But skin cancer was really not used before the rates all of sudden increase. We sued to send a lot more time being exposed ot sunlight so it doesn't make sense that rates rise now.

The short version: skin cancer rates were rising long before sunscreen became common, and the rise tracks changes in sun behavior and detection, not sunscreen failure.

Melanoma rates climbed from about 1 in 100,000 in the 1930s to 6 in 100,000 by 1980, well before sunscreen use took off. That steep increase happened during a period when people started spending more time in intense, intermittent sun, on vacations and in sunny climates, which is the pattern most strongly linked to melanoma. Sunscreen came later, and when people use it, they often stay out longer, apply too little, and never reapply. A filter is not a force field.

The other major factor is detection. Skin cancer screening programs and public awareness campaigns mean more lesions are found and biopsied than ever before. A Western Australian screening program found 24.7 suspected melanomas per 1,000 screens but only 3.0 confirmed [11]. That is a lot of overdiagnosis. Better detection alone can explain a large share of the rising incidence, especially for thin melanomas that would never have caused trouble.

The Norwegian offshore workers study is worth a close look. It found that frequent sunscreen use was associated with a doubled risk of squamous cell carcinoma, and the authors said this was likely because sunscreen users spent more time in the sun [6]. That is confounding, not causation, but it shows how hard it is to separate the effect of the product from the behavior it enables.

My call: the rising rates are real but driven mostly by changing sun exposure patterns and better detection, not by sunscreen failure. Confidence: moderate.