"... cloud-based methods such as cloud whitening, stratosphere-based methods such as aerosol injection, and spaced-based methods such as shields"
"...SRM (Solar Radiation Management) methods could be deployed faster than CDR methods should the need arise to cool the planet quickly."
"Cloud whitening is another proposed method for enhancing albedo. Cloud whitening is the dispersion of cloud-condensation nuclei (e.g., small particles of sea salt) in clouds in desired areas on a continual basis (see Figure 2). Aircraft, ships, or unmanned, radio-controlled seacraft could disperse the nuclei."
"The long-term implications of deploying cloud whitening are not yet fully understood."
"Aerosol injection is the dispersal of aerosols, such as hydrogen sulfide (H2S) or sulfur dioxide (SO2), into the stratosphere to direct solar radiation back toward space or absorb heat, thus cooling the Earth. Military aircraft, artillery shells, or stratospheric balloons could be employed to inject the aerosols."
"The benefits and risks of aerosol injection would not be evenly distributed around the globe. A potential benefit, in addition to cooling of the planet, could be reduced or reversed sea and land ice melting (as long as the aerosols don’t settle on and darken snow and ice). Some risks could be drought in Africa and Asia leading to a loss in agricultural productivity, the GHG impact that would accumulate from transporting the aerosol to the site of injection, stratospheric ozone depletion, weakening of sunlight for solar power, a less blue sky, and obstruction of Earth-based optical astronomy."
