Assessing the Role of Urbanization in Climate Change: An Analysis of Land Use and Temperature Trends in Ranchi City, India

The present study aims to examine the temporal variations in temperature in Ranchi City, Jharkhand, India. To achieve this, both linear trends and eleven-year moving averages were analyzed to understand temperature patterns. The linear trend analysis revealed an overall increase in mean and maximum temperatures, while minimum temperatures showed a declining trend, leading to an increase in the diurnal temperature range. Moving average analysis identified two distinct periods of significant temperature rise: the post-independence industrialization era (1955-1965) and the more recent phase of urbanization (post-2000). Notably, the temperature changes during the industrialization phase were more pronounced than those during recent urbanization. Further analysis of monthly and seasonal temperature patterns showed a sharp decline in minimum temperatures during the winter season, particularly in January, compared to other months. Temporal Landsat imagery was also utilized to derive land use/land cover (LULC), land surface temperatures (LST), and to track urban expansion and Urban Heat Island Intensity (UHII) for the years 1992, 2001, and 2013. The impact of urbanization on UHII was assessed through land use changes from 1992 to 2013. The findings indicate that urban built-up areas grew by 251.89% during this period, leading to a significant increase in UHII by 1.42 K. This is an alarming sign for a city traditionally cooler due to its higher elevation. The analysis also showed that land converted from agriculture to urban areas had the highest Contribution to UHII (CUHII) by 2013, compared to other forms of land transformation. These findings offer crucial insights into the impact of urbanization on the thermal environment and are valuable for guiding decision-making and urban planning efforts to make Ranchi an environmentally sustainable city.