by Rajshri Ravichandran
Trade winds sweep west along the equator in the Pacific Ocean under typical conditions, carrying hot water from Latin America towards Asia. Upwelling is the process by which cool water flows from the deep to substitute that warm water. These typical conditions are disrupted by the opposing climate patterns known as La Nina and El Nino. The El Nino-Southern Oscillation (ENSO) cycle is the term used to describe this phenomenon. La Nina that lasts longer than a year are rather typical. It’s more likely that an El Nino will only occur once per year.
The term “El Nino” refers to the extensive ocean-atmosphere climate interaction associated with cyclical increases in sea surface temperatures throughout the central and eastern Equatorial Pacific.
The air rises and the surface air pressure over the Eastern Pacific decreases as a result of this warm water. On the other side, the temperatures cool off Asia and the western Pacific. Increased surface pressure results from this over the Indian Ocean, Australia and Indonesia. Therefore, as high pressure accumulates over the cool ocean waters, the drought begins to spread throughout Asia while it is raining in the Eastern Pacific. Pressure difference in the western Pacific is connected to it. El Nino has a negative effect on India’s agriculture and, consequently, its monsoon season. Seabirds and marine mammals struggle to survive or breed during El Nino.
Source: Galapagos Conservation Trust
Contrary to El Nino, La Nina occurs. The weather patterns are stronger than what drives ocean temperatures into Asia as during La Nina phenomena.
Source: The Hindu
Warmer water builds up in the western Pacific Ocean as a result, and cold water in the central and eastern Pacific Oceans. The eastern and central Pacific Ocean tides are colder than usual because of the strong easterly trade winds, which direct warm water into the western Pacific Ocean. Drought in Peru and Ecuador, severe flooding in Australia, high temperatures in the West Pacific, Indian Ocean, off the coast of Somalia, and abundant monsoon rains in India are all effects of La Nina. The Indian monsoon really benefits from a La Nina.
In the Indian continent, warm weather emerges in the winter while dry conditions and insufficient monsoons develop in the summer. In India, El Nino typically results in a weaker monsoon. However, this isn’t always the case. A study claims that an El Nino is to responsible for 60% of India’s droughts during the previous 130 years. These were years with below-average rainfall of more than 10%. But not every El Nino has been followed by a disastrous monsoon or a catastrophic drought. 70% of farmers rely on rainfall, while the remaining 30% rely on irrigation. As a result, the monsoon is essential for India, where agriculture accounts for over 18% of the country’s GDP (GDP). Demand declines in rural areas as a result of bad rainfall and the ensuing decline in agricultural revenue. Additionally, the government might be compelled to set a minimum support price for crops. Inflation will rise as a result of consumers having to pay more for staples like rice, sugar, and other food goods like cereals and pulses.
- “What are El Niño and La Niña?”. National Oceanic and Atmospheric Administration
- Priyali Prakash, “Explained | El Niño, La Niña and changing weather patterns”. The Hindu, 25 November 2022.
- M R Ramesh Kumar, “El Nino, La Nina and the Indian sub-continent”. Down To Earth, 30 November 2022.
- Amitabh Sinha, “The ‘triple dip’ La Niña, and its likely impact in India”. The Indian Express, 23 September 2022.