This article is from the Ozone Depletion: UV Radiation and its Effects FAQ, by Robert Parson firstname.lastname@example.org with numerous contributions by others.
Most skin cancers fall into three classes, basal cell carcinomas.
squamous cell carcinomas, and melanomas. In the US there were
500,000 cases of the first, 100,000 of the second, and 27,600 of
the third in 1990. [Wayne] More than 90% of the skin carcinomas in
the US are attributed to UV-B exposure: their frequency varies
sharply with latitude, just as UV-B does. The mechanism by which UV-B
induces carcinomas has been identified - the pyrimidine bases
in the DNA molecule form dimers when they absorb UV-B radiation.
This causes transcription errors when the DNA replicates, giving
rise to genetic mutations.[Taylor] [Tevini] [Young et al.] [Leffell
and Brash]. Fortunately, nonmelanoma skin cancers are
relatively easy to treat if detected in time, and are rarely fatal.
Fair-skinned people of North European ancestry are particularly
susceptible; the highest rates in the world are found in Queensland,
a northerly province of Australia, where a population of largely
English and Irish extraction is exposed to very high natural UV
[Madronich and de Gruijl] have estimated the expected increases in
nonmelanoma skin cancer due to ozone depletion over the period 1979-1992:
Lat. % ozone loss % increase in rate, % increase in rate, 1979-1992 basal cell carcinoma squamous cell carcinoma 55N 7.4 +-1.3 13.5 +-5.3 25.4 +-10.3 35N 4.8 +-1.4 8.6 +-4.0 16.0 +-7.6 15N 1.5 +-1.1 2.7 +-2.4 4.8 +-4.4 15S 1.9 +-1.3 3.6 +-2.6 6.5 +-4.8 35S 4.0 +-1.6 8.1 +-3.6 14.9 +-6.8 55S 9.0 +-1.5 20.4 +-7.4 39.3 +-15.1