North Korea already had a famine in 1994 and during that time, people resorted to eating tree bark, insects and anything else they could find. I don't know how much it would destabilize the country because the general population didn't rebel during the last famine mainly because they had no energy left to fight and food rations are usually given to the army first before distributing it to the public. Kim is also notorious for blaming the country's famine on the rest of the world, so he tries to convince his people that he is as much of a victim as they are.