Answer
This will cause more UV radiation to reach the earth's surface.
Work Step by Step
UV radiation can cause the formation of harmful oxygen free radicals, which can attack DNA directly or can alter fats and proteins in a way that makes them harmful to DNA. Damaged DNA can then produce mutations (a change in the DNA base sequence) which can subsequently lead to the production of a non-functioning protein. (I.e in mutations such as addition/deletion mutations which cause a frameshift and alter the primary, secondary and tertiary structure of the protein.) More UV radiation reaching the surface of the earth would increase the number of mutations in the organisms on its surface which would subsequently increase the risk of developing cancer.
