Physical Geography / Oceans and Seas — UPSC Mains Model Answer

Under normal conditions, easterly trade winds push warm surface water toward the Indo-Pacific warm pool, enabling upwelling of cold, nutrient-rich water off South America's coast. During El Niño, these trade winds weaken or reverse, allowing warm water to spread eastward across the central and eastern Pacific. This redistribution fundamentally alters the Walker Circulation, the atmospheric engine linking tropical ocean and weather systems.

El Niño typically brings drought to Australia, Southeast Asia, and southern Africa, while triggering excess rainfall along the western coast of South America — reversing the statement that Australia receives excess rainfall. India's southwest monsoon often weakens during El Niño years, raising food security concerns. The 2015–16 El Niño was among the strongest on record, contributing to severe droughts across multiple regions simultaneously.

Anticipating El Niño events requires robust early-warning systems, cross-border data sharing, and pre-positioned relief stocks. India's National Disaster Management Authority and meteorological agencies now integrate El Niño forecasts into seasonal agricultural advisories. However, translating probabilistic climate forecasts into actionable district-level responses remains an institutional gap, particularly for rain-fed farming communities.

Strengthening climate-resilient agriculture, expanding irrigation buffers, and aligning food procurement policies with El Niño outlooks can mitigate economic shocks. International frameworks such as the Sendai Framework for Disaster Risk Reduction provide a normative basis for integrating climate variability into national risk governance.