Those deadlines always remind me of some apocalyptic cults that predict the end of the world to the day and then find all kinds of flimsy excuses why it did not happen. Cry Wolf too many times and people are not going to listen to you anymore. Why does it still work in Climate Change? Well, so far people had a feeling that they could have the cake and eat it. Now they start to find out that this crap is really expensive and their lives go to the dumpers as a result. Expect more of a backlash.
Climate Scientist Mike Hulme has stirred a hornets nest by suggesting setting climate deadlines is counterproductive, because when the deadlines are missed people point and laugh.