Decline in China’s aerosol emissions has accelerated global warming

According to the results, the reduction in China’s aerosol emissions has increased the global mean surface temperature by about 0.07 °C from 2010 to 2023 – that is about 0.05 °C per decade. Between 2010 and 2023, warming independent of natural climate variability has been about 0.06 °C per decade faster than before, and the reduction in China’s aerosol emissions explains most of this acceleration.

The study was published in July in Communications Earth & Environment. Eight different climate models and a total of 160 simulations were used. The Finnish Meteorological Institute contributed by producing comprehensive simulations with the EC-Earth3 climate model.

“The reduction in China’s sulfur emissions does not in itself warm the climate but removes their temporary cooling effect, which has previously masked the long-term warming effect of greenhouse gases,” says Senior Researcher Joonas Merikanto from the Finnish Meteorological Institute.

“In part, our study is good news regarding climate warming, as it reduces concerns about the climate being more sensitive to greenhouse gases than assumed. On the other hand, future global reductions in aerosol emissions may still cause significant warming,” Merikanto continues.

Warming effect is visible across the entire Northern Hemisphere

The study shows that the impact of reduced aerosol emissions in China is not limited to East Asia, but extends across the entire Northern Hemisphere. The climate has warmed at an accelerating pace since 2010, and recent years have been the warmest in the measurement record.

Previous studies have estimated that reductions in sulfur emissions from international shipping can also contribute to warming. However, these only began in 2020 and cannot alone explain the observed acceleration.

According to the World Health Organization, outdoor particulate matter causes more than four million premature deaths annually. Improving air quality is therefore extremely important for health, but at the same time, greenhouse gas emissions must be reduced urgently to mitigate climate change.

The study is part of the Finnish Meteorological Institute’s long-term international cooperation on research into the climate effects of aerosols and part of the ACCC flagship (Atmosphere and Climate Competence Center).