Climate Change – Overview, Causes and Effects

Climate Change: Causes, Effects, and Mitigation (UPSC Prelims + Mains)

In the last few years, Indians have felt climate change in daily life—longer heatwaves, sudden heavy rain in cities, stronger cyclones on the coast, and irregular monsoon spells that worry farmers. Climate change is no longer only an "environment" topic. It affects agriculture, health, economy, internal security, disaster management, and India's global diplomacy—so it is a high-priority theme for UPSC.

1) Climate Basics for UPSC: Weather vs Climate

Weather is what happens today or this week (a rainy day in Delhi). Climate is the average pattern over long periods (Delhi has hot summers, cool winters, and a monsoon season).

2) The Greenhouse Effect: Why the Planet Warms

Sunlight reaches Earth. Some energy is reflected back to space. The rest warms land and oceans. Earth then releases heat (infrared radiation). Greenhouse gases (GHGs) trap part of this heat and keep the planet warm enough for life. This is the natural greenhouse effect. The problem begins when human activities add extra GHGs, strengthening the greenhouse effect and pushing the climate system out of balance.

3) Causes of Climate Change

3.1 Natural Causes (Long-term, but not the main reason today)

• Solar variation: small changes in solar output can affect climate.
• Volcanic eruptions: large eruptions can cool the planet temporarily by aerosols reflecting sunlight.
• Earth's orbital changes: over thousands of years, orbital cycles affect ice ages and warm periods.
• Natural ocean cycles: El Niño/La Niña influence short-to-medium-term climate variability.

These factors exist, but they do not explain the rapid warming trend observed in recent decades.

3.2 Human (Anthropogenic) Causes: The Main Driver Today

Human activities add extra GHGs and reduce natural carbon sinks. The major sources are:

• Burning fossil fuels: coal, oil, and gas for electricity, industry, and transport (largest source of CO₂).
• Deforestation and land-use change: reduces carbon sinks; also releases stored carbon.
• Agriculture: methane from rice fields and livestock; nitrous oxide from fertilizers.
• Industrial processes: cement production releases CO₂; refrigeration and electronics release industrial gases.
• Waste: landfills emit methane; wastewater also releases GHGs.

3.3 Major Greenhouse Gases: Sources and Significance

4) Effects of Climate Change

4.1 Global Effects

• Rising temperature: more frequent and intense heatwaves.
• Changing rainfall patterns: intense rainfall events, longer dry spells.
• Melting glaciers and ice sheets: contributes to sea level rise.
• Sea level rise: coastal flooding, erosion, saltwater intrusion.
• More extreme events: stronger cyclones, floods, droughts, wildfires.
• Ocean warming and acidification: coral bleaching; harm to marine food chains.
• Biodiversity loss: habitat shifts, species stress, ecosystem disruption.

📘 Ocean Acidification

When oceans absorb CO₂, seawater becomes more acidic. This harms corals and shell-forming organisms and can disrupt fisheries and marine ecosystems.

4.2 Effects in India (High-Value UPSC Content)

4.3 Economic and Social Effects (Mains ready)

• Livelihood stress: farmers, fishers, and informal workers are highly vulnerable.
• Disaster costs: more frequent disasters increase spending on relief and reconstruction.
• Migration: climate stress can increase rural-to-urban movement and coastal displacement.
• Inequality: poorest households have least capacity to adapt (housing, water, healthcare).

5) Mitigation: How to Reduce Climate Change

📘 Mitigation

Mitigation refers to actions that reduce greenhouse gas emissions or enhance carbon sinks to slow down climate change (e.g., renewable energy, energy efficiency, afforestation).

UPSC trap to avoid: Mitigation reduces future warming; adaptation reduces current and future damage. Both are needed.

5.1 Mitigation at Global Level: Key Frameworks

• UNFCCC: global treaty framework for climate action.
• Kyoto Protocol: binding targets for developed countries (historical relevance).
• Paris Agreement (2015): all countries submit NDCs; focus on keeping warming well below 2°C and pursuing efforts for 1.5°C.
• IPCC: scientific assessment body; its reports guide policy.

5.2 Mitigation Pathways: Sector-wise (Prelims + Mains)

A) Power and Energy

• Renewable energy expansion: solar, wind, small hydro, biomass.
• Grid modernization: storage (batteries, pumped hydro), smart grids, better transmission.
• Energy efficiency: LED programs, efficient appliances, industrial efficiency.
• Cleaner cooking: reducing biomass burning improves health and lowers emissions.

📘 Energy Efficiency

Using less energy for the same output (e.g., LED bulbs instead of incandescent). It is one of the cheapest mitigation options and reduces import dependence.

B) Industry

• Low-carbon manufacturing: efficient boilers, waste heat recovery.
• Green cement and green steel: alternative fuels, new processes, recycling.
• Electrification and green hydrogen: especially for hard-to-abate sectors.
• Circular economy: reduce, reuse, recycle to cut material and energy demand.

C) Transport

• Public transport: metro, buses, suburban rail—high mitigation per rupee in cities.
• Electric mobility: EVs, charging infrastructure, battery recycling.
• Fuel efficiency standards: better engines and logistics reduce emissions.
• Rail and waterways: shift freight from road to cleaner modes.

D) Agriculture and Livestock

• Methane reduction in rice: improved water management, alternate wetting and drying.
• Better livestock practices: feed improvement, manure management.
• Efficient fertilizers: balanced nutrient use, neem-coated urea, precision farming.
• Agroforestry: trees on farms increase resilience and store carbon.

E) Forests and Land Use

• Afforestation and reforestation: increase carbon sinks.
• Prevent forest fires and degradation: protects biodiversity and stored carbon.
• Restore wetlands and mangroves: strong carbon storage and coastal protection.

F) Waste and Cities

• Segregation at source: reduces landfill burden and methane.
• Composting and biomethanation: convert organic waste into useful products.
• Landfill gas capture: reduces methane emissions.
• Green buildings: cool roofs, ventilation, efficient materials.

5.3 Carbon Pricing and Carbon Markets (High-scoring Mains topic)

Carbon pricing makes emissions costly so that cleaner choices become economically attractive.

• Carbon tax: direct tax on carbon content of fuels (simple but politically sensitive).
• Emissions trading system (ETS): cap total emissions and allow trading of permits.
• Carbon credits/offsets: emissions reduction projects generate tradable credits.

5.4 Carbon Dioxide Removal (CDR): Limits and Use

• Afforestation, soil carbon, biochar: nature-based removal (needs land and careful planning).
• CCUS and Direct Air Capture: technology-based options (currently expensive, energy-intensive).

UPSC balance: CDR can help, but it cannot replace deep emissions cuts, especially in energy and industry.

6) Adaptation: Living Safely in a Changing Climate

6.1 Key Adaptation Areas in India

• Disaster risk reduction: early warning systems, cyclone shelters, floodplain zoning.
• Water security: rainwater harvesting, watershed management, micro-irrigation.
• Climate-resilient agriculture: drought-tolerant crops, crop diversification, weather advisories.
• Heat action plans: cool roofs, public alerts, drinking water points, work-hour changes.
• Coastal adaptation: mangroves, resilient infrastructure, setback lines.
• Urban resilience: stormwater systems, sponge city approaches, more green cover.

📘 Disaster Risk Reduction (DRR)

Policies and actions that prevent new disaster risk, reduce existing risk, and manage residual risk—critical as climate extremes increase.

6.2 Adaptation is Development

For a developing country like India, adaptation is closely linked with basic development goals—safe housing, health systems, water supply, and climate-resilient infrastructure.

7) India's Climate Action: Policies and Initiatives (UPSC-ready)

7.1 National Action Plan on Climate Change (NAPCC)

India's key policy framework includes missions such as:

• National Solar Mission
• National Mission for Enhanced Energy Efficiency
• National Mission on Sustainable Habitat
• National Water Mission
• National Mission for Sustaining the Himalayan Ecosystem
• National Mission for a Green India
• National Mission for Sustainable Agriculture
• National Mission on Strategic Knowledge for Climate Change

7.2 International Leadership by India (Examples for Mains)

• International Solar Alliance (ISA): mobilizes solar deployment, especially in tropical countries.
• Coalition for Disaster Resilient Infrastructure (CDRI): focuses on resilient infrastructure against climate and disasters.

7.3 India's Broader Climate Position (Answer writing points)

• Equity and CBDR: developed countries have historical responsibility.
• Development needs: poverty removal and growth are legitimate priorities.
• Clean transition: India supports clean energy but stresses finance and technology support.

8) UPSC Answer Framework: How to Write Mains Answers

8.1 10-line Structure for Mains

1. Start with a crisp definition of climate change.
2. State key drivers (GHGs, land-use change).
3. Give 2–3 major impacts (global + India-specific).
4. Add 1–2 data-like statements (heatwaves, cyclones, monsoon extremes) without overloading.
5. Explain mitigation vs adaptation in one line.
6. Give sector-wise mitigation (energy, transport, agriculture).
7. Give adaptation measures (DRR, water, resilient farming).
8. Mention India's policy framework (NAPCC, missions, LiFE).
9. Add global framework (Paris Agreement, NDCs, climate finance).
10. Conclude with a balanced line: development + sustainability + equity.

8.2 Common Mistakes to Avoid

• Confusing ozone depletion with global warming (they are different problems).
• Writing only "effects" and missing "mitigation + adaptation."
• Using only global examples and ignoring Indian contexts like Sundarbans, Himalayas, monsoon.
• Making climate change purely environment—UPSC expects economy, health, disaster, security links.

9) Prelims Quick Revision Points

• Climate change is a long-term shift in climate patterns; current trend mainly human-driven.
• Main GHGs: CO₂, CH₄, N₂O, industrial gases (HFCs etc.).
• Key impacts: heatwaves, extreme rainfall, droughts, cyclones, sea level rise, glacier melt, ocean acidification.
• Mitigation reduces emissions; adaptation reduces vulnerability.
• India's key framework: NAPCC (8 missions) + State Action Plans.
• Important principles: CBDR-RC, equity, climate justice.
• International basics: UNFCCC, Kyoto Protocol, Paris Agreement (2015), NDCs, IPCC.

10) UPSC-Style Practice Questions

10.1 Mains Practice Questions

1. "Climate change is not only an environmental issue but a developmental and security challenge." Discuss in the Indian context.
2. Differentiate between mitigation and adaptation with suitable Indian examples. Suggest an integrated strategy for India.
3. Explain how climate change can impact the Indian monsoon and agriculture. What policy measures are needed?
4. Discuss the role of carbon markets in mitigation. What are the opportunities and concerns for developing countries?

10.2 MCQs (With Answers + Explanations)

1. Which of the following best describes "climate"?

   

   A) Day-to-day condition of atmosphere
   B) Average weather pattern over long periods
   C) Rainfall in a single month
   D) Wind speed in a city today

   Answer: B — Climate is the long-term average pattern, not day-to-day variation.

2. The enhanced greenhouse effect mainly occurs due to:

   A) Earth's rotation
   B) Increase in greenhouse gases from human activities
   C) Ocean tides
   D) Changes in Earth's orbit every year

   Answer: B — Human emissions increase heat-trapping gases and strengthen warming.

   

3. Methane emissions are strongly associated with:

   A) Nuclear power plants
   B) Livestock and rice cultivation
   C) Solar panels
   D) Mountain glaciers

   Answer: B — CH₄ commonly comes from livestock digestion, rice fields, landfills, and fossil fuel leaks.

4. Ocean acidification mainly happens because:

   A) Oceans absorb CO₂ from air
   B) Oceans absorb oxygen from air
   C) Sunlight increases ocean salt
   D) Melting glaciers add freshwater

   

   Answer: A — CO₂ dissolves in seawater and increases acidity, harming corals and shell organisms.

5. Which is an example of adaptation?

   A) Switching to solar power
   B) Planting mangroves to reduce cyclone damage
   C) Improving fuel efficiency in cars
   D) Closing a coal plant

   Answer: B — Mangroves reduce vulnerability to storms and coastal flooding (adaptation).

6. Which is an example of mitigation?

   

   A) Building cyclone shelters
   B) Heatwave advisory system
   C) Energy-efficient appliances and buildings
   D) Flood evacuation drills

   Answer: C — Energy efficiency reduces emissions, so it is mitigation.

7. CBDR-RC is most closely linked to:

   A) Equal responsibility for all countries regardless of history
   B) Different responsibility based on capability and historical emissions
   C) Only developed countries should act
   D) Only developing countries should act

   Answer: B — It supports shared action but differentiated responsibility.

   

8. Which one is a carbon sink?

   A) Forests and soils
   B) Diesel engines
   C) Plastic waste
   D) Brick kilns

   Answer: A — Forests and soils absorb and store carbon.

9. Urban Heat Island effect increases mainly due to:

   A) More lakes in cities
   B) More trees and parks
   C) Concrete surfaces, low greenery, and waste heat
   D) More rainfall in cities

   Answer: C — Built surfaces store heat and tree cover is lower.

10. Which is a likely climate-related risk to the Sundarbans?

    A) Volcanic eruption
    B) Sea level rise and salinity intrusion
    C) Earthquake every year
    D) Ozone hole expansion over India

    Answer: B — Low-lying mangrove coasts are vulnerable to sea level rise and saltwater intrusion.

11) Conclusion

Climate change is a "whole-of-society" challenge. For India, the best approach is balanced and practical: rapid clean energy expansion, strong energy efficiency, cleaner transport, climate-smart agriculture, protection of forests and wetlands, and climate-resilient infrastructure—while demanding fairness in global finance and technology under climate justice and equity. In UPSC, the highest scoring answers are those that connect causes to India-specific impacts and present mitigation + adaptation solutions in a structured way.