Wow, I thought it was written for the film until now! How embarrassing… Not only for the song suiting, but the title too. As it’s a bleak post-ecological society.
There is a story about how Ridley Scott wanted to use this specific piece and a couple more by Vangelis in Blade Runner, and Vangelis told him: why reuse my old pieces, I can make a new score for this film specifically.
I think it was a piece of music from another film, also by 20th Century Fox, that they used as a temp track, and Scott liked it so much he made it happen. Goldsmith was not best pleased.
It'll probably be the music for the opening titles, because when I bought the album in the 80s I was suprised (disappointed actually) that piece wasn't on it, and leaving off the opening titles is a real omission in a movie soundtrack.
And so he did, in some short timeframe.