I have tended to call it human impact, and call it idiocy to clame that human impact as a whole for hundreds of years has no effect on global climate.
I have also been sceptic about this "co2 balancing" project.
You will find this in the threads.
However co2 does in increased measure function as a warming gas. It's just not much compared to methane with it's power.
And I have mentioned that, as far as I remember as a paralell to turning on a switch, - if human impact is enough to warm the globe to the level of the permafrost melting and releasing all it's methane, then you are going to see some really wild stuff happen. I leave it up to debate about whether it's going to be enough for a Venus scenario, but IMHO you'll be seeing a climate that you won't like.
So, - small doomsday or the real one. Wan't to take the chance?