White Roofs - Albedo Effect. by MakeItWhite

This doesn't seem to fit the transportation category. Maybe move to geoengineering?

Thank you for sharing your ideas and for the work invested to create this proposal. Your proposal has been considered carefully, and while the proposal has interesting ideas, it appears unlikely to have the effects that are intended. Please note the following study on the effects of white roofs: Mark Z. Jacobson and John E. Ten Hoeve, "Effects of Urban Surfaces and White Roofs on Global and Regional Climate", Journal of Climate, 2012. From the paper: "A conversion of rooftops worldwide to white roofs, accounting for their albedo effect only, was calculated to cool population- weighted global temperatures by 0.02 K but to warm the earth overall by 0.07 K. Local ground cooling stabilized surface air, reducing sensible and latent heat fluxes and local cloudiness, increasing local surface solar radiation, resulting in local cooling smaller in magnitude than without the cloud reduction. Higher reflection also increased air heating by black and brown carbon in soot. Feedbacks of local changes to the global scale were magnified over high-latitude snow and sea ice, causing a net but highly uncertain warming effect on global climate. The local cooling due to white roofs may reduce or increase energy demand and thus other emissions as well, a factor not accounted for in these simulations. This feedback should be considered in any final assessment of the effects of white roofs on climate."