Now I'm all curious.

Can you imagine any distant technology that could permanently eradicate life on earth?

Im thinking we just relentlessly pump CFCs into the atmosphere until we destroy the ozone layer? But I have no idea if that could actually keep it from reforming.

A predictable and steady level of cosmic particles hitting dna though

holy shit, like some kind of extreme photosynthesis based on gamma?

You reckon cellular life forms would wait out nuclear fallout underground?

If not immediately sterilizing you dont suppose enough radiation over time would cause cumulative damage to DNA & their evolution?

Nuclear annihilation is a far worse threat than climate change.

Life will always return, unless we irradiate the planet too severely for even single cell life.