That's a rough global temperature spread over the important eras on Earth, in terms of life, at least. You'll note we're still in the blue, even with anthropogenic warming; the dividing line there is "does the planet have ice caps". The entire Quaternary Ice Age, so the last several million years, is that low point right before it kicks up to "today"; humanity has only ever existed within the Quaternary.
If we spike up to even the Eocene maximum, that's a global average some 20 degrees Fahrenheit (around 11C) higher. That's warm enough that the temperatures would kill humans if you're outside in the tropics. Hell, we already hit similar heat waves; anything north of about 105F can get deadly. You get a bit more leeway in dry climates, but in humid climates, that shit will kill you if you have to deal with it long term.
And that's without pointing out that we'd lose the ice caps. That's about 230 feet of sea level rise. This isn't something we can just handle. Earth would become nearly as hostile to human life as, say, Mars, just in vastly different ways.