Black carbon harms health, and traps heat, melts snow and disturbs rain patterns for as long as it is airborne. While long-lived carbon dioxide (CO2 ) needs fast-tracked action to stabilize global temperature rise to within 1.5 degrees Celsius, black carbon needs elimination to contain short-term warming spikes and to protect public health. Global action to reduce black carbon from sources such as diesel vehicles, brick kilns, cookstoves and ships, and co-control of CO2 from the same sources can provide co-benefits of public-health protection and climate change mitigation. But scientists say that stronger global action on air pollution is beginning to eliminate both cooling and warming aerosols and unmasking the warming already committed from high CO2 concentration. This can lead to new heat extremes. An even more aggressive action on CO2 is needed to counter the unmasking effect of air pollution control to not add to warming, while stronger black carbon emissions control can prevent millions of deaths worldwide. Adopting a global and regional cooperation framework for stronger support to sectoral action on black carbon in the global South is vital to enable clean pathways.