What could hurt North Korea?

Sanctions don't really work because it hurts the people more then the government.

Military action is not really an option due to the millions of lives that would be loss.

An attack on the North would just give them reasons to fire their artillery at the south whos capital is well in range from the north side of the boarder. The North isn't stupid and isn't going to attack first knowing full well that they would be leveled in a war. China wants to maintain the status quo because they don't wont a U.S. ally on their doorstep.

So what really options are there that could hurt the North Korean government and make them rollback on their aggression?