A start-up for-profit company, Make Sunsets Inc. announced a plan to start very small scale stratospheric aerosol injection (SAI) with balloons that release reflective aerosol particles in the stratosphere, and then scale up to using airplanes when any other organization makes transport planes that can fly high enough.  The company is offering to sell $10 “cooling credits” for releasing one gram of SO2 in the stratosphere—enough, it asserts, to offset the warming effect of one ton of carbon for one year. News Report.