Final answer:
The major risk to humans from the depletion of ozone is the increase in UV radiation reaching Earth.
Step-by-step explanation:
The major risk to humans from the depletion of ozone is the increase in UV radiation reaching Earth. Ozone depletion allows more UV-B rays to penetrate the atmosphere, which can cause health issues such as skin cancers and eye cataracts. It also disrupts ecosystems by disturbing the nitrogen cycle, killing plankton, and disrupting ocean food webs.