My non-scientific gut feeling is that regardless of what we do, we’re too late to stop the natural feedbacks already in progress. Which was the problem all along - humans were never the sole cause of global warming, they were the catalyst with their emissions to set things rolling. Even twenty years ago if we had done everything right and stopped emissions, we had already pushed the environment to change. And we didn’t, so we’ve been pushing that boulder down the hill even as it gains its own momentum. Smart, we are. The boulder will stop when it stops, not when we wish it.