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Ecostani | Indian monsoon getting longer, hotter and less predictable

The IPCC has warned of intensification of rainfall by more than 20% and exponential surges in heat waves and cyclone events in the Indian sub-continent.

Published on: Oct 21, 2024 07:55 PM IST
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The 2024 Indian monsoon was much better when it came to overall precipitation with 108% rainfall of the Long Period Average (LPA) recorded. With heavier rain, extreme and very heavy rainfall events, which caused landslides and flooding, were also much higher, constant with the rising trend of such climate change-induced events.

PREMIUMTwo men who were riding a two-wheeler take shelter outside a closed shop during a heavy rain in Kochi, southern Kerala state, India. (AP Photo/ R S Iyer)
Two men who were riding a two-wheeler take shelter outside a closed shop during a heavy rain in Kochi, southern Kerala state, India. (AP Photo/ R S Iyer)

According to the India Meteorological Department (IMD), between June 1 to September 30, India recorded 934.8 mm of rain, surpassing the seasonal norm of 868.6 mm. The data showed

The 2024 Indian monsoon was much better when it came to overall precipitation with 108% rainfall of the Long Period Average (LPA) recorded. With heavier rain, extreme and very heavy rainfall events, which caused landslides and flooding, were also much higher, constant with the rising trend of such climate change-induced events.

PREMIUMTwo men who were riding a two-wheeler take shelter outside a closed shop during a heavy rain in Kochi, southern Kerala state, India. (AP Photo/ R S Iyer)
Two men who were riding a two-wheeler take shelter outside a closed shop during a heavy rain in Kochi, southern Kerala state, India. (AP Photo/ R S Iyer)

According to the India Meteorological Department (IMD), between June 1 to September 30, India recorded 934.8 mm of rain, surpassing the seasonal norm of 868.6 mm. The data showed that the maximum contribution came in the form of very heavy to extremely heavy rainfall.

This year’s monsoon was longer like the ones in the past five years but it failed to cool down nights unlike it used to do previously. With ground surface temperature rising due to climate change, deforestation and higher use of vehicles, air-conditioners and industrial units, these alterations in the Indian monsoon system are here to stay.

A leading climate expert said the changes have become increasingly evident with each passing monsoon season in the last decade. “During the last five-six years, weather systems have been travelling through Central India, which used to follow the northward trend. Changes in rainfall patterns are driven by global warming and at the same time driven by El Nino, IOD (Indian Ocean Dipole) and MJO (Madden Julian Oscillation). High-intensity and short-duration precipitation is driven by climate change. The longevity of monsoon systems has increased because of back-to-back systems. These systems led to the saturation of soil moisture. When systems move over such areas, soil provides the same momentum as it is over the ocean. It may not be of the same magnitude but it does increase the shelf life of the weather system,” said IMD’s former director general, K J Ramesh,

When asked whether the monsoon would return to former normal patterns, Ramesh said it was highly unlikely. “Man-made conditions on the ground are not going to change much and climate change is already there. In such a scenario, the monsoon predictability would become difficult in coming years as IMD cannot factor in all causes that may be impacting monsoon,” he said.

The monsoon data for the last three decades has already established the link between monsoon rain variations and climate change. Drier periods during the monsoon are getting longer and the probability of intense rainfall has increased. A study by IIT-Gandhinagar showed that the intensity of extreme rainfall has increased by 30% in the Himalayan, western and Kerala-Karnataka coastal regions in the past 30 years.

The IMD data showed that very heavy rainfall events have increased from 1912 in 2020 to 2632 in 2024. Similarly, extreme rainfall events have increased from 341 to 473 in this period. Rainfall is classified as very heavy when a station records between 115.6 mm and 204.5 mm of rainfall within 24 hours. If more than 204.5 mm of rain falls in that period, it is classified as extremely heavy rainfall.

Data with IMD showed the 2024 monsoon recorded the highest number of heavy rainfall events in the last five years; June recorded the second-highest very heavy rainfall events in the last five years while July 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.

This monsoon, out of 729 districts, 340 districts recorded normal rainfall, 158 districts experienced excess rainfall, 48 districts saw large excess rainfall, 167 districts faced a rainfall deficit and 11 districts saw large deficit rainfall. So, the data clearly shows huge variations in rainfall patterns across districts, which can have implications for agriculture.

A recent study showed that India now experiences extended summer-like conditions between June and September, which are the monsoon months. These shifting patterns are creating a new norm of aggravated, erratic, and incessant monsoons, making dry years drier and wet years wetter. Around 70% districts now experience persistent and erratic rainfall more frequently.

Districts with higher heat wave occurrences from June to September also tend to see more frequent extreme rainfall events, studies have shown. The data also showed that despite excess monsoon rains, there has been a constant rise in minimum temperatures during the monsoon months, which experts say, has a bearing on agriculture production. Central India recorded higher night temperatures during the months of monsoon; India has recorded the highest night temperature, with an anomaly of 0.61 degree Celsius.

With the Intergovernmental Panel on Climate Change (IPCC) predicting global temperature to rise up to 3 degree Celsius to pre-industrial level by the turn of the century, northeastern and Central India are bracing for hotter summers and highly unpredictable monsoons. The IPCC has warned of the intensification of rainfall by more than 20% and an exponential surge in heat waves and cyclone events in the Indian subcontinent.

Chetan Chauhan, national affairs editor, analyses the most important environment and political story in the country this week

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ABOUT THE AUTHOR
Chetan Chauhan

Chetan Chauhan is the National Affairs Editor looking into all aspects of news and features from across India. A Chevening scholar with over three decades of experience in reporting and news management, Chetan has extensively covered all important aspects of the social sector, political economy, environment and climate change nationally and internationally. He did a journalism course at the Reuters Institute of Journalism in Oxford and Digital Media training at Nanyang Technological University in Singapore. He started as a reporter with The Statesman in 1996 and joined the Hindustan Times in 2000 in the metro bureau covering environment, crime and Delhi politics. He covered hot local news, from the Jessica Lal murder case to the rebellion of Delhi Congress MLAs against then Chief Minister Sheila Dikshit, to the replacement of toxic vehicle fuel with cleaner compressed natural gas (CNG) in the national capital. Some of his stories on air pollution became part of the Supreme Court’s landmark MC Mehta versus Government of India case in the National Capital Region (NCR), forcing the government to take corrective measures. As part of the national political bureau since 2004, he covered important central sectors such as environment, education, social justice, labour, rural development, water resources, renewable energy, agriculture, broadcasting and the Planning Commission for more than a decade producing several exclusive and investigative breaking stories. His specialisation is the environment, having covered at least a dozen United Nations global conferences on climate change, biodiversity and wildlife including climate summits in Paris, Copenhagen and Bali. He also covered India’s two five-year plans ---11th and 12th and reported on drafting and execution of right based laws such as Right to Education, Right to Information and rural job guarantee law, MG-NREGA, now being introduced in new format as VG-RAM-G Act. He has in-depth knowledge of social sector issues. He was one of the first to report on tigers vanishing from Sariska and Panna wildlife reserves in 2004 and 2008, respectively, leading to the setting up of the National Tiger Conservation Authority (NTCA) and the introduction of stringent penal provisions for poaching. He has written extensively on the rising human-animal conflict in India and the degradation of India’s biodiversity hotspots because of mining and other activities. Since 2004, Chetan has covered Parliament comprehensively and participated in training on the nuanced coverage of Parliament proceedings. He has travelled extensively across India to cover national and provincial elections since 1998, especially in the Hindi heartland states, considered India’s road to power. He writes a regular column for Hindustan Times, Ecostani, on important national politics, economy, Himalayan ecology and environmental issues. His other responsibilities include providing inputs for edits and edit page articles for the publication, apart from managing news flow from across India.

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