SSC CGL - Detailed Guide 2025
Self-Paced Course
Climate Change & Global Environmental Issues
Reference: Lucent GK, NCERT Class 6–12
1. Global Warming
Definition: A long-term rise in Earth's atmospheric temperature due to increased greenhouse gases (GHGs).
| Cause | Description |
|---|---|
| CO₂ (Carbon Dioxide) | From fossil fuel burning, deforestation |
| CH₄ (Methane) | From agriculture (rice fields), cattle, landfills |
| N₂O (Nitrous Oxide) | From fertilizer use and combustion |
| HFCs & CFCs | Industrial coolants and refrigerants |
Greenhouse Effect: Natural process that warms Earth's surface. Enhanced by human activities → leads to global warming.
Major Effects:
- Melting of glaciers & polar ice caps
- Sea-level rise → coastal flooding
- Extreme weather (droughts, heatwaves)
- Coral bleaching & ocean acidification
- Biodiversity loss
India's Glaciers (Himalayas) are receding at an alarming rate.
2. Ozone Layer Depletion
Definition: Stratospheric layer (~15-35 km) that protects Earth from harmful ultraviolet (UV) radiation.
| Cause | Details |
|---|---|
| Chlorofluorocarbons (CFCs) | Used in air-conditioners, refrigerators, aerosols |
| Halons, HCFCs | Fire extinguishers, solvents, etc. |
| UV Exposure Effects | Skin cancer, cataracts, immune suppression, crop damage |
Montreal Protocol (1987):
- Global agreement to phase out ozone-depleting substances (ODS).
- One of the most successful international environmental treaties.
3. Acid Rain
Definition: Precipitation (rain, snow, fog) with pH < 5.6 due to dissolved acidic gases like SO₂ and NOₓ.
| Cause | Emitted From |
|---|---|
| Sulfur Dioxide (SO₂) | Thermal power plants, refineries, smelters |
| Nitrogen Oxides (NOₓ) | Vehicle exhaust, burning fossil fuels |
Impacts:
- Corrodes buildings (especially marble — e.g., Taj Mahal)
- Damages crops and forests
- Makes lakes/rivers acidic → kills aquatic life
Taj Trapezium Zone (TTZ) was declared to reduce air pollution near the Taj Mahal.
4. El Niño & La Niña
Definition: Periodic climatic phenomena associated with warming/cooling of central Pacific Ocean with global impacts.
| Event | Description | Indian Impact |
|---|---|---|
| El Niño | Abnormal warming of Pacific Ocean waters near South America | Weakens monsoon, causes drought in India |
| La Niña | Abnormal cooling of Pacific Ocean waters | Strengthens monsoon, increases rainfall |
El Niño years often see reduced rainfall and increased temperatures across India.
El Niño is monitored by the Indian Meteorological Department (IMD) for monsoon predictions.
5. Sustainable Development Goals (SDGs)
- Launched by: United Nations (2015)
- Target Year: 2030
- Number of Goals: 17
- India's Role: Active participant via schemes like Swachh Bharat, Jal Jeevan Mission, Ujjwala Yojana, PM-KUSUM
Select SDGs (out of 17):
| SDG | Goal Description |
|---|---|
| SDG 1 | No Poverty |
| SDG 2 | Zero Hunger |
| SDG 3 | Good Health and Well-being |
| SDG 6 | Clean Water and Sanitation |
| SDG 7 | Affordable and Clean Energy |
| SDG 13 | Climate Action |
| SDG 15 | Life on Land |
| SDG 17 | Partnerships for the Goals |
India's NITI Aayog tracks national progress on SDGs through the SDG Index.
Quick Revision Points:
- GHGs cause global warming, not ozone depletion.
- CFCs = Ozone depletion | CO₂, CH₄ = Global warming
- India signed both Montreal Protocol & Paris Climate Agreement (2015)
- El Niño = drought in India; La Niña = more rain
- SDGs replaced MDGs (Millennium Development Goals) in 2015
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