The mechanism behind this cooling is rooted in the biological and physical properties of the gardens themselves. While concrete reflects and traps heat, the soil and vegetation found in allotments actively work to cool the air through a process known as evapotranspiration. Plants absorb water through their roots and release it into the atmosphere as vapor through their leaves, a process that consumes heat energy and naturally lowers the surrounding temperature. Additionally, the presence of unpaved, permeable soil allows for better moisture retention in the ground, further contributing to the cooling effect compared to the dry, sun-baked surfaces of city pavements.
The study’s authors emphasize that the benefits of allotments go beyond the immediate cooling of the air. They represent a multifunctional approach to urban resilience. While their primary role in this context is temperature regulation, they also serve as vital hubs for biodiversity, providing habitats for pollinators and birds within the concrete jungle. Moreover, they offer social and psychological benefits, providing city residents with a connection to nature and a space for community interaction. However, from a strictly climate-focused perspective, their ability to act as a heat sink is perhaps their most urgent contribution to modern city life.
In light of these findings, the study advocates for a significant shift in spatial and urban planning policies across Europe. The authors recommend that municipal governments and urban developers prioritize the placement of smaller allotments directly within city centers rather than relegating them to the outskirts or the "green fringes" of the commuting zone. The logic is clear: the cooling effect is most needed where the population density is highest and where the infrastructure concentration is most intense. By embedding these gardens into the heart of the city, planners can enhance heat resilience in the very areas that are currently most vulnerable to the UHI effect.
This recommendation poses a challenge to traditional development models that often view every square meter of city-center land through the lens of commercial or residential value. The research suggests that the long-term value of allotments—measured in terms of public health, reduced energy demand for air conditioning, and climate adaptation—may far outweigh the immediate economic gains of further densification. Integrating these spaces requires a rethink of how "commuting zones" and "urban cores" are structured, moving toward a model where green infrastructure is treated with the same level of importance as transport or utility networks.
