What would happen to the stratosphere if humans were to increase the amount of ozone within it?

The increase in amount of ozone layer in stratosphere, will be beneficial in preventing the intense and harmful radiations, such as Ultra Violet Rays, to reach the surface of earth.

Explanation:

Ozone layer is formed when a single atom of oxygen (O) reacts with a molecule of oxygen (O₂) to form O₃ (Ozone). The ozone layer in the stratosphere is formed by the reaction of oxygen molecule (O₂) with a single atom of oxygen (O), which is formed by splitting up of an oxygen molecule, by the sunlight.

This ozone layer in stratosphere absorbs harmful radiations, such as Ultra Violet Rays and prevents them to reach the earth. If these rays reach the surface of earth, they can cause life damage to human bodies.

Thus, the increase in amount of ozone layer in stratosphere, will be beneficial in preventing the intense and harmful radiations to reach the surface of earth.