Shillong’s Emerging Urban Heat Islands: Mapping Climate Vulnerability Through Land Use Change (1995–2025)

Shillong‘s Emerging Urban Heat Islands: Mapping Climate Vulnerability Through Land Use Change (1995–2025)

Pradakshina Borbora and Sonika Choudhury

An Urban Heat Island refers to the phenomenon where urban areas experience higher temperatures than their surrounding rural areas due to human activities and built environments.

These are metropolitan areas significantly warmer than surrounding rural areas due to human activities, infrastructure, and lack of vegetation, often 3-5° C hotter, result from dark, impermeable surfaces (asphalt/concrete) absorbing solar radiation and releasing it slowly.

Climate vulnerability refers to the degree to which a system (people, ecosystems, or places) is susceptible to, and unable to cope with, the adverse effects of climate change, including climate variability and extreme events.

Mapping of Climate Vulnerability indicates the process of spatially assessing and representing the degree to which a system, region, or population is susceptible to and unable to cope with adverse effects of climate change, using tools like GIS and remote sensing.It answers the question: “How badly will this place be affected by climate change, and how well can it handle it?”

Shillong, once known for its moderate climate, is increasingly experiencing urban warming due to rapid land use change.

Geographically, Shillong is situated approximately between 25.57°N latitude and 91.88°E longitude, at an average elevation of about 1,496 meters above mean sea level. The city is characterized by undulating terrain, hills, and valleys, which influence its microclimate and urban development patterns.Shillong experiences a subtropical highland climate, marked by mild summers, cool winters, and heavy monsoonal rainfall.The region receives significant precipitation during the southwest monsoon season (June–September), contributing to its historically moderate thermal conditions.

However, recent trends indicate increasing temperature variability linked to urbanization and land use changes. Over the recent decades Shillong has developed identifiable heat zones which represents an alarming concern for the impacts of global climate change in the North Eastern States of India.

Traditionally, Shillong had extensive vegetation, but rapid urban expansion over recent decades has led to the conversion of forest and open land into built-up areas. This transformation has significantly altered the local surface energy balance.The city’s land use pattern currently includes:Dense built-up urban core (commercial and residential areas), Institutional and semi-urban zones, Remaining-forest and green spaces and Water bodies such as theUmiam Lake. From our research we got to know that from 1995 – 2025 Shillong has gradually started developing identifiable heat zones in some parts of the city.

Even though Shillong is widely known for its pleasant and cool climate, rapid urban growth over the years has changed the city’s landscape and local temperature conditions.Areas with dense buildings, heavy traffic, concrete roads, and reduced vegetation tend to become warmer than surrounding areas. Localities such as Police Bazaar, Laitumkhrah, Nongthymmai, and Mawprem are likely to experience higher heat retention because these places are more urbanized and crowded compared to greener parts of the city.

The major objectives of the study includes: To identify the development of identifiable heat zones in Shillong, to examine the neighbourhoods showing the highest heat retention in Shillong, to analyse the relationship between built-up density and temperature variation in Shillong.The Thermal comfort map of the recent years i.e. 2022, 2023, 2024 & 2025, it has been seen that many areas in Shillong experience Warm and Hot climatic conditions that represents the temperature above 18°C and minor areas also display Very Hot thermal zones with temperature above 26°C.

The NDVI maps of 1995 and 2025 show how vegetation cover in the study area has changed over the last three decades. In 1995, much of the study area was covered by moderate to dense vegetation. The northern and northeastern parts especially showed large patches of dense and very dense vegetation, reflecting the presence of forested and natural landscapes. Built-up areas and sparse vegetation were mainly concentrated in the central and southwestern parts, but they were relatively limited in extent.

Overall, the region still maintained a strong natural vegetation cover during this period. By 2025, clear changes in land cover can be observed. Particularly in the central parts of the study area, indicates expansion of built-up land and reduction in vegetation cover. This reflects the growth of settlements, roads and other human activities over time. The NDBI maps of 1995 and 2025 clearly show how the study area has changed over time due to increasing urban development.

In 1995, most parts of the region were covered by vegetation and open land, Built-up areas were limited and mostly scattered in small pockets across the central and southern parts of the region. Very high built-up zones were comparatively few, showing that urban development was still at an early stage and the natural landscape was largely preserved.

By 2025, the pattern changed noticeably. Dense built-up zones became more concentrated in the central and eastern parts of the study area, suggesting rapid growth of settlements, infrastructure and human activities over the last three decades.

The comparison of the two maps highlights the gradual transformation of the landscape from a predominantly natural environment to a more urbanised one. This increase in built-up surfaces may also influence local environmental conditions by reducing vegetation cover and increasing land surface temperatures, which can contribute to the formation of urban heat island effects.

Analysis of Land Surface Temperature (LST), NDVI, NDBI, and Thermal Comfort Zones indicates that densely populated and highly urbanized areas exhibit higher surface temperatures compared to surrounding vegetated and peri-urban regions. The reduction of green cover and the growth of impervious surfaces have intensified localized heat accumulation, leading to the formation of emerging urban heat islands within the city. 

The findings further show that recent years, particularly from 2022 to 2025, have witnessed a shift from predominantly comfortable thermal conditions toward warmer and hotter thermal comfort zones in several parts of Shillong. Areas with dense infrastructure, traffic concentration, and limited vegetation were found to be more vulnerable to heat stress, while forested and elevated regions maintained relatively cooler conditions.

This demonstrates a strong relationship between urban development patterns and thermal variability.Climate vulnerability in Shillong is further amplified by changing climatic conditions, irregular rainfall patterns, increasing temperature trends, and unplanned urban growth. These changes may negatively affect human health, water availability, ecosystem stability, and overall urban livability in the future.

The emergence of heat-prone zones in a hill city like Shillong highlights the urgent need for sustainable urban planning and climate-sensitive development strategies. 

Therefore, the study emphasizes the importance of increasing urban green spaces, conserving existing forest cover, promoting sustainable land use practices, and integrating climate adaptation measures into urban planning policies.

Effective strategies like urban tree planting, developing green infrastructure, improving drainage systems, and responsible urban expansion can help lessen urban heat islands and boost Shillong’s climate resilience in the years ahead.

Pradakshina Borbora and Sonika Choudhury are the post-graduate students of NEHU (Geography Department) and interns of Mahabahu Climate Forum

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