Bengaluru’s Torrential Rain: Freak Year or Climate Change?

The science behind Bengaluru’s torrential rains.

This year, Bengaluru has recorded the highest rainfall in the last 115 years. The total rainfall in Bengaluru city was recorded at 1,621 mm, which was more than the 1,606 mm recorded in 2005. This is despite more than two months left in the year and the north-west monsoon on its way.

Is the heavy rainfall an impact of climate change or is it just a freak year? The experts differ, but agree there is a need for more studies on this phenomenon.

The Extreme Weather

As per normal rain patterns, Bengaluru should receive heavy rainfall during the monsoon months of June and July. The way the monsoon began, it seemed like it was going to be another dry year. In June and July, more than 61 percent rain deficiency was reported in Bengaluru. The government had even ordered a cloud seeding project, to ensure dry parts of the state received enough water.

While monsoon remained dry, the post monsoon months saw torrential rainfall. In fact, the rainfall broke several records. In August, September and October alone, Bengaluru received more than a normal year’s rainfall. Out of 1,621mm of rain recorded this year, 1,222mm rain was recorded during these months.

What Caused This Change in Weather?

According to experts, post monsoon showers are natural. “There will be some depression, low pressure or cyclone circulation, which could cause the post monsoon rains. However, there were several cyclonic systems in the coastal areas , which resulted in the rainfall. These were considerably higher than previous years. And this year, the monsoon season has extended and it is yet to withdraw,” said Sundar Metri, head of India Meteorological Department (IMD), Bengaluru.

Not Amount, but the Nature of Rain That’s Worrisome

For the experts it is not the amount of the rainfall, but how the city received the rainfall, which has been a point of interest. The incidents of heavy rain spells, i.e more 12mm of rainfall in an hour, has increased this year. Although specific figures are not available, Metri said the city saw one of the highest number of heavy spells this year. These have resulted in water-logging and the rain-related deaths.

Is It Permanent Climate Change?

Experts are divided on whether the increased rainfall can be directly attributed to climate change.

In an interview given to the The Hindu, Venugopal V from the Centre for Atmospheric and Oceanic Sciences, IISc said that even though extreme weather events are symptomatic of climate change, they could not link the intensity of rainfall of one particular year to climate change.

Metri added that these rainfall figures should be studied further to understand if there is a pattern to the dry years and years with torrential rainfall.

However, some believe there is a connection to change in weather patterns and climate change. “ The activities in the Arabian Sea and the Bay of Bengal have resulted in this increased rainfall. There is no doubt that there is higher activity in these parts. Climate change certainly has a part to play in these changes. However, we cannot categorically say that these are permanent changes,” said GS Srinivasa Reddy, Director of Karnataka State Natural Disaster Monitoring Centre.

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