Artificial harmonic just means that it's not generated by an open string.
This example is a natural-sounding "12th fret" harmonic, except you've shortened the string length to the 9th fret (9+12=21). You lightly touch the string 12 frets above the fretted note.
Pinch harmonics are the same thing, technically, but with a twist. They both involve using the flesh of the picking thumb to create the harmonic during the pick stroke, rather than touching it later. Since that touch is very close to the pick attack it's a different technique that is almost, but not quite, a pinch.