---
title: "Climate change: cause, impact and mitigation"
subject: "Technology, Environment and Society"
chapter: 6
key: "semester_7/technology_environment_and_society:cc-cause-impact-mitigation"
source: https://www.bctengineer.com/q/semester_7/technology_environment_and_society/cc-cause-impact-mitigation
site: BCT Engineering
---

# Climate change: cause, impact and mitigation

Technology, Environment and Society · Chapter 6: Climate Change

- Asked in: 2073 Shrawan, 2+6 marks
- Video: [Climate Change – MIND MAP ENVIRONMENT | Drishti IAS ENGLISH](https://www.youtube.com/watch?v=7o3EFSFAEFM) — Drishti IAS : English
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/technology_environment_and_society/cc-cause-impact-mitigation
- Whole chapter: https://www.bctengineer.com/md/semester_7/technology_environment_and_society/chapter-6

## Question

What do you mean by climate change? Discuss about its cause, impact and mitigation measures.

## Short answer

Climate change is a long-term shift in temperature, rainfall, wind and seasons, attributed to human alteration of the global atmosphere. Main causes: fossil-fuel burning, deforestation, agriculture, industry, waste and urbanisation. Impacts: heat waves, glacier retreat, floods/droughts, lower crop yields, disease, biodiversity loss, economic damage. Mitigation: clean energy, efficiency, transport, forests, agriculture, waste, industry, carbon pricing, awareness; adaptation also needed.

## Answer

**Climate change** is a long-term change in the average weather patterns – temperature, rainfall, wind and seasons – of a region or the whole Earth, lasting for decades or longer. The UNFCCC defines it as change attributed directly or indirectly to human activity that alters the composition of the global atmosphere, over and above natural variability.

#### Causes

**Natural causes** (minor in the present warming)
- Changes in solar output and in the Earth's orbit.
- Volcanic eruptions (dust and SO₂).
- Natural ocean–atmosphere cycles such as El Niño.

**Human (anthropogenic) causes** (main cause today)
1. **Burning fossil fuels** – coal, petrol, diesel and gas for power, transport and industry release CO₂.
2. **Deforestation** – fewer trees absorb CO₂, and burning forests releases it.
3. **Agriculture** – paddy fields and livestock release methane; chemical fertilisers release N₂O.
4. **Industry** – cement, steel, brick kilns; halocarbons from refrigeration.
5. **Waste** – landfills and open dumping give methane.
6. **Urbanisation and population growth** – more energy demand and land-use change.

These activities raise greenhouse gases: CO₂ is now over 420 ppm compared with about 280 ppm before 1750.

#### Impacts

| Area | Impact |
|---|---|
| Temperature | Global average already 1.1–1.2 °C higher; more heat waves |
| Ice and water | Glacier retreat, GLOF risk, drying springs, sea level rise |
| Weather | Erratic monsoon, floods, landslides, droughts, storms |
| Agriculture | Lower yields, pests, food insecurity |
| Health | Dengue, malaria, heat stress, water-borne diseases |
| Ecosystems | Species extinction, upward shift of plants, forest fires |
| Economy | Damage to hydropower, roads, tourism; climate migration |

In Nepal, temperature in the mountains is rising faster than the global average, glaciers are retreating and floods and landslides are increasing.

#### Mitigation measures

- **Clean energy:** expand hydropower, solar, wind and micro-hydro; phase down coal, oil and gas.
- **Energy efficiency:** LED lights, efficient motors, better building insulation, energy audits in industry.
- **Clean transport:** electric vehicles and electric public transport, cable cars, non-motorised transport (cycling, walking).
- **Forests and land:** stop deforestation, plant trees, community forestry, REDD+ (Reducing Emissions from Deforestation and Forest Degradation).
- **Agriculture:** less chemical fertiliser, organic farming, better manure handling, improved paddy water management.
- **Waste:** reduce, reuse, recycle; capture landfill methane; biogas from kitchen and animal waste.
- **Industry:** cleaner production, replacing old brick kilns with zig-zag kilns, low-carbon cement.
- **Carbon pricing and policy:** carbon tax, emissions trading, removing fossil fuel subsidies.
- **Awareness and lifestyle:** saving energy, less food waste, using public transport.

**Adaptation** measures are also needed, for example GLOF early-warning systems, drought-tolerant crops, water harvesting and climate-resilient infrastructure, as planned in Nepal's NAPA and National Adaptation Plan.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. How does the UNFCCC define climate change?
   A. Any change in weather within a week
   B. Change attributed directly or indirectly to human activity that alters the composition of the global atmosphere, over and above natural variability
   C. Only natural variation in solar output
   D. Changes in sea level only
   Answer: B. The UNFCCC definition links climate change to human alteration of atmospheric composition beyond natural variability. (Key point: UNFCCC definition)

2. Which is a natural cause of climate change, minor in present warming?
   A. Burning fossil fuels
   B. Deforestation
   C. Volcanic eruptions, solar output changes and El Niño
   D. Cement manufacturing
   Answer: C. Natural causes are solar changes, orbit, volcanoes and ocean currents; fossil fuels, deforestation and industry are human causes. (Key point: Natural vs human causes)

3. Which gases do agriculture emit?
   A. Methane from paddy and livestock, N2O from chemical fertilisers
   B. SF6 from paddy
   C. CFCs from livestock
   D. Only CO2 from fertilisers
   Answer: A. Paddy fields and livestock release methane while chemical fertilisers release N2O. (Key point: Agriculture causes)

4. Why does deforestation contribute to climate change?
   A. Trees emit CO2 only
   B. Fewer trees absorb CO2, and burning forests releases it
   C. Trees reflect heat
   D. It increases ozone only
   Answer: B. Forests are carbon sinks; cutting and burning them reduces absorption and adds CO2. (Key point: Deforestation effect)

## Related in Technology, Environment and Society

- [Climate change threat, impact and mitigation](https://www.bctengineer.com/question.md?key=semester_7%2Ftechnology_environment_and_society%3Acc-threat-impact-mitigation) — Technology, Environment and Society, chapter 3
- [Climate change gases, impact and mitigation](https://www.bctengineer.com/question.md?key=semester_7%2Ftechnology_environment_and_society%3Acc-gases-impact-mitigation) — Technology, Environment and Society, chapter 6
- [Short note: Climate change mitigation and adaptation](https://www.bctengineer.com/question.md?key=semester_7%2Ftechnology_environment_and_society%3Acc-mitigation-adaptation-note) — Technology, Environment and Society, chapter 6
- [Climate change gases, mitigation and international efforts](https://www.bctengineer.com/question.md?key=semester_7%2Ftechnology_environment_and_society%3Acc-gases-international-efforts) — Technology, Environment and Society, chapter 6
- [Climate change gases and mitigation interventions](https://www.bctengineer.com/question.md?key=semester_7%2Ftechnology_environment_and_society%3Acc-gases-interventions) — Technology, Environment and Society, chapter 6
- [Climate change impacts in Nepal and international efforts](https://www.bctengineer.com/question.md?key=semester_7%2Ftechnology_environment_and_society%3Acc-impacts-nepal-international) — Technology, Environment and Society, chapter 6

## Related in other subjects

- [Climate change and renewable mitigation](https://www.bctengineer.com/question.md?key=semester_7%2Fenergy_environment_and_society%3Aclimate-change-renewables-mitigation) — Energy Environment and Society, chapter 4
- [Mitigation measures of erosion](https://www.bctengineer.com/question.md?key=semester_4%2Fengineering_geology_ii%3Aerosion-mitigation) — Engineering Geology II, chapter 5
- [Biogas routes and climate change](https://www.bctengineer.com/question.md?key=semester_7%2Fenergy_environment_and_society%3Abiogas-routes-climate-change) — Energy Environment and Society, chapter 3
- [APA and MLA: newspaper article (Clinton on Climate Change)](https://www.bctengineer.com/question.md?key=semester_5%2Fcommunication_english%3Aapa-mla-harris-clinton-climate) — Communication English, chapter 4