Why can´t be my roof white?
I live in a 9 plant house and we are facing several maintenence/repairing operation last years due to the age of the building. With my limited knowledge I participate in a small comission to check our next project, which involves changing our wasted roof. As we were talking with the architach about the project Y asked why we could not use a white material (or at least paint it) instaed of the greyish one we will finally use. He simply did not take the question into consideration.
Maybe he thought it was about aestetics but it was about albedo. This strange word plays a role in our climate and can be explained with few words (although maybe not bery precisely): It is the amount of light and so, energy, from our sun that our land reflects. For that reason a quick trick to improve our situation could be to increase this and reflect more solar radiation. I know it sounds quite artificial, but we are not in a situation with too many choices and anyway we are reducing our albedo by melting several glaciers and polar snow. And its easy and in many cases costless at least in some buildings, roofs, etc… It is not the definitive solution for climate change but it could help.
Composition if 3 images from Google Maps. Left: My home city with red roofs, not very reflective. Right: An industrial area not far from the left image, the albedo is much higher. Bottom: Image from Iceland snow, real great albedo.
However, it is not commented anywhere and no goverment (local or higuer) has it included in building rules or politics. So, standard arquitetchs and building material producers will continue thinking it is about colour preference.
I would not be difficult to encourage people to love white for their houses roofs and we could counteract some tons of CO2 without terrible effort. Or at least explain its possibilities for all of us to make choices.
Amateur Climate Change 