PRELIMS 120+

https://t.me/knowupscdemands Newspaper to Concept Series EL NIÑO & INDIAN OCEAN DIPOLE (IOD) ⸻ 1) What is El Niño? El Niño is the warm phase of the El Niño–Southern Oscillation (ENSO), a natural climate phenomenon that originates in the central and eastern equatorial Pacific Ocean. It occurs when: Sea Surface Temperatures (SST) become warmer than normal in the central and eastern Pacific. Trade winds weaken or reverse. Warm ocean water shifts eastward towards South America. Atmospheric circulation changes, altering rainfall and temperature patterns across the globe. Key Facts Occurs every 2–7 years Usually lasts 9–12 months Strongly influences the Indian monsoon, agriculture and global climate. ⸻ 2) Consequences of El Niño 🇮🇳 India • Weak southwest monsoon • Drought conditions • Heat waves • Reduced agricultural production • Water shortages ⸻ 🇦🇺 Australia • Severe drought • Bushfires • Water scarcity • Crop failures ⸻ 🇮🇩 Indonesia • Drought • Forest fires • Haze pollution • Decline in agricultural output ⸻ 🌍 East Africa (Kenya, Ethiopia & Somalia) • Heavy rainfall • Flooding • Landslides • Disease outbreaks ⸻ 🌍 Southern Africa • Drought • Crop failures • Food insecurity • Water shortages ⸻ 🇵🇪 Peru & 🇪🇨 Ecuador • Heavy rainfall • Floods • Landslides • Fisheries decline due to reduced upwelling ⸻ 🇧🇷 Brazil (Amazon Basin) • Drought • Forest fires • Reduced river flow • Biodiversity stress ⸻ 🇺🇸 North America • Southern USA receives above-normal rainfall • Northern USA and Canada experience warmer winters • Weather extremes become more frequent ⸻ 🌍 Europe • Milder winters in many regions • Weather anomalies • Increased heat events in some years ⸻ 🌎 Global Impacts • Rise in global average temperatures • Coral bleaching • Increased wildfire risk • More frequent extreme weather events • Marine ecosystem disruption ⸻ 3) What is the Indian Ocean Dipole (IOD)? The Indian Ocean Dipole (IOD) is an ocean-atmosphere phenomenon characterized by the difference in Sea Surface Temperature (SST) between: Western Indian Ocean (near East Africa) Eastern Indian Ocean (near Indonesia) ⸻ 4) Types of Indian Ocean Dipole ✅ Positive IOD (+IOD) Western Indian Ocean becomes warmer than normal Eastern Indian Ocean becomes cooler than normal Rainfall shifts towards East Africa Indonesia and Australia receive less rainfall Effect on India ✔ Stronger southwest monsoon ✔ Better rainfall ✔ Can reduce the adverse impact of El Niño ⸻ ❌ Negative IOD (−IOD) Western Indian Ocean becomes cooler than normal Eastern Indian Ocean becomes warmer than normal More rainfall over Indonesia and Australia Effect on India ✔ Weaker southwest monsoon ✔ Less rainfall ✔ Can worsen drought during El Niño years ⸻ ⚪ Neutral IOD Sea Surface Temperatures remain close to normal across the Indian Ocean. Very little influence on the Indian monsoon. ⸻ 5) Consequences of IOD on the Indian Monsoon 🌊 Positive IOD Strengthens the southwest monsoon Increases rainfall over India Can offset the effects of El Niño Improves agricultural prospects ⸻ 🌊 Negative IOD Weakens the southwest monsoon Reduces rainfall Increases drought risk Can intensify El Niño’s adverse effects ⸻ 🌊 Neutral IOD Little independent effect on rainfall ENSO (El Niño/La Niña) becomes the dominant climate driver

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