Without a doubt it's astounding that the Lake could go from record low in 2013 to record high in 2020. Still, it's not like it's moving feet in the duration of a single rain event. The flow valves mentioned should provide options before the Lake could ever truly encroach on the city.
I remember hearing years ago when the Lake was low that there were studies to reverse the flow of the river back into the Lake and cleanup and return more sewage and storm water. I have to think the future involves flexible infrastructure to add cleaned-up wastewater when it's low and divert it away when it's high. For example, when it's especially high we could pipe water to other parts of the country who need it (a dangerous proposal for sure that would require strict guidelines and protections).
Diana must have copied the (also fear-mongering)
NYT article from a couple months back that presented Chicago as more susceptible to climate change than most ocean coastal cities because of the speed in which the water levels change. There's some truth there, but, as others have said, there's no comparison to the scale of ocean water. If the ocean takes a piece of land, it's pretty much gone.