You have probably heard of staying under the 2C goal.

At 2C the warming feedback loop is self sustaining and will grow to 8 or 10C. At 2C, the permafrost melts, a LOT of methane is released. The oceans turn acidic and with a higher temperature can no longer support the algae that supplies most of the oxygen on the planet. By that point most of the planet will already be a desert because the majority of plant life and animal life cannot survive routine 130 or 140 degree temperatures.

Good luck surviving without plants, animals, or oxygen.