The year 2021 was the fifth warmest year since nationwide records commenced in 1901, while the seasonal rainfall during the northeast monsoon season over the core region of the south peninsula was the highest since 1901, the ‘Statement on Climate of India during 2021’ released on Friday said.
As per India Meteorological Department (IMD), for temperature, the long period average (LPA) is considered based on 1981-2010 period, while for rainfall, the LPA is based on 1961-2010 period.
The annual mean land surface air temperature averaged over India during 2021 was 0.44-degree Celsius above the LPA based on 1981-2010 period. Thereby, the year 2021 was the fifth warmest year since nationwide records commenced in 1901, the statement said, adding, “However, this is lower than the highest warming observed over India during 2016 when it was 0.71-degree Celsius above the LPA.”
The winter (January to February) and post-monsoon (October to December) seasons with all-India mean temperature anomalies (Actual – LPA Temperature) of +0.78-degree Celsius and +0.42-degree Celsius, respectively, mainly contributed to this warming, the IMD explained.
The five warmest years on record, in descending order, are: 2016 (+0.71-degree Celsius), 2009 (+0.55-degree Celsius), 2017 (+0.541-degree Celsius), 2010 (+0.539-degree Celsius), and 2021 (+0.44-degree Celsius).
It may be mentioned that 11 out of 15 warmest years were during the recent 15 years (2007-2021).
The past decade (2011-2020/ 2012-2021) was also the warmest decade on record with the decadal averaged annual mean temperature anomaly (Actual-LPA) of 0.34-degree Celsius/0.37 degree-Celsius.
The country averaged annual mean temperature during 1901-2021 showed an increasing trend of 0.63-degree Celsius/100 years with a significant increasing trend in maximum temperature (0.990C/100 years) and a relatively lower increasing trend (0.260C/100 years) in minimum temperature.
The country averaged seasonal mean temperatures in 2021 which were also above the LPA during all the seasons with the winter (January to February), pre-monsoon (March to May), monsoon (June to September) and post-monsoon (October to December) seasons recording anomalies of +0.78-degree Celsius, +0.35-degree Celsius, +0.34-degree Celsius and +0.42-degree Celsius, respectively.
The country averaged mean monthly temperatures were warmer than normal during all the months of the year except for four months (April, May, June, and November). Among the months, the highest country averaged monthly mean temperatures were recorded in March (1.24-degree Celsius, third warmest since 1901), followed by August (0.52-degree Celsius, third warmest since 1901), January (0.67-degree Celsius, fifth warmest since 1901), and October (0.77-degree Celsius, fifth warmest since 1901).
Record rainfall in 2021
The 2021 annual rainfall over the country as a whole was 105 per cent of its LPA based on the 1961-2010 period. The southwest monsoon season rainfall over the country as a whole was 99 per cent of its LPA. However, it was the 2021 northeast/post-monsoon season (October-December) rainfall over the country as a whole that was above normal (144 per cent of LPA).
The seasonal rainfall during the northeast monsoon season over the core region of the south peninsula was exceptionally above normal (171 per cent of LPA) and was the highest (579.1 mm) since 1901. All the five subdivisions of the core region except coastal Andhra Pradesh and Yanam received large excess/excess rainfall during the season.