Is La Nina in the offing? How the shift from El Nino may impact monsoon, summer in India this year

Is La Nina in the offing? How the shift from El Nino may impact monsoon, summer in India this year

Subject: Geography

Section: Climatology

Context:

• India is likely to see increased rainfall during the southwest monsoon season following a dry winter and predictions of a hot spring and summer in the northwest, northeast, and central regions.

Details:

• This expected increase in rainfall is attributed to the development of a La Nina event, contrasted with the current El Nino conditions and global warming effects, which typically result in higher temperatures and reduced rainfall.
• El Nino and La Nina are phases of the El Nino Southern Oscillation (ENSO) that influence global climate patterns, with La Nina generally bringing cooler temperatures and more rainfall to India.
• Despite La Nina’s tendency to increase rainfall, recent observations, such as early and intense heatwaves during a La Nina year, suggest changes in its impact.
• The current El Nino is anticipated to end by early summer, followed by a brief neutral period, then shifting to La Nina conditions, with a greater than 70% chance of a La Nina event by late 2024.
• Predicting ENSO conditions is challenging due to the spring barrier, but historical trends show a significant correlation between strong El Ninos and subsequent La Nina events.
• The upcoming La Nina could result in above-average rainfall for India during the latter part of the monsoon season, potentially impacting all India mean rainfall positively, although some states may experience deficits.
• The previous La Nina event led to above-normal rainfall and extreme weather events across India, and a similar pattern could occur in 2024, exacerbated by global warming and regional sea temperature increases.

ENSO cycle:

• El Nino–Southern Oscillation (ENSO) is an irregularly periodic variation in winds and sea surface temperatures over the tropical eastern Pacific Ocean.
• Every three to seven years, the surface waters across the tropical Pacific Ocean warm or cool by 1°C to 3°C, compared to normal.
• The warming phase of the sea temperature is known as El Nino and the cooling phase as La Nina.
• Thus, El Nino and La Nina are opposite phases of what is known as the El Nino-Southern Oscillation (ENSO) cycle.
• These deviations from normal surface temperatures can have large-scale impacts not only on ocean processes but also on global weather and climate.

Source: DTE