Understanding the Impact of El Niño on India's Gloomy Monsoon

A deep dive into the Southwest Monsoon of 2023 paints a gloomy picture, as India closes the season with 'Below-Normal' rainfall. Data as of September 29 reveal a shortfall in the countrywide cumulative rainfall by 6% from the long-period average (LPA) seasonal total. From the usual 865 mm of rain, the country received only 814.9 mm. This shortage is a clear illustration of the impact of the evolving El Niño in the Pacific Ocean on the Indian Monsoon.

El Niño and the Monsoon Journey

The monsoon season began under the looming threat of the evolving El Niño. Traditionally associated with lower rainfall during its height in the latter half of the monsoon season, experts had already put forward warnings of lesser rain. However, the inherent power of the monsoon manifested in September, as two low-pressure areas revived the rainfall, fending off a potential drought.

Unfortunately, the season was not without its challenges. Starting with a delay in monsoon onset and slow progress, June saw a deficit in rainfall by 10%. The emergence of Cyclone Biparjoy in the Arabian Sea marked the onset of the monsoon in Kerala, but an increase in its intensity sapped the country's moisture, stunting both progress and performance of the monsoon. Such an imbalance created high humidity levels, leading to heatwaves in East India, a sign of worsening global warming due to excessive evaporation and atmospheric moisture.

The Tug-of-War: El Niño versus Monsoon 2023

El Niño, characterized by abnormal warming of the eastern Pacific Ocean's surface waters, influences global wind patterns, often leading to decreased monsoon rains in India. Despite initial resilience in June and July, El Niño did cast its shadow on Monsoon 2023. According to weather models, there's a likelihood exceeding 95% of persisting El Niño during the Northern Hemisphere winter of 2023-24, favoring a moderate-to-strong El Niño (ONI at or greater than 1.0ºC).

Unfortunately, 80% of El Niño events have adverse outcomes on monsoon rainfall, concluding with 'drought' or 'below normal' situations. G P Sharma, President- Meteorology and Climate Change, Skymet Weather suggests, "Almost 60% of these occurrences end in drought, with rainfall deficit beyond 10% of LPA." In compliance with these warnings, Monsoon 2023 remained deficient by 6% of the LPA, despite falling under the 'normal' rainfall category as per India Meteorological Department (IMD).

Uneven Rainfall Distribution and Climatic Anomolies

Despite the overall classification, deeper scrutiny of the data reveals considerable disparities in rainfall distribution. Over 200 districts of the total 717 registered deficient rainfall. Contrary to general patterns, traditionally dry regions like West Rajasthan and Saurashtra-Kutch recorded surplus rainfall. In stark contrast, typically wet regions like Kerala, Gangetic West Bengal, Bihar, and Jharkhand experienced a dry season due to inadequate rainfall.

Investigation into these unusual patterns carried out by Dr Roxy Mathew Koll, Climate Scientist, Indian Institute of Tropical Meteorology, indicates a correlation between rising sea-surface temperatures in the Indian Ocean and the anomalies in South Asian precipitation, along with the spatial distribution of rainfall. These trends potentially suggest the deeper implications of climate change on Indian Monsoons.

In conclusion, the Indian Monsoon of 2023, while escaping the full onslaught of a drought, provided clear indications of the growing impact of El Niño and global warming on the monsoon pattern. The fluctuating, uneven distribution of rainfall across regions hints at complex meteorological changes in the wake of evolving climatic conditions. These changes, if left unchecked, could drastically alter the monsoonal norms, affecting water security, agriculture, and the overall economy of the country.