Core definition
El Niño is the periodic warming of surface waters in the central and eastern equatorial Pacific Ocean. It is the warm phase of the El Niño–Southern Oscillation, commonly called ENSO.
Why it matters to India
Changes in Pacific Ocean temperatures can alter atmospheric circulation and influence the Indian summer monsoon. El Niño is often associated with a greater risk of weaker monsoon rainfall, but the relationship is not automatic. Every El Niño year does not produce an all-India drought because other oceanic and atmospheric conditions also influence rainfall.
Exam-ready points
- ENSO has three commonly described conditions: El Niño, La Niña and neutral.
- El Niño is the warm phase; La Niña is the cool phase.
- The Indian summer monsoon generally occurs from June to September.
- Monsoon effects should be described as a tendency or risk, not a guaranteed outcome.
- Possible impacts include agriculture, reservoirs, food prices, power demand and rural livelihoods.
Common mistake
Do not write “El Niño always causes drought in India.” A safer statement is: “El Niño can increase the risk of weaker monsoon rainfall, but the final outcome depends on several interacting conditions.”
Quick self-check
- Is El Niño the warm or cool phase of ENSO?
- Why should its effect on the Indian monsoon not be presented as certain?
- Name two sectors that may require preparedness during a weak monsoon.