The original version of this story appeared in Quanta Magazine.
In 1896, the Swedish physicist Svante Arrhenius realized that carbon dioxide (CO2) traps heat in Earth’s atmosphere—the phenomenon now called the greenhouse effect. Since then, increasingly sophisticated modern climate models have verified Arrhenius’ central conclusion: that every time the CO2 concentration in the atmosphere doubles, Earth’s temperature will rise between 2 and 5 degrees Celsius.
Still, the physical reason why CO2 behaves this way has remained a mystery, until recently.
First, in 2022, physicists settled a dispute over the origin of the “logarithmic scaling” of the greenhouse effect. That refers to the way Earth’s temperature increases