This article discusses the ideas of geoengineering to deflect sunlight as a possible option to reduce global warming effects. It talks briefly about the issues surrounding sulfate sprays and the negative impacts that are associated with them in regards to ozone layer depletion, due to the process of sulfates being introduced into the atmosphere that then can lead to sulfuric acid, and also solar energy output. The article goes on to explain that a group of Harvard researchers have suggested two additional alternatives that would be less damaging to the environment, alumina and, possibly more interesting, diamond dust. The researches go on to say that diamond dust would be twice as effective as sulfate sprays. However, they also warn that the risk of spraying diamond dust into the atmosphere is unknown at this time.