I think I've found enough evidence to doubt the official climate deadlines. There was the prediction by Noel Brown, setting it as 2000: http://nl.newsbank.com/nl-search/we/Archives?p_product=SJ&s_site=mercurynews&p_multi=SJ&p_theme=realcities&p_action=search&p_maxdocs=200&p_topdoc=1&p_text_direct-0=0EB7304FF9A84273&p_field_direct-0=document_id&p_perpage=10&p_sort=YMD_date:D&s_trackval=GooglePM. Noel Brown was in the U.N. climate panel: http://www.bluecommunity.info/topics/view/51cbfc77f702fc2ba8129a34/. Christiana Figueres wrote a letter to Nature saying 3 years for a carbon budget of 1.5 degrees Celsius: https://www.nature.com/news/three-years-to-safeguard-our-climate-1.22201. And now it's 2030 with the same carbon budget. What happened there? Did we somehow emit so little CO2 that it didn't reduce the carbon budget at all? I'm aware that the headline wouldn't be nice if it was something like 1.49898989435435343 or whatever, but did it really reduce the carbon budget by such a small amount, and if so, why is it such a big issue?

Most debunkings to wrong climate predictions are that they lied: https://skepticalscience.com/Hansen-1988-prediction.htm, https://skepticalscience.com/search.php?Search=Prediction+Wrong&x=0&y=0.

I decided to look up some correct U.N. climate predictions. I took a video of me doing so, but I had to compress it in order to upload it; decompress it with 7zip; and it's not 20 hours long or so, but around 34 minutes and 20 seconds. Here's the file: https://files.catbox.moe/bu9mxb.7z

While it seems the U.N. can accurately predict warming and ice sheets (apparently), when it comes to the rather apocalyptic forecasts, there haven't been many (or any) correct ones. Of course, if the ice sheets and all that are correct, they may eventually be right. In any case, categorizing predictions seems somewhat problematic: what if some prediction falls into categories where one has been mostly incorrect and another where its type have been mostly correct? What if there are other categories which can be made, which give different answers on whether the majority of its type were correct or not? But then again, the wrong predictions do make me suspicious (and not like the 1988 one, apparently that was taken out of context [and it was a prediction of warming, that which I do not deny]). I haven't gone too in depth though, so I'm not too sure.

In any case, I think it's rational to doubt the official deadlines.