The El Niño Effect
- El Niño is a climate phenomenon in which surface temperatures in the equatorial Pacific Ocean see an unusual rise.
- El Niño is not a regular cycle, or predictable in the sense that ocean tides are.
- El Niño events repeat themselves in a two- to seven-year cycle, with a strong El Niño expected every 10-15 years.
- El Niño has an impact on ocean temperatures, the speed and strength of ocean currents, the health of coastal fisheries, and local weather from Australia to South America and beyond.
Impact of El Nino on Indian Monsoon
- El Nino and the Indian Monsoon rains are inversely related.
- Trade winds coming from South America normally blow westward towards Asia during Southwest Monsoon.
- Warming of the Pacific Ocean results in weakening of these winds.
- Therefore, moisture and heat content gets limited, and results in reduction and uneven distribution of rainfall across the Indian sub-continent.
- While warmer temperatures are known to suppress monsoon rainfall, the opposite phenomenon of La Niña has been found to be helpful in bringing good rainfall.
- According to NOAA, weak El Niño conditions had already built up in January and there is high probability of continuing of this condition for few months.
- The warming in the Niño 3.4 region of the Pacific Ocean, has been forecast to remain in excess of 0.5°C above normal, which is likely to decrease rainfall in India.
- However, it is not certain whether it will grow until springs or extend to summers.
- If the El Niño will grow until summers, it may cause a drought in India.
Increased frequency of El Nino
- As per new scientific research, increased frequency of extreme El Niños is due to climate change.
- If the average annual global temperatures reached 1.5°C above pre-industrial times, such extreme events could happen twice as often as today.
- However, the increased frequency could be because of other reasons as well.
Section : Environment & Ecology