UV-A destroys the connective tissue under the outer layer of skin, which causes the skin tissue to sag and lose elasticity. The wrinkly, leathery look can result from too much UV-A exposure.

Everything else on this chart is mainly a cause of excessive UV-B exposure, which could result if the stratospheric ozone layer were to be severely depleted.

Carcinoma is a type of skin cancer that can be "cured" if detected early. These can appear as red, blue, or black spots in sun-exposed areas (back of neck, shoulders, ear tips, nose, face, back of arms). Leave them too long, and they can develop into something more serious, involving other parts of the body and requiring stronger, debilitating treatments. Melanomas are more frequently fatal, because there more resemble cancers found in other parts of the body, except it's the skin that is first involved. Many melanomas are not really caused by excessive sun exposure.