5.0

That's a bleak setting!
I think it's only the second time I've read a story involving Earth's magnetisim (first being the amazing short story 月夜 / Moonlight, by Liu Cixin), so I don't know or understand much about the topic, but it does scare me a lot.
Little Mushroom's world has very cruel rules they put together in order to survive. What's really scary to me though, is the popular reaction of people, instead of weighing whether human survival is worth it in those conditions, when they have to be this ruthless in order to survive, is survival worth it, most of them shift their focus on the person they designated to apply the rules of their society. As if the person applying the rule is the guilty one & not just an instrument of the will of the society, that can & is replaceable.
They also start from the premise that the Arbiter use of force is excessive & unwarranted, that he commits murder & never seeem to mention that they were killed, according to the rules, that is early in their mutation before they could infect or kill other people. Instead of being angry at a world that is progressively becoming more hostile, they blame the person they chose to give the right to be decisive about keeping them safe.
While the organisation of the Base is undubitably a very harsh, inequitable system that manufactures kids & then gives them a handful of years before they are judged worthy or worthless, determining the rest of their life & depriving most of them of opportunities for growth & developpement, they do value human life & they let people have pursuits that are outside the scope of fighting for the survival of the human species, which seems like a huge waste to me, how could they afford to not have everyone working on fixing the problem? How could you live in that world & not want to fix the problem?
(I'll stop here, I'm halfway through the second volume, I'll write the rest of my thoughts there)