Aerosol injections and Cloud Brightening.
Radiation management literally aims to reduce warming of the planet by deflecting sunlight.
Methods include stratospheric aerosol injections, marine cloud brightening, space mirrors and painting roofs white.
Aerosol injections involve spraying aerosols into the stratosphere so that the particles block and reflect the sun’s rays, to bring temperatures down.
Marine cloud brightening works in a similar way and involves seeding clouds with a fine spray of saltwater to encourage micro-droplets to form. These micro-droplets scatter incoming radiation and make clouds last longer.
These measures are relatively cheap, some estimates suggest they would only cost between $3 billion and $30 billion a year, which is very affordable compared to global GDP of $75 trillion.
But the report warns that because these techniques are inexpensive, some countries may make individual decisions to use them to respond to real or perceived climate emergencies. Or they may simply want to set the “global thermostat” to their preferred temperature.
This makes it very difficult to control the use of these techniques.
The measures also do not do much to address other problems like ocean acidification, greater ozone depletion and could also make solar power less productive.
They also throw up new risks as their effectiveness in controlling temperatures has not been tested in field experiments. Any small-scale tests would be unlikely to predict the exact outcomes.
There’s also the risk that if the measures had to be stopped suddenly, the rapid warming of the planet afterwards could be devastating.
Science doesn’t really require that scientist has a brain… cool.