Why can over exposure to the sun be heath risk?

Answer 1

Personal response- I have worked outdoors for many years as an Engineer. During those years I failed to use sunblock, as we did not really understand the hazards of sun. I now have to see my doctor for treatment of areas of sun damaged skin on my face, neck, ears and head. If these areas are not treated, they may develop into melanoma, or skin cancer. This CAN be a fatal illness. Moral of the story- use the sun block, wear a hat- or in future years, plan on seeing your doctor twice a year to have little bits of skin frozen with liquid nitrogen. It is not pleasant, but much better than skin cancer.