The United States government has known about the potential of solar geo-engineering since at least the 1960s
Although solar geo-engineering and stratospheric aerosol injection (SAI) sound like modern concepts or something out of a science fiction novel, the truth is that the United States government has been aware of the potential of SAI since at least the 1960s when the first reports predicting the future effects of climate change were being presented to high level members of government.
These reports primarily highlighted the groundbreaking discovery that global concentrations of carbon dioxide (CO₂) in the atmosphere were increasing, along with early predictions of the consequences of this increase on the environment 1. In the report's conclusion, there is no mention of the need to reduce CO₂ emissions, but rather the report discusses the potential of solar geoengineering as a method to mitigate the effects of climate change. The method proposed in the report was the release of highly reflective particles on the sea surface to reflect sunlight and cool the Earth. An excerpt from the conclusion of the President's Science Advisory Committee's 1965 report titled "Restoring the Quality of Our Environment" is provided below:
"The climatic changes that may be produced by the increased CO2 content could be deleterious from the point of view of human beings. The possibilities of deliberately bringing about countervailing climatic changes therefore need to be thoroughly explored. A change in the radiation balance in the opposite direction to that which might result from the increase of atmospheric CO2 could be produced by raising the albedo, or reflectivity, of the earth. Such a change in albedo could be brought about, for example by spreading very small reflecting particles over large oceanic areas. The particles should be sufficiently buoyant so that they will remain close to the sea surface and they should have a high reflectivity, so that even a partial covering of the surface would be adequate to produce a marked change in the amount of reflected sunlight. Rough estimates indicate that enough particles partially to cover a square mile could be produced for perhaps one hundred dollars. Thus a 1% change in reflectivity might be brought about for about 500 million dollars a year, particularly if the reflecting particles were spread in low latitudes, where the incoming radiation is concentrated. Considering the extraordinary economic and human importance of climate, costs of this magnitude do not seem excessive. An early development of the needed technology might have other uses, for example in inhibiting the formation of hurricanes in tropical oceanic areas." 1