HYDERABAD: The land temperature in the city has been on the rise for the last several years, and to control this the government has to take more serious efforts rather than just planting saplings.
According to a study by researchers from the Indian Institute of Technology, Kharagpur, in the last 20 years, the minimum land surface temperature of Hyderabad has increased by 5-11 degree Celsius depending upon the category of land use.
The study by IIT Kharagpur titled, ‘Assessing land surface temperature and land use change through spatio-temporal analysis: a case study of select major cities of India’, assesses the change in land usage in four cities - Hyderabad, Mumbai, Delhi, and Kolkata. The study was done on land surface temperatures in four categories of lands - urban, vegetation, water bodies, and others. For Hyderabad, the researchers considered the HMDA region covering around 7,257 square km.
The study says that in all categories of land use, temperatures have increased in HMDA region in 17 years between 1999 to 2016. While in urban areas where the land is covered with concrete and roads, the temperature has increased from 26 to 31 degree Celsius, in other three categories the minimum temperature has increased from 22 to 33 degree Celsius, 25 to 32 degree Celsius and 21 to 32 degree Celsius. As per the study, three main factors are responsible for this change -- increased concretization, fall in vegetation cover and the ‘others’ category.
The study reports that the area under the ‘urban’ category in Hyderabad --concretised area --has increased from 3.39 per cent in 1998 to 24.18 per cent in 2016. However, the land under vegetation in Hyderabad till 2016 was just 2.43 percent much less than other cities.
Meanwhile, there has been a drastic fall in the area under water bodies in Hyderabad. The study claims that the area under water bodies in Hyderabad has declined from 2.89 per cent in 1999 to just 0.64 per cent in 2016.
While speaking to Express, assistant professor at IIT Kharagpur and lead author of this study, Dr Bharath H Aithal, said that reason behind rising land surface temperatures is the falling levels of groundwater in the city. He said that even groundwater like surface water bodies, act as heat sinks and the falling levels of groundwater contribute to the heating up of land. He added that there are also natural reasons for land heating.
The ‘Others’ category of land use might sound insignificant but almost 73 per cent of Hyderabad is under such land which consists of barren land, quarries, mining area, and agricultural lands. Aithal points out that such areas are more prone to heating up due to lack of any vegetation and also for the fact that many such open areas are covered by rocky terrain which heats up quickly. When asked, does planting trees help solve the heating crisis? Aithal points out, it is just part of the solution. He said proper urban planning promoting mixed land use is required to keep temperatures under control.