Air quality improvement masks global cooling from CO2 reductions under China’s carbon neutrality policies for half a century

Achieving carbon neutrality and improving air quality are pivotal sustainability strategies for the Global South countries. However, their global climate impacts over a realistic timescale remain unclear. Here we evaluate the climate impacts of China's carbon neutrality and Beautiful China policies using a fully coupled Earth system model and updated future anthropogenic emission scenarios. We find that, for an unexpectedly long time through ~2070, China's air pollutant reductions can cause a large global surface warming (0.12 ± 0.09 K for 2050-2070) that almost offsets the cooling from concurrent CO₂ emission reduction (0.16 ± 0.05 K for 2050-2070), compared to a business-as-usual scenario. This warming is mainly attributed to reduced SO₂ and organic matter emissions. Moreover, combined air pollutants and CO₂ declines create a striking hemispheric temperature change contrast, because of the stronger aerosol-induced heating in the Northern Hemisphere. Considering that most future air pollutant reductions represent synergistic effects of carbon neutrality policies, the associated inevitable warming effect over decades highlights the importance of exploring more aggressive policies including early carbon neutrality, methane reductions, and negative carbon emissions.