Monsoon 2024: Climate Change Drives Extreme Rains And Floods In India

PICTURE COURTESY : MISSION INDIA

As forecast by the country’s nodal weather agency, India Meteorological Department (IMD), the Southwest Monsoon 2024 concluded with above- normal rainfall, reaching 108% (of the long term average?) . Between June 1 to September 30, India recorded 934.8 mm of rain, surpassing the seasonal norm of 868.6 mm.

June began under the shadow of El Nino, typically associated with below normal Monsoon rains, leading to a 11% deficit. However, as the El Nino Southern Oscillation returned to neutral, the monsoon gained pace, resulting in above normal rainfall from July to September.

Much like recent years, the 2024 monsoon was marked by extreme weather events, with the year recording the highest number of heavy rainfall events in the last five years.

Maximum contribution came in the form of very heavy to extremely heavy rainfall The number of stations to record very heavy rainfall for the month of 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.

Monsoon performance over the recent past years has shown increasing annual variability. Scientists attribute the rise in extreme weather events such as increasing monsoon variability, to global warming.

The summer monsoon, once predictable, is now 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. Around 70 percent districts now experience persistent and erratic rainfall more frequently. Districts with higher heat wave occurrences during JJAS also tend to see more frequent extreme rainfall events.

Key Findings:

● Out of 729 districts, 340 districts recorded normal rainfall, 158 districts experienced excess rainfall, and 48 districts saw large excess rainfall. 167 districts faced a rainfall deficit while 11 districts saw large deficit rainfall

● 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 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

● Role of Climate Change: Longevity of the Monsoon systems has increased. Simultaneously weather systems are now tracking more from Central India, south to their normal position

● Despite excess Monsoon rains, rise in global warming has led to a consistent rise in minimum temperatures. India has recorded the highest night temperature, with an anomaly of 0.61 degree Celsius

● Central India, in particular, consistently recorded higher night temperatures throughout the monsoon season

“India is witnessing more intense patterns of extreme events compared to previous years. Recent occurrences in Kerala, like prolonged and erratic rainfall causing landslides and abrupt city shutdowns, highlight the impact of climate change. Our analysis indicates that by 2036, 8 out of 10 Indians will be affected by extreme events, with these numbers expected to peak,” said Abhinash Mohanty, Head- Climate Change and Sustainability Practice, IPE Global.

“During the last 5-6 years, weather systems have been travelling through Central India, which used to follow the northward trend. Changes of 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. 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 Dr K J Ramesh, Former Director General, India Meteorological Department.

The writer of this article is Dr. Seema Javed, an environmentalist & a communications professional in the field of climate and energy