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Recent studies reveal that projected rainfall changes due to global warming, expected by 2040, are already occurring in India.
This suggests that current climate models need urgent updates to address the accelerated warming and its impacts.
The frequency of extreme rainfall events is rising, challenging existing models and highlighting the need for new approaches in climate science.
The scenarios for changes in rainfall, especially during the monsoon season, for India due to global warming and consequent climate change that were projected for 2040 and beyond may already be occurring. This indicates that the current global and regional climate models may need to be upgraded to keep pace with the accelerated warming and consequent changes.
One such scenario is regarding the increase in the frequency of extreme rainfall events across the country. Under various scenarios of the latest Sixth Coupled Model Intercomparison Project (CMIP6) climate models, scientists expected the frequency of extreme rainfall events to increase during the latter part of the 21st century, rather than the immediate future.
The scenarios included lowest emission to the business as usual, according to a research paper published in the journal Atmospheric Research in June 2025. In the worst-case scenario known as the Shared Socio-economic Pathway 5-8.5 (SSP 5-8.5), CMIP6 climate models indicate a pronounced increase in monsoon rainfall starting around 2027, according to the paper. This seems to have already happened.
The annual frequency of daily rainfall extremes (>100 mm per day) in the past several decades (1951 to 2022) show that the trend is already increasing, with higher numbers in recent years, according to a research paper published in the journal Natural Hazards Research in September 2024.
Data from the India Meteorological Department (IMD) for the month of June in the past five years shows that the year 2025 clearly stands out. The number of daily rainfall events above the very heavy (>115.6 mm) category were the highest in 2025 at 502. The year 2023 recorded 494 such events, the second highest number.
The collated figures for very heavy and above rainfall events for the months of July and August in 2025 are not yet publicly available. But the frequent activity of low-pressure areas, western disturbances and other monsoon related weather systems along with the floods, flash floods and landslides across the country indicate much higher than normal number of very heavy and above rainfall events.
It is interesting that the lowest number of very heavy or above rainfall events in June occurred in 2021 when a La Niña event was ongoing in the Equatorial Pacific Ocean. During a La Niña event, the chances of extreme daily rainfall over India increases. The second highest number came in 2023, when an El Niño event was ongoing in the Equatorial Pacific Ocean. During an El Niño event, the chances of extreme daily rainfall over India decreases.
Such instances indicate that the understanding of natural atmospheric and oceanic phenomena such as the El Niño Southern Oscillation (ENSO) and its interaction with global warming and consequent climatic impacts are changing in a way that perhaps humans do not understand.
The fact that climate models are not able to keep pace with the acceleration of global warming, the consequent changes in the planet’s climate and the resulting impacts has been highlighted by many climate scientists. In a research paper published in the journal Environment: Science and Policy for Sustainable Development in February 2025, a group of scientists talked about the acceleration of global warming and its consequences.
The team was led by James Hansen, director of the Climate Science, Awareness and Solutions (CSAS) Program at Earth Institute, Columbia University and one of the foremost climate scientists in the world. The study pointed out that global warming has accelerated since 2010 by more than 50 per cent as compared to the rate of warming between 1970 and 2010, which was 0.18°C per decade.
In fact, the last two years witnessed a spike in global average temperatures of 0.4°C and the El Niño event of 2023-2024 and the decrease in aerosols from shipping could not completely explain the rise, according to the scientists.
In the paper, the scientists further warn about the various ‘point of no return’ scenarios that could occur due to this accelerated warming such as the sudden shutdown of the Atlantic Meridional Overturning Circulation (AMOC).
The shutdown of the AMOC, the ocean circulation that brings warm water and nutrients from the Equator to Europe and North America, could cause cascading impacts to a lot of other Earth systems which are not fully understood, say the scientists. They also highlight that these ‘point of no return’ scenarios are not well represented in the current climate models.
The scientists also propose an alternative approach for climate modelling, different from the IPCC. Such models could be based on ongoing observations driving the climate modelling processes and greater use of the understanding of paleoclimate to test the models. They also suggest more observations from the Arctic and Southern Oceans and of the ice changes in the polar regions.