The correct option is Heavy rainfall in the arid west coast of South America.
Explanation
El Niño is a climate pattern characterized by the unusual warming of surface waters in the eastern tropical Pacific Ocean. It represents the warm phase of the El Niño-Southern Oscillation (ENSO) cycle and significantly alters global atmospheric circulation.
- Floods in Australia and drought in China is incorrect: During an El Niño event, high pressure builds up over the western Pacific. This results in suppressed convection, leading to droughts and dry conditions in Australia and Indonesia, rather than floods.
- Heavy rainfall in the arid west coast of South America is correct: The accumulation of warm water off the coast of Peru and Ecuador increases evaporation and atmospheric instability. This leads to heavy rainfall and potential flooding in the coastal regions of South America, which are otherwise arid and influenced by the cold Humboldt Current.
- Consistent heavy rainfall in India is incorrect: El Niño is generally associated with the weakening of the trade winds and the disruption of the Walker Circulation. For India, this typically results in a weakened Southwest Monsoon, leading to below-average rainfall or drought conditions, not consistent heavy rainfall.
- Strengthening of the cool Peruvian current is incorrect: The El Niño event is defined by the replacement of the cold, nutrient-rich Peruvian (Humboldt) Current with warm tropical waters. Consequently, the cool current and the associated upwelling of nutrients are weakened or halted, negatively impacting local fisheries.
Key Takeaway: El Niño involves the warming of the Eastern Pacific Ocean, causing heavy rains in South America (Peru/Ecuador) and droughts in the Western Pacific (Australia/Indonesia), while often suppressing the Indian Monsoon.