·         In this chapter, we will study social relationships with the environment as they have changed over time and as they vary from place to place.
·         All societies have an ecological basis.
·         The term ecology denotes the web of physical and biological systems and processes of which humans are one element.
·         Mountains and rivers, plains and oceans, and the flora and fauna that they support, are a part of ecology.
·         The ecology of a place is also affected by the interaction between its geography and hydrology.

Introduction to Ecology and Ecosystem Ecology :
·         Oikos: ‘home’ or ‘surrounding’, logos: ‘study’
·         Ecology: Science of interrelationship between organisms and their relationship with the environment
·         Ecosystem: Natural unit which consists of biotic communities and their abiotic environment
·         Basic functional unit in ecology, Types: Freshwater, grassland, marine, desert
Characteristics of ecosystem
·         Biotic component: producer (green plants), consumers (animals), decomposers (microorganisms)
·         Abiotic component: air, water, soil
·         Energy flow: sun main source of energy
·         Matter
·         Interrelationship
·         Biological integration
·         Flexibility
·         Ecological regulation
Human impact on environment/ecosystem
·         Destruction or modification of habitat
·         Overexploitation for commercial, scientific and education purpose
·         Overgrazing for domestic animals
·         Change in arable land
·         Forestry
·         Traditional rural practice
·         Industrialization, Urbanization
·         Mining and quarrying
·         Pressure from introduced plants
·         Population pressure
·         Use of drugs and chemicals
·         Destruction of ecological balance
Environmental sanitation
Cleaning of environment Environmental sanitation includes the following:
·         Collection and disposal of refuse and sewage from houses, buildings and other public places
·         Proper ventilation for the control of indoor air pollution: fresh air circulation
·         Sufficient light in the buildings for healthy conditions of human body
Social environment
·         Social environments emerge from the interaction between biophysical ecology and human interventions.
·         This is a two-way process. Just as nature shapes society, society shapes nature.

Nature shapes society
Society shapes nature.
Ex. Indo-gangetic plain has dense population due to availability of fertile soil for cultivation. Where as hilly areas have thin population due to difficult terrain and climate.
Ex. Capitalist commodity producing society has transformed lives and nature. Air pollution, commercially exploiting natural resources like forests, natural oil, water impacts nature.

·         The interaction between environment and society is shaped by social organisation
o   e.g. if forests are owned by the government, it will have the power to decide whether it should lease them to timber companies or allow villagers to collect forests produce.
·         Different relationships between environment and society also reflect different social values and norms as well as knowledge systems
o   for example - the values underlying CAPITALISM have supported the COMMODIFICATION of nature, socialistic values of equality into another. e.g. Bacillus Thuringiensis have been introduced into cotton species, making it resistant to the bollworm.
·         Human relations with the environment have become increasingly complex. With the spread of industrialisation, resource extraction has expanded and accelerated, affecting ecosystems in unprecedented ways.
1. Resource Depletion
·         Nonrenewable Resource
o   Energy source which will be exhausted
o   Coal, petroleum products
·         Renewable Energy source
o   which can supply continuously
o   Hydropower (including micro-hydro), biogas, solar, and wind energy Biomass: fuelwood, agricultural residues, and animal waste Biogas
o   Methane-rich gas produced by methanogenic bacteria by anaerobic digestion of animal and human excreta
o   Use: for cooking Solar
o   Traditional use: drying crops, clothes, fuelwood, and others.
o   Two methods of utilizing solar energy: solar thermal systems for heating water and solar photovoltaic systems for generating electricity Wind
o   Wind power for grinding grains, generating electricity Hydropower
o   Electricity from hydropower, clean energy
2. Pollution
·         Water pollution
o   Water pollution: presence of various types of impurities that tends to degrade its quality and either constitutes a health hazard or otherwise decrease the utility of water
Sources of water pollution
o   • Natural: Soil erosion, solutions of mineral in water, rain water, storms, earthquake, seawater intrusion, dust/dirt falling from atmosphere, deposition of animal wastes and fallen leaves etc.
o   • Man made: Due to agriculture, sewage, wastes, industry
Impact of water pollution
o   • Health hazard due to the presence of pathogenic bacteria from domestic sewage, toxic materials and industrial waste Water borne diseases: typhoid, cholera, dysentery, infectious hepatitis
o   • Economic loss: disturbance recreation, aesthetics, agriculture, industry, property
o   • Impact on aquatic and plant life
Prevention of pollution
o   • Treatment of sewage
o   • Treatment of industrial waste
o   • Providing training and technical facilities in industry to treat waste water
o   • Not using water source for discharging sewage
o   • Rules and regulations for controlling pollution
o   • Proper planning of towns

·         Air pollution
o   Composition of atmosphere N2: 78%, O2: 21%, Other gases: 1% e.g. Argon, CO2, H2, He, CH4, O3, Neon, CO, NO2, NH3 etc.
o   Air pollution: presence of certain substances in the air in high enough concentrations and for long enough duration to cause undesirable effects
Sources of air pollution
o   1. Natural sources
§  Forest fires, dust storms, volcanic eruption, salt sea spray, pollen grains
o   2. Man made sources
§  Fuel combustion: coal, gas
§  Automobile emissions
§  Industrial emissions: iron and steel manufacturing, oil refining, brick factory, cement factory, chemical and petrochemical operations, pulp and paper industry, fertilizer plants, thermal power plants, textile industry etc.
§  Decomposition of organic waste and municipal garbage

·         Noise pollution
o   Noise pollution: unwanted sound which produce undesirable physiological and psychological effect.
o   • Traffic: air traffic, road traffic and seashore and inland water traffic
o   • Industries
o   • Others: loudspeaker, siren, shouting, ringing bell, general daily activities
o   • General discomfort
o   • Reduction in efficiency of persons
o   • Psychological effect
o   • Effect on sleep, recreation and personal communication
o   • Reduction in gastric activity, dizziness, rise in breathing
o   • Irritation, anxiety and stress
o   • Lack of concentration
o   • Mental fatigue
o   • Effect of prolonged exposure: Physical damage to ear, temporary/permanent hearing loss, or nervous breakdown, increase in blood pressure
·         Solid waste pollution
·         Deforestation,
·         Land degradation
Global environmental issues:
·         Global warming
o    Rise in global mean temperature of the earth
Greenhouse effect
o   • Concept of conventional greenhouse with glass: transmit short wave radiation, opaque to long wave radiation
o   • Greenhouse effect: effect caused by greenhouse gases in the atmosphere in which short wave radiation is transmitted to the earth’s surface, but the long wave radiation from the earth is absorbed thereby increasing the temperature
 Major greenhouse gases ƒ
§  CO2: major, responsible 60% of total GHG
§  CH4 ƒ
§  NOx, mainly N2O: responsible 7% of total GHG ƒ
§  Chlorofluorocarbons (CFC): responsible 25% of total GHG ƒ
§  O3 ƒ
§  Water vapor
Impact of global warming
o   • Rise in temperature: 0.3 to 0.6 deg c in the last century
o   • Sea level rise: due to thermal expansion of water on oceans and melting of ice caps and glaciers, 1-2 mm/year over the last century, flooding of coastal areas, beach erosion, saltwater intrusion into coastal areas
o   • Effect on water resources: change in the pattern of evaporation and precipitation, increase in evaporation and precipitation, more precipitation on the form of rain, increase in runoff
o   • Effect on storms and desertification: more storms, expansion of deserts and sub-arid areas with higher evaporation
o   • Socio-economic effect: chances of disease due to high temperature, increase in poverty due to flood and drought
o   • Ecological effect: effect on agriculture and forest ecosystem
·         Acid rain deposition
o   • Emission of SO2 and NOx into the atmosphere
§  o Natural source: decomposition and forest fire, volcanic eruptions
§  o Anthropogenic: burning of fossil fuels, industrial process and gasoline powered automobiles
o   • Transformation into mild sulfuric or nitric acid by combining with water vapor
o   • Dissolution of H2SO4, HNO3 and oxides of Nitrogen and Sulfur and other gases in cloud containing rain and settling down of acid rain
Impact of acid rain
o   • Lowering of PH in lakes and rivers, springs, wells, harming fish and aquatic life
o   • Decline in forest, reduction in pollination of crops, crop quality and quantity
o   • Deterioration of building materials, e.g. steel, paint, plastics, cement, masonry, limestone, marble, sandstone
o    • Potential infiltration to groundwater and increase in solubility of toxic materials (Pb, Cu, Zn) in groundwater
o   • Effect on human health: due to acidic surface and groundwater consumption, respiratory illness, asthma
o   • Corrosion of water pipes, dissolving metals, e.g. lead , cupper and iron in water pipes causing direct harm to human through consumption
o   • Damage to soil fertility
·         Ozone layer depletion
o   Important role with regard to atmospheric chemistry in both troposphere and the stratosphere
o   Pollutant at ground level, but stratospheric O3 is crucial for life on the earth: blocks/absorbs most of the harmful ultraviolet (UV) rays coming from the sun, thus protecting plants and animals
Effect of UV
o   • Human skin cancer, eye cataracts, suppression of immune system response
o   • Effect on plants and aquatic life
Ozone hole:
o   ozone depleted region over Antarctica
o   Main cause of O3 depletion: presence of Chlorofluorocarbons (CFC) in atmosphere
o   Source of CFC: using refrigerant, air-conditioning, fire extinguisher, cleaning solvent, blowing agent, aerosol spray
D. Genetically Modified Organisms
§  New techniques of gene-splicing allow scientists to import genes from one species into another, introducing new characteristics.
§  Genetic modification may also be done to shorten growing time, increase size and the shelf-life of crops.
E. Natural and Man-made Environmental Disasters
Natural Types of Disasters
§  Drought and water shortage
§  Emergency diseases (pandemic influenza)
§  Hail
§  Thunderstorms and lighting
§  Tornadoes
§  Tsunamis
§  Wildfire
§  Sinkholes

 Man-Made and Technological Types of Disasters
§  Power service disruption &blackout
§  Explosion

Environmental problems are also social problems
·         Social ecology refers to the fact that social relations ie organisation of property and production, shapes how environment is understood and used.
·         Social status and power determine to what extent people can protect themselves from environmental crises or overcome it.
·         Securing the public interest e.g. construction of dams or commercial exploitation of forest for timber may actually serve the interests of particular politically and economically powerful groups but hurt the interests of the poor and politically weak.
Environment – Society conflicts :
·         Different social groups stand in different relationships to the environment and approach it differently.
o   e.g. A forest department geared to maximising revenues from supplying large volumes of bamboo to the paper industry with view and use forest very differently from an aritisan who harvests bamboo to make baskets. Their varied interests and ideologies generates environmental conflicts.

o   Thus environmental crises have their roots in social inequality.

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