Are El Niño-La Niña weather patterns changing?

Source: The post is based on the article “Are El Niño-La Niña weather patterns changing?” published in The Hindu on 24th November.

What is the News?

A new study projects that climate change will significantly impact El Niño-La Niña weather patterns approximately by 2030 — a decade before what was earlier predicted.

What are El Nino and La Nina?

El Nino and La Nina, which mean ‘the boy’ and ‘the girl’ in Spanish, are mutually opposite phenomena.

La Niña refers to the phase in which sea-surface temperatures are cooler than normal. The warmer phase is known as El Niño.

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What is the impact of El Nino and La Nina?

Impact of El Nino: The phenomena of upwelling, where nutrient-rich waters rise towards the surface, is reduced under El Niño. This in turn reduces phytoplankton. Thus, fish that eat phytoplankton are affected, followed by other organisms higher up the food chain.

– Warm waters also carry tropical species towards colder areas, disrupting multiple ecosystems.

– El Niño also causes dry, warm winters in the Northern U.S. and Canada and increases the risk of flooding in the U.S. gulf coast and south-eastern U.S. It also brings drought to Indonesia and Australia.

Impact of La NiñaThis leads to drier conditions in the Southern U.S., and heavy rainfall in Canada. La Niña has also been associated with heavy floods in Australia.

What is the effect of El Nino and La Nina on India’s monsoons?

In India, El Niño causes weak rainfall and more heat, while La Niña intensifies rainfall across South Asia particularly in India’s northwest and Bangladesh during the monsoon. 

At present, India, like the rest of the globe is witnessing an extended ‘triple dip’ La Niña. This is why India saw surplus rain in September, a month that usually sees the monsoon retreat, for the third year in a row.

What are the study’s findings?

The combination of El Niño, La Niña and the neutral state between the two opposite effects is called the El Niño Southern Oscillation(ENSO). ENSO’s scale is significant enough to influence the global climate. 

The study has projected that climate change will significantly impact El Niño-La Niña weather patterns approximately by 2030 — a decade before what was earlier predicted.

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