And it always balances. Energy moves around the system, but the system doesn't gain or lose energy, it is always at 1. A perfect economy.
I'm not sure I entirely agree with this... I don't think it is perfectly balanced because we introduce new energy into the system every day with sunlight and energy also escapes the planet through the atmosphere as well. The problem with global warming is that for the first time in millions of years the system is unbalanced, we're keeping more energy than we're sending out.
I agree that nature might be unkillable... but it could be reduced to a few bacteria deep in the ocean if an asteroid hit.