When i saw the graphic the bottom fell out of my stomach. Not the red, which is so very very clear, but the blue. (Fiddling with the tool at https://www.ncdc.noaa.gov/cag/mapping/global , it seems altogether more remarkable that eastern North America isn't more blue given the very cold extremes of February and March.)
I've gone off to reread about the shutdown of thermohaline circulation and the rapid onset of the Younger Dryas ice ages.
Oscillations aren't tidy little things. I have an intuitive feel for nonlinear dynamics from studying them as an undergraduate -- strange attractors with oscillations were part of my senior project -- and i really understand what the butterfly wing metaphor means (which is not how it is often represented). Slowing a natural system as massive as the oceans' circulation pattern terrifies me.
Source of my awareness:
This is also posted at http://elainegrey.dreamwidth.org/577638.html .