As we move through November, North India continues to experience unusually warm temperatures, with daily highs still reaching around 30°C—significantly hotter than the seasonal average. This unseasonable warmth is a reminder of shifting climate patterns affecting cities across the region. During the summer of 2024, the Northern Hemisphere faced unprecedented heatwaves, with July recording the highest global temperatures ever. The World Meteorological Organisation warned earlier this year that Asia is heating up faster than the global average, leading to increased casualties and economic losses from floods, storms, and intensifying heatwaves.
As heatwaves become more frequent and intense, their impact is most intense in urban areas where heat accumulates and is trapped in heat islands (so called Urban Heat Island). This summer, Delhi’s Mungeshpur recorded 52.3°C, a new high for temperatures in India. While the entire urban population faces risks, the most vulnerable are often those in the most heat-exposed jobs and living conditions. Construction workers, street vendors, and slum dwellers endure extreme heat with minimal protection. Such high temperatures coupled with high humidity—measured as wet bulb temperature—pose severe health risks and even death. A study in Pune, Maharashtra, using Landsat satellite images, revealed significant heat variations within the city. Affluent areas like Prabhat Road and Fergusson College, with extensive vegetation, exhibited lower surface temperatures. In contrast, densely populated areas, including slums, experienced extreme surface temperatures (such as asphalt), reaching as high as 69°C. This contrast underscores the spatial vulnerabilities faced by economically disadvantaged populations, especially with limited financial resources and healthcare access. Already marginalised, they bear the brunt of UHI effects.
Interestingly, a study in Nature Cities analyses 20 years of data from 30 Chinese cities and finds that a green buffer ring of rural land around a city, like a donut, can help lower urban temperatures. Connecting patches of rural land to form a surrounding buffer ring and strategically managing its land cover by increasing woodlands or establishing permaculture farms, along with creating fewer but larger lakes, can reduce the UHI. This approach could mitigate the heat dome effect, which further exacerbates the UHI phenomenon, and potentially turn it into a benefit for the city.
A urban heat dome
An urban heat dome is a weather phenomenon caused by a high-pressure system in the atmosphere that traps hot air over a city, resulting in extreme, prolonged heat and dry conditions. Acting like a lid, the high-pressure system prevents warm air from rising and cooling. Instead, the system pushes the air downwards, where it compresses and heats up even further. This creates a dome-shaped zone of intense heat that can last for days or even weeks, significantly raising local temperatures. Without any heat exchange or inflow of cooler air, the trapped heat intensifies, amplifying its impact on the city. This sustained heat poses severe health risks, especially to vulnerable and marginalised groups, leading to higher mortality during these events.
Several meteorological factors work together to create a high-pressure system in the atmosphere that leads to the formation of a heat dome. Urban areas consistently experience higher temperatures than their rural counterparts due to the heat-retaining characteristics of urban infrastructure. Dense building clusters, heat-absorbing materials like concrete, and human activities such as vehicle emissions all contribute to the UHI. This excessive heat, combined with high-pressure conditions, gets trapped and compressed, resulting in the formation of a “heat dome.” The urban planning narrative often emphasises on mitigating the UHI and dome effect by mostly focusing on strategies that seek solutions within the city limits. However, it is found that making changes to land use beyond the boundaries of a city can make a big difference to temperatures downtown.
Urban heat radiates outward, impacting neighbouring rural areas that often boast more natural land cover, such as trees, rivers, and croplands. This outward spread of heat allows for a dynamic exchange between the scorching city and the cooler countryside, a process that can potentially alleviate the dome effect. However, for this natural cooling mechanism to be effective, the surrounding rural land must be carefully managed to maximise its cooling potential. When these rural areas are optimized for cooling, the pressure differences between the heated urban core and the cooler rural zones can drive a beneficial heat exchange, helping to dissipate the intense heat trapped within cities. Cooler breeze from the neighbouring rural areas around the city blow into the urban centre, exchanging heat between the dome and surrounding area.
Cooling green belt
This interaction highlights the potential of landscape management to transform the relentless heat of urban areas into a more balanced local climate. By effectively managing the land on the city’s periphery, we can create a buffer zone that optimises land use and climate interactions, providing a unique solution to the UHI challenge.
Areas with more vegetation tend to be cooler because plants reduce the surface’s reflectivity (albedo), absorbing more energy rather than reflecting it. This absorbed energy is then used for evapotranspiration—a process where plants convert water into vapour, thereby cooling the area by using energy that would otherwise heat the surrounding air. Additionally, vegetation increases surface roughness, creating turbulence that helps dissipate heat close to the ground. In contrast, barren areas like concrete parking lots lack vegetation, causing absorbed energy to directly heat both the surface and the surrounding air, intensifying the heat.
Based on these land-climate interactions, the study suggests that rural land within a 10–15 km radius from the city boundary is particularly effective in cooling urban areas. This buffer zone can reduce UHI intensity by up to 30 pe cent in city centers, with the density and richness of vegetation patches playing a crucial role in this cooling effect. Proper management of these rural areas can facilitate desired heat exchange and could lower urban temperatures by up to 0.5°C. In essence, this rural buffer acts as a transitional zone—a bridge between urban and rural environments.
More research on such land and climate interactions is needed to evaluate their effectiveness in cities with different shapes, development levels, and climatic conditions.
Building Synergies
It is essential to implement “synergistic action” that harmonize land management between urban and rural areas. This requires a coordinated effort from various stakeholders, including municipalities, urban planners, hydrologists, agriculturalists, and gram panchayats. Developing a minimum percentage of functional green belts—such as permaculture farms, woodlands, and grasslands for grazing—around city peripheries and integrating water bodies or lakes into the landscape can offer cooling effect and other co-benefits such as addressing water scarcity issues in rural areas. Financial and technical support is crucial for developing these transitional landscapes. Public-private partnerships can significantly contribute to this effort; collaboration between government agencies, research institutions, and private companies can drive large-scale urban-rural cooling projects. Leveraging Corporate Social Responsibility funds can further support and expand these initiatives.
Such action must be backed by policy changes. It is essential to prioritize zoning regulations that preserve rural and natural lands, thus preventing urban sprawl and fostering the creation of ecological buffer zones. Engaging local communities in this process is vital — their involvement can highlight challenges that may not be apparent to external stakeholders. Sensitising local communities and urban dwellers is most important to help them understand the significance of and adapt to these initiatives in building climate resilience.
While such action and policy development may take time, redirecting development of nature-based carbon offset projects around city peripheries could provide an immediate opportunity. These initiatives can generate funds for rural communities through carbon credits while also offering a practical solution to mitigate UHI effects. Additionally, they can serve as valuable pilot studies and a research foundation for understanding the cooling impact of integrated rural-urban land management practices.
This strategy not only helps manage heat in urban areas but also enhances the natural environment in rural regions, particularly those at risk from rapid urban expansion. It supports moderate temperatures and reinforces practices that benefit food systems and promotes social justice for agricultural communities.
The writer is an independent researcher who works on carbon markets
