Oh that’s a whole 'nother thing entirely. I meant purely from an environmental perspective that my bet is that not only will the temperature increase continue to speed up much faster than expected, but that we’re probably going to see some crucial ecological system go really spectacularly to shit – at a guess something related to the oceans, or could even be something like runaway warming (speedrun to Venus, yay!).

None of the events we’ve thought of have a very high probability of happening according to climate models, but our capability for modeling systems as complex as a whole planet’s climate and all its ecosystems is… well, it’s not zero, but that’s about it. The likelihood of something unexpected going to shit is pretty high, and after it does happen we’ll all go “oh, we should have seen this coming”.

Nassim Nicholas Taleb, who came up with the concept, had this to say regarding “Black Swans” (I’ve not been capitalizing it, oh no!):

What we call here a Black Swan (and capitalize it) is an event with the following three attributes.

First, it is an outlier, as it lies outside the realm of regular expectations, because nothing in the past can convincingly point to its possibility. Second, it carries an extreme ‘impact’. Third, in spite of its outlier status, human nature makes us concoct explanations for its occurrence after the fact, making it explainable and predictable.

I stop and summarize the triplet: rarity, extreme ‘impact’, and retrospective (though not prospective) predictability. A small number of Black Swans explains almost everything in our world, from the success of ideas and religions, to the dynamics of historical events, to elements of our own personal lives.