A History of Aerosols in the Western Arctic During Recent Centuries

Aerosols from sea spray, biomass burning, continental dust, and volcanic and industrial emissions are important components of climate forcing in the atmosphere and when deposited to bright snow and ice surfaces. These aerosols also are a major source of pollution in the Arctic and so impact human and ecosystem health. Despite their importance, few measurements are available prior to the mid- to late-20th century when modern measurements began and there is only limited understanding of transport pathways from primarily mid-latitude source regions to the Arctic. If appropriately analyzed, ice cores can provide high-time-resolution, long-term records of aerosol concentrations that place current concentrations and trends in historical perspective and extend recent observations back in time to recent centuries and millennia. We describe a unique analytical system that produces high-depth-resolution, broad-spectrum measurements of aerosols and aerosol tracers from ice cores. We present historical reconstructions of aerosol deposition at an array of high northern latitude ice core locations, evaluate changes in atmospheric transport pathways from the mid-latitudes to the Arctic during recent decades and centuries, and discuss the implications for past and future climate forcing and ecosystem health in the Arctic.