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Climate Change and Its Impact – UPSC Geography Notes
Overview: Climate change refers to long-term alterations in temperature, precipitation, wind patterns, and other elements of the Earth's climate system. It is one of the most serious global challenges of the 21st century, affecting ecosystems, economies, and human life. Understanding its causes, impacts, and solutions is essential for UPSC Geography and Environment studies.
Table of Contents
- 1. What is Climate Change?
- 2. Difference Between Weather, Climate, and Climate Change
- 3. Causes of Climate Change
- 4. Greenhouse Effect and Global Warming
- 5. Major Greenhouse Gases
- 6. Evidences of Climate Change
- 7. Impacts of Climate Change
- 8. Effects on India
- 9. Global Initiatives to Combat Climate Change
- 10. Measures for Mitigation and Adaptation
- 11. UPSC Quick Revision Notes
- 12. Previous Year Question
1. What is Climate Change?
Climate change refers to significant and lasting changes in global or regional climate patterns over decades or centuries. It is mainly caused by natural processes and human activities (anthropogenic factors).
2. Difference Between Weather, Climate, and Climate Change
| Term | Definition | Time Scale |
|---|---|---|
| Weather | Day-to-day atmospheric conditions | Short-term (hours to days) |
| Climate | Average weather pattern of a region | Long-term (30 years or more) |
| Climate Change | Long-term alteration in average climate patterns | Decades to centuries |
3. Causes of Climate Change
(a) Natural Causes
- Volcanic Eruptions: Emit large amounts of ash and gases, reducing solar radiation and cooling the Earth temporarily.
- Solar Variations: Changes in solar energy output affect global temperatures.
- Ocean Currents: Changes in ocean circulation alter heat distribution.
- Plate Tectonics: Shifting continents modify ocean and atmospheric circulation.
(b) Human-Induced Causes (Anthropogenic)
- Burning of Fossil Fuels: Releases CO₂, methane, and nitrous oxide.
- Deforestation: Reduces carbon absorption and increases greenhouse gas concentration.
- Industrialization: Emissions from factories and transport increase atmospheric pollution.
- Agriculture: Methane emissions from livestock and paddy fields.
- Urbanization: Heat islands and increased energy consumption add to warming.
4. Greenhouse Effect and Global Warming
Greenhouse Effect: The natural process by which certain gases in the atmosphere trap heat radiated from Earth’s surface, keeping the planet warm enough for life.
Global Warming: The enhanced greenhouse effect caused by increased levels of greenhouse gases due to human activities.
5. Major Greenhouse Gases
| Gas | Chemical Formula | Main Source |
|---|---|---|
| Carbon Dioxide | CO₂ | Burning of fossil fuels, deforestation |
| Methane | CH₄ | Livestock, paddy fields, waste decomposition |
| Nitrous Oxide | N₂O | Fertilizers, biomass burning |
| Ozone | O₃ | Photochemical reactions in lower atmosphere |
| Water Vapour | H₂O | Evaporation, condensation |
6. Evidences of Climate Change
- Global temperature rise by about 1.2°C since pre-industrial levels.
- Melting of glaciers and Arctic sea ice.
- Rising sea levels (about 3 mm/year).
- Increased frequency of extreme weather events – heat waves, cyclones, droughts.
- Shifts in rainfall patterns and growing desertification.
7. Impacts of Climate Change
(a) Environmental Impacts
- Melting glaciers and polar ice caps.
- Rising sea levels threatening coastal regions and islands.
- Coral bleaching and biodiversity loss.
- Increased frequency of forest fires and floods.
(b) Economic Impacts
- Reduced agricultural productivity due to erratic rainfall.
- Damage to infrastructure from extreme weather events.
- Increased energy demand for cooling.
(c) Social and Health Impacts
- Water and food insecurity.
- Migration and displacement due to rising sea levels.
- Health issues – heat strokes, vector-borne diseases (malaria, dengue).
8. Effects on India
- Increased intensity of monsoon variability and cyclones (especially in Bay of Bengal).
- Melting of Himalayan glaciers affecting river flows.
- Coastal erosion and sea-level rise threatening cities like Mumbai and Chennai.
- Frequent droughts and floods in central and eastern India.
- Decline in agricultural yields and forest productivity.
9. Global Initiatives to Combat Climate Change
- UNFCCC (1992): Framework for global cooperation on climate change.
- Kyoto Protocol (1997): Legally binding emission reduction targets for developed countries.
- Paris Agreement (2015): Limit global warming to below 2°C (preferably 1.5°C).
- IPCC (Intergovernmental Panel on Climate Change): Provides scientific assessments on climate change.
- India’s Commitments: National Action Plan on Climate Change (NAPCC), renewable energy expansion, and afforestation.
10. Measures for Mitigation and Adaptation
(a) Mitigation (Reducing Causes)
- Promoting renewable energy (solar, wind, hydro).
- Improving energy efficiency and reducing carbon footprint.
- Afforestation and reforestation.
- Carbon capture and storage technologies.
- Reducing waste and encouraging sustainable lifestyles.
(b) Adaptation (Adjusting to Effects)
- Climate-resilient agriculture (drought-resistant crops).
- Coastal protection and flood management systems.
- Water conservation and rainwater harvesting.
- Disaster management and early warning systems.
11. UPSC Quick Revision Notes
Causes → Natural (volcanic, solar) + Human (fossil fuels, deforestation).
Major GHGs → CO₂, CH₄, N₂O, O₃, H₂O.
Effects → Melting glaciers, sea-level rise, droughts, biodiversity loss.
Global efforts → UNFCCC, Kyoto, Paris Agreement.
India → NAPCC, renewable energy, afforestation.
Mitigation = reduce emissions; Adaptation = adjust to impacts.
12. Previous Year Question
Q. Which of the following greenhouse gases has the highest global warming potential?
(a) Carbon Dioxide
(b) Methane
(c) Nitrous Oxide
(d) Chlorofluorocarbon (CFC)
Answer: (d) Chlorofluorocarbon (CFC)
Related Keywords
Climate Change UPSC Notes, Global Warming, Greenhouse Effect, Paris Agreement, IPCC, Climate Change Impacts in India, Geography Notes for UPSC, Environment GS Paper 3.
Sources: NCERT Class XI – Fundamentals of Physical Geography, IPCC Sixth Assessment Report (AR6), UNFCCC, Government of India – NAPCC (simplified for UPSC students).
