According to Wikipedia, the term black swan derives from a period when it was believed that such birds did not exist. They were, however, later discovered in the wild and were regarded as both a surprise and extraordinary.

In his book “Black Swan,” Nassim Nicholas Taleb refers to hard-to-predict and rare events that are beyond the realm of “normal expectations” as black swans.

Another way to describe a black swan occurrence is as an outlier. Examples from history would be the sinking of the Titanic; the Wall Street crash of 1929; the Black Death; the Spanish Flu; and 9/11 (to name just a few).

Taleb, in establishing his criteria, also makes the point that nothing in our past can convincingly point to its possible occurrence. As well, a black swan must have a significant and memorable impact. After the fact, it is in our nature to frame the phenomenon in terms of understandable explanations such as the unstructured randomness we experience in our lives. In other words, a random sequence has no order and lacks any pattern or predictability.

There are of course events, sometimes catastrophic, that are stitched into the fabric of history. And the idea of random black swan phenomena are therefore embedded in our thinking as we attempt to make sense of our world.

Consider Hurricane Harvey and the massive amounts of rain that fell day after day at rates that were unheard of and accompanied by devastating flooding. It has been described as “unprecedented,” “biblical,” “once in 100 years or 500 years.” The images have been harrowing: overwhelmed people in civilian rescue boats; many were seen wading in waist-high water desperate to find high ground; others were trapped on roofs of cars and houses. All defy adequate description. And we know that search and rescue will not be over until they’re over.

Harvey meets all of Taleb’s criteria for a black swan event wherein the heavens exploded and released what seemed a century worth of water creating a relentless devastation.

What has yet to occur, amid all of the analysis of Harvey, given how we think of extreme weather events, is a discussion that would put Harvey in a larger context, meaning that what we reflexively refer to such events as black swan occurrences, but are actually part of a kaleidoscope of what science refers to as global climate change, of which Harvey is a part.

The larger truth is that Harvey is not a black swan event; rather, it is a precursor, signaling the coming of many super storms that will ultimately be defined as the new normal.

While true that Harvey is “incomparable” or “one for the record books,” a hurricane the likes of which has never impacted the continental U.S., when considered in the context of global warming it should not be regarded as an outlier.

While it was a surprise, and while it lies outside the realm of all expectations and has had, and continues to have, an incomprehensible impact, it may reside in that sweet spot of those global/extreme weather events that are simultaneously taking place across our planet and which we know now are interrelated.

To say again, if we are to begin to make the link of black swan climate events to global warming then we must commit to a shift in our thinking from randomness to predictability and view Harvey as part of a newly forming global pattern. This demands that we resist the inclination to rationalize Harvey as a black swan; instead we must fit it into a framework that allows us to understand it apart from the Taleb construct.

We must view extreme weather as part of a climate synergy that is already touching all of our lives. The future is here: droughts and floods and rising sea levels are now part of a new reality. While describing some random events (earthquakes and resulting tsunamis) as black swans, with regard to global warming and extreme weather the definition no longer applies.

Hopefully, Harvey will be discussed as part of a new reality. Meanwhile it is a human tragedy beyond comprehension that will likely take years to overcome.

— Chris Honoré of Ashland is a Daily Tidings columnist.