Realistically, extreme negative emissions are a practical impossibility. Zero emissions are as well.

We still have an opportunity to reduce the extent of the damage. Major climate change is likely inevitable at this point as, realistically, the modest measures taken to date are insufficiently binding to be effective.

I don't think we've past the point of no return, yet, but we will certainly do so at some point given the real cost of taking action appears to grow faster than the political will to take action.