Emission offsets by albedo manipulations strategies based on bright materials and greening in urban areas assessed by hyperspectral remote sensing

Climate neutral cities require climate mitigation strategies such as albedo manipulation approaches. This could be a low-cost approach able to reach short term results while working on reducing emissions on the long term. Currently, only few studies were carried out to investigate the potentiality of albedo changes to effectively reduce radiative forcing (RF) at city scale. This study makes use of high-resolution hyperspectral remote sensing (RS) to simulate three scenarios of albedo manipulation in the city of Prato (Italy). The scenarios are “W” (white, where roofing materials are substituted by white painted concrete), “G” (green, simulating the albedo of green roofs) and “B” (bright, where the dark asphalt of the roads is substituted by brighter paving materials), also considering restrictions due to cultural heritage constraints. Albedo manipulation is then translated into equivalent CO2 savings/emissions via a global warming potential (GWP) model and these CO2 amounts are compared with the city's inventorial emissions. Results show that the W scenario can offset up to 10.3 % of the whole city's emissions. This study suggests that while RF-based interventions on urban materials are unable to totally compensate direct CO2eq emissions, they can still contribute especially when coupled with decarbonization and urban emission reduction strategies.