Ozone depletion refers to the thinning and loss of ozone whereas global warming refers to the widespread warming of average temperatures across the globe caused primarily by the build-up of human-produced greenhouses gases, mostly carbon dioxide and methane, which trap heat in the lower levels of the atmosphere.
The ozone layer allows some energy in and some energy out. The ozone protects us from UV rays, which can be very harmful. With less ozone, more UV- rays reach the earth's surface, harming humans and other animals as well as plants.