You are looking at the wrong end point. Yes, the planet will survive. Very few people are worried about that. You have to be a real doomer / gloomer to stay away worrying about Venus level runaway heating. But you can have a number of other scenarios that can be considered less than pleasant:
- Intensifying the sixth major extinction event. The other five really changed the planet around, much to Randall's comfort. The planet will survive this next one but since apex predators tend to be significantly effected and humans are the ultimate apex predator, this might be considered a Bad Idea.
- Increasing temperatures increase arable land (generally). The problem is that of time frames. It may take hundreds of thousands of years to convert warm swamps into farmland. Most Americans can't handle fasting between gas stations, much less millennia
- Increasing resource stresses - you may have noticed that humans are having a bit of a problem creating stable geopolitical structures during geologically and biologically stable periods. Add big swings in weather / climate, no matter which way, creates more stressors and more reasons for us not to get along with each other.
- Which segues into another bit of bad timing. Changing climate while simultaneously cranking human population to over seven billion. For a number of important resources it can be argued that we have exceeded the carrying capacity of the planet. The degree and speed of upcoming climate events may well overcome our ability to feed, water and house all of us.
So, it's not even a big issue which way the climate goes. The only way climate can mitigate the other problems is if it stays relatively constant. That doesn't appear to be happening.