The last prediction from that quote was made in 2013 and predicted 2016 +/- 3 years.
Inaccuracies aren't the issue here. The problem is that well-intentioned scientists and politicians are making overly-alarming predictions that keep eroding the populations trust when they keep failing to come true. How do you convince someone to believe you when you say climate change is a real, serious, and immediate threat when they have been lied to about the subject over and over again?