How can we convince young people that pale skin is beautiful, to decrease skin cancer?

Education: It is a slow process, unfortunately. (along the lines of "how can we convince people to stop smoking?") until it becomes hip to be pale, i recommend sunless tanning products, which can give the look without the aging and skin cancer effects.

Sunscreen, check-up.: Sunscreen and less intense sunlight exposure can really help lower risk of skin cancer. Frequent check-ups with your doctor/dermatologist also help greatly.