The climate effect attributed to aerosols is one of the main uncertainties in our current understanding of Earth’s climate system. A regional hotspot for climate warming is the Arctic. Even though the concentrations of aerosols in the Arctic are lower than at lower latitudes, several lines of evidence points to the importance of aerosols on the Arctic climate, with estimated effects equal to about half that of CO2. Black carbon (BC, as part of soot) is one important aerosol component affecting the climate system. It has a net warming effect on the average global temperature due to strong absorption of sunlight. As a consequence of its effect on the snow and ice albedo, where BC not only covers the brighter layers but also increases melting of snow, it plays a relatively larger role in the Arctic than elsewhere. BC also causes climatic effects, e.g. by influencing clouds, monsoon circulation and the hydrological cycles in SE-Asia. Combustion particles such as BC from open fire places have also serious impact on human respiratory health and thus, a decrease of BC emission would also have medical co-benefits, as air pollution leads to several million deaths annually.
In order to guide society’s efforts to mitigate BC emissions, we need to improve the scientific understanding of the contributions from different combustion sources. Unfortunately, there is a notable discrepancy in source apportionment of BC in several regions between top-down studies relying on measured ratios of BC to total carbon or other aerosol components, as compared with bottom-up emission inventories based on fuel consumption and laboratory-derived emission factors. This dichotomy can be addressed by analysis of natural radiocarbon (14C) measurement (half life t½ = 5730 years) as a tool to distinguish between fossil fuels (14C void) and contemporary 14C (modern) biomass burning sources of BC.
Latest scientific papers
The sources of atmospheric black carbon at a European gateway to the Arctic
Isotope-Based Source Apportionment of EC Aerosol Particles during Winter High-Pollution Events at the Zeppelin Observatory, Svalbard