People are remarkably resilient, but they depend on the natural infrastructure and supply chain that isn't so. The seas and oceans harbor life that will die if temps rise by more than a couple of degrees and they form the foundation of all life. If we lose the lowely plankton we lose humanity.

The temperatures you are referring to came about over thousands, if not millions, of years, not decades. Such rapid change has always been associated with massive die-offs in our planet's history. We might survive the immediate effect, but we will probably wish we hadn't.