What are EL Niño and La Niña?
They are two natural climate phenomena occurring across the tropical Pacific Ocean and
influence the weather conditions all over the world.
● While the El Niño period is characterised by warming or increased sea surface temperatures
in the central and eastern tropical Pacific Ocean, a La Niña event causes the water in the
eastern Pacific Ocean to be colder than usual.
What causes El Nino?
- El Nino sets in when there is an
anomaly in the pattern.
- The westward-blowing trade winds
weaken along the Equator and due
to changes in air pressure, the
surface water moves eastwards to
the coast of northern South America.
- The central and eastern Pacific
regions warm up for over six months
and result in an El Nino condition.
Weather changes because of La Nina:
- The Horn of Africa and central Asia will
see below average rainfall due to La
- East Africa is forecast to see drierthan-usual conditions, which together
with the existing impacts of the desert
locust invasion, may add to regional
- It could also lead to increased rainfall
in southern Africa.
- It could also affect the South West Indian Ocean Tropical Cyclone season, reducing the
- Southeast Asia, some Pacific Islands and the northern region of South America are expected
to receive above-average rainfall.
- In India, La Niña means the country will receive more rainfall than normal, leading to floods.
El Niño years in India have witnessed extreme heat and below normal rainfall levels during
monsoon, even though El Niño might not be the only factor or even have direct links to them. In
2014, a El Niño year, India received 12 per cent deficient rainfall from June to September.