---
title: "Greenhouse gases and global control efforts"
subject: "Engineering Chemistry"
chapter: 3
key: "semester_2/engineering_chemistry:greenhouse-gases-efforts"
source: https://www.bctengineer.com/q/semester_2/engineering_chemistry/greenhouse-gases-efforts
site: BCT Engineering
---

# Greenhouse gases and global control efforts

Engineering Chemistry · Chapter 3: Environmental Chemistry

- Asked in: 2069 Bhadra, 1+2+2 marks
- Video: [Greenhouse Effect and Global Warming | Environmental Science | LetsTute](https://www.youtube.com/watch?v=d7Ci_EooW-k) — Let'stute
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_2/engineering_chemistry/greenhouse-gases-efforts
- Whole chapter: https://www.bctengineer.com/md/semester_2/engineering_chemistry/chapter-3

## Question

What are major gases responsible for causing green house effect and how are they released into the atmosphere? Give an account of the global efforts to control the release of these gases.

## Short answer

Major greenhouse gases: CO₂ (fossil fuel combustion, deforestation), CH₄ (paddy fields, cattle), N₂O (fertilisers), and CFCs (refrigerants). Global efforts include the Montreal Protocol phasing out CFCs, the UNFCCC, the Kyoto Protocol with binding emission targets, and the Paris Agreement aiming to limit warming below 2°C.

## Answer

#### Major greenhouse gases and their release
| Gas | Main sources |
|---|---|
| CO₂ (about 60 % of the effect) | Burning of coal, oil, wood; deforestation; cement industry |
| CH₄ | Paddy fields, cattle (rumination), landfills, natural gas leaks, wetlands |
| N₂O | Nitrogenous fertilisers, burning of biomass, nitric acid industry |
| CFCs | Refrigerators, air conditioners, aerosols, foam |
| O₃ (troposphere) | Photochemical reactions of vehicle exhaust (NOx + hydrocarbons) |

Water vapour is also a greenhouse gas but is not increased directly by human activity.

#### Global efforts to control release
- **Montreal Protocol (1987):** phase-out of CFCs and related ozone-depleting gases (also GHGs); Kigali Amendment (2016) reduces HFCs.
- **UNFCCC (1992, Rio Earth Summit):** framework treaty to stabilise greenhouse gas concentrations.
- **Kyoto Protocol (1997):** binding targets for industrialised countries to cut emissions of six GHGs.
- **Paris Agreement (2015):** all countries make national targets to keep warming well below 2 °C and aim for 1.5 °C above pre-industrial level.
- Nepal has submitted its Nationally Determined Contributions and promotes clean energy and community forestry.

## Check yourself

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

1. CO2 contributes about what share of the enhanced greenhouse effect?
   A. About 6%
   B. About 20%
   C. About 60%
   D. About 95%
   Answer: C. CO2 is the largest contributor, about 60%. (Key point: CO2 share)

2. Which are main sources of methane?
   A. Nitrogenous fertilisers and nitric acid industry
   B. Cement industry and deforestation
   C. Refrigerators and aerosols
   D. Paddy fields, cattle, landfills, natural gas leaks and wetlands
   Answer: D. These are the CH4 sources; the others describe N2O, CO2 and CFCs. (Key point: CH4 sources)

3. The Kyoto Protocol (1997)
   A. Set binding emission targets for industrialised countries for six GHGs
   B. Phased out CFCs
   C. Required all countries to target 1.5 C
   D. Created the UNFCCC
   Answer: A. Kyoto: binding targets for industrialised countries. (Key point: Kyoto)

4. The Paris Agreement (2015) aims to
   A. Ban HFCs only
   B. Keep warming well below 2 C and aim for 1.5 C with national targets from all countries
   C. Phase out CFCs by 1987
   D. Limit warming to 5 C
   Answer: B. All countries submit national targets. (Key point: Paris)

## Related in Engineering Chemistry

- [Water pollutants, harmful effects, control measures](https://www.bctengineer.com/question.md?key=semester_2%2Fengineering_chemistry%3Awater-pollutants-effects-measures) — Engineering Chemistry, chapter 3
- [Acid rain; sources and control of CO and SO₂](https://www.bctengineer.com/question.md?key=semester_2%2Fengineering_chemistry%3Aacid-rain-co-so2) — Engineering Chemistry, chapter 3
- [Organic/inorganic water pollutants, effects, remedies](https://www.bctengineer.com/question.md?key=semester_2%2Fengineering_chemistry%3Awater-pollution-substances-effects-remedies) — Engineering Chemistry, chapter 3, asked 2×

## Related in other subjects

- [Global warming and greenhouse gases](https://www.bctengineer.com/question.md?key=semester_7%2Fenergy_environment_and_society%3Aglobal-warming-ghg-climate) — Energy Environment and Society, chapter 4
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- [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
- [Global warming and international efforts](https://www.bctengineer.com/question.md?key=semester_7%2Ftechnology_environment_and_society%3Aglobal-warming-international) — Technology, Environment and Society, chapter 6