Cover the ice free Arctic Ocean and melted tundra peat bog lakes with white or aluminum coated ping pong balls.
Advantage: This would return the albedo of those ice free areas to a value closer to the ice covered state, preventing the absorption of solar heat.
The air would not be affected.
Space launches would not be required. It is low tech.
The ping pong balls would blow and ride currents into the other oceans, raising the albedo of a larger area.
Disadvantages: It would take a lot of ping pong balls.
Animals might eat the ping pong balls.
The ping pong balls would blow and ride currents into the other oceans.
Research required: Ping pong balls are only a starter idea. The optimal
size, shape, materials, etc. need to be researched. Perhaps the balls
should be transparent with corner reflectors inside.
Is there anything ping pong balls could be made to do about the methane
bubbling up from below? Catalysts would be an expensive coating for the
ping pong balls.