Most likely chaotic artifact, it's repetitive in the same way a whirlpool that follows an oar dip is repetitive in nature but chaotic in origin, the human temporal scale is so granular that momentary idiosyncracies are often mistaken for meaningful patterns...which of course begs the question: what events are meaningful in a climate change context? well, I'd personally answer that with "we simply do not have enough knowledge to answer that"...there are obvious candidates: die off blue-green algae, expansion of Gobi to all of central China, death of Gulf Stream and resultant "siberification" of Europe, but for all of the threats we can name, I'm betting the one that writes the history of our species will be one that we aren't able to foresee