Great thing is, we probably won't know what that point is until we've past it.
Ocean acidification, the methane clathrate gun, some of the most serious climate issues that we've identified aren't even within the window of public discussion. The Green New Deal isn't even close to being passed.
I can't even imagine America pulling together to pass a boring infrastructure bill right now. I honestly can't fathom how previous presidents got anything done at all, let alone the massive public works projects that shaped America in the middle of the 20th century.