Lucknow: When rainwater entered Sachin Sharma's house in Noida this month, it was not the flooding that left him bewildered.
It was the forecast.
Like millions of Indians, Sharma had heard repeated warnings that July was likely to be drier than normal because of a strengthening El Niño, the climate phenomenon that has long been considered one of the most reliable indicators of India's monsoon.
Instead, his neighbourhood went under water.
"We were expecting a dry July. Then our colony was flooded and water entered our home. We have weather satellites. What are they doing?" Sharma asked this reporter.
His frustration reflects a question that has troubled weather scientists this monsoon: How did one of the world's most dependable climate signals get it so wrong?
The answer, researchers say, is not that El Niño has stopped influencing the monsoon. It is that climate change is increasingly competing with it, making India's rainy season more erratic and much harder to predict.
July became the latest reminder that the old rules governing the monsoon are changing.
Between July 1 and 26, India received 238.2 mm of rainfall against the normal 233.9 mm despite forecasts of below normal rainfall. A succession of low pressure systems also reduced the country's rainfall deficit from 40 per cent at the end of June to 16 per cent by July 29.
But behind the national figures lay a striking contrast.
While Maharashtra, Gujarat, Himachal Pradesh, Jammu and Kashmir and Assam struggled with floods and overflowing rivers, East and Northeast India remained 30 per cent below normal rainfall. South India recorded a deficit of 26 per cent. In the same season, one part of the country battled inundation while another waited for rain.
For decades, meteorologists have relied on El Niño to gauge the strength of the southwest monsoon. A warmer eastern Pacific Ocean usually weakens India's rainfall.
This year, however, nature ignored the script.
Scientists say warming in the western Pacific, repeated low pressure systems over the Bay of Bengal and changing western disturbances combined to blunt El Niño's expected influence, exposing how climate change is reshaping one of the world's most complex weather systems.
Former India Meteorological Department Director General Dr K. J. Ramesh said unusually warm waters in the western Pacific generated weather systems that repeatedly strengthened the monsoon over India, while changing western disturbances transported additional moisture into northern parts of the country.
"The climate models did not capture these phenomena," he said, adding that climate change is altering monsoon behaviour in ways existing forecasting systems are still struggling to understand.
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Dr Akshay Deoras of the University of Reading said the monsoon's resilience during an El Niño year had surprised scientists. Even without strong support from other climate drivers such as the Indian Ocean Dipole and Madden-Julian Oscillation, rainfall remained vigorous, suggesting that climate change is exerting a growing influence on the monsoon.
Scientists are also watching the Indian Ocean Dipole, another key driver of India's rainfall, while warmer temperatures are changing the behaviour of western disturbances, increasing the risk of cloudbursts, flash floods and landslides across the Himalayan region. Assam alone has witnessed around 75 deaths and more than three lakh people affected by floods this season, according to media reports cited in the study.
The consequences of this uncertainty reach far beyond weather offices.
On Thursday, even as scientists continued to analyse July's unexpected rains, the Uttar Pradesh government's Department of Relief and Disaster Management issued an orange alert for parts of Agra, Auraiya, Etawah and Jalaun, warning of thunderstorms, lightning, winds of 30 to 40 kmph and light to moderate rainfall over the next three hours.
The alert highlighted a paradox that is likely to define India's future.
Climate change is not making weather forecasts irrelevant. It is making them indispensable. But it is also making the atmosphere more unpredictable, forcing scientists to rethink forecasting models that have guided India for decades.
For generations, Indians looked to the monsoon with hope and to forecasts for certainty. Today, hope remains. Certainty is becoming harder to find.
