North Carolina did not outlaw sea level rise
But this is not quite what's going on. If you look at the text of the law, the focus is on banning the state and its subdivisions from making plans for dealing with sea level rise. Non-coastal counties are banned from planning for sea level rise at all, while coastal areas may only base plans on linear projections, which are much lower than the estimates of current climate science.
This focus on planning for sea level rise fits with the growing grassroots conservative framing of environmentalism. It's of a piece with the Agenda 21 panic. The basic belief is that environmentalists, working with the United Nations, are using concerns about environmental degradation and climate change as excuses to destroy our freedoms. Such laws would ultimately turn Americans into serfs of the totalitarian One World Government.
These conspiracy theories are obviously ridiculous. But if you believe them, then a law like North Carolina's makes perfect sense. You're not trying to legislate away sea level rise, you're trying to block false claims of sea level rise from being used to pass new restrictions on people's lives and property.
Ultimately, the debate over addressing climate change is not about a clash between willful ignorance and critical thinking. It's about the clash between ways of life -- the patriarchal homestead and the hippie commune, to reduce them to crude stereotypes. One side is quick to accept the reality of a threat like climate change because it justifies their preferred way of life. The other sees, for exactly the same reason, that the threat makes a convenient way for their opponents to undermine their own way of life. The sooner environmentalists can figure out how to fight on this terrain, the better.