I have no idea what a difference it makes to the world that North Korea has let off a nuclear bomb. I did already say a couple of months ago that these things were probably the worst things which mankind has invented.
However, proabably the best thing is not too make too much of a noise about it. I am not aware that North Korea is actually threatening any other country or peoples, at least no country which the US or China are not very well capable of defending themselves. As with Iran, when the 'West' sees another power getting nuclear capability, the way we look at it is dependent upon whether we regard them as friend or foe.
I seem to remember George Bush congratulating both India and Pakistan on having nuclear capabilities... these countries which are in perpetual virtual war with each other, but fairly friendly to Western interests. If Iran or North Korea want a capability to defend themselves against the implacable pressure from the West, the West tends to get very upset, very upset indeed. So, with North Korea having proved it has the capability, it might feel more confident and less scred that it would otherwise be of an imminent invasion from the US supported South Korea. maybe it might styart treating its own citizens slightly better. But if they do not, I hardly think that we in the West are in much of a position to do anything about it.
In the meantime, the best places to be in the world have got to be in the southern hemisphere, far away from all this shenanigans. Better air quality too. Here are some photos of the deserts in Kaokoland, Namibia.