North Korea conducted the fifth nuke test recently, reaching >20k tons of TNT. This indicates that NK has now been a nuke nation and is able to deliver nuke warheads by long range missiles over 8000 km away. Nobody is happy about it because nobody would like to see the presence of nuke bombs in the Korean penisular.
The nuke tests may result in a deadly consequence - that NK may be attacked in the near future - that will trigger the second Korean war. However, such war must not be permitted to happen again. If it took place, that would be the third world war. If that happens, this world will go back to the stone age. Period.