GEOGRAPHY OPTIONAL – PAPER I
PAGE 13 : CLIMATE CHANGE, GLOBAL WARMING & ENSO
UPSC / UPPSC Geography Optional
Shaktimatha 369 Learning
1. Climate Change – Meaning
Climate change refers to long-term alterations in temperature, precipitation, wind systems and other climatic elements, over decades or longer.
It may occur due to natural processes or human-induced activities.
Exam Importance: Very high – direct questions + GS linkage
2. Global Warming
Global warming is the gradual increase in Earth’s average surface temperature primarily due to enhanced greenhouse effect.
Major Greenhouse Gases
- Carbon dioxide (CO₂)
- Methane (CH₄)
- Nitrous oxide (N₂O)
- Chlorofluorocarbons (CFCs)
Key Concept: Enhanced greenhouse effect traps outgoing radiation.
3. Causes of Climate Change
(a) Natural Causes
- Volcanic eruptions
- Solar radiation variation
- Plate tectonics
- Orbital changes (Milankovitch cycles)
(b) Anthropogenic Causes
- Fossil fuel combustion
- Deforestation
- Industrialisation
- Agricultural practices
4. Impacts of Climate Change
Global Impacts
- Rising sea levels
- Melting glaciers & ice sheets
- Extreme weather events
- Ocean acidification
Indian Impacts
- Monsoon variability
- Heat waves & floods
- Himalayan glacier retreat
- Threat to coastal regions
5. ENSO – El Niño Southern Oscillation
ENSO is a periodic climatic phenomenon associated with changes in sea surface temperatures and atmospheric pressure over the equatorial Pacific Ocean.
6. El Niño
- Abnormal warming of eastern Pacific Ocean
- Weakens trade winds
- Suppresses Indian monsoon rainfall
Indian Impact: Droughts, reduced agricultural output
7. La Niña
- Abnormal cooling of eastern Pacific Ocean
- Strengthens trade winds
- Enhances Indian monsoon rainfall
Indian Impact: Floods, excess rainfall
8. Southern Oscillation
- Seesaw pattern of pressure between Tahiti & Darwin
- Measured using Southern Oscillation Index (SOI)
Diagram Mandatory: Walker circulation during El Niño & La Niña
9. Global Responses
- UNFCCC
- Kyoto Protocol
- Paris Agreement
- Nationally Determined Contributions (NDCs)
India’s Stand: Climate justice & sustainable development
10. Answer Writing Strategy
- Define climate change clearly
- Differentiate global warming & climate change
- Use ENSO diagrams
- Link with Indian monsoon & disasters
Golden Rule: ENSO diagram + Indian impact = top marks
PYQ Orientation
- ENSO and Indian monsoon
- Impacts of climate change
- Global warming causes & effects
NEXT PAGE
Geography Optional – Page 14:
Oceanography – Ocean Relief & Temperature
End of Geography Optional – Page 13
Shaktimatha 369 Learning
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