How many nuclear weapons will exist globally in 2050?

According to the Federation of American Scientists there were 13,150 nuclear warheads in existence in 2021*. This number includes retired warheads. Nuclear stockpiles peaked in 1986 at an estimated 64,400 warheads, and have declined with the end of the cold war.

Neuroscientist and fiction author Erik Hoel wrote the following about nuclear weapons in the year 2050 in a blog post published August 25, 2021

There will not be a World War III during this period. Indeed, nuclear disarmament will continue.

*This number includes 40-50 nuclear warheads for North Korea based on an estimated amount of fissile material available. See footnote r in the linked estimate.