As you change the macroscopic variables of a system, sometimes its properties will abruptly change, often in a dramatic way. For example, it might change from a solid to a liquid, or from a liquid to a gas. These are examples of phase transitions.
Here in the Bay Area, we have a lot of fog...
This painting could be viewed as a metaphor for the changes we are experiencing globally. IMHO, some of the conversations we are having are long overdue.