The only "penalty" for missing a Kyoto emission target, is that a country must cut emissions 30% "more" in the next target period. But "more" than what? More than its target would have been. So it will just say its target would have been low. And if it misses again? Then next time it must cut 30% more again, and so on forever. This is ridiculous. And of course, no one is even pretending it will happen.
Scott Barret has written about this in much more detail, and we will provide references pretty soon.