You are conflating a world that is becoming warmer with a world that just *is* warmer. It may be true (I take no position) that a world that is 4-5 C warmer is better for certain classes of poor people (e.g., subsistence farmers). But a world that is changing rapidly is a calimity to poor people tied to the land, especially in a modern world with national boundaries and private property where you just can't pick up and move like our paleolithic ancestors would have.