Climate change villain behind mad monsoon, say experts

CHENNAI: Despite recording an average rainfall of 108 per cent, country’s monsoon was largely uneven this year with only 340 of the 729 districts registering normal rainfall. Experts are attributing the erratic southwest monsoon to climate change.

According to data, of the 729 districts, 158 districts experienced excess rainfall, and 48 districts saw large excess rainfall. As many as 167 districts faced a rainfall deficit while 11 districts saw large rainfall. Moreover, the country has recorded the highest number of heavy rainfall in the last 5 years.

“The number of stations to record very heavy rainfall in June was the second-highest in the last five years. July also reported the second-highest number of extremely heavy rainfall events. In August, 753 stations recorded very heavy rainfall, the highest since 2020, while September marked a new record, with 525 stations recording very heavy rainfall,” an analysis by Climate Trends said.

The analysis explained that the summer monsoon, once predictable, is becoming more erratic and unreliable due to climate change. “A recent study shows that India now experiences extended summer-like conditions during the June to September (JJAS) months. These shifting patterns are creating a new norm of aggravated, erratic, and incessant monsoons, making dry years drier and wet years wetter,” it added.

Also, around 70 per cent districts experience persistent and erratic rainfall more frequently. Districts with higher heat wave occurrences during JJAS months also tend to see more frequent extreme rainfall events.

Abhinash Mohanty, Head of Climate Change and Sustainability Practice, IPE Global, opined that recent occurrences in Kerala, like prolonged and erratic rainfall causing landslides and abrupt city shutdowns, highlight the impact of climate change. Analysis indicates that by 2036, 8 out of 10 Indians will be affected by extreme events, with these numbers expected to peak. The analysis pointed out that monsoon dynamics have been understood as a result of the difference in heat capacity between land and the upper ocean, which causes a seasonal reversal of winds, driven by the much greater temperature changes over land compared to the ocean. However, the constant rise in temperature has altered the monsoon patterns over the years. The changes have become increasingly evident with each passing monsoon season in the last decade, it added.

Apart from global warming and climate change, local factors such as deforestation, irrigation practices, and urbanisation have contributed to an increase in mean daily rainfall.

Despite above normal monsoon rains, the country experienced a rise in the night-time temperatures. In 2024, Northwest India recorded its second highest minimum temperatures since 1901, while East and Northeast reported the highest minimum temperature on record.

Meanwhile, the Indian Ocean has witnessed its strongest warming in seven decades, at a rate of 1.2 degrees Celsius per century. This extends beyond the surface, with the ocean’s heat content increasing to the depths of 2,000 metres. The Indian Ocean is currently warming at a rate of 4.5 zetta-joules per decade. This is predicted to accelerate at 16–22 zetta-joules per decade.