This hilly region used to be a good forested area towards the turn of century and used to receive fairly frequent afternoon showers favouring tea plantations. Following the destruction of forests, rainfall declined in chhota Nagpur to such an extent that tea gardens also disappeared from the region.

CASE STUDY 3Waning rainfall in Udhagamandalam (Ooty)

The sub normal rainfall during 1965-1984 at Ooty in Nilgiri Mountains has been found to be closely associated with declining forest cover in this region in the past 20 years. The rainfall pattern was found to fluctuate with wooded land area in the hills. When the NIlgiri mountains had luxuriant forest cover annual rainfall used to be much higher.

MAJOR ACTIITIES IN FORESTS

Timber Extraction Mining

Effects of Timber Extraction poor logging results in degraded forests. soil erosion, especially on slopes. sedimentation of irrigation systems. loss biodiversity. climatic changes, such as lower precipitation. new logging roads permit shifting cultivators

and fuel wood gatherers to gain access to logged areas.

loss of non-timber products

WATER RESOURCES

WORLD WATER DISTRIBUTIONLocation Volume in

million cubic km

% of Total

Land Area

Fresh water Lakes

Saline lakes and inland seas

Rivers

Soil moisture

Ground water

Glaciers and ice caps

0.125

0.104

1.25 × 10-3

0.067

8.3

29.2

0.009

0.008

0.0001

0.005

0.61

2.14

Total land are water

Atmosphere

Oceans

37.0

0.013

1320

2.8

0.001

97.3

Total world water 1360 100

WATER USE AND OVER EXPLOITATION

Increased Human Population + Rapid Development → Increased water withdrawal demands + Wastage due to Pollution (anthropogenic activities)

Globally, 70% of water withdrawn is used for agriculture

India – 93% water for agriculture sector Water Poor Countries – 4% for watering crops

Global Industrial Usage – 25% Developed Countries – 70% Less Developed Countries – 5%

Per Capita Usage of water - wide variations In USA an average family of 4 members consumes 1000M 3 of

water every year.`

Ground Water vs Surface Water Ground Water – Aquifers

A layer of sediment or rock that is highly permeable and contains water is called as an aquifer.

Unconfined Aquifer – overlaid by permeable and is rechargeable

Confined Aquifer – sandwiched between two impermeable layers of rock or sediments, recharged only where aquifers intersects with the land

Surface Water – Streams, ponds, lakes…

Effects of Ground water Usage

Subsidence when ground water withdrawal is more than its

recharge rate the sediments get compacted Results - Sinking of overlying land surface

- Structural damage to buildings

- Reversing the flow of sewers and canals

Lowering of Water Table

Water Logging

Sustainable Water Management Building several small reservoirs instead of a

few mega projects Developing small catchment dams and

protecting wet lands Soil Management, and afforestation permits

recharging of underground aquifers, thus reducing the need for big dams

Treating and recycling municipal waste water for agricultural use

Preventing leakages from dams and canals Preventing loss in municipal pipes

Effective rain water harvesting in urban environment

Water conservation measures in agriculture, such as using drip irrigation

Implementing methods to retain moisture and re-vegetate the degraded areas

MINERAL RESOURCES

Mineral Resources

Minerals – Naturally occurring, inorganic, crystalline solids having definite chemical composition and characteristic physical properties

e.g., Quartz, Feldspar, Biotite, Dolomite, Calcite, Leterite…

Composed of elements like silicon, oxygen iron, magnesium, calcium, aluminum…

Uses and ExploitationDevelopment of industrial plants and machineryGeneration of energy – Coal, Liginite, UraniumConstruction, Housing and other SettlementsTransportation meansCommunication – Telephone wires, cables,Electronic devices Medicinal usesFormation of alloysAgriculture – as fertilizers, seed dressings,

fungicides…Jewellery

MINERALS

Non-Metallic Minerals

graphite, diamond, quartz, feldspar…

Metallic Minerals

Bauxite, Laterite, Hematite…Critical Minerals – essential for the economy of

a nation e.g., iron, aluminum, copper, gold…Strategic Minerals – required for the defence of

the country e.g., Manganese, Cobalt, Platinum, Chromium…

Impacts of Mining

Devegetation and Defacing of Landscape Subsidence of Land Ground water Contamination Surface water Pollution Air Pollution Occupational Health Hazards

Indian ScenarioJaduguda Uranium Mine, Jharkhand – exposing

local people to radio active hazards.Jharia Coal Mines, Jharkhand – underlying fire

leading to land subsidence and forced displacement of people.

Sukinda Chromite Mines, Orissa – Seeping of Cr6++ into river posing serious health hazard, Cr6++ being highly toxic and carcinogenic.

Kudremukh Iron Ore Mine, Karnataka – causing river pollution and threat to biodiversity.

East Coast Bauxite Mine, Orissa – Land encroachment and issue of rehabilitation unsettled.

North-Eastern Coal Fields, Assam – very high sulfur contamination of groundwater.

Remedial MeasuresIt is desirable to adopt eco-friendly mining

technology.The low grade ores can be better utilized by

using microbial leaching technique.

Thiobacillus ferroxidans has been successfully and economically used for extracting gold embedded in iron sulfide ores

Restoration of mined areas by re-vegetating them with appropriate plant species.

FOOD RESOURCES

Food Resources

The main food resources – wheat, rice, maize, barley, oats, pulses, sugarcane, other fruits and vegetables, meat milk…

The FAO estimation – minimum calorific intake on a global scale is 2,500 calories/day.

Undernourished - < 90% of min requirement

seriously under nourished - < 80%Deficiency or lack of nutrition malnutrition

World Food ProblemsLast 50 years

world grain production increased three times increase in per capita production by about 50%

population growth (mostly in less developed countries)

Every year 40 million people die of under nourishment and malnutrition

INDIAN SCENARIO

3rd largest producer of staple crops

300 million Indians are under nourished

Overgrazing Livestock wealth plays a crucial role in the rural life of

our country India leads in livestock population The huge population of live stock needs to be fed and

the grazing land or the pastures areas are not adequate

Livestock grazing on a particular piece of grass land or pasture surpass the carry capacity

Carrying capacity of any system is the maximum population that can be supported by it on a sustainable basis

However, most often, the grazing pressure is so high that its carrying capacity is crossed and the sustainability of the grazing land fails

Impacts of Overgrazing Land Degradation

Overgrazing removes the vegetal cover over the soil and the exposed soil gets compacted due to which the operative soil depth declines

• Roots cannot go deep into the soil • Adequate soil moisture is not available

Organic recycling also declines in the ecosystemBecause → not enough detritus or litter remains on the soil to be

decomposed The humus content of the soil decreases and overgrazing

leads to organically poor, dry, compacted soil Due trampling by cattle the soil loses infiltration capacity,

which reduces percolation of water into the soil and as a result of this more water gets lost from the ecosystem along with surface runoff

Thus overgrazing leads to multiple actions resulting in loss of soil structure, hydraulic conductivity and soil fertility

Impacts of Overgrazing Soil Erosion

Due to overgrazing by cattle, the cover of vegetation almost gets removed from the land

The soil becomes exposed and gets eroded by the action of strong wind, rainfall etc…

The grass roots are very good binders of soil When the grasses are removed, the soil becomes

loose and susceptible to the action of wind and water

Impacts of Overgrazing Loss of useful species

Overgrazing adversely affects the composition of plant population and their regeneration capacity

The original grassland consists of good quality grasses and forbs with high nutritive value

Heavy grazing – root stocks which carry the reserve food for regeneration gets destroyed

Replacement by secondary species The secondary species are hardier and are less nutritive in

nature Ultimately the nutritious, juicy fodder giving species like

Cenchrus, Dicanthium, Pancium and Heteropogon etc… are replaced by unpalatable and sometimes thorny plants like Parthenium, Lantana, Xanthium etc…These species do not have a good capacity of binding the soil particles and, therefore, the soil becomes more prone to soil erosion

Thus overgrazing makes the grazing land lose its regeneration capacity and once good quality pasture land gets converted into an ecosystem with poor quality thorny vegetation

Agriculture

Slash and burn cultivation or shifting cultivation

Modern agriculture

The types of agriculture are very different in their process and their outputs in terms of yield as well as their impacts on the environment

Traditional Agriculture and its Impacts It usually involves a small plot, simple tools, naturally

available water, organic fertilizers and a mix of crops It is more near to natural conditions and usually it results

in low production

The main Impacts of this type of agriculture are Deforestation

The slash and burn of trees in forests to clear the land for cultivation and frequent shifting results in loss of forest cover

Soil ErosionClearing of forest cover exposes the soil to wind, rain

and storms, thereby resulting in loss of top fertile layer of soil Depletion of Nutrients

During slash and burn the organic matter in the soil gets destroyed and most of the nutrients are taken up by the crops within the short period, thus making the soil

nutrient poor which makes the cultivator to shift to new area

Modern Agriculture and its Impacts It makes use of hybrid seeds of selected single crop

variety, high-tech equipments and lots of energy subsidies in the form of fertilizers, pesticides and irrigation water

The food production has increased tremendously, evidenced by the “green revolution”

The Impacts Impacts related to high yielding varietiesFertilizer related problemsPesticide related problemsWater loggingSalinity problems

Impacts related to high yielding varieties

The use f high yielding varieties encourage monoculture

In case of an attack by some pathogen, there is total devastation of the crop by the disease due to exactly uniform conditions, which help in rapid spread of disease

Fertilizer related problems Micronutrient ImbalanceMost of the chemical fertilizers used in modern agriculture have

nitrogen, phosphorus and potassium which are essential macronutrients

Farmers use these indiscriminately to boost up crop growth. Nitrate PollutionNitrogenous fertilizers applied in the fields often leach deep into

soil and ultimately contaminate the ground waterThe nitrates get concentrated in the water and when their

concentration exceeds 25 mg/L, they become the cause of a serious health hazard called “Blue Baby syndrome”

EutrophicationEutrophication means Over Nourishment Due to eutrophication lakes get invaded by algal blooms; these

algae grows very fast by rapidly using up the nutrients, they often are toxic and badly affect the food chain

Pesticide related problems Creating resistance in pests and producing new pestsSome individuals of the pest species usually survive

even after pesticide sprayThe survivors give rise to highly resistant generationsAbout 20 species of pests are now known which have

become immune to all types of pesticides an are known as “super pests”

Death of non-target organismsMany insecticides are broad spectrum poisons which not

only kill the target species but also several non-target species which are useful to us

Biological magnificationMany of the pesticides are not biodegradable and keep

on accumulating in the food chain, this process is called as biomagnification

Water logging Over irrigation of croplands by farmers for good

growth of their crop usually leads to water logging Inadequate drainage causes excess water to

accumulate underground and gradually forms a continuous column with the water table

Under water logged conditions, pore spaces in the soil get fully drenched with water and the soil-air gets depleted

The water table rises while the roots of the plant do not get adequate air for respiration

Mechanical strength of the soil declines, crop plants get lodged and crop yield fails

Preventing excessive irrigation, sub-surface drainage technology and bio-drainage with trees like Eucalyptus are some of the remedial measures to prevent water logging

Salinity ProblemsAt present ⅓rd of the total cultivable land area

of the world is affected by saltsIn India about 7 million Hectares of land are

estimated to be salt affected Saline soils are characterized by the

accumulation of soluble salts like sodium chloride, sodium sulphate, calcium chloride, magnesium chloride…

The most common method for getting rid of salts is to flush them out by applying more good quality water to such soils. Another method is laying under ground network of perforated drainage pipes for flushing out the salts slowly

ENERGY RESOURCES

Energy Resources Energy consumption is considered as an index

of its developmentThe first form of energy known was FIREWind and Hydropower have been in use for the

last 10,000 yearsThe invention of steam engines replaced the

burning of wood by coal and coal was later replaced to a great extent by oil.

In 1970’s due to Iranian revolution and Arab oil embargo the prices of oil shoot up, leading to exploration and use of several alternate sources of energy

Growing Energy Needs

Per capita energy use and GNP

(Data from World Resources Institute, 1997)

Energy Sources A source of energy is one that can provide adequate

amount of energy in a usable form over a long period of time

These sources are of two types: Renewable Resources – which can be generated

continuously in nature and are inexhaustible (also called as non-conventional energy sources)

e.g., wood, solar energy, wind energy, tidal energy, hydro power, bio-mass energy, bio-fuels, geo-thermal energy and hydrogen

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 thorium…

Solar Energy Sun is the ultimate source of energy. The nuclear fusion reaction taking place inside the sun

release enormous quantities of energy in the form of heat and light

The solar energy received by the near earth space is approx. 1.4kJ/m2-s (solar constant)

Traditional uses – drying clothes and food grains, preservation eatables, for obtaining salt from sea-water…

Techniques for harnessing Solar energy→ Solar Heat Collectors → Solar Cells→ Solar Cookers → Solar Water Heaters→ Solar Furnaces → Solar Power Plants

Solar Heat Collectors

These can be passive or active in naturePassive heat collectors are natural

materials like stones, bricks…which absorb heat during day time and release it slowly at night

Active solar collectors pump a heat absorbing medium (air or water) through a small collector which is normally placed at top of the building

Solar CellThey are also known as photovoltaic cells

Solar cells are made of thin wafers of semi-conducting materials like silicon or gallium

When solar radiations fall on them, a potential difference is produced which causes the flow of electrons and produces electricity

The potential difference produced by a single PV cell of 4 cm2 size is about 0.4-0.5 volts and a current of 60 mA is produced

A solar pump run by electricity produced by solar cells

Simple box type solar cooker Solar cookers make use of solar heat by reflecting the solar radiations using a mirror directly on to a glass sheet which covers the black insulated box within which the raw food is kept.

The food cooked in a solar cooker is more nutritious due to slow heating

It has limitation that it cannot be used at night

Solar Water Heater It consists of an insulated box painted black from inside

and having a glass lid to receive and store solar heat Inside the box it has black painted copper coil through

which cold water is made to flow in, which gets heated and flows out into storage tank.

Solar Furnace Thousands of plane mirrors are arranged in concave

reflectors, all of which collect the solar heat and produce a high temperature.

Solar Power Plants Solar energy is harnessed on a large scale by using

concave reflectors which cause boiling of water to produce steam; the steam turbine drives a generator to produce electricity

Wind Energy The high energy winds have lot

of energy in them as kinetic energy due to their motion

The driving force of winds is sun The wind energy is harnessed

by making use of wind mills The blades of the wind mill keep

on rotating continuously due to the force of the striking wind

the rotational motion of the blades drives a number of machines like water pumps, flour mills and electricity generators

A large number of wind mills installed in clusters are called wind farms, and feed power to the utility grid and produce a large amount of electricity

The minimum wind speed required for satisfactory working of a wind generator is 15km/hr

Wind energy is very useful as it does not cause any air pollution; after initial installation cost, the wind energy is very cheap

Hydro Power Water enters the plant when an intake gate is opened,

and moves through the penstock. Gravity and a narrowing scroll case increase the pressure of the water as it enters the turbine. Water exits the turbine and is returned to the river. The turbine spins a rotor directly above it, and electricity produced by the interaction of rotor and stator is transmitted through a transformer at the station and thence to the grid.

Hydro power 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.

Tidal EnergyOcean tides are produced by gravitational

forces of sun and moo, and contain enormous amount of energy.

The tidal energy can be harnesses by constructing tidal barrage

High Tide Low Tide

Ocean Thermal EnergyThe 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

A difference of 20˚C or more is required between surface water and deeper water of ocean for operating Ocean Thermal Energy Conservation power plants

The warm surface water of ocean is used to boil a liquid like ammonia, the high pressure vapors of the liquid are then used to turn turbine of a generator and produce electricity

Geothermal EnergyThe 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, this heat comes from the fission of the radioactive material naturally present in the rocks

Holes are drilled artificially upto the hot rocks and and pipes are put through which the steam gushes out at high pressure which turns the turbine of a generator to produce electricity

Bio-mass EnergyBio-mass is the organic matter produced by the

plants or animals which include wood, crop residues, cattle dung, manure, sewage…

The bio-mass is directly used as a fuel but the efficiency of such furnaces is very low and it produces lot of smoke causing air pollution

It is therefore more useful to convert the bio-mass into bio-gas or bio-fuels

Bio-gas Bio-gas is mixture of methane, carbon dioxide,

hydrogen and hydrogen sulfide, the major constituent being methane

Bio-gas is produced by anaerobic degradation of animal wastes in presence of water

Bio-gas is non-polluting, clean and low cost fuel No storage problems (direct supply from plant) The sludge left over is a rich fertilizer containing

bacterial biomass with most of the nutrients preserved as such

Bio-gas plants in our country are basically two types:1. Floating gas holder type2. Fixed dome type

Floating gas holder type bio-gas plant

Fixed gas holder type bio-gas plant

Bio-FuelsBio-mass can be fermented to alcohols like

ethanol and methanol which can be used as fuels.

Ethanol can be easily produced from carbohydrate rich substances like sugarcane, it burns clean and is non-polluting.

Gasohol is a mixture of ethanol and gasolineMethanol is very useful as it burns at a lower

temperature than gasoline or diesel

Hydrogen as a FuelAs hydrogen burns in air it forms water liberates

a large amount of energy(150 kJ/gm)Due to its high calorific value, hydrogen can

serve as an excellent fuel; moreover, its non-polluting and can be easily produced

Production of hydrogen is possible by thermal dissociation (at 3000 ˚K or above), photolysis dissociation (breakdown of water in presence of sunlight) or electrolysis of water (passing electric current)

Hydrogen is highly inflammable and explosive in nature

Nuclear Fission

Nuclear Fusion

LAND RESOURCES

Land as a resource

Land is a finite and valuable resource upon which we depend for the basic amenities of life

Soil is classified as a renewable resourceThe rate of regeneration of soil is very

slow, about 200-1000 years are needed for the formation of 1” of soil, depending on the climate and soil type.

Land degradation With increasing population growth the demand

for arable land for producing food, fiber and fuel wood are also increasing more and more pressure on the limited land resource; degraded due to over exploitation

Soil degradation is a real cause of alarm because soil formation is an extremely slow process

Soil erosion, water-logging, salinization and contamination of the soil with the various industrial wastes … cause land degradation

Soil Erosion Soil erosion means wearing away of the soil; defined

as movement of soil components, especially surface litter and top soil from one place to another

Soil erosion results in loss of fertility because it is the top soil layer that is fertile

Types Normal erosion or geologic erosion

gradual removal of top soil by natural processes which bring an equilibrium between physical, biological and hydrological activities and maintain a natural balance between erosion and renewal

Accelerated erosioncaused by anthropogenic activities; the rate of erosion is much faster than the rate of formation of soil; Overgrazing, deforestation, mining accelerated erosion

Agents causing soil erosion Climatic Agents Water and wind are the climatic agents of the soil erosion. Water

effects soil erosion in the form of torrential rains, rapid flow of water along slopes, run-off, wave action and melting and movement of snow

Wind affects soil erosion in the form of saltation (vertical movement of soil under the influence of direct pressure of stormy winds), suspension and surface creep

Biotic AgentsExcessive grazing, mining and deforestation are the major biotic

agents responsible for soil erosion

Due to these processes the top soil is disturbed or rendered devoid of vegetal cover

Soil Conservation Practices1. Conservational till farming

2. Contour farming

3. Terracing

4. Strip Cropping

5. Alley Cropping

Conservation till farming

Special tillers are used to break up and loosen the subsurface soil without turning up the top soil

The tilling machine make slits in the un-ploughed soil and injects seeds, fertilizers, herbicides and a little water in the slit, so that the seed germinates and the crop grows.

Contour Farming

Growing of crops in rows across, rather than up and down is called as contour farming

Each row planted horizontally along the slope of the land acts as a small dam to help hold soil and slow down loss of soil through run-off water

Terracing

Strip cropping

Shelter Belt

Land SlidesVarious anthropogenic activities like hydro-electric

projects, large dams, reservoirs, construction of roads and railway lines, construction of buildings, mining … are responsible for clearance of large forested areas.

During the construction of roads, mining activities etc., huge portions of fragile mountainous areas are cut or destroyed by dynamite and thrown into adjacent valleys and streams. These activities weaken the already fragile mountain slopes and lead to land slides

They also increase the turbidity of various nearby streams thereby reducing their productivity

DesertificationDesertification is a process whereby the

productive potential of a rid and semi-arid land falls by 10% or more

Moderate desertification – 10-25% dropSevere desertification – 25-50% dropVery Severe desertification – >50% dropDesertification is characterized by devegetation

and loss of vegetal cover, depletion of ground, salinization ans severe soil erosion

Causes

→ Deforestation, Overgrazing, Mining…

Conservation of Natural Resources- Role of an individual

Equitable use of Resources for Sustainable Lifestyle