El Niño is here, but can the Indian Ocean Dipole save India’s monsoon?
Global weather organizations, including those in the United States, predicted El Niño would return earlier this year. Some forecasts suggest its impact could extend into 2027, potentially affecting weather for a long period of time.
According to the IMD, the atmosphere has responded to rising sea surface temperatures in the Pacific, and the combined ocean-atmosphere system now shows features associated with El Niño.
How does El Niño affect India’s monsoon?
El Niño is a naturally occurring climate pattern that develops as sea surface temperatures in the central and eastern Pacific Ocean become warmer than normal. Historically, strong El Niño events have been associated with reduced monsoon rainfall in India, leading to concerns about agriculture, water availability and rural livelihoods.
Because millions of farmers depend on the southwest monsoon to grow crops, any significant rainfall deficit could have wide-ranging economic and social consequences. This phenomenon is also associated with hotter-than-normal summers in the Indian subcontinent.
What is the Indian Ocean Dipole (IOD)?
As El Niño forms in the Pacific Ocean, meteorologists are closely monitoring another climate pattern much closer to India, the Indian Ocean Dipole (IOD).
According to NASA, IOD is a climate phenomenon caused by differences in sea surface temperatures between the western and eastern regions of the Indian Ocean. During a positive IOD, warmer waters accumulate in the western Indian Ocean near Africa, while colder waters develop in the eastern Indian Ocean near Indonesia. During a negative IOD this pattern is reversed. Scientists classify IOD into three stages:
Positive IOD
Negative IOD
Neutral IOD
IOD plays a crucial role in shaping rainfall and temperature patterns in countries bordering the Indian Ocean. A positive IOD typically strengthens the moisture flux towards India, increasing the likelihood of increased rainfall during the monsoon season.
NASA notes that a positive IOD could bring heavy rainfall to parts of East Africa, while contributing to drier conditions in Australia. This event may also affect sea levels and increase the risk of coastal flooding in affected areas.
Can the Indian Ocean Dipole offset the impact of El Niño?
Currently, IOD remains in a neutral phase. However, the Japan Meteorological Agency (JMA) stated that a positive IOD may develop later this year. The agency was among the first major weather organizations to declare the onset of El Niño.
Climate experts say it is too early to determine the strength and timing of any positive IOD events. However, historical data shows that a positive IOD can sometimes reduce the negative impact of El Niño on the Indian monsoon.
One of the most notable examples occurred in 1997, when one of the strongest El Niño events on record coincided with a strong positive IOD. Despite intense El Niño, India avoided a severe monsoon deficit as it helped offset the positive IOD effects.
What awaits monsoon rains in India?
While the possibility of a positive Indian Ocean Dipole offers some hope, weather experts caution against assuming it will guarantee normal or above-normal rainfall. The extent to which it can offset El Niño depends on when it develops and how strong it becomes during the monsoon season.
For now, meteorologists will continue to closely monitor both climate systems as the interaction between El Nino and the Indian Ocean Dipole may play a major role in determining the fate of monsoons in India in the coming months.
