I'm interested in this as a potential Extinction Level Event. I understand that life would end due to the destruction of the ozone layer, causing cancers and the collapse of the food chain. How long would this take from, say, the catastrophic effects on the ozone layer to the first cancers and then to the extinction of life on Earth? Would anything survive? If a man could survive that initial trauma, what kind of precautions would he need to take in order to go outside? Sorry for the melodrama... I'm a writer interested in what if...