My understanding is that the climate sensitivity per doubling of CO2 is about 3 degrees celsius; if we keep putting CO2 into the atmosphere at our current rate

My understanding is that the climate sensitivity per doubling of CO2 is about 3 degrees celsius; if we keep putting CO2 into the atmosphere at our current rate we'll get to one doubling in about 56 years; therefore we'll probably wind up at one doubling or a bit less by the time we go completely renewable. That would be around 2.5 degrees of warming. Which is very bad, but not civilization-ending. Have I missed something?