Just what exactly do you expect will happen if you almost double the amount of the atmospheres main persistent infra red absorber? And if you think it will have no effect can you please explain why you think this.
I'm just curious because I'm sure your stand is based on sound scientific reasoning rather than a rather pathetic attempt at self justification for a "lets carry on business as usual I don't care" approach to the issue which unfortunately is a standard human response to a lot of big problems.
The mean temperature may rise 0.6C. Could be marginally less due to negative feedbacks (hitherto underestimated cloud cover) and other random causes (more than average volcanoes popping, the sun having a fit, an asteroid impact...), could be marginally more due to positive feedbacks (water vapor amplification, hitherto belied by the facts) and other random causes (less than average volcanoes popping, the sun having a fit, ...). Let's assume another doubling follows after that before we can't pull any (hydro)carbon out of the ground anymore, because it's not worth to get. We're looking at 1.2C worst case, coming from a post-ice-age low.
I'm old enough to have lived through a significant part of the warming period, and experienced and wise enough to see and comprehend that its supposed negative effects are ranging from undetectable to utterly insignificant and easily adapted to, and will continue to remain so.
AGW biggest problems are its side effects: destructive interference by an idiocracy of dogooders, busybodies, recycled leftists and politicians and the time lost by more sensible people having to push back. Look at the cost to the society due to loss of productivity by this discussion alone.