Natural Resources PDF

Natural Resources Life on this planet earth depends upon a variety of goods and services provided by the nature, which are known as Natural resources. Thus water, air, soil, minerals, coal, forests, crops and wildlife are all examples of natural resources. Any stock or reserve that can be drawn fro...

Natural Resources Life on this planet earth depends upon a variety of goods and services provided by the nature, which are known as Natural resources. Thus water, air, soil, minerals, coal, forests, crops and wildlife are all examples of natural resources. Any stock or reserve that can be drawn from nature is a natural resource. The natural resources are of two kinds: e Renewable resources which are inexhaustive and can be regenerated within a given span of time e.g. forests, wildlife, wind energy, biomass energy, tidal energy, hydro power etc. Solar energy is also a renewable form of energy as it is an inexhaustible source of energy. e Non-renewable resources which cannot be regenerated e.g. Fossil fuels like coal, petroleum, minerals etc. Once we exhaust these reserves, the same cannot be replenished. Even our renewable resources can become non-renewable if we exploit them to such extent that their rate of consumption exceeds their rate of regeneration. For example, if a species is exploited so much that its population size declines below the threshold level then it is not able to sustain itself and gradually the species becomes endangered or extinct. It is very important to protect and conserve our natural resources and use them in a judicious manner so that we do not exhaust them. It does not mean that we should stop using most of the natural resources. Rather, we should use the resources in such a way that we always save enough of them for our future generations. In this unit we shall discuss the major natural resources: (i) Forest. resources (ii) Water resources (iii) Mineral resources (iv) Food resources (v) Energy resources (vi) Land resources. 11 a 12 Chapter 2 2.1 FOREST RESOURCES esources on this earth ‘tant natural r fon most ee Banilet these forests not only Produc,. Ee But alta provide several environmenta, 5, 4 Forests are one of th Covering the earth like innumerable material ee Si services which are essentia Id’s land area is forested which include, he wor About 1/3rd of t r about a 5¢ das well as open forests. Former USSR Se eat ci a a world’s forests, Brazil for about a 7th and Can diethoone ‘or 6-7%, But it is a matter of concern that almost mpl seatest lone of the natural forests has declined over the years. be tthest'reabbucas have occurred in tropical Asia where one third of t - oe | have been destroyed. However, latest reports reveal that m | of forest cover is currently taking place in Brazil. M USES OF FORESTS Forests are of immense value to us. They are not only useful for industry but also for rural economic growth. They offer huge potential for reducing poverty while also conserving their valuable key resources, Fig. 2.1.1 compares the value of forests in terms of economic products and environmental services. Commercial uses (Approx. annual value Rs.-30,000) Environmental uses (Approx. annual value Rs. 10 lacs) Regulates water cycle Produces oxygen Timber Pulpwood Fruits, condiments spices, beverages Absorbs pollutants Fodder. Act as sink of Carbon & \ dioxide(reduces global Rubber, gum warming) Fibres » SRR XX XXX Sea (High tide) KX KOXOXX XX Ceatatatatanen / IX XXX? area DY Reservoir (Contd.). ——— Chapler 20 | Water stored ‘ at high tide in reservoir ee oir to turn the turbine 2.5.6 Water flows into the reserv =] ws out from the reservoir to the Fig. bine at low tide (b). at high tide (a), and flo sea, again turning the tur m OCEAN THERMAL ENERGY (OTE) to the difference in temperature of water a oceans and at deeper levels is called Ocean ¢ 20°C or more is required betwee cean for operating OTEC (Ocean The energy available due the surface of the tropical: Thermal Energy. A difference 0 surface water and deeper water of o Thermal Energy Conversion) power plants. The warm surface water of ocean is used to boil a liquid like ammonia. The high pressure vapour of the liquid formed by boiling are then used to turn the turbine of a generator and produce electricity. 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. @ GEOTHERMAL ENERGY The energy harnessed from the hot rocks present insid arth i called geothermal energy. High femmpenabnce and high Soa wen fields exist below the earth’s surface in many places. This heat coms 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; < and Sohana, Haryana. Sometimes the steam or boiling wate ber ae ten earth does not find any place to come out. We ©! oa rime a hole up to the hot rocks and by putting a pipe i eaten - or hot water gush out through the pipe at high pressure ag acl e turbine of a generator to produce electricity. In USA and : Zealand, there are several geothermal plants working successful’y By, ett bee: FS ie ; ee el at ; Natural Resources 55 oa BIOMASS ENERGY. by t. Biomass 1s the organic matter includes wood, crop residues, wastes etc. Biomass energy is (a) Energy plantations: through photosynthesis and produced by the plants or animals which cattle dung, manure, sewage, agricultural of the following types : Solar energy is trapped by green plants converted into biomass energy. Fast growing trees like cottonwood, poplar and Leucaena, non-woody herbaceous grasses, Crop plants like sugarcane, sweet sorghum and sugar beet, aquatic weeds like water hyacinth and sea-weeds and carbohydrate rich potato, cereal etc. are some of the important energy plantations. They may produce energy either by ‘burning directly or by getting converted into burnable gas or may be converted into fuels by fermentation. () Petro-crops: Certain latex-containing plants like Euphorbias and oil palms are rich in hydrocarbons and can yield an oil like substance under high temperature and pressure. This oily material may be burnt in diesel engines directly or may be refined to form gasoline. These plants are popularly known as petro-crops. (c) Agricultural and urban waste biomass: Crop residues, bagasse (sugarcane residues), coconut shells, peanut hulls, cotton stalks etc. are some of the common agricultural wastes which produce energy by burning. Animal dung, fishery and poultry waste and even human refuse are examples of biomass energy. In Brazil 30 % of electricity is ‘obtained from burning bagasse. In rural India, animal dung cakes are burnt to produce heat. About 80 % of rural heat energy requirements are met by burning agricultural wastes, wood and animal dung cakes. In rural areas these forms of waste biomass are burned in open furnaces called ‘Chulhas’ which usually produce smoke and are not so efficient (efficiency is