>>15
Is that another joke? There are four trillion metric tons of nitrogen in the atmosphere. There are incalculable stores of carbon products underground out of our reach. It's not just a matter of setting off enough bombs; you need such an even distribution of bombs both throughout the atmosphere and underground to irradiate all the elements, and you'd need to set them off simultaneously so that unblasted portions don't just dissipate into the irradiated materials. It really doesn't make sense because this process would be making more by irratiating higher elements that decay to stable carbon, nitrogen and oxygen.
You are gravely underestimating the size and resilience of the planet. If we took all the uranium and plutonium on earth and blasted our atmosphere to smithereens, the earth wouldn't even feel it. Couple thousand years, and it would be in better shape than it has ever been in millions.