Green House Gases

Introduction

Greenhouse gases (GHGs) are gases in the Earth’s atmosphere that trap heat and contribute to the greenhouse effect, maintaining Earth's temperature.
However, excessive GHG emissions lead to global warming and climate change.
Bihar, being flood- and drought-prone, is highly vulnerable to climate change caused by these gases.

Major Greenhouse Gases

Carbon dioxide (CO₂)
- Source: Burning of fossil fuels, deforestation
- Contributes ~76% of global GHG emissions
- Remains in the atmosphere for ~100 years
Methane (CH₄)
- Source: Cattle farming, rice fields, landfills, natural gas leaks
- More potent than CO₂ (×25 warming potential)
- Life: ~12 years
Nitrous oxide (N₂O)
- Source: Chemical fertilizers, vehicle emissions, industrial processes
- ~300 times more warming than CO₂
- Life: ~114 years
Fluorinated gases (CFCs, HFCs, SF₆, etc.)
- Source: Refrigerants, aerosols, industrial chemicals
- Synthetic gases, do not occur naturally
- High global warming potential (GWP)
Water vapor (H₂O)
- Natural, not directly emitted by humans
- Amplifies warming through feedback

📝 PYQ (BPSC): Which gas is most responsible for global warming? → Carbon dioxide
📝 Expected MCQ: Which GHG is mainly emitted from rice fields? → Methane

The Greenhouse Effect

Sun’s rays enter Earth → Earth’s surface reflects heat
GHGs trap some of this heat → warm the atmosphere
Natural greenhouse effect is essential
Excess GHGs cause global warming

📝 Expected MCQ: What causes the greenhouse effect? → Trapping of heat by GHGs

Impacts of Greenhouse Gases

Rise in global temperature
Melting of glaciers, rising sea levels
Increased frequency of floods, droughts, and heatwaves
Crop failure and food insecurity
Threats to biodiversity and ecosystems

📝 Expected MCQ: Which sector is most affected by GHG-induced climate change? → Agriculture

GHG Emission Sources in Bihar

Rice cultivation: Large CH₄ emission (paddy fields)
Livestock farming: CH₄ from enteric fermentation
Biomass burning: CO₂ and black carbon
Brick kilns: Major CO₂ emitters
Poor solid waste management → CH₄ from landfills

Climate Initiatives (National + Bihar)

National Action Plan on Climate Change (NAPCC)
State Action Plan on Climate Change (SAPCC-Bihar)
Promotion of:
- Solar energy, LED lighting
- Bio-fertilizers, low-carbon farming
- Electric vehicles, public transport

📝 Expected MCQ: Which Bihar initiative targets climate resilience? → SAPCC

Global Treaties to Reduce GHGs

Kyoto Protocol (1997): Binding targets for developed nations
Paris Agreement (2015): All countries to cut emissions; limit warming to <2°C
Montreal Protocol: Phasedown of CFCs (also greenhouse and ozone-depleting)

📝 PYQ (BPSC): Which agreement deals with CFC phaseout? → Montreal Protocol
📝 Expected MCQ: Main goal of Paris Agreement? → Limit global warming below 2°C

PYQs + Expected MCQs

📝 PYQ: Major contributor of greenhouse effect? → Carbon dioxide
📝 PYQ (BPSC): Which gas is released from paddy fields? → Methane
📝 Expected MCQ: Which GHG comes from chemical fertilizers? → Nitrous oxide
📝 Expected MCQ: Fluorinated gases are found in...? → Refrigerants, ACs
📝 Expected MCQ: Which gas traps heat most effectively? → Water vapor (but it’s not man-made)

Quick Revision Points

GHGs = CO₂, CH₄, N₂O, CFCs, H₂O
CO₂ → fossil fuels; CH₄ → rice, cattle; N₂O → fertilizers
Paris Agreement → limit warming <2°C
Bihar → paddy fields, cattle, brick kilns = high GHG contributors
NAPCC & SAPCC → key climate policies

Sources Used

NCERT Class 9–10 Science – Climate & Pollution Chapters
Lucent GK – Environment Section
Drishti Bihar Special – Environment
Bihar SAPCC Report – Dept. of Environment & Forest
PIB & India State of Forest Report (ISFR)
Ghatna Chakra & EduTeria PYQs – BPSC, CDPO, Teacher