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Rooftop gardens, once a niche feature of luxury buildings, are increasingly promoted by city planners as a practical response to urban heat and stormwater runoff. A layer of vegetation and growing medium absorbs solar radiation that would otherwise be reflected as heat from bare rooftops, lowering surrounding air temperatures during summer months. The same layer also retains rainwater, releasing it slowly rather than allowing it to overwhelm drainage systems during storms. Structural considerations, however, limit adoption: older buildings frequently lack the load-bearing capacity to support saturated soil and mature plants without expensive reinforcement. As a result, rooftop gardens remain far more common on newly constructed buildings, where architects can plan for the additional weight from the outset.