Kerala warmed up by 1.67 deg Celsius since 1901, says India’s first state-level climate report

“This is a statistically significant figure,” Dr D Sivananda Pai, senior meteorologist and director, ICCS, told The Indian Express.

The annual minimum temperatures in Kerala have also increased since 1901. “The average minimum temperature saw a relatively lower increasing trend, which was 0.42 degrees Celsius/100 years,” the report stated. However, the minimum temperatures over Kollam and Thiruvananthapuram districts showed an exceptional cooling trend between 1901 and 2021.

The India Meteorological Department, since 2016, has been releasing the annual Climate of India report every January. “But that report’s findings may not be applicable and actionable at regional or state levels. That is where the need for having state or even district-level climate reports arise, for effective planning, performing sector-wise assessments and undertaking future climate studies,” said Pai.

Set up in 2014, the ICCS aims to publish state-level annual climate reports every January, which will act as a ready scientific reference for policy makers, local administrations and climate researchers. The institute, in the coming months, also plans to conduct climate and weather awareness sessions and organise local climate fora in Malayalam.

Since 2018, Kerala has faced repeated extreme heavy rainfall events that have caused massive destruction to hillside properties and establishments. “This may have prompted the state government to take climate studies more seriously,” said an expert.

Incidentally, 2021 was Kerala’s eighth warmest year in 121 years, with the annual mean land surface temperature recorded last year being 0.4 degree Celsius above the average. Eight of the 10 warmest ever years, since 1901, over Kerala were recorded between 2011 and 2020, also making it the warmest decade ever.

Kerala is a high rainfall recording state and receives rain during two seasons — the Southwest Monsoon between June and September and the Northeast Monsoon between October and December. Kerala records an average of 2049mm and 450mm of rain, during June to September and October to December seasons, respectively.

But of late, Kerala has been receiving below normal rainfall, as per observations noted since 1901. The average seasonal rainfall (both seasons) over Kerala reduced by 10 per cent of the Long Period Average (LPA) over the last century. The Southwest Monsoon 2021 had ended with minus 10.4 per cent of the LPA.
Climate scientists said the state’s Southwest Monsoon

rainfall was lower than average for 26 out of the total 122 years since 1901. The state’s worst June to September rainfall performance was recorded in 1981, when the seasonal deficiency was about 57 per cent. The state’s best monsoon season since 1901 was nearly a 100 years ago, in 1924, when the seasonal average was 79.9 per cent of the LPA.

During October to December 2021, Kerala recorded its wettest Northeast Monsoon season, touching a seasonal average of 401 per cent above normal.

On the district-wise rainfall trends, scientists said that 13 districts showed a downward trend, with Alappuzha, Kottayam and Pathanamthitta districts recording significant decline in the rainfall recorded during the crucial June to September months.

These districts are known for cultivation of paddy and spices along with extensive fishing and tourism activities. Notably, Idukki was the lone district where rainfall during summer monsoon showed an increasing trend from 1901 to 2021.

Similar declining rainfall trends during the Northeast Monsoon season were recorded across the 13 districts, except the northernmost district of Kasargod.