However, that was thirteen years ago, and we now find ourselves in the year 2019 and the global warming apocalypse has not yet taken place.

Uhh, actually, it has been taking place for years now. See: the floods, loss of biodiversity, fires, deadly heat waves, etc. The "apocalypse" comes in stages, many of which are so slow that shifting baselines come into place, making what would seem as apocalyptic to older generations seem normal to current ones.

Edit: an article I linked on the subreddit /r/shiftingbaselines a while ago: https://permaculturenews.org/2016/09/09/shifting-baseline-syndrome/.