The Seesaw Effect
What are the origins of past, present, and future climate change? In his Perspective, Stocker discusses ways in which the climate system can act like a seesaw, as the high northern latitudes push and pull against the Southern Hemisphere to create abrupt shifts. Stocker briefly discusses a report in the same issue by Steig et al., showing that Northern and Southern Hemisphere climate shifts act in synchrony. A related Perspective by Cane looks at the role of the tropics in paleoclimate. Recent observations and model calculations indicate that effects of climate change in the tropical latitudes merit a closer look.