Questions related to El Nino and La Nino are widely asked in the UPSC Prelims and Mains exams regarding their definitions, implications, and what their impact actually is. Today, in this article, we will clear a few concepts regarding El Nino and La Nino UPSC and its impact on India’s weather phenomenon and mechanism.
Monsoon is the most looked after season in India, be it for agriculture and disaster management or the various economic policies that are framed. Monsoon is a recurring season and comes every year, but the real factor is the density and uniformity of the rainfall every year. Every year, a different density of rain occurs, changing a country’s functioning completely.
In India, the monsoon happens because of the temperature variations in the Indian ocean that creates winds laden with moisture. These moisture-laden winds get affected due to the difference in the temperature distributions, which causes phenomena like El Nino, La Nino, Indian ocean dipole, Indian Ocean Oscillation (EQUINOO), and many others.
What is La Nino and El Nino?
La Nino and El Nino are the climatic weather patterns that happen due to variations in the oceanic temperature differences in the Equatorial Pacific Region. These climatic phenomenons are actually opposite phases to the El Nino Southern Oscillation (ENSO) cycle. The ENSO cycle is nothing but a factor determining the fluctuations and variations in temperature between the atmosphere and ocean in the east-central Equatorial Pacific.
What is La Nino?
La Nino basically describes the patterns of unusual cooling of water in the tropical eastern Pacific. It is known as the “cool phase” of the ENSO cycle. In the east-central equatorial pacific region, the below-average temperatures of sea surfaces make La Nino occur. The temperatures of the sea surface, reducing by more than 0.9 degrees Fahrenheit for five consecutive three-month sessions, can result in La Nino occurring.
Strong high pressure is built over the eastern equatorial Pacific, which is observed when the water temperature in the ocean gets comparatively colder than normal. La Nino does not occur more frequently, but it lasts for between one to three years at least.
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What is El Nino?
On the other hand, El Nino is the unusual warming up of the temperatures in the surface waters of the eastern tropical Pacific ocean. It is known as the “warm phase” that defines the unusual warming of the ENSO cycle. El Nino occurs more frequently than La Nino, but it lasts for no more than a year.
El Ninos are actually very unpredictable and occur irregularly. It is known for its irregular nature, and it seems to be more than just warming up of sea surface waters. The atmospheric pressure over the ocean reduces when the sea surface waters get warmer during El Nino.
What are the Impacts of El Nino and La Nino?
The climatic phenomenons in the name of El Nino and La Nino can cause various impacts on the oceans, temperatures, rainfalls, natural disasters, etc. Below are the positive and negative impacts of El Nino followed by La Nino –
Positive Impacts
- El Nino can sometimes be a cause of reducing the chances of hurricanes in the Atlantic region.
Negative Impacts
- El Nino impacts ocean temperatures and the speed and strengths of ocean currents that can ultimately affect the weather of countries like Australia and South America. It can affect the health of fisheries and agriculture of coastal areas near these regions.
- El Nino also leads to a drastic uprise in rainfall for the regions in South America and a slight uprise in the regions of Australia. It can cause significant instances of droughts and weaker monsoons in the parts of the south of India. This happens due to the result of the higher precipitation occurring due to warmer sea surface waters.
- El Nino can also lead to floods and droughts in the regions of majorly South America, Australis, South-Asian countries, and India, causing natural disasters and hazards. This can lead to increased diseases in the form of dengue, cholera, typhoid, malaria.
Impacts of La Nino
Positive Impacts
- La Nino has a huge impact on the fishing industries of western South America. It also reduces many instances of autumnal hurricanes in the European regions.
- La Nino leads to snow in the Mediterranean regions and causes colder winters in the southwestern parts of the European regions.
Negative Impacts
- La Nino causes stronger winds in the equatorial Pacific regions that can also result in hurricanes in the parts of central Atlantic and Caribbean countries. It can also result in instances of tornados in some states of the US.
- La Nino also increases the instances of landfall in the western pacific area, including China and Continental Asia. It leads to heavy rainfall and floods in Australia and increased temperatures of sea surface waters in the Indian ocean, Somalian Coast, and Western Pacific.
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Final Words
There can be strong implications of El Nino and La Nino in the Indian regions, with El Nino causing more droughts and weaker monsoons in Southeast Indian and La Nino causing summer monsoon more than usual in the parts of Northwest India and Bangladesh. La Nino produces more cold air in South India like Tamil Nadu and contributes to unpredictable rainfall and monsoon.
We hope that in the above article, you were able to understand what these phenomena are, how they happen, and their impacts. You will also be able to understand how El Nino impacts monsoon rainfall in India?
The UPSC aspirants must regularly prepare well on El Nino UPSC and La Nino UPSC as questions related to natural phenomena are asked in the UPSC Prelims and UPSC Mains.
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