Ultraviolet is the major known cause of skin cancer. It is not disputed that exposure to sun increases the risk of skin cancer. It is believed that the riskiest types of exposure are sunburn, particularly during childhood, and intermittent exposure - such as office workers taking two-week holidays in the sun. Such intermittent exposure is thought to increase the risk of malignant melanoma by 70 per cent, while sunburn is supposed nearly to double the risk.
The mechanism by which sunshine leads to malignant melanoma is not fully understood. Some people are more at risk, for example if they have red hair and freckles, but the full genetic predisposition is not understood. One paradox which has been difficult to explain is that people who work in the sun appear to have a reduced risk of melanoma.
This strategy features in the framework of Agenda 21 as formulated at UNCED (Rio de Janeiro, 1992), now coordinated by the United Nations Commission on Sustainable Development and implemented through national and local authorities.
Skin cancer has become the focus of intervention campaigns in Australia, Europe and North America.