huber models

East-west winds are plotted as a function of height and latitude with reds representing westerly winds. The left panel shows an idealized modern atmospheric circulation with the jet stream (in red) at 30° N/S and easterlies (blue) near the equator. The right panel shows a transition to a new atmospheric state with weaker jet streams and a jet stream along the equator.

 

Under such conditions, the cold ocean upwelling off the coast of South America disappears and warming like a permanent El Niño occurs. Something like this might have happened three million years ago in the Pliocene when carbon dioxide levels were 400 ppm, or close to today's atmospheric concentration. Courtesy of Matt Huber.