BHUBANESWAR: On Wednesday, mercury soared past 44 degree Celsius in Bhubaneswar. Moreover, the Capital city has experienced its hottest March since it came into being in 1948.Climate scientists blame it all on the urban heat island effect wrought on by what they term as “mindless and unplanned city development and expansion destroying not only the core characteristics of the Capital city but also denuding its green cover.”
From Dr Otto Konigsberger’s design for 40,000 people in what was to be the administrative capital of the State, Bhubaneswar is now home to over a million. However, it is in the last two decades that the City’s urban space has witnessed a drastic change. Fast conversion of agricultural land making way for housing and other infrastructure, more buildings, asphalt-topped road have led to exposure of more surface area to heat. With green cover vanishing and very little of natural wetlands left, Bhubaneswar appears to be bearing the brunt of ‘urban heat island effect’, say researchers.
A study by School of Earth, Ocean and Climate Sciences in Indian Institute of Technology, Bhubaneswar (IIT-BBS) reveals that area under urbanisation in the City during 2003-2017 increased by 77.05 per cent and the highest urbanisation of 71 per cent was recorded during 2003–2008. The report “Rapid urbanisation and associated impacts on land surface temperature changes over Bhubaneswar Urban District” jointly authored by Anasuya Barik, Debadatta Swain and Velu Vinoj points out that urbanisation increase saw loss of other canopy types, vegetation and fallow land simultaneously. Between 2000 and 2014, at least 89 per cent urbanisation was recorded at the cost 83 per cent loss of dense vegetation.
The urbanisation took a heavy toll on cropland that helps absorb heat and prevent radiation. A staggering 82.64 per cent crop land was converted into urban land during this period. In 2003, the fallow and agricultural land, as per the report, was about 52.3 per cent in the study area which dropped to 19.3 per cent in 2017. Water-bodies coverage declined from 2.9 per cent to 0.9 per cent during the same phase.
All this impacted land surface temperature (LST) of the city which is witnessing a gradual surge every five years. As the urban area expanded during 2003-2017 period, there was an eight percent increase in mean summer LST in the airport area which was used a reference point for the study.
What is interesting is that despite a decline in urbanisation pace subsequent to the 2003-2008 period, land surface temperature has been on the rise. The 2013–2017 span saw a 12 per cent expansion of urban area but LST saw a rise of 9.84 per cent. “This indicates that although rate of urbanisation in the study area has shown a decreasing trend in the later years, its impacts show a pronounced hike. This could also be a direct indication of the profound footprint of urban heat island resulting from the conversion of vegetation and bare soil cover to urban structures,” says the report.
The LST saw a rise of about 0.25 degree Celsius a year at the airport region during 2003-2017. Despite the change in micro-climate of the city, loss of vegetation continues due to expansion work and development projects. “At least 1,700 trees were felled for NH expansion project on Khandagiri-Tamando stretch. Plantation of 3,400 saplings to compensate the loss of this green cover is yet to start,” admitted an official of the division.
Adding to the heat
2,000 to 3,000 dwelling units constructed every year in and around the City, CREDAI sources
Vehicles have outnumbered Bhubaneswar’s population. City has more than 1.4 million registered vehicles against a population of 1 million by 2019
Number of registered vehicles increasing at a rate of 3-5 per cent annually