> So where's the adverse effect from reducing the ppm by 10 a year - or month (hah, unlikely), until we hit target? Apart from reversing the recently observed

> So where's the adverse effect from reducing the ppm by 10 a year - or month (hah, unlikely), until we hit target? Apart from reversing the recently observed greening of the planet, it will be dangerous if we have built all our infrastructure around zero/negative CO2 and are not able to stop removing CO2 just like now we don't seem to be able to limit the increase quickly enough.