Black carbon concentrations and fluxes during recent millennia from a developing array of Arctic ice cores

Short-lived aerosols such as black carbon (BC) and dust are important components of climate forcing, although warming from increased carbon dioxide and other greenhouse gas concentrations is the long-term driver of climate change. With their short lifetimes in the atmosphere, aerosol concentrations and deposition rates are dominated by regional – rather than global – sources and intra- and inter-annual variability is high. Such aerosols in snow are especially important in the high latitudes because of their strong impact on albedo. Because most BC aerosols in high latitudes originate in lower latitudes, changes in long range transport processes and pathways may dominate over changes in source strength in determining concentrations and deposition rates in these regions. However, detailed understanding of past and present concentrations, deposition rates, sources, and transport pathways of BC to and within the Arctic is lacking. Here we present and discuss detailed records of BC measured in a developing array of ice cores widely distributed around the Arctic. We use a range of elemental and chemical tracers measured in the same ice cores to identify likely sources and to investigate spatial and temporal patterns of BC deposition during recent centuries and millennia.