GS Paper 1 10 marks · 150w 9 min Medium
Most of the unusual climatic happenings are explained as an outcome of the El-Nino effect. Do you agree?
Subtopic: Geography · El Niño, ENSO and climatic anomalies
How to structure your answer
Introduction: define El Niño/ENSO and weakened Walker circulation → Anomalies El Niño does explain: Indian monsoon deficits, Peru floods, Australian droughts, global heat spikes → Counter-view: La Niña, IOD, MJO and jet-stream drivers of extremes → Anthropogenic warming and exceptions like 1997 → Conclusion: partial agreement — major but not sole explanation
Detailed model answer
200 words · target 150 words · 9 min
El Niño is the anomalous warming of sea-surface waters in the central-eastern equatorial Pacific that weakens the Walker circulation; with the Southern Oscillation it forms ENSO, the strongest single driver of year-to-year climate variability.
What El Niño does explain
- Deficient Indian monsoons and droughts — the 2015 and 2023 deficit years coincided with El Niño episodes.
- Droughts and forest fires in Australia and Indonesia; torrential rain and floods on the Peru–Ecuador coast.
- Suppressed Atlantic hurricane activity and global temperature spikes — the record warmth of 2016 and 2023–24 rode on El Niño.
Why “most” is an overstatement
- La Niña years produce equally unusual, opposite anomalies — floods in eastern Australia and hyperactive Atlantic hurricane seasons.
- Other oscillations matter: a strong positive Indian Ocean Dipole delivered surplus monsoon rainfall in 2019 despite El Niño-like conditions early that season.
- The Madden–Julian Oscillation, jet-stream meanders, western disturbances and polar-vortex breakdowns drive many extremes independently.
- Anthropogenic warming now amplifies extremes in all years; nor is every El Niño year a drought year in India — 1997, among the strongest El Niños, saw a normal monsoon.
Hence only partial agreement is warranted: El Niño is a major, but not the sole, explanation of unusual climatic happenings.
What an examiner expects to see
- Define El Niño precisely: anomalous central-eastern equatorial Pacific warming, weakened Walker circulation, part of the coupled ENSO system
- Credit its real teleconnections: weak Indian monsoons, Peru–Ecuador floods, Australian/Indonesian droughts, subdued Atlantic hurricanes, global temperature spikes
- Challenge the word ‘most’: La Niña produces opposite but equally unusual anomalies
- Bring in other drivers — Indian Ocean Dipole, Madden–Julian Oscillation, jet-stream and polar-vortex behaviour, western disturbances
- Note exceptions: 1997 strong El Niño with a normal Indian monsoon; 2019 positive IOD offsetting deficit
- Anthropogenic climate change is now an independent amplifier of extremes
- Balanced verdict: major contributor, not a universal explanation
Concrete cases, schemes and judgments
- 2015 and 2023 Indian monsoon deficit years coincided with El Niño; 2016 and 2023–24 were record-warm years globally
- 1997–98 was among the strongest El Niños on record, yet India received a near-normal monsoon
- 2019: strong positive Indian Ocean Dipole produced above-normal monsoon rainfall despite unfavourable Pacific conditions
- 2010–12 back-to-back La Niña brought severe Queensland (Australia) floods and active Atlantic hurricane seasons
Terminology to weave into the answer
ENSOWalker circulationSouthern OscillationIndian Ocean DipoleteleconnectionLa Niña