The high albedos and zenith angles in the Arctic cause mixed-phase clouds to warm the Arctic surface during most of the year by absorbing long wavelength (LW) terrestrial radiation and re-emitting LW radiation back to the surface. Most of the LW radiation is absorbed by super-cooled liquid droplets near the top of the cloud. These clouds may be glaciated by seeding with ice crystals, allowing most of the LW radiation to escape into space and thereby cooling the Arctic surface. This study proposes cooling the Arctic by seeding Arctic mixed-phase clouds during the fall, winter, and spring with 200 nm diameter ice crystals sprayed into the clouds by effervescent nozzles deployed on aircraft.