What is the set standard temperature for the planet?

with all the "debate" about global warming, how are we as temporary stewards of this planet actually going to determine what is the standard temperature for earth? are we now that arrogant to think we can control the climate of something as large as our atmosphere, or for that matter even make a scratch on the surface of it. this planet will survive with or without humans on it. we cannot destroy earth. rather, we will be a small blip on the time line of earth when it is all said and done over the multi-billion year course of it's lifespan.