[palae]

> The thing that makes a crisis into a crisis is that it's highly discrete in time and there is a temporally very limited window of opportunity to take action.

That is your definition, but not necessarily the one meant by others. From Merriam-Webster (https://www.merriam-webster.com/dictionary/crisis):

"Essential Meaning of crisis : a difficult or dangerous situation that needs serious attention"

[...] Definition 3b: "a situation that has reached a critical phase // the environmental crisis"

[gyulai]

My point exactly. The dictionary editors must have noticed that "environmental crisis" entered into common parlance, and didn't fit the pre-existing definitions of "crisis", so they had to invent a new definition to be able to cover it.

Besides: The definition is a really bad one, as it's circular.

[palae]

What about the "essential meaning"? It's non-circular and (to me) fitting.