Complete  notes on Climate Change and Global Warming  for BPSC and Other Competitive Exams in 2025

Complete  notes on Climate Change and Global Warming  for BPSC and Other Competitive Exams in 2025

General Science- 24 (Environment)

Climate Change and Global Warming

1. Introduction

• Climate Change: Long-term alteration in Earth’s climate patterns, especially temperature and precipitation, due to natural variability and anthropogenic activities.
• Global Warming: Gradual increase in Earth’s average surface temperature, primarily due to increased greenhouse gases (GHGs) from human activities.
• Relationship: Global warming is a major driver of contemporary climate change.

2. Causes

A. Natural Causes

• Volcanic eruptions (ash & aerosols)
• Variations in solar radiation
• Ocean circulation changes (El Niño, La Niña)
• Plate tectonics affecting ocean/atmosphere circulation

B. Anthropogenic Causes

• Burning of fossil fuels → CO₂, CH₄ emissions
• Deforestation → reduced carbon sink
• Industrial processes → GHGs, aerosols
• Agriculture → methane from livestock, nitrous oxide from fertilizers
• Waste management → landfill methane

3. Greenhouse Effect

• Natural greenhouse effect keeps Earth’s average temperature ~15°C.
• Enhanced greenhouse effect due to excess GHGs traps more heat → warming.

Major GHGs & Global Warming Potential (GWP over 100 years):

4. Impacts of Climate Change

A. Environmental

• Melting glaciers & polar ice → sea level rise
• Ocean acidification → coral bleaching
• Increased frequency of extreme events (cyclones, droughts, floods)
• Loss of biodiversity & habitat shift

B. Economic

• Crop yield fluctuations → food insecurity
• Infrastructure damage from extreme weather
• Higher adaptation & mitigation costs

C. Social

• Health impacts: heat stress, spread of vector-borne diseases
• Climate refugees due to sea-level rise, desertification
• Water scarcity & conflict risk

5. Indicators of Climate Change

• Global temperature rise (~1.1°C since pre-industrial era)
• Shrinking ice sheets (Greenland, Antarctica)
• Sea level rise (~3.3 mm/year)
• Increasing ocean heat content
• Changing precipitation patterns

6. Global Initiatives

A. International Agreements

• UNFCCC (1992): Framework for climate action
• Kyoto Protocol (1997): Legally binding targets for developed nations
• Paris Agreement (2015): Limit warming to well below 2°C; aim for 1.5°C; NDCs by all countries
• Montreal Protocol (1987): Ozone layer protection (indirect climate benefit)

B. IPCC Reports

• Assessment Reports (AR6 in 2021–22) highlight urgency of mitigation
• “Code Red for Humanity” warning

7. Indian Initiatives

• National Action Plan on Climate Change (NAPCC) – 8 national missions:
  1. Solar Mission
  2. Energy Efficiency Mission
  3. Sustainable Habitat Mission
  4. Water Mission
  5. Sustaining Himalayan Ecosystem Mission
  6. Green India Mission
  7. Sustainable Agriculture Mission
  8. Strategic Knowledge for Climate Change Mission
• State Action Plans on Climate Change (SAPCCs)
• National Electric Mobility Mission
• Perform, Achieve, and Trade (PAT) Scheme
• Renewable Energy Goals: 500 GW non-fossil capacity by 2030
• Lifestyle for Environment (LiFE) movement

8. Mitigation & Adaptation Strategies

Mitigation – Reduce GHG emissions:

• Renewable energy adoption (solar, wind, hydro)
• Afforestation & reforestation
• Energy efficiency technologies
• Carbon capture & storage (CCS)
• Sustainable transport

Adaptation – Adjust to impacts:

• Climate-resilient crops
• Coastal zone protection (mangroves, sea walls)
• Early warning systems
• Urban heat island mitigation (green roofs, cool pavements)

9. Current Affairs Pointers for Exams

• India’s updated NDCs under Paris Agreement (2022)
• COP28 outcomes (UAE, 2023) – Loss & Damage Fund operationalisation
• Global Methane Pledge
• IPCC AR6 Synthesis Report highlights
• India’s net zero target year: 2070

MCQs : Climate Change and Global Warming

Q1. Which gas has the highest global warming potential among the following?
A) CO₂
B) CH₄
C) N₂O
D) CFC-12

Q2. The Paris Agreement aims to limit global warming to:
A) Below 3°C
B) Below 2°C with efforts to limit to 1.5°C
C) Exactly 2°C
D) Below 1°C

Q3. Which of the following is NOT a greenhouse gas?
A) Ozone
B) Nitrogen
C) Methane
D) Nitrous oxide

Q4. The Indian mission under NAPCC focusing on forest cover increase is:
A) Green India Mission
B) Energy Efficiency Mission
C) Sustainable Agriculture Mission
D) Water Mission

Q5. The main objective of UNFCCC is to:
A) Protect biodiversity
B) Stabilize GHG concentrations
C) Ban fossil fuels
D) Fund renewable energy exclusively