> 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"