Science book class 8

Modern Concept Science and Environment – 8 343

iii) It kills useful microorganisms and other creatures like earthworms.
iv) Polluted land pollutes water bodies.
v) The industrial and household wastes dumped on the roadside gives off bad smell

to the surrounding areas.

Noise pollution

Sound that affects the listener by causing irritation

and disturbance in any form is called noise pollution.

It is the undesirable sound produced in a wrong

place at a wrong time. Sound pollution is a relative

term. Different people consider different sounds as

pollutants. For example : sound from loudspeakers

can be disturbing to one person but entertaining to

the rest. Noise from aircrafts, vehicles, machineries,

crowds, loudspeakers, explosive blasts etc. are the

sources of sound pollution. Noise pollution

Causes of noise pollution

i) Operation of heavy machinery in industries and factories.

ii) Sound from operation of aircrafts and heavy vehicles.

iii) Congested houses, large families sharing small space, fighting, quarrelling,

debate, etc. cause noise pollution.

iv) A social event like feasts, festivals, get-together,etc. causes noise.

v) Construction activities like mining/ blasting, equipment used in large construction

works etc. produce noise.

vi) Playing loudspeakers, television etc. in a large volume.

Effects of noise pollution
i) Constant exposure to loud levels of noise can damage our eardrum temporarily
or permanently resulting in deafness.
ii) Excessive noise pollution in working areas affects the psychological health of the
employees and thus decreases productivity.
iii) Long term exposure to irritating sound may cause aggression, insomnia, stress
fatigue and even infertility.
iv) Noise increases blood pressure and can also trigger cardiovascular diseases.
v) Noise disturbs wild animals and birds.

23.3 Greenhouse Effect

The atmosphere of the earth is composed of different Greenhouse effect
gases like nitrogen, oxygen, carbon dioxide, water vapour,
inert gases, etc. Among these gases, some gases absorb
large amount of sun’s heat while some absorb less. Gases
like carbon dioxide, methane, water vapour, oxides of
nitrogen, etc. that absorb large amount of heat are called
greenhouse gases. These gases allow the short wavelength
of solar radiation to enter into the earth’s atmosphere. But,

344 Environmental degradation and its conservation

when they reflect back from the surface, they lose energy and are emitted in the form of long
wavelength. The greenhouse gases trap most of the heat and do not allow them to escape
from the earth back to the sky. As a result, the trapped heat increases the temperature of the
earth. This phenomenon of trapping of solar heat of longer wavelength inside the earth’s
atmosphere is called greenhouse effect.

Due to the greenhouse effect, the overall temperature of the earth is increasing. This is called
global warming. Global warming has caused the melting of polar ice, rise in sea level, increase
in the temperature of Himalayan region and other numerous environmental effects. According
to a report of Ministry of Science, Technology and Environment of Nepal, the temperature of
Nepal is increasing by 0.6 degree Celsius every decade.

23.4 Artificial Greenhouse Effect

The name greenhouse effect comes from the process that
occurs in an artificial greenhouse. An artificial greenhouse
is a house made up of glass or plastic that can trap solar
heat the same way as the earth does. It is used to grow
summer crops in winter or other off season.

Importance of greenhouse effect

Greenhouse effect is advantageous to the earth and life on Artificial greenhouse effect
it. It maintains the temperature of the earth’s surface to an

average of about 150C. In the absence of greenhouse gases, the temperature of the earth would

be very low i.e. up to -180C. There would be no life in such cold environment. But, excessive

greenhouse effect is bad. The human activities have increased the levels of greenhouse gases

higher than normal. This has resulted in the warming of the earth’s surface and oceans.

Sources of greenhouse gases

i) Burning of fossil fuels releases greenhouse gases like carbon dioxide, carbon monoxide,
sulphur dioxide, nitrogen dioxide, nitrous oxide etc. into the atmosphere.

ii) Forest fires increase the concentration of carbon dioxide and carbon monoxide in the
atmosphere.

iii) Agricultural activities like large paddy fields, solid wastes cattle dung etc. release
methane gas.

iv) Evaporation of water as a result of natural processes or from industries, nuclear power
plants etc. releases water vapour in the atmosphere.

v) Use of chlorofluorocarbons (CFCs), hydrofluorocarbons (HFs) etc. in refrigerator, body
sprays etc.

FACT WITH REASON

Greenhouse effect is important for us, why?

Greenhouse effect is important for us because it keeps the earth warm, prevents global freezing and
supports life.

Modern Concept Science and Environment – 8 345

Adverse impacts of greenhouse effect

Greenhouse effect itself does not adversely affect the environment. It is mostly advantageous.
But, when the trapping of the solar rays is higher than the usual, it causes rapid global
warming, that affects the environment. Some of its major impacts are listed below:

i) It causes global warming and climate change.
ii) Rate of melting of polar ice, ice-capped mountains and glaciers increases.
iii) Sensitive organisms like the fishes and amphibians are affected due to global warming.
iv) It forces native animals to change their natural habitat and migrate to new habitats.
v) It also results in the increase in sea level and submerges the low lying lands, islands and

sea shores.
vi) It creates favorable environment for the growth and development of disease causing

germs and insects.

Ways of controlling greenhouse effect

i) Discouraging the use of refrigerators, air coolers, body sprays, etc. that contains
greenhouses gases like CFCs can reduce greenhouse effect.

ii) Afforestation should be done on a regular basis. The trees absorb a large amount of CO2
from the atmosphere. Carbon dioxide is a major greenhouse gas.

iii) The conventional sources of energy like coal and fossil fuels should be replaced by
cleaner sources of energy like solar power, hydropower, wind energy, tidal energy etc.

iv) Using improved cooking stoves (ICS) instead of traditional stoves, biogas instead of
natural gas, hydropower instead of coal plants, etc.

v) Following energy friendly habits like use of public vehicles, mass transport system,
short distance walking, cycling, etc. which decreases the consumption of fossil fuels and
finally reduce greenhouse gas emission.

FACT WITH REASON

Long wave radiation does not escape easily from the earth’s surface, why?
Long wave radiation does not escape easily from the earth’s surface because they are absorbed by
the greenhouse gases of the atmosphere but released only in a low quantity out in the sky. Most of the
radiation is transferred back to the earth’s surface.

23.5 Climate Change

Climate is the average of weather in a place over a long time. The statistical change in the long
term average (at least for 30 years) of the weather condition of a place is called climate change.
The climate of the earth changes over thousands of years due to natural reasons. But, it also
changes due to human activities. The climate change due to human activities is faster and
irreversible than the change due to natural reasons. The increase in greenhouse gases due to
burning of fossil fuels, forest fires, industrialization, farming etc. is changing the climate of the
earth adversely. The earth is warming more than ever. But, it does not mean that every places
would heat up. The change is very complex. Some places heat up and some bring extreme
coldness. But, the overall effect around the globe is bad.

346 Environmental degradation and its conservation

Effects of climate change

i) It changes the climate of a place or a region mainly by increasing temperature.

ii) It can result in climate hazards like storms, drought, landslide, fires, floods, etc.

iii) It increases the melting rate of snow-capped Memory Tips

iv) mountains and polar ice. As a result, sea level rises 1. 2014 was the world’s hottest
and submerges the low lying places of the world. year on record.

Change in occurrence and distribution of plants 2. About 1 m rise in sea level can
and animals occur. For example - shifting of tree displace more than 100 million
line in higher altitudes, growth of mosquitoes in people living in coastal areas.
higher altitudes, occurrence of tropical vegetation in
3. The golden toad was the first
temperate areas etc.
species to go extinct because of
v) New germs and diseases appear and existing germs climate change and habitat loss.
and diseases spread and develop resistance.

vi) It causes loss of biodiversity by causing the extinction of some vulnerable, endangered
and rare animals and plants.

vii) It changes the patterns of rainfall, snow fall, seasons change, winds etc.

FACT WITH REASON

Rise in sea level is an effect of climate change. Explain.
Rise in sea level is an effect of climate change because change in climate results melting of ice in polar
caps and in snow caps. As a result, more volume of water is added to the sea and thus sea level rises.

23.6 Acid Rain

The mixing of small amount of acids in rain water due to Memory Tips

the chemical reactions caused by industrial gases in the 1. Normal rain has a pH of 6.5.
atmosphere is called acid rain. Simply, acid rain is the rain Acid rain has a pH of 5.7 or less.
or any other form of precipitation that is acidic in nature. It
produces harmful effects in the environment and affects the 2. Acid fog is ten times more
natural resources. acidic than acid rain.

Cause of acid rain

Air pollution is the major cause of acid rain. It is the result of human activities. When industrial
gases like carbon dioxide, sulphur dioxide, nitrous oxide, etc. are released into the atmosphere,
they undergo several chemical reactions and combine with rain water. Then, they fall upon
the animals, plants, soil etc. and affect them. The acids that mix with rain are: hydrochloric
acid (HCl), sulphuric acid (H2SO4), nitric acid (HNO3), etc. The chemical reactions below show
the formation of these acids from industrial gases.

H2O + CO2 H2CO3 (Carbonic Acid)
2SO2 + O2 2SO3

SO3 + H2O H2SO4 (Sulphuric acid)

Modern Concept Science and Environment – 8 347

NO + O3 NO2 + O2
O2 2N2O5
4NO2 + H2O 2HNO3 (Nitric acid)
N2O5 +
Effects of acid rain

i) Acid rain corrodes the skin of animals and human beings and causes skin diseases.
ii) It affects the growth and development of plants by making the soil acidic.
iii) It increases the acidity of water and affects aquatic plants and animals.
iv) It corrodes historical and architectural monuments like buildings, statues, arts, etc.
v) It increases the acidity of land, kills microorganisms and decreases the fertility of

the soil.
vi) It damages the crops and decreases productivity.

Control measures of acid rain

i) Reducing the use of fossil fuels and promoting alternative and clean sources of energy.

ii) Adopting techniques of reuse of emitted gases from industries.

ii) Development of technology that controls production of SO2 and CO2.

ACTIVITY 1

Discuss the major environmental problems occurring in your neighbourhood including its causes,
effects and control or preventive measures.

23.7 Disaster and Disaster Management

Disaster is a sudden and unexpected natural or man-made event causing significant damage
or destruction to human, plants and animals, infrastructures and even permanent change in
the environment. Disaster causes human, material, economic and environmental losses. The
losses are sometimes irreparable. Some of the common natural disasters are: landslides, flood,
fire, aircraft accidents, industrial accidents, etc.

Landslide Flood Earthquake

Disasters can be mainly classified into two groups. They are:

a) Natural disaster

A sudden, violent and destructive activity caused by nature that destructs life and property is
called a natural disaster. Wild fires, earthquake, flood, landslide, drought, disease outbreak,
volcano, cyclone, tsunami etc. are natural disasters. Damage and destruction of life, property
and resources are the effects of natural disasters.

348 Environmental degradation and its conservation

b) Human induced disaster

Disastrous events that are caused by human activities are called human induced disasters or
man-made disasters. Nuclear explosions, war, aircraft accidents, fire, oil spills, etc. are some
of the examples of human induced disasters.

FACT WITH REASON

We should be prepared for the disaster earlier than coping it after occurrence. Support the statement.
We should be prepared for the disaster earlier than coping it after occurrence because prevention
requires much less effort and capital than mitigation. To be prepared beforehand reduces damage,
saves life and property.

Causes of disasters

The common natural disasters of Nepal are landslide, flood, forest fire, lightning and
earthquake. The topography, climate and geology of Nepal favours such disasters. The major
causes of disasters are:

i) Human activities like deforestation, slope encroachment, flood plain encroachment
etc. It triggers landslides and floods.

ii) Due to the continuous collision of Indian tectonic plate with the Eurasian plate,
earthquakes occur in Nepal.

iii) Poor sanitation habits and dense settlements are the causes of disease outbreaks.
iv) Improper traffic management and carelessness are the causes of aircraft and road accidents.
v) Extreme dryness and carelessness are the main causes of forest fires and so on.

Management and mitigating measures of disaster

There are various kinds of disasters. These disasters are different in nature and therefore
need to be managed accordingly. Management and mitigation of disasters is possible by the
following ways:

i) Conducting awareness raising programmes about disasters, their effects, causes and
measures of mitigation

ii) Development of pre-disaster planning and implementation

iii) Mobilizing rescue and rehabilitation effectively

iv) Providing relief to the victims as soon as possible

v) Mobilizing emergency services effectively

Management and mitigation measures for earthquake

An earthquake is a violent shaking of the Earth’s
crust. It releases a tremendous amount of energy by
the movement of the earth’s crust. Earthquake does
not directly damage the human life but it damages or
destroys man-made infrastructures that take human life.

Earthquake in 2072 BS

Modern Concept Science and Environment – 8 349

Nepal lies on the lap of the region where the Indian plate is colliding continuously with the
Eurasian plate. So, it faces earthquake frequently. Earthquake of 1990 B.S, 2045 B.S and 2072
B.S. are the some of the major earthquakes that struck Nepal and took thousands of life and
caused huge loss of infrastructures. The Earthquake of 12th Baisakh, 2072, at local time 11:56
AM, is the recent earthquake of Nepal. Its magnitude was 7.6 Richter scale. It struck western
and central Nepal with its epicentre at Barpak VDC of Gorkha District. There were thousands
of aftershocks after the main quake. One of them which struck on 29thBaisakh, 2072 was of
magnitude 6.8 Richter scale. 8,790 people lost their life and 22,300 were injured thus affecting
8,000,000 people of 31 districts. The earthquake also damaged more than 416,359 houses.

Preparedness before earthquake
i) Identify a safe place inside your house.

ii) Identify the nearest open place outside your house where your family members
and neighbours can gather after disaster.

iii) Prepare your own emergency bag that should contain first aid, water, dry foods,
a torch, etc. Replace them before their expiry.

iv) Fix cupboards, television, racks and other wall furniture firmly to the wall to
avoid accidents.

Preventive measures during an earthquake
i) Do not hurry and run here and there.

ii) Switch off the main electric circuit.

iii) Hide yourself covering your head in ‘duck’ position in the identified safe place
inside your house.

iv) Stay away from racks, cupboard, partitions blocks, etc., if you are inside the house.

v) Go to the nearby safe place if you are outside. Avoid buildings, walls, tall structures, etc.

vi) If you are in a vehicle, stop the vehicle or ask the driver to stop immediately.

Curative measures after earthquake
i) Be in a safe place.

ii) Do not enter the house immediately without getting its conditions checked by
technicians.

iii) Stay in a group along with your family members.

iv) Get yourself and your family members treated by health workers if injured.

v) Help victims and old aged people.

vi) Listen carefully to the news broadcasted over the radio or other communication means.

vii) Do not panic or create panic by listening to news informed by unreliable sources.

Management and mitigating measures for flood and landslide

Overflow of large amount of water outward from the bank of the water body is called flood.
Rainfall, bursting of natural or artificial dam, rapid melting of glaciers and snow, etc. are
some of the causes of flood. Flat land along the river and Terai terrain of Nepal get flooded
every year. Flood takes the lives of people and causes huge loss to crops, animals and other
properties. Lot of people of Nepal become landless and homeless every year due to floods.

350 Environmental degradation and its conservation

The falling of the mass of earth or debris from a higher altitude to a lower altitude is called

landslide. Continuous and heavy rainfall, blasting, mining, earthquake, volcano, soil erosion

etc. are the causes of flood. Hill and mountain regions of Memory Tips

Nepal suffer from landslides every year, during monsoon.
Landslide causes human injury, loss of life, damage of 1. Monsoon is the lifeline of
Nepalese people as the
property and destruction of infrastructures.
agriculture in Nepal is
Mitigation measures for flood and landslide
dependent on monsoon rain.
i) Avoid encroachment of flood plains and sloping But, it brings disastrous flood
lands for settlements.
and landslides every year.

ii) Do not attempt to cross the flooded river 2. Every year, flood washes away
without seniors or guardians.
the fertile soil of Nepal and

iii) Avoid deforestation and engage in reforestation transports it to the Ganges

and afforestation programmes in hill slopes Basin of India.

and near water sources.

iv) Help flood and landslide victims to get emergency relief services.

v) Never drink water from flooded sources without any treatment.

Management of flood and landslide
i) Construction of embankments along the river bank can manage flood.

ii) Afforestation and reforestation should be done in barren areas, sloping areas and
flood plains.

iii) Practising scientific techniques like terrace farming and bioengineering.

iv) Conducting a survey of flood and landslide prone areas

v) Rehabilitation of people affected by floods and landslides.

Management and mitigation measures for fire

Rapid burning of something that causes the loss of life

and property and is beyond the immediate control of

people is called fire. Fire can be in any form like wild

forest fire, house fire, industrial fire, grassland fire etc.

Except some wild forest fires, fire is usually human

induced disaster. Natural fire in the forest is caused by

lightning, volcanic eruptions, earthquakes, etc. Forest fire

In Nepal, wild and human-induced forest fires occur usually in hot and dry season. Fire due

to careless activities like throwing cigarette butts, mishandling of electrical appliances, short

circuits etc. are common human induced causes of fire. Fire destroys the life of people. It

burns forests and kills animals and plants. It destroys crops. It damages buildings and other

infrastructures. Therefore, fire should be managed and mitigated properly.

Prevention, control and management of fire
i) Lighter, matchbox and other combustible materials should be kept away from the children.

ii) Avoid throwing burnt cigarette butts in areas that may catch fire.

iii) Keeping fire brigades ready-to-go during emergency situations.

Modern Concept Science and Environment – 8 351

iv) Keep fire extinguishers in home, industries, school etc.
v) Install safe wiring system.
vi) Develop fire controlling lines in forests and grasslands.
vii) Help fire victims by providing first aid.
viii) Create public awareness in people regarding fire and its destruction.

Epidemic management and mitigating measures

The widespread of a disease infecting many individuals within a community at a faster rate in
a given period of time is called epidemic. Simply, it is a sudden outbreak of diseases affecting
large number of people or animals. It degrades the health of people, animal or plants finally
causing the loss of life and property.

Prevention and control of epidemics

Epidemics can be prevented, controlled or its effects can be reduced by applying the following measures:

i) Create public awareness regarding epidemics.
ii) Maintain the personal and communal sanitation.
iii) Make your home and surrounding environment fresh and healthy.
iv) Protect, clean and conserve water resources.
v) Provide immediate and controlled treatment to the affected people.
vi) Isolate the affected people and group in a controlled environment until they

receive medical treatment.
vii) Do not come in contact with affected people. Follow precautionary measures if

you have to handle or care the affected people.

23.8 Environment Conservation Measures

Environment gets conserved itself if we conserve the major components of the environment. The
components of the environment are water, air, soil, rocks, minerals, sunlight etc. Continuous
exploitation and degradation of resources can cause adverse effect in the environment and
livelihood of people. Therefore, it is necessary to conserve the environment. Environment
resources should not be conserved by protection only but they should be wisely utilized.
Some of the measures for the conservation of environment are described below:

a) Public awareness

People should be made aware about the importance of environmental resources. Once people
have knowledge of their wise use, they actively participate in conservation activities with
interest and will. Public awareness can be generated by broadcasting information through
mass media like radio, television, etc. Awareness through newspapers, magazines, awareness
campaigns, street and school dramas etc. can be other effective methods.

b) Afforestation and forest conservation

Tree plantation and forest conservation activities promote the growth and development of
forest. Forests are the major environmental resources that provide us various natural goods
and services. Forests provide timber, fodder, fresh air, water etc. It helps to control flood, soil
erosion and landslide. Forests can be conserved by controlling illegal deforestation.

352 Environmental degradation and its conservation

c) Conservation of water resources

Water resources should be conserved for environmental conservation. Water resources like
pond, lake, streams, rivers, well, springs etc. should be protected from pollution. Human
activities like overuse of chemical fertilizers and pesticides, draining waste water into rivers
and ponds, throwing waste in or near water bodies etc. should be stopped. Similarly, industrial
and factory wastes should be treated before draining into water bodies. Water resources like
springs, rivers, ponds and wells should be cleaned regularly.

d) Conservation of soil

Soil is the major source of food, water and clothes for human beings. Excessive use of chemical
fertilizers, unplanned urbanization, deforestation etc. are degrading the quality of soil.
Conservation of soil is necessary. Agricultural land, residential land, forests etc. should be
separated. We should use organic manure in crop production. We should also plant trees in
sloping, barren and unproductive lands. Overgrazing should be controlled and regulated.
Using highly productive agricultural land for construction purposes should be stopped.

e) Environment sanitation and pollution control

Environment sanitation can be maintained by making our surrounding clean and healthy.
Personal and household sanitation can lead to proper environment sanitation. Control of
pollution is the chief measure for maintaining sanitation of the environment. Biodegradable
wastes should be converted into compost manure. Non-degradable waste should be recycled,
reused or disposed in sanitary landfill sites. Household and industrial wastes should be treated
and used in agriculture and local gardening. Alternative sources of energy like improved
cooking stoves, biogas etc. can be used for cooking purposes. Industries and factories should
not be allowed to establish in or near the settlement areas. Drinking water sources should be
cleaned. Plantation should be done in barren and sloping lands.

f) Conservation of cultural heritages

Cultural heritages are the important aspects of environment as they preserve the culture,
tradition and lifestyle of people for upcoming generations. The heritages can be conserved by
their proper maintenance and renovation. Regular cleaning programs should be conducted
nearby the heritages. People should be made aware about the need of cultural heritages.

g) Public participation

Public participation is a must in conservation activities. People should participate in plantation,
sanitation, population control and the conservation of land and water. Environmental
conservation cannot be achieved without people’s participation.

23.9 NationalandInternationalOrganizationsforConservationandPromotionofEnvironment

National and international organizations play a vital role in conservation of environmental
resources. They are engaged in local, national and International level. They conduct various
programmes related to conservation and promotion of environment by the people and for the
people. They also support to formulate environment related plans, strategies and policies for
the government. Some of the main organizations are discussed below:

Modern Concept Science and Environment – 8 353

a) National Trust for Nature Conservation (NTNC)

The National Trust for Nature Conservation (NTNC) is a national

environment conserving organization established in 1982 (2039 B.S),

in Lalitpur. It’s headquarter is located at Khumaltar, Lalitpur. It was

established as a non-profit organization to work in the field of nature

conservation in Nepal. It is implementing its conservation plans

through Biodiversity Conservation Centre (BCC), Bardia Conservation

Program (BCP), Suklaphanta Conservation Program (SCP), Annapurna NTNC
Conservation Area Project (ACAP), Manaslu Conservation Area

Project (MCAP) and Gaurishankar Conservation Area Project (GCAP), Central Zoo and

Bagmati River Conservation Project (BRCP). Currently, it has started to work in energy and

climate sector also.

b) International Union for Conservation of Nature (IUCN) IUCN

IUCN is an International Non-Government Organization (INGO). It
works in the field of nature conservation and sustainable use of natural
resources. This organization involves in research, analysis, field projects,
advocacy and education related to the environment. It also includes the
issues related to gender equality, poverty mitigation and sustainable
business in its projects. IUCN was established in 1948 AD. Nepal got its
membership in 1973 AD. It was previously called International Union
for Protection of Nature (1948-1956) and the World Conservation Union
(1990-2008).

This organization has made contributions in policy reforms in Nepal like National Conservation
Strategy 1998, National Environmental Policy and Action Plan I and II, Environment Impact
Assessment and Environment Protection Act, 1996. It also helps to design curricula to educate
about environmental education.

c) World Wide Fund for Nature (WWF)

The  World Wide Fund for Nature  (WWF) is the world’s largest

international  non-governmental   conservation organization. It was

founded in April 29, 1961 in Morges, Switzerland. It works in the

field of the environment preservation and the reduction of impacts

of human activities on the  environment. Its mission is “to stop the

degradation of the planet’s natural environment and to build a future

in which humans live in harmony with nature.” It was formerly named

the  World Wildlife Fund, which is its official name in  Canada  and

the  United States. It works in more than 100 countries supporting WWF

environment and conservation projects. Giant Panda is the symbol of

WWF. This organization has contributed to conserve rare wild animals and plants of the world.

Its country office was established in Nepal in 1993 as WWF Nepal. This organization is
contributing in conservation of watershed and endangered species of plants and animals. It
is also engaged in prevention of illegal trade of wild animals. WWF involves in its works
through scientific study, research and environment awareness.

354 Environmental degradation and its conservation

The major objectives of WWF are:
i) To conserve genetic, species and ecosystem diversity.
ii) To ensure sustainable use of renewable of natural resources.
iii) To promote the reduction of pollution and wasteful consumption

d) Global Environment Fund (GEF)

The Global Environment Fund (GEF) was established in 1992. It is working

with 183 countries to address the world’s most challenging environmental

issues. It helps to reduce poverty, strengthen governance and achieve

greater equality between women and men. The GEF has a large network of

civil society organizations. It works closely with the private sector around

the world. The GEF also receives continuous inputs from an independent

expert scientists. Over the past 25 years, the GEF has supported the GEF
establishment of protected areas, conservation of landscapes, sustainable

management of trans-boundary river basins, climate change etc. In Nepal, it provides funds

for numerous environment conservation projects.

e) United Nations Environment Programme (UNEP)

The  United Nations Environment Programme  (UNEP) is an agency of UNEP
the United Nations. It coordinates its environmental activities and assists
developing countries in implementing  environmentally sound policies
and practices. It has its headquarters in Nairobi, Kenya. UNEP has overall
responsibility for environmental problems among United Nation’s
agencies. In Nepal, it is supporting the government to formulate plans and
policies and to implement projects in environment conservation.

f) International Centre for Integrated Mountain Development (ICIMOD)

ICIMOD is a regional intergovernmental organization

that was established as a learning and knowledge

sharing centre. Nepal, Myanmar, India, China, Bhutan,

Bangladesh and Afghanistan are its member countries.

The organization serves all of these countries. These ICIMOD

countries lie in a belt of Himalayas known as the Hindu

Kush Himalayas. It was founded in 1983 AD. Its central office is in Khumaltar, Lalitpur, Nepal.

The vision of this organization is “Men, women and children of the Hindu Kush Himalayas
enjoy improved wellbeing”. Its mission is to enable sustainable and resilient mountain
development for improved livelihoods. It aims to do this through knowledge and regional
cooperation.

ICIMOD works with both regional and global partners to help reduce mountain poverty,
vulnerability and increase in environmental sustainability. ICIMOD works on disaster risk
management, climate change and water resources management of mountain areas.

Modern Concept Science and Environment – 8 355

ACTIVITY 2

List the name of the local clubs or organizations working for environment conservation and promotion
in your neighbourhood. Also mention what kind of conservation works have been done.

ACTIVITY 3

Make a list of environmental problems of your locality and search for the suitable solutions. Prepare a
report and submit it to your teacher.

ANSWER WRITING SKILL

1. What is environment degradation? Write down any three examples.
Ans: The deterioration of environment or its components due to the exploitation of the resources by

natural disasters or human activities is called environment degradation. Air pollution, water
pollution, decrease in fertility of soil, loss of habitat of plants and animals, desertification, etc. are
some examples of the environment degradation.
2. Acid rain over city is increasing day by day, why?
Ans: Cities have crowded of vehicles and industries. They release large amount of industrial gases in
air. These gases mix up with rain and form respective acids. So, acid rain is increasing over the city.
3. Industries should be away from the human residence, why?
Ans: Industries should be away from the human residence because industries produce lot of poisonous
gases, solid waste, noise, etc. that harm human health, plants, atmosphere, etc.
4. Which region of Nepal is mostly affected by flood and landslide?
Ans: Usually Terai region of Nepal is mostly affected by flood and Hilly region of Nepal is usually
affected by landslide.
5. Which organization is devoting itself for the development of hilly region?
Ans: ICIMOD is a organization which runs programmes for the development of hilly region.
6. What is climate change?
Ans: The change in statistical distribution of weather pattern when the change lasts for millions of years
is called climate change.
7. What are the causes of water pollution?
Ans: The causes of water pollution are:
i) Mixing of sewage and drainages into river.
ii) Mixing of insecticides and pesticides from fields into water.
iii) Washing clothes, bathing, cleaning, etc. in water resources.
iv) Mixing of hospital waste, industrial waste, etc. in river.
8. Write down the function of ICIMOD.
Ans: Functions of ICIMOD are:
i) It conducts research on district level energy project.
ii) It helps in protection of watershed area.
iii) It creates employment opportunity in hilly region.
iv) It conducts programs on horticulture and bee keeping.

356 Environmental degradation and its conservation

STEPS EXERCISE

STEP 1

1. Fill in the blanks with appropriate words.
a) …………………smog decreases the visibility for aircrafts and vehicles.
b) Many aquatic animals and plants are affected by harmful chemicals like heavy
…………………
c) Social events like feasts, festivals, etc. cause…………………
d) The temperature of Nepal is increasing by ………………… degree Celsius in a decade.
e) ………………… effect maintains the average surface temperature of about 150C.
f) Sea level rise is an effect of …………………
g) Continuous ………………… activities make Nepal prone to earthquake hazards.
h) Annapurna Conservation Area Project (ACAP) is one of the successful projects of
…………………

2. Write True for the correct and False for the incorrect statements.
a) Pollution is one of the important causes of environment degradation.
b) Ground level ozone is an air pollutant.
c) Oxygen is a greenhouse gas.
d) Oxides of sulphur form nitric acid in the atmosphere.
e) Preparedness after a disaster is more important than before a disaster.
f) Embankments along the river banks can control flood.
g) Fire is an example of an epidemic.

STEP 2

3. Answer the following questions in one word.
a) What causes the drying of water resources in the environment?
b) Which region of Nepal is mostly affected by flood?
c) Which region of Nepal is usually affected by landslide?
d) What is the point from where earthquakes begin called?
e) Which organization is devoting itself for the development of hilly region?

4. Write any two differences between:
a) Water pollution and air pollution
b) Greenhouse effect and acid rain
c) Climate change and disaster
d) Manmade and natural disaster
e) Flood and landslide

5. Give reasons.
a) Acid rain is an example of air pollution.
b) Long wave radiation does not escape easily from the earth’s surface.
c) Rise in sea level is an effect of climate change.
d) Water pollution can cause epidemics.

Modern Concept Science and Environment – 8 357

e) Greenhouse effect is important to us.
f) We should be prepared for a disaster before than coping it after occurrence.
6. Observe the given diagram and answer the following questions:

a) Which disaster is shown in figure A? Write its one effect.
b) Which disaster is shown in figure B? Write its one cause.
c) Name a common control method for both the natural disasters.

STEP 3

7. Answer the following questions
a) What is air pollution? List out the causes of air pollution.
b) Mention two major effects of air pollution.
c) What is water pollution? What are the major causes of water pollution?
d) What is noise? Write any of its three causes and effects.
e) Define soil pollution. Write its two effects and preventive measures.
f) Define greenhouse gas. Name any four greenhouse gases. List out the major
effects of increased greenhouse gases.
g) What is acid rain? Name two major air pollutants that form acid in atmosphere.
h) Mention any two effects and two control measures of acid rain.
i) Write down any two major causes and four major effects of climate change.
j) What is climate change? How can we mitigate, control or prevent human induced
climate change?
k) What is disaster? What are the measures for mitigating disasters? List them.
l) What is an earthquake? How can you manage and mitigate the effects of
earthquakes? List the measures.
m) Define flood and landslide. Write down how flood and landslide can be managed.
n) Define fire and epidemics.
o) Mention the local measures for conserving the environment.
p) List any six national and international organizations working in Nepal for
environment conservation.
q) Briefly explain about NTNC and ICIMOD.

8. Gather some more information about Gorkha Earthquake of Nepal, 2072 B.S and

prepare a report on how such disaster should be managed before and after.

3U58NITEnvironmEesntitmaanteddstuesatcahiinngapbleerioDdesveloThpe8moerny t Practical
2

24 Environment and sustainable
Development

Syllabus issued by CDC Genetic biodiversity
 Introduction to biodiversity and its types
 Introduction to sustainable development
 Principles of sustainable development
 Global efforts for sustainable development
 Importance of sustainable development

LEARNING OBJECTIVES

At the end of this unit, students will be able to:
 introduce biodiversity and its types.
 explain the principle of sustainable development.
 describe global efforts for sustainable development and importance of sustainable development.

Key terms and terminologies of the unit

1. Biodiversity : The existing number of living organisms in a particular area is called

biodiversity.

2. Ecosystem diversity : The variety and number of distinct ecosystems of a particular geographical

area is called ecosystem diversity.

3. Gene : Gene is the smallest hereditary unit that transfers parental characteristics to

the offspring.

4. Species : The group of individuals in a population that can freely interbreed with each

other to produce a fertile offspring are called species.

5. Genetic diversity : The variation in the genes of the same species that makes them different from

each other is called genetic diversity.

6. Species diversity : The variation in the organisms of different species of a particular area is called

species diversity.

7. Sustainable development : Any long term developmental activity that meets the need of present

generation and also does not compromise the ability of the future generation

to meet their demands is called sustainable development.

8. Ecosystem : A self-sustaining system in which living organisms interact with each other

and with their environment is called ecosystem.

24.1 Introduction

Natural environment is a combination of physical world and biological world. Physical world
consists of non-living substances like air, water, land, rocks, minerals etc. and climatic factors
like sunlight, temperature, rainfall and wind. Biological world consists of living beings like
animals and plants including human beings. It includes all the varieties of life forms. This
biological world interacts with physical world in the presence of climatic factors to continue
the life on the earth.

Modern Concept Science and Environment – 8 359

Advancement of mankind has developed a socio-economic and cultural world. Hence,
environment should also represent the socio-cultural structures like parks, temples, hospitals,
schools, buildings, etc. Therefore, our environment is a combination of physical, biological,
socio-economic and cultural world. The physical and the biological aspects of the environment
are the resources for the development of socio-economic and cultural aspects. Human beings
exploit these resources and modify the environment according to their need. Such continuous
exploitation and modification results in the loss of natural environment.

24.2 Biodiversity

The existing number of living organisms in a particular area is called biodiversity. Living forms
like plants and animals are important components of environment. All plants are not same;
they vary among themselves. Bacteria, fungi, algae, mosses, pteridophytes, angiosperms,
monocots, dicots etc. are different groups of plants. There is variation in these groups. There is
variation in the individuals of each group too. The same is applicable for animals. Animals can
be divided into a number of different groups like invertebrates, vertebrates, fishes, amphibians,
reptiles, aves, mammals etc. Each individual of these groups also differ from each other. This
variability among living beings and within living beings is called bio-diversity or biological
diversity. Biodiversity is the term used to describe the variety of life found on the earth.

FACT WITH REASON

Human activities are threat to biodiversity. Give reason.
The human activities like urbanization, industrialization, commercial farming, hunting, deforestation,
poaching, etc. have caused different species of the biodiversity to become endangered, rare, vulnerable
and even extinct. So, human activities are threat to biodiversity.

Types of biodiversity

Biodiversity can be mainly classified into 3 types. They are:

a) Genetic diversity b) Species diversity c) Ecosystem diversity

a) Genetic diversity

Genes are the hereditary units present in the chromosomes of

the cell. There are 23 pairs of chromosome in a non-reproductive

human cell. In these chromosomes, there are smaller units of

heredity which transfer traits from parents to the offspring

called genes. Genes of organisms differ from each other. The

variation in the genetic makeup of different individuals of same

species is called genetic diversity.Homo sapiens is the single

species of human being. But, still all humans look different

from each other. Races like African, Aryan, Mongolian, etc. are

the result of genetic variations within humans. Also, genes of

one African individual differ from another individual. That is

why our characteristics are only similar to our parents but not Genetic biodiversity

exactly the same. Two children of the same parents are different from each other. Even

the identical twins are also different in some respects.

360 Environment and sustainable Development

FACT WITH REASON

Two children of the same parents are not exactly same, why?
Two children of the same parents are not exactly same because of the variation in their genes as a
result of sexual reproduction.

b) Species diversity

The group of individuals in a population that

can freely interbreed with each other to produce

offspring are called species. The variation among

the species of living organisms is called species Species biodiversity

diversity. Some organisms may be similar in shape, size or external appearance.

However, their species may differ from each other. Domestic cat and leopard cat looks

same but their species are different. Two organisms may look similar to us,but they may

belong to different species. Both pea and grams are dicot plants but they are different

species. Similarly, both eagles and vultures are birds but they fall in different species.

Nepal is rich in species diversity. A glimpse of animal diversity of Nepal is shown in
the table below:

S.N Animals Total no. of species
1. Mammals 185
2. Birds 874
3. Amphibians 118
4. Reptiles 78
5. Fish 187
6. Butterflies 651
7. Moths 785
8. Spiders 175

FACT WITH REASON

A lion and a tiger are different species. Why?

A lion and a tiger cannot interbreed normally. If they do, their offspring is infertile. For example, ligers
are produced when a male lion and a female tiger interbreed. But a liger cannot have offspring. So,
lions and tigers are different species.

c) Ecosystem diversity

A self-sustaining system in which living and non-living components interact with each
other in their environment is called ecosystem. The whole ecosystem is divided into
two major groups : terrestrial ecosystem and aquatic ecosystem. Grassland ecosystem,
forest ecosystem, desert ecosystem, etc. are the examples of terrestrial ecosystem.
Similarly, pond ecosystem, river ecosystem, etc. are the examples of aquatic ecosystem.
The variation among the ecosystems of the earth is called ecosystem diversity. There are
118 ecosystems recorded in Nepal. Ecosystem diversity increases the species diversity
and species diversity increases the genetic diversity.

Modern Concept Science and Environment – 8 361

Differences between biodiversity and ecosystem diversity.

S.N. Biodiversity S.N. Ecosystem diversity

1 The existing number of living 1 The variety and number of distinct

organisms in a particular area is ecosystems in a particular geographical

called biodiversity. area is called ecosystem diversity.

2 It includes species diversity, genetic 2 Itincludesbioticandabioticcomponents.
diversity and ecosystem diversity

ACTIVITY 1

Visit a nearby ecosystem. List out at least ten species of plants and animals that are found in that
ecosystem. Write their common names and two important external body features of each.

24.3 Principles of Sustainable Development

Development activities benefits people by promoting livelihood and economic status of the
people. Development activities also need natural resources. Overexploitation of resources
from the environment can cause adverse effects. If we overuse the resources, they will finish
or lose their ability to renew. So, future generations are sure to be affected by them. Therefore,
there is a need of long term development with least impact to the environment. For this, a
latest development concept called ‘Sustainable Development’ has been widespread.

Sustainable development is a long term developmental activity that meets the need of present
generation and also does not compromise the ability of the future generation to meet their
demands. Hence, it is a planned development activity that keeps in mind, the well-being of
not just the present generation but the future generation too.

Sustainable development is based on three major pillars; the environment, the economy and
the society. The main principles of sustainable development are discussed below:

a) Conservation of ecosystem

The principle of sustainable development aims at the conservation of ecosystems as it conserves
all the biotic and abiotic components. Earth can only be sustainably conserved if all the types
of terrestrial and aquatic ecosystems are conserved.

b) Conservation of biodiversity

We obtain food and other resources from the biodiversity. Each and every organism on this
earth is special. They are the active part of the biodiversity. If one group of organisms are extinct,
then it affects the whole structure of the ecosystem. So, biodiversity should be conserved.

c) Development of sustainable society

All people should get quality food, safe home, quality health services, quality education
and jobs. If the society is healthy and prosperous, it can continue development activities
sustainably. Sustainable society helps to achieve sustainable development easily. So,
sustainable development also aims in the development of sustainable society.

362 Environment and sustainable Development

d) Control of population growth

The population of the world is increasing day by day but the resources are limited. Therefore,
population growth should be controlled for meeting the goals of sustainable development.
If population growth is controlled, the consumption of natural resources also decreases. It
results in environment conservation and availability of resources for future generations.

e) Development of human resource

Not only natural resources, but also the human resources are needed for sustainable
development. Well educated, trained and qualified human resources are necessary to
implement sustainable development projects. They have better abilities to understand the
problems of the nature and hence can achieve a higher degree of sustainability.

f) Increase in public participation

No programs or projects can be successful without public participation. Sustainable
development is for general public. Public participation develops interest, positive attitude
and commitment towards sustainable development.

g) Conservation of cultural heritages

Cultural heritages are also our resources preserved and left by ancestors. They should be
preserved for future generation. Proper reconstruction of heritages for their protection,
conservation of positive values and giving continuity to this practice are the steps for
sustainable development.

h) Limit of carrying capacity

The earth is a reserve of limited resources. If the population and the development works
demand more resources than the earth can generate, then the whole structure crashes.
Development will be stopped and people will fail to progress. Therefore, population growth
and development should be controlled to achieve sustainable development.

FACT WITH REASON

Sustainable development is a scientific development concept. Explain.
Sustainable development is a scientific development concept because it is based on the concept of
proper use of resources, capacity growth, utility for future generation, etc. It is tested for better outcome.

ACTIVITY 2

List some sustainable development practices found in your society and state their role in environment
conservation. One is done for you.

S.N. Sustainable practices Role in environment conservation

1 Collection of garbage,papers, Recycles wastes, saves resources and prevents pollution

metal scraps

2

3

Modern Concept Science and Environment – 8 363

24.4 Global Efforts for Sustainable Development

Sustainable development is a modern concept for maintaining economic growth and
development of society through sustainable use of resources. The term ‘sustainable’ was
used for the first time in modern sense by a group of scientists called Club of the Rome,in
their report Limits to Growth, in 1972. In 1980, International Union for Conservation of
Nature (IUCN) published a world conservation strategy where the term ‘Sustainable
Development’ was introduced. But, the most widely used concept of sustainable development
was recognized in the report ‘Our Common Future’ released by the United Nations World
Commission on Environment and Development (UNWCED), in 1987. The report was also
known as the Brundtland Report because it was formulated by the commission led by the
then Norwegian prime minister Gro Harlem Brundtland. Brundtland was the chairperson of
the commission and the only environment minister to become a prime minister later on. The
commission defined sustainable development as “the development that meets the needs of
present generation without compromising the ability of future generation to meet their own
needs.” Since then, this definition is globally accepted and widely used.

In 1992, UN Conference on Environment and Development, also known as the Earth Summit,
published a 350 paged document known as Agenda 21. Agenda 21 is a dynamic program that
aims to conserve nature, implement plans sustainably and help in economic growth. Similarly,
United Nations Millennium Declaration in 2000 declared 8 International development goals
called Millennium Development Goals. It was followed up by another summit called World
Summit which was organized in 2005. Finally, on September, 2015, UN General Assembly
adopted 2030 Agenda for Sustainable Development. It consists of sets of 17 sustainable
development goals (SDGs) that are to be implemented and achieved by every countries from
the year 2016-2030.

Some of the sustainable development goals (SDGs) are No poverty, Zero hunger, Good health
and well-being, Quality education, Gender equality, Clean water and sanitation, Affordable
and clean energy, Decent work and economic growth, etc.

Importance of Sustainable Development

Sustainable development is: for the human and by the human. It benefits us in long term by
balancing the environment and managing the development works. It helps to conserve the
natural resources. Proper conservation of the resources increase their availability to meet the
economic growth and development. Sustainable development can be achieved by meeting all
the Sustainable development goals (SDGs). It requires mutual cooperation and partnership in
local, national and global level to fulfil the SDGs.

The importance of sustainable development is discussed below:

a) Proper use of natural resources

The practice of development in the past and present demands excessive use of natural
resources. These practices aim to achieve economic growth through overexploitation of
resources. More animals and plants are used to manufacture more goods and services.
More fossil fuels are burnt, more minerals are extracted and more trees are cut in the
name of development. It is the demand of the increasing population growth. But, the

364 Environment and sustainable Development

concept of sustainable development focuses on the use of natural resources according

to its ability of reproduction. We should protect forests and natural resources at any

cost. Fertile land should not be used for settlement on a large scale. In the name of

development, polluting rivers, air and land should be stopped. These efforts can be

practically realized if we follow the principles of sustainable development. For example

– if we set up natural parks or botanical gardens, the natural resources are used in a

proper manner. They not only conserve plants and small organisms relying on them,

but also can be the site for scientific study, research and investigation. Revenue can

be generated from tourism and research. These protected areas sustain the life of the

people living nearby. Keeping the renewal time of the resources in mind, they can be

used by the general public too. Thus, sustainable development enables the proper use

of resources. Memory Tips

b) Continuation and improvement of livelihood Kulekhani Reservoir (Indrasarowar)

Human beings survive on the earth till they get of Makwanpur district is an example
resources from it. Shortage of natural resources of sustainable development. Forest
like water, air, plants, agricultural lands, etc. user group around the reservoir
make human life miserable. Current development protectstheforestfromdeforestation
practices degrade the environment as it focuses only and grazing. This checks soil erosion
on providing facilities and services. Sustainable and decreases sediment in the
development, on the other hand, balances the human reservoir. Less sediments increases
needs and resources. In the past and the present, the reservoir life and hence enables
huge areas of forests are destroyed to create human electricity generation for a longer
settlements for landless or migrating people. Such time. Local people also get some of
haphazard settlements lack goods and services for its revenue from the government
the improvement of people’s lives. Scattered houses for their economic development.
make development works costly. It is very difficult for They also have installed many cages
scattered neighbourhood to achieve all development and farmed fishes which are the
goals. It is because it requires very high investment sources of income. Similarly, locals
and enormous resources. When the forests are are benefited by visitors coming to
destroyed, basic needs like fresh water, fresh air, the reservoir for refreshment. In this
medicinal herbs, firewood, timber etc. also get scarce. way, sustainable development helps
The scarcity of these goods makes human living in proper use of natural resources.
more miserable. Hence, sustainable development is

important for continuation and improvement of livelihood.

c) Sustainability of natural resources

Seas can provide lots of fishes and aquatic foods. But, Memory Tips

what happens if fishermen continuously catch fish BP Highway was constructed with a
from the same place? They might get large number minimum impact to the environment
of fishes for a few days but afterwards, the number and in a sustainable manner.
decreases. It is because the rate of catching fish is

higher than the rate of reproduction of fish. Similarly, if we cut a large number of trees in

a forest, we can get a lot of timber but the resource replenishes. But,if trees are cut from

selective areas once in years, then we can get timber for hundreds of years regularly.

The practice of irregular fishing, fishing in different locations, selective cutting of trees,

Modern Concept Science and Environment – 8 365

etc. are some of the examples of sustainable practices. They provide time for renewal of
resources. If the nature is provided enough time for renewing its resources, we can get
its resources for a longer time. In this way, sustainable development is important for
sustainability of natural resources.

d) Maintaining the limited capacity of natural resources

The resources on the earth are limited. For examples, overgrazing causes the grasslands
to become barren soon. The ground water can dry up if we extract water continuously and
block water recharge. Fuels like coals and petroleum have fixed deposit. Minerals like
metals and non-metals also have fixed deposit. We should wait for them to renew again,
if they are depleted. Imagine what happens if all the petroleum fuels get exhausted?
Would we be able to pay for vehicles that uses other expensive fuel? No, we cannot.
So, we should be careful about the sustainability of resources on earth. Sustainable
development principle is based on limited capacity of natural resources. It focuses on
maximum and long term development works within limited use of resources. Use of
clean and alternative sources of energy, economic and wise use, etc. are some of the
concepts of sustainable development which is important for maintaining the limited
capacity of natural resources.

e) Capacity growth at local level

Development initiatives that come from the local level is long term and effective.
Sustainable development focuses local level development using local resources and
manpower. During this process, local people also become aware of environment and
development. They will be equipped with the knowledge and practices of conservation
of resources and its sustainable use. They themselves can conduct campaign and
awareness programs regarding the sustainable use of environment resources. Such
practices increase the capacity of local people and encourage them to be nature-
friendly development leaders in local level. In long term, they can observe the positive
effects of their awareness in the sustainability of development. Therefore, sustainable
development is important for capacity growth at local level.

f) Development of ‘conservation spirit’

Conservation of resources and its wise use is one of the basic thought of sustainable
development. In sustainable development, developers are encouraged for best long
term and sustainable practices. They compete for maximum facilities and services by
maintaining maximum conservation of resources. It builds conservation spirit among
the developers and users. Therefore, the whim of sustainable development increases
the conservation spirit among people. Conservation spirit enables people to put
environment in priority: emotionally and socially. This results in the conservation of
natural resources in long term.

g) Utility for future generation

Large scale structures and facilities cannot be developed time and again. Huge investment
and resources are used up during their construction and development. Such structures
also affect the environment adversely during their construction. Development activities
should be done in such a way that the utility of both the resources and the development

366 Environment and sustainable Development

activity can be achieved by the future generations. This idea is also called long lasting
development. Development works of the present generation should be the utilities of
the future generation. In this way, sustainable development enables the provision of
utility for future generations.

h) Growth of mutual cooperation Memory Tips

Effects of development of a place or a country affect Architecturally and historically
another place or country. For example, increase in important buildings like the
air pollution in one place affects the quality of air in Singhadurbar,theNarayanhitiPalace
another place. Pollution in river not only affects the Museum, the Chhauni Museum,
nearby upstream areas but also downstream areas. the Ranimahal, etc. were built many
If the development works in the upstream of rivers decades ago, which became the
do not pollute water, the downstream areas are less utilities for this generation.
affected. Therefore, a sustainable development effort

in the local level contributes to the regional and global level. This increases mutual

cooperation between two or more stakeholders. Nepal has large quantity water resources

and all water finally drains to India. Due to this, Government of Nepal and India are in

mutual cooperation to develop water resources of Nepal. Similarly, many other national

and international organizations come together for sustainable development works.

ACTIVITY 3

List a few development works in your society like community forestry, green roads, organic farming,
waste processing, composting, improved cooking stove projects etc. that is based on sustainability.
Give reasons on why these works are sustainable based on their present, past or future outcomes. One
is done for you.

S.N. Sustainable works Resources used Reasons for sustainability
1 Community Forestry Human Resources i) Increase in the number of trees
ii) Increase in forest areas
Program iii) Protection of wild animals
iv) Conservation of water resources
2 v) Sustainable use of fodder, waste woods, etc.

3

ANSWER WRITING SKILL

1. What is Biodiversity?
Ans: The existing number of living organisms in a particular area and the difference between them is

called biodiversity.
2. Define genetic diversity and species diversity.
Ans: The variation in the genes of the same species that makes them different from each other is called

genetic diversity. Similarly, the variation in the organisms of different species of a particular area
is called species diversity.

Modern Concept Science and Environment – 8 367

3. Principal of sustainable development is necessary to apply by poor and rich countries equally, why?
Ans: Principle of sustainable development is necessary in poor and rich countries equally because rich

country may finish resources whereas and poor countries may not utilize resources scientifically alone.
4. What is sustainable development?
Ans: Any long term developmental activity that meets the need of present generation and also does not

compromise the ability of the future generation to meet their demands is called sustainable development.
5. Adopting sustainable development is important for us, why?
Ans: Sustainable development is important for us because it helps us to use the available resources

wisely to increase quality of our life and also helps to preserve resources for future generations.
6. What is the importance of sustainable development?
Ans: Importance of sustainable development are:

i) It encourages proper use and management of natural resources.
ii) It helps to raise public awareness among people about conservation of the natural resources.
iii) It helps to save natural resources for future generation.
iv) It increases the probability of using natural resources for a long time.

STEPS EXERCISE

STEP 1

1. Fill in the blanks with appropriate words.
a) ………………… is the group of living organisms that can interbreed to produce
fertile offspring.
b) Genes are …………………units.
c) The variation between the ecosystems of the earth is called ………………… diversity.
d) Environment, …………… and society are the three pillars of sustainable development.
e) The Club of the Rome published the report named ………………… in 1972.
f) …………………is the name of the commission named after the Prime Minister of
Norway -Gro Harlem Brundtland.

2. Write True for the correct and False for the incorrect statements.
a) Biodiversity is the degree of similarity among life forms.
b) Cow and buffalo are different species.
c) There are 118 different ecosystems in Nepal.
d) Development is for the benefit of people.
e) ‘Limits to growth’ is the report that provides modern definition of sustainable
development.

STEP 2

3. Answer the following questions in one word.
a) How many types of ecosystems are there in Nepal?
b) What is the variety of living beings in a particular area called?
c) According to which concept, resources must be used wisely and preserved for
future generation?

368 Environment and sustainable Development

d) What is the variety and number of distinct ecosystems in a particular geographical
area called?

e) How many chromosomes are there in a non-reproductive human cell?
4. Write any two differences between:

a) Genetic diversity and species diversity
b) Species diversity and ecosystem diversity
c) ‘Limits to growth’ and ‘Our common future’
5. Give reasons.
a) A lion and a tiger are different species.
b) Two children of the same parents cannot exactly be the same.
c) Sustainable development is a scientific development concept.
d) Sustainable development is important for development of conservation spirit.
6. Write down the name of the ecosystem shown in the following diagrams:

a) b) c) d)

STEP 3

7. Answer the following questions
a) What do you mean by biodiversity? List its types.
b) Define species diversity.
c) What do you mean by genetic diversity?
d) How can you say that Nepal is rich in biodiversity? Illustrate with some data.
e) Define ecosystem and ecosystem diversity.
f) Define sustainable development. List out the general principles of sustainable
development.
g) Mention any 6 specific principles of sustainable development.
h) Describe how global efforts were made for sustainable development.
i) List out the major importance of sustainable development.
j) How is sustainable development important for sustainability of natural resources?
k) Sustainable development helps to achieve proper use of natural resources. Explain.
l) Describe briefly the importance of sustainable development for the preservation
of utility structures for future generation.
m) How does the sustainable development help to develop conservation spirit?

8. Write down the full forms of:

a) UNWCED b) UNO c) UNCED
d) MDG e) SDG