Increasing the ratio of black carbon to sulphate in the atmosphere increases climate warming, suggests a study published online this week in Nature Geoscience. Black carbon aerosols absorb solar radiation and are thought to be a significant source of global warming.
Veerabhadran Ramanathan and colleagues used surface and aircraft measurements of aerosol plumes in China to examine the impact of different ratios of black carbon to sulphate on warming. They found that the amount of solar radiation that was absorbed increased as the ratio rose. Furthermore, black carbon plumes derived from fossil fuels were 100% more efficient at warming than plumes that arose from biomass burning.
The authors suggest that climate mitigation policies should aim to reduce the ratio of black carbon to sulphate in emissions, as well as the total amount of black carbon released.