space. Carbon dioxide removal (CDR) has multiple practices, the simplest being reforestation, to more complex processes such as direct air capture. The latter is rather difficult to deploy on an industrial scale, for high costs and substantial energy usage would be some aspects to address. Another geoengineering discipline is solar radiation management (SRM), which is the process of rapidly cooling down the Earth's temperature. Examples of this process include stimulating the cooling effect of volcanoes and enhancing the reflectivity of marine clouds. When a volcano erupts, small particles known as aerosols proliferate throughout the atmosphere, reflecting the sun's energy back into space. This results in a cooling effect, and humanity could conceivably inject these aerosols into the stratosphere, spurring large-scale cooling. Marine cloud brightening (MCB) is a solar radiation management theory that is designed to make marine clouds brighter, reflecting light back into deep space. By reflecting light from the sun, this process could help offset anthropogenic global warming, which threatens the lives of all human beings and life on Earth. One proposal involves spraying a vapor into low-laying sea clouds, creating more cloud condensation nuclei. This would in theory result in the cloud becoming whiter, and reflecting light more efficiently. See also Astroengineering Macro-engineering Megascale engineering Moving the Earth Virgin Earth Challenge References Further reading External links Geoengineering: A Worldchanging Retrospective – Overview of articles on geoengineering from the sustainability site Worldchanging Space colonization Engineering disciplines