Picture a staircase with two tall steps and long, flat landings in between. That's exactly how Earth's temperature changed from 1950 to 2013, according to the researchers.
So almost all the warming happened not gradually, but in two short bursts. In between, greenhouse gases kept accumulating, yet temperature held steady. This contradicts the familiar idea that climate should smoothly track rising carbon dioxide.
This behavior is reminiscent of a home thermostat: it keeps a room at one temperature, and when you turn the dial, it quickly shifts to another. Perhaps climate has a similar mechanism that models don't yet capture. For now, this finding helps build more accurate statistical descriptions of temperature, but practical use for forecasts is not yet apparent.
The idea of a climate thermostat was discussed as early as 1991, when the New York Times wrote about possible self-regulation of climate, and a cloud-based mechanism was proposed by Ramanathan and Collins.