La Nina and Its Impacts

Context

The India Meteorological Department (IMD) has recently forecasted above-normal rain in the upcoming monsoon season in India, with “favourable” La Nina conditions expected to set in by August-September. 

About

• El Niño and La Nina are weather phenomena that are a result of ocean-surroundings interactions, which affect the temperature of waters within the primary and eastern  tropical Pacific Ocean.
• El Niño events are way more common than La Nina ones. Once in every two to seven years, neutral ENSO conditions get interrupted by both El Niño or La Nina.
• Coriolis Effect: The Earth’s east-west rotation causes all winds blowing among 30 tiers to the north and south of the equator to slant their trajectory.
  • As a result, winds in the location glide towards a southwesterly course within the northern hemisphere and a northwesterly course within the southern hemisphere. This is called the Coriolis Effect.
  • Due to this, winds on this belt referred to as extrade winds blow westwards on either side of the equator. 
• Normal Conditions: During regular situations in the Pacific ocean, trade winds blow west alongside the equator, taking heat water from South America towards Asia. 
  • To replace that warm water, cold water rises from the depths — a procedure called upwelling. 
  • The warmer floor waters near Indonesia create a vicinity of low-strain area, inflicting the air to upward thrust upwards. This additionally results in formation of clouds and heavy rainfall. 
  • The air flow also facilitates in building up the monsoon machine which brings rainfall over India.

La Niña

• It is called ” Little Girl in Spanish. La Niña is also every so often called El Viejo, anti-El Niño, or sincerely “a cold event.” La Niña has the opposite effect of El Niño. 
• The trade winds end up stronger than regular, pushing extra warmer waters closer to the Indonesian coast, and making the eastern  Pacific Ocean colder than everyday.

El Nino & La Nina

• Impacts

• • Increased rainfall: Regions along with Southeast Asia, northern Australia, and elements of South America regularly revel in above-average rainfall in the course of La Niña occasions.
    • Except in east and northeast India, all closing areas are expected to get hold of ordinary or above seasonal rainfall for the duration of La Nina.
    • Similar to India, Indonesia, the Philippines, Malaysia and their neighbouring nations acquire exact rainfall for the duration of a La Nina year.
  • Drier situations in a few areas: Conversely, regions like the southwestern United States and elements of Africa experience below-common rainfall, leading to drought conditions.
  • Stronger Atlantic hurricanes: La Niña tends to lessen wind shear in the Atlantic, developing conditions that are extra conducive to the development of hurricanes.
    • For instance, the Atlantic Ocean churned out a record 30 hurricanes all through the La Nina year 2021.
  • Cooler temperatures: Some regions enjoy cooler temperatures than ordinary, particularly in the Pacific Northwest of the USA and parts of South America.

What is El Nino?

• El Niño is calledLittle Boy in Spanish. South American fishermen first noticed durations of unusually warm water within the Pacific Ocean within the 1600s.
• It is a climate phenomenon characterized by means of the periodic warming of sea floor temperatures inside the vital and eastern  equatorial Pacific Ocean.
• During El Niño, extrade winds weaken. Warm water is driven back east, toward the west coast of the Americas and as a result bloodless water is pushed closer to Asia.

Impact of El Nino

• Low Rainfall: El Niño often correlates with under-common monsoon rainfall in India, leading to droughts in many elements of the country. This can have extreme results for agriculture, water resources, and the economy.
• Increased Temperature: El Niño additionally leads to an increase in temperatures throughout diverse parts of India. 
• Forest Fires: The drier conditions associated with El Niño increase the threat of forest fires, specifically in areas with dense vegetation. These fires cause environmental harm, lack of biodiversity, and air pollutants.
• Water Scarcity: Decreased rainfall throughout El Niño events result in water shortage in many elements of India. This has an effect on drinking water components, irrigation for agriculture, and hydropower technology.
• Impact on Fisheries: El Niño also has an effect on marine ecosystems and fisheries along India’s coastline. trades in sea floor temperatures and ocean currents disrupt fish migration patterns and cause fluctuations in fish populations.

Conclusion

• Scientists say that weather trade is about to impact the ENSO cycle. Many studies endorse that international warming tends to change the mean oceanic conditions over the Pacific Ocean and trigger more El Niño events.
• The World Meteorological Organization (WMO) has also stated that climate change is probably to affect the intensity and frequency of severe weather and climate events connected to El Niño and La Nina.

Source: The Indian Express

UPSC Mains Practice Question

Q. What are the El Niño and La Niña events? How do these phenomena impact the monsoon in India? (250 words)

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