Unfortunately, you're simply failing to grasp the scope of the problem.
You're quite right that poverty is the biggest killer on the planet, but poverty is also the primary reason why people will die (and already are dying) due to global warming.
You see, when a system of oscillators accumulates energy, the amplitude of the oscillations tends to increase. This means that the extremes become more extreme, and you get both extreme droughts and extreme floods. Haven't you noticed that Texas and Arizona are burning while the Mississippi floods? That sort of thing starts happening much more frequently as the temperature increases.
So it's not just a matter of being slowly inundated by the encroaching sea, it's more like being alternately inundated with record flooding and parched with severe drought, repeatedly for many years, and then being slowly inundated by the encroaching sea.
You are fortunate that denial is, as they say, not just a river in Africa, because when the rivers of Africa start to experience alternating severe drought and flooding the way Australia already is, you're probably not going to want to be clinging desperately to any African rivers anyway.
So, what effect do you suppose all of this will have on food commodity prices? And what effect do you suppose that will have on the poor? It's already happening, food prices are way up and many people are dying because of it. And this is only the beginning, Mother Nature is just getting warmed up.
Let's call things what they are for a change, shall we?
When multiple independent well-established lines of evidence all point unequivocally to the same conclusion, I call that science.
When thousands of papers, the official statements of every major scientific organization in the world, and the professional opinion of ~97% of active researchers in the field support the same conclusion, you might just want to consider whether that conclusion might not be science, you think?
When the incoherent antiscientific blatherings of professional corporate shills contradict the vastly overwhelming body of scientific evidence, I call that propaganda.
To elaborate, what you're doing is citing a study without understanding anything about it, out of context, and claiming it relates to an issue upon which it has very little bearing. That experiment didn't disprove that the moon is made of green cheese either.
You read about that paper on some non-scientific propaganda site like WUWT or Denial Depot. People there, who have no more understanding of science than you do, claimed that the paper meant something it doesn't, and you believed them because it fit in with your preconceived notions.
Dig a little deeper next time.
Hmmm... that's not what the scare-mongers over at MIT say:
Um... because that theory is not real science and has been completely debunked.
This whole line of reasoning seems plausible on the surface, until you actually do some research into it.
It's not a matter of optimal, it's a matter of what we're used to. Radical, rapid change in climate (such as we're already experiencing, and it'll get much worse) changes rainfall patterns and other factors that will force us to change where we build our cities, where we grow our food, etc. That kind of adjustment is incredibly expensive, much more expensive than taking reasonable mitigation steps now.
You want to move people out of areas that might be affected? OK, then start with the entire continental US, which is projected to experience severe drops in precipitation that will make the dustbowl look like a monsoon. And that's just one dimension of the probable impacts.
See this article, "Real adaptation is as politically tough as real mitigation, but much more expensive and not as effective in reducing future misery":
"...a most excellent barbarian ... Genghis Kahn!" -- _Bill And Ted's Excellent Adventure_