Change happens slowly. Then all at once

It’s the tipping points you have to watch for that might cause change to happen all at once.

There is no apparent difference between an ice cube at 0 degrees and 31 degrees, but at 32 degrees, change occurs rather dramatically.  Underneath, there is change from 0 to 31, because otherwise the dramatic change at 32 could not happen, its just that we cannot see it.