Within the writing of St. Malachy, the situation is no better. According to writer Vittorio Messori, they are apocalyptic prophecies based on factual mistakes.
"Here we enter a topic that has little or nothing to do with a serious reflexion. The prophecies of St. Malachy in reality are not his. They're a farce, an apocrypha established in the 1500's about a power struggle during a conclave. They are false, but certainly interesting, because by chance a few of them will seem to be true.”
In theory, Nostradamus spoke about the arrival of a black Pope. Pope Francis wears white of course, but Jorge Bergoglio does belong to the Jesuit Order, who's leader is informally known as the black Pope. He's not African, but the term refers to the black priestly clothes he wears and his influence when it comes to decision-making.
Malachy, on the other hand, spoke about a Pope from the ends of the world. If this sound familiar, it's because they're the same words Pope Francis said on the balcony on his election night.
Written in very vague phrases, there are no indications that their apocalyptic prophecies are any different than say the Mayan prediction, which foresaw the end of the world on December 21, 2012, which obviously, did not happen.