Anyone who thinks global populations are going to level off, in the absence of some pandemic, has completely lost the plot.
No matter what their academic credentials and no matter for whom they are working, writing or who fund them.

Human population growth is accelerating, NOT slowing down and I'd guesstimate the current 7.2 billion will be well over 10 billion by 2050 and on course for over 25 billion by 2100.

And not steady off at under 10 billion by 2100 as the UN (insanely) seems to think.