The visible reflectance of water clouds depends upon its composition, particularly the size distribution and concentration of water droplets and the total liquid water content. In clouds of low droplet concentration, typically found over the oceans, the addition of a few more cloud condensation nuclei could significantly alter the cloud's reflectance to visible light. When averaged over the entire globe this effect could cancel the presumed warning arising from the increase of carbon dioxide in the atmosphere. However, even if this global effect is unrealized the physics of aerosol pollution, and cloud reflectance remains intrinsically interesting.
