A. The Urban Heat Island (UHI) effect, a phenomenon where metropolitan areas are significantly warmer than their surrounding rural counterparts, is exacerbated by the dense concentration of buildings and impervious surfaces like asphalt and concrete. These materials absorb and retain solar radiation, releasing it slowly and elevating ambient temperatures. In the quest for sustainable urban cooling strategies, vegetated or 'green' roofs have emerged as a prominent solution. Beyond their aesthetic appeal and biodiversity benefits, their primary contribution lies in their capacity to fundamentally alter the thermal dynamics of a building's envelope and its immediate micro-environment. However, the precise mechanisms through which they achieve this cooling, and the variability of their effectiveness, warrant a closer scientific examination. B. The most potent active cooling process facilitated by green roofs is evapotranspiration. This is a dual process involving the evaporation of water from the soil substrate and transpiration, whereby plants release water vapour into the atmosphere through their leaves. This phase change from liquid water to vapour consumes significant energy, know…
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