Chennai feels the heat as climate change makes presence felt

CHENNAI: Over the years, Chennai has seen weather vagaries — from increasing temperatures to declining rainfall, coupled with more intense cyclones and floods — not as a consequence of the urban heat island effect (when cities replace the natural land cover with dense concentrations of pavement, buildings, and other surfaces that absorb and retain heat) alone, but also as a result of climate change. On Friday, on the occasion of World Earth Day, climate activists and naturalists caution that more climate change and adverse weather conditions are on the cards for the metropolis and the State, thanks to the round-the-clock emission from industries and vehicles.

“The fuel-burning emission from the industries and burgeoning traffic are serious issues leading to a surge in pollution levels in TN cities,” warn experts in climate change research and weather monitoring. DT Next spoke to a few climate experts on World Earth Day (April 22) when most of them attributed the weather pattern changes visible in Chennai over the past 10 years or more to global warming and climate change.

Dr S Balachandran, Deputy Director-General of Meteorology, Regional Meteorological Centre (RMC), Chennai said the impact of climate change on rainfall patterns is visible and will occur at a slower pace leaving the rainfall pattern to go erratic.

“The weather pattern variation is there in the State, reflecting on atmospheric circulations and low pressures. This will certainly change the rainfall pattern for the years to come. For instance, the State had witnessed a significant decrease in the cyclonic activities over the Bay of Bengal between 1961 and 2010, particularly during and post northeast monsoons,” Balachandran explained adding the cyclonic data is being studied for the current decade.

“Usually the month of March is known for its dry conditions. In March 2022, the highest maximum temperature was recorded at Karur with 40.5 degrees Celsius on March 29 and this is a steep increase,” noted weather blogger Pradeep John. In the last 150 years, only twice — in 1984 and 2008 — the State had experienced the wet weather and these are parameters that have to be documented and studied in detail,” added the blogger.

According to the RMC database, Thondi in Ramanathapuram and Kanniyakumari had recorded temperatures above normal by two-three degrees. In at least five districts — Chennai, Cuddalore, Madurai, Nagapattinam and Tiruchy — the maximum temperature had increased by one-two degrees Celsius this year. Rainfall in March month is rare, whereas last month, Karur and Karaikal districts of Tamil Nadu received 60 per cent excess rainfall, 11 districts received normal rainfall, and Ranipet did not get any rain, the weather office sources said.

“Not only the rainfall, but the cyclonic activities will also change if the pollution and afforestation are not addressed. Only 10 depressions or cyclones have formed in the month of March in the last 130 years. However, this March saw two depressions in the Bay of Bengal, of which one was close to Tamil Nadu,” says Pradeep John.