Chapter 4 – Environment (Revision)

4.1 Definition of Environment 20732070

Environment: The totality of all external conditions (physical, chemical, biological, social) affecting an organism.
Ecosystem: A community of living organisms (biotic) interacting with their non-living components (abiotic) in a functional unit. Energy flows & nutrient cycles bind them.
Ecology: The scientific study of relationships between organisms and their environment.

Components of Environment

Component	Examples
Lithosphere	Land, soil, minerals, rocks
Hydrosphere	Water (rivers, lakes, oceans, groundwater)
Atmosphere	Air, gases, weather, climate
Biosphere	All living organisms

📝 Past Questions — §4.1 (2 Qs) ★

#	Question	Marks	Year
1	Define environment and ecosystem?	Part of 8	2073
2	Define environment, and ecosystem.	Part of 8	2070

4.2 Importance, Ecology & Ecosystem 20742072207120702069

Ecosystem Characteristics

Producers: Plants, algae (convert solar energy)
Consumers: Herbivores, carnivores, omnivores
Decomposers: Bacteria, fungi (recycle nutrients)
Energy Flow: Sun → Producer → Primary Consumer → Secondary Consumer → Decomposer

Human Intervention in Ecosystem 20742072

Deforestation: Habitat loss, soil erosion, CO₂ increase
Urbanization: Concrete replacing green spaces, heat islands
Agriculture: Monoculture, pesticides reducing biodiversity
Industry: Pollution of air, water, soil
Population Growth: Increased resource demand beyond carrying capacity

Natural Resources Converted to Wealth

Forests → timber, furniture, paper
Water → hydropower, irrigation, fisheries
Minerals → construction, industry, exports
Tourism (natural beauty → economic revenue)

📝 Past Questions — §4.2 (5 Qs) ★★★

#	Question	Marks	Year
1	Define ecosystem & ecology. How increasing population disturbs natural ecosystem?	2+3	2070
2	Primary reasons for human interventions in the ecosystem?	8	2074
3	Primary reasons for human interventions? How natural resources converted to wealth?	8	2072
4	Write notes on: Ecology and Ecosystem.	4	2071
5	Write short notes on: Ecology, ecosystem and its characteristics.	4	2069

4.3 Conservation of Environment

In-situ: National parks, wildlife reserves, community forests
Ex-situ: Zoos, botanical gardens, seed banks, gene banks
Sustainable use: 3R (Reduce, Reuse, Recycle), EIA for projects
Legal framework: EPA 1997, Buffer Zone regulations, CITES

No direct questions asked. Supplements §4.8 answers.

4.4 Optimum Utilization of Natural Resources 20812079

Optimum utilization: Using natural resources efficiently to meet present needs without compromising future generations’ ability to meet theirs.

Balance between development and conservation
Efficient irrigation (drip, sprinkler) vs flood irrigation
Sustainable forestry (selective logging, replanting)
Renewable energy over fossil fuels
Integrated water resource management (IWRM)

📝 Past Questions — §4.4 (2 Qs) ★★

#	Question	Marks	Year
1	Define conflict of resources and optimum use of natural resources with examples.	4	2081
2	What do you understand by optimum utilization of natural resources for environment conservation?	3	2079

🔗 Resource optimization connects to: §4.6 Conflict of Resources → §4.5 Renewable / Non-Renewable →

4.5 Renewable and Non-Renewable Resources 20792071

Renewable	Non-Renewable
Solar, Wind, Hydro, Biomass, Geothermal	Coal, Oil, Natural Gas, Nuclear
Replenished naturally in human timescale	Finite; takes millions of years to form
Cleaner, less pollution	Major GHG source when burned
Higher initial cost, lower running cost	Lower initial cost, higher env. cost

Nepal’s Potential

Hydropower: ~83,000 MW theoretical; ~42,000 MW economically viable
Solar: 300 sunny days/yr; Terai & Mid-hills ideal
Biogas: 400,000+ plants installed; cattle-dung based
Wind: Limited but feasible in Mustang, Khumbu

📝 Past Questions — §4.5 (2 Qs) ★★

#	Question	Marks	Year
1	What are the renewable and non-renewable energy resources?	3	2079
2	Differentiate between renewable and non-renewable energy.	5	2071

4.6 Conflict of Resources 20812078

Conflict of Resources: Disagreement among stakeholders over the use, ownership or distribution of limited natural resources.

Examples

Hydropower vs Agriculture: Dam reservoirs submerge fertile farmland
Industry vs Community: Factory effluent polluting drinking water sources
Urbanization vs Forest: Expanding cities encroaching on forest land
Tourism vs Conservation: Trekking/mountaineering degrading fragile alpine ecosystems
Upstream vs Downstream: Water diversion depriving downstream users (Melamchi project)

📝 Past Questions — §4.6 (2 Qs) ★★

#	Question	Marks	Year
1	Describe about conflict of resources with suitable examples.	4	2078 Chaitra
2	Discuss about conflict of resources with suitable example.	4	2078 Kartik

4.7 Global Environmental Issues 20792077

Global Warming: Rising CO₂ & GHGs → temperature increase → ice melt, sea rise
Ozone Depletion: CFCs destroying O₃ layer → UV radiation increase
Biodiversity Loss: Species extinction at 100–1000x natural rate
Acid Rain: SO₂ & NOx emissions → acidic precipitation → forest/lake damage
Deforestation: 10M hectares lost/yr globally; CO₂ sink reduction
Ocean Pollution: Plastic, oil spills, eutrophication
Desertification: Land degradation in arid/semi-arid regions

Driving Forces of Global Warming 2077

Fossil fuel combustion (CO₂)
Industrial processes (CH₄, N₂O)
Deforestation (reduced CO₂ absorption)
Agriculture (methane from rice paddies, livestock)

📝 Past Questions — §4.7 (2 Qs) ★★

#	Question	Marks	Year
1	Define regional and global environmental issues. Factors contributing to global warming.	4	2079
2	Discuss briefly on the Global Environmental issues and its driving force.	4	2077

🔗 Global env. issues overlap with: Ch1 §1.2 Technology Impact on Environment → Ch5 §5.7 Air Pollution Sources → Ch6 §6.1 Climate Change Causes →

4.8 Environmental Issues of Nepal 20802074207220702069

Major Issues

Air Pollution: Kathmandu Valley PM2.5 exceeds WHO limits; brick kilns, vehicles
Water Pollution: Bagmati, Bishnumati rivers severely polluted; untreated sewage
Deforestation: Chure hills degradation, landslides, Terai flooding
Solid Waste: Sisdol landfill — inadequate; open dumping, no segregation
Soil Erosion & Landslides: Steep terrain + deforestation + monsoon
Climate Change: Glacial retreat, erratic rainfall, GLOF risks
Loss of Biodiversity: Poaching (tiger, rhino), habitat encroachment

Causes

Rapid urbanization without planning
Industrial effluent without treatment
Population pressure on limited arable land
Weak enforcement of environmental laws
Poverty → unsustainable resource use

Kathmandu Valley Specific 2080

Brick kilns (Bull’s Trench Kilns) → major PM source
Vehicle emissions (old diesel vehicles)
Road dust (unpaved roads)
Open burning of waste
Encroachment of rivers & wetlands

Acid Rain 2072

SO₂ + NOx from vehicles/industries react with water vapor
Form H₂SO₄ / HNO₃ → acidic precipitation (pH < 5.6)
Damages forests, aquatic life, buildings, monuments
Nepal: mainly from brick kilns & vehicle emissions in Kathmandu

📝 Past Questions — §4.8 (6 Qs) ★★★★

#	Question	Marks	Year
1	List out the major environmental issues of Nepal.	3	2070
2	Discuss about the major environmental issues of Nepal.	Part of 8	2074
3	Key environmental issue of Kathmandu valley and pressing factors.	1+3	2080
4	Major environmental issues in Nepal? Causes and mitigation measures.	8	2074
5	Major environmental issues of Nepal? What are the causes of acid rain?	8	2072
6	What is the major environmental problem of Nepal?	4	2069

🔗 Nepal env. issues & mitigation shared with: Ch5 §5.7 Air Pollution (Kathmandu focus) → Ch5 §5.8 Mitigation Measures → Ch6 §6.1 Climate Change Impacts on Nepal →

Quick-Revision Summary

Section	Topic	Qs	Freq.
4.1	Definition of Environment	2	★
4.2	Ecology & Ecosystem	5	★★★
4.3	Conservation	0	—
4.4	Optimum Utilization	2	★★
4.5	Renewable / Non-Renewable	2	★★
4.6	Conflict of Resources	2	★★
4.7	Global Environmental Issues	2	★★
4.8	Environmental Issues of Nepal	6	★★★★

4.1 Definition of Environment 20732070

Environment: Surroundings of all living and non-living things. ISO: “surroundings in which an organization operates including air, water, land, natural resources, flora, fauna, humans and their inter-relations.”

Ecosystem: A grouping of organisms that interact with each other and their environment, including both biotic (living) and abiotic (non-living) components functioning as a unit.

5 Components of Environment

Hydrosphere — Water
Atmosphere — Air
Lithosphere — Land
Biosphere — Flora, Fauna, Microbes
Anthrosphere — Man-made things

Biotic: Producers (autotrophs—plants), Consumers (heterotrophs—animals), Decomposers (fungi, bacteria)
Abiotic: Climatic (temperature, light, moisture) and Edaphic (soil-related) factors

4.2 Ecology & Ecosystem 20742072207120702069

6 Characteristics of Ecosystem

Structure: Biotic + abiotic components
Energy Flow: Unidirectional — sun → producers → consumers
Nutrient Cycling: C, N, P, S cycle between organisms and environment
Dynamic Nature: Constant change through succession
Self-Regulating: Homeostasis via feedback (predator-prey)
Interdependence: All components interconnected (holocoenotic)

Population Disturbance to Ecosystem

Excessive fossil fuels → GHG & global warming
Deforestation → destroying carbon sinks
Overfishing, overgrazing
Industrial waste in water, air, soil
Biodiversity loss & species extinction
Excessive agrochemicals

8 Reasons for Human Intervention 20742072

Population Growth
Economic Development
Energy Needs
Agricultural Expansion
Resource Extraction
Urbanization
Technological Advancement
Consumption Patterns

Conversion of Resources to Wealth 2072

Agriculture: Soil, water, sunlight → crops & livestock
Energy: Fossil fuels & renewables → electricity
Mining: Minerals, metals, building materials
Forestry: Timber, medicinal plants
Water: Irrigation, hydropower, fisheries
Tourism: Natural landscapes & biodiversity

4.3 Conservation of Environment

Conservation: Wise management and utilization of natural resources in sustainable manner to ensure biodiversity maintenance.

4 Types of Conservation

Energy: Reduce consumption, use renewables
Water: Reduce usage, recycle wastewater
Soil: Prevent erosion, chemical contamination
Plant: Conserve rare/endangered plants, control invasive species

4.4 Optimum Utilization of Natural Resources 20812079

Allocate natural resources to best use — satisfying human needs at minimum cost on sustainable basis.

Types of Resources

Perpetual: Virtually inexhaustible (solar, wind)
Renewable: Available over time; can be produced (forests, fisheries)
Non-renewable: Fixed amounts; exhausted after time (some recyclable)

Nepal Examples

Community Forestry: 29% (1994) → 40.36% (2015)
Micro-Hydro: 3,000+ plants serving rural Nepal
Solar energy replacing diesel generators
Sustainable agriculture: crop rotation, organic farming, IPM
Rainwater harvesting for dry-season use

4.5 Renewable & Non-Renewable Resources 20792071

Aspect	Renewable	Non-Renewable
Definition	Not depleted; reproducible in short time	Finite; cannot regenerate in human timescales
Availability	Inexhaustible or reproducible	Fixed, finite, exhaustion risk
Examples	Solar, hydro, wind, geothermal, biofuel	Coal, petroleum, natural gas
Environmental	Clean, sustainable	GHG, pollution, global warming
Cost	High initial, low long-term	Low initial, rising prices
Formation	Short or continuous	Thousands to millions of years
Global Usage	~15–20%	~80%

4.6 Conflict of Resources 20812078

Definition: Situation where allocation, management, or use of natural resources results in violence, human rights abuses, or denial of access. ~40% of international conflicts due to resource disputes.

Causes

Rapid population growth → environmental degradation
Social inequality → skewed resource access
Failure of governing bodies
Unsustainable consumption
Economic globalization

Conflicts in Nepal

Land: Boundary disputes, ownership changes, tenant eviction
Forest: Ownership disputes, product access, illegal collection, poaching
Water: Source disputes, drinking/irrigation sharing, compensation for water projects

4.7 Global Environmental Issues 20792077

Issue	Driving Forces
Pollution	Industry, vehicles, fossil fuels; toxins in air, water, soil
Global Warming	GHG emissions (CO₂, CH₄, N₂O); deforestation
Overpopulation	Unsustainable growth; resource scarcity
Resource Depletion	Excessive fossil fuel and non-renewable use
Climate Change	Global warming → seasonal changes, diseases, floods
Biodiversity Loss	Habitat destruction, species extinction
Ocean Acidification	25% CO₂ absorbed by oceans; 2B tons/yr
Genetic Engineering	Genetic modification → toxins, toxic to wildlife

Remedies: Carbon sinks, renewable resources, biodiversity conservation, awareness, cleaner technology.

4.8 Environmental Issues of Nepal 20802074207220702069

6 Major Issues

Climate Change & Warming: Glacial melt, rainfall pattern changes
Air & Water Pollution: Untreated sewage, arsenic (Terai), vehicular emissions
Deforestation & Land Degradation: Overgrazing, floods, soil erosion
Illegal Mining: Sand/stone → soil instability, water table lowering
Poaching: Illegal wildlife hunting → endangered species extinction
Water-borne Diseases: Cholera, diarrhea, typhoid; 7,882 diarrheal deaths (WHO 2017)

Kathmandu Valley 2080

Air pollution (vehicular, industrial, brick kilns)
Water pollution (untreated sewage in Bagmati)
Haphazard urbanization
Solid waste management crisis

Causes & Mitigation

Issue	Mitigation
Climate Change	Renewable energy, forestation, emission reduction
Air/Water Pollution	Emission standards, wastewater treatment, ban old vehicles
Deforestation	Afforestation, community forestry, sustainable agriculture
Illegal Mining	Regulation, law enforcement, alternative materials
Poaching	National park protection, anti-poaching laws
Waterborne Disease	Water treatment, sanitation, health education

Acid Rain 2072

SO₂ + NO₂ → sulfuric & nitric acids mixed with rain
Sources: Fossil fuel burning, vehicular emissions, industrial processes, volcanoes
Effects: Forest damage, lake acidification, infrastructure corrosion, soil nutrient leaching

Past Exam Questions (21 Total)

4.1 Definition of Environment (2 Qs) ★

#	Question	Marks	Year
1	Define environment and ecosystem?	Part of 8	2073 Magh
2	Define environment, and ecosystem.	Part of 8	2070 Magh

🔗 Cross-ref: Always combined with §4.2 (Ecology & Ecosystem). Both Qs are near-identical.

4.2 Ecology & Ecosystem (5 Qs) ★★★

#	Question	Marks	Year
1	Define ecosystem and ecology. How increasing population disturbs natural ecosystem and how to minimize the disturbance?	2+3	2070 Bhadra
2	What are the primary reasons for human interventions in the ecosystem?	8	2074 Bhadra
3	What are the primary reasons for human interventions in the ecosystem? How natural resources of ecosystem is converted into wealth?	8	2072 Ashwin
4	Write notes on: Ecology and Ecosystem.	4	2071 Magh
5	Write short notes on: Ecology, ecosystem and its characteristics.	4	2069 Bhadra

🔗 Cross-ref: Q2 & Q3 are near-identical. Q3 also relates to §4.4 (optimum utilization of resources).

4.3 Conservation of Environment (0 Qs)

Never asked directly. Content supplements §4.4 and Ch6 §6.6 (national parks/conservation) answers.

4.4 Optimum Utilization of Natural Resources (2 Qs) ★★

#	Question	Marks	Year
1	Define conflict of resources and optimum use of natural resources with examples.	4	2081 Chaitra
2	What do you understand by optimum utilization of natural resources for environment conservation?	3	2079 Jestha

🔗 Cross-ref: Q1 also covers §4.6 (Conflict of Resources).

4.5 Renewable & Non-Renewable Resources (2 Qs) ★★

#	Question	Marks	Year
1	What are the renewable and non-renewable energy resources?	3	2079 Jestha
2	Differentiate between renewable and non-renewable energy.	5	2071 Bhadra

4.6 Conflict of Resources (2 Qs) ★★

#	Question	Marks	Year
1	Describe about conflict of resources with suitable examples.	4	2078 Chaitra
2	Discuss about conflict of resources with suitable example.	4	2078 Kartik

🔗 Cross-ref: Both Qs are near-identical (same year, different sessions). Also covered in §4.4 Q1.

4.7 Global Environmental Issues (2 Qs) ★★

#	Question	Marks	Year
1	Define regional and global environmental issues. Discuss briefly about the factors contributing to global warming.	4	2079 Chaitra
2	Discuss briefly on the Global Environmental issues and its driving force.	4	2077 Chaitra

🔗 Cross-ref: Global warming factors overlap with Ch6 §6.1 (causes of climate change). Environmental issues also covered in Ch5 §5.7 (air pollution). Ch3 §3.3 covers industrial revolution’s environmental consequences.

4.8 Environmental Issues of Nepal (6 Qs) ★★★★

#	Question	Marks	Year
1	List out the major environmental issues of Nepal.	3	2070 Bhadra
2	Discuss about the major environmental issues of Nepal.	Part of 8	2074 Bhadra
3	List out the key environmental issue people facing in Kathmandu valley and discuss about the pressing factors.	1+3	2080 Chaitra
4	What are the major environmental issues in Nepal? Discuss along with the causes and mitigation measures.	8	2074 Magh
5	Discuss the major environmental issues of Nepal? What are the causes of acid rain?	8	2072 Ashwin
6	What is the major environmental problem of Nepal?	4	2069 Bhadra

🔗 Cross-ref: Q3 (Kathmandu) shares answer with Ch5 §5.7 (air pollution in Kathmandu) and Ch5 §5.8 (mitigation). Q5 acid rain also in Ch5 §5.7. Nepal env. issues link to Ch6 §6.1 (Nepal climate impacts) and Ch6 §6.5 (deforestation).

Quick-Revision Summary

Section	Topic	Qs	Freq.
4.1	Definition (5 components)	2	★★
4.2	Ecology & Ecosystem	5	★★★★
4.3	Conservation	0	—
4.4	Optimum Utilization	2	★★
4.5	Renewable vs Non-Renewable	2	★★
4.6	Conflict of Resources	2	★★
4.7	Global Environmental Issues	2	★★
4.8	Environmental Issues of Nepal	5	★★★★