The annual average land surface temperatures in Calcutta have grown across 90% of its geographic area, with a notable increase over 49% of it, according to a study by scientists at Vidyasagar University in Midnapore.
The Dhulagarh Industrial Park, Biparna Para, Domjur, Bankra, Dankuni Bil, and Newtown areas of Greater Calcutta showed the highest rates of temperature rise, according to the peer-reviewed study that was published in the Journal of Cleaner Production.
The Vidyasagar researchers claim theirs is the first attempt to quantify which areas of the four cities are experiencing the most pronounced and statistically significant temperature changes. Although numerous earlier studies had tracked temperature changes in Indian cities, they claim theirs is the most comprehensive study to date.
Between 2003 and 2020, the average annual and seasonal nighttime temperatures in Calcutta, Chennai, Delhi, and Mumbai climbed over 33% to 100% of their respective areas by 0.27°C to 0.75°C each decade.
These rates are much higher than the 0.15°C per decade national average annual warming trend between 1986 and 2015 that was noted in a 2020 research by the Union earth sciences ministry that examined climate change trends over India.
However, the average annual daytime temperatures in Delhi and Mumbai have somewhat decreased, which the researchers have attributed to an increase in air pollution where aerosols, or soot particles, block sunlight.
The average annual daytime temperature in Calcutta has risen by around 0.46°C during the past ten years, while the average annual nighttime temperature has risen by 0.37°C over the same period. The rise ranges from 0.29°C per decade to 0.88°C per decade across 49% of Calcutta’s geographic area, where the trend of rising temperatures is statistically significant.
The researchers analyzed the daytime and nighttime temperatures in the four cities using satellite-based datasets and the Google Earth Engine platform.
Between 1901 and 2018, India’s average temperature rose by about 0.7°C. Although scientists claim that the presence of aerosols in the atmosphere has mitigated this growth, the majority of this increase is due to warming brought on by heat-trapping greenhouse gases.
However, the observed warming is not uniform. The earth sciences ministry report, which examined a number of past studies, revealed that between 1986 and 2015, north India experienced the biggest annual average temperature increase, of more than 0.2°C each decade.
News Mania Desk
