After China launched a major air-cleaning campaign in 2013, sulfur dioxide (SO₂) emissions in East Asia dropped by 75%.

Scientists carried out 160 complex computer simulations using eight different global climate models. They specifically modeled the air pollution reduction scenario that had actually occurred since 2010. The results were both precise and significant: the decrease in aerosol pollution in East Asia led to approximately 0.07°C of additional global warming.

Previously, climate scientists had estimated that, based on greenhouse gas emissions alone, global temperatures would rise by +0.23°C since 2010. But actual measurements showed an increase of +0.33°C.

Modeling revealed that the extra 0.1°C can largely be attributed to the reduction of air pollution in East Asia. Other contributing factors—such as lower emissions from shipping and rising methane concentrations—also played a role, but the aerosol effect in East Asia was the dominant factor.

Pollution particles, especially sulfate aerosols formed from SO₂, either directly reflect part of the sun’s rays back into space or alter cloud microphysics, making clouds brighter and more reflective. According to researchers, this cooling effect had grown so significant that over the past century it may have offset up to 0.5°C of human-caused warming.

The computer simulations also suggested a new perspective on warming: the elimination of coal smog and other pollutants accelerates warming, thereby revealing the true scale of climate change driven by solar influence.