In The Enigma of Capital: And the Crises of Capitalism by David Harvey on page 240 the author alludes to an "... anti-democratic, money-saturated and carcareal drift of capitalist state policies..." which, as far as I can see, is the only time the word 'carcareal' occurs in the book.
I've searched Google and some on-line dictionaries but so far haven't found any definition or use of the word in a similar context that would give me a clue what it means. To me the context makes me think of the word 'carcass' and connotes morbidity and death but that's a wild guess.