It's probably up there with the Korean DMZ, Chernobyl, and Bikini Atoll as unintentional nature preserves.
I'm a engineer inspecting an unrelated project next to a superfund site in NJ (Toms River). The superfund site is now 22,000 acres of untouched wilderness. The municipal workers say it's now filled with all sorts of wildlife including coyote and turkeys.
I recently read an article describing how NK was way more willing to get on board climate change proposals than, say, curbing their Nuclear ambitions. This is because they're peninsula is particularly sensitive to ocean and climate change.
Climate change also serves to hobble their rich industrialized enemies and provide an excuse for building nuclear plants.