Historical Trends of Atmospheric Black Carbon on Tibetan Plateau As Reconstructed from a 150-Year Lake Sediment Record

Black carbon (BC) is one of the key components causing global warming. Especially on the Tibetan Plateau (TP), reconstructing BC's historical trend is essential for better understanding its anthropogenic impact. Here, we present results from high altitude lake sediments from the central TP. The results provide a unique history of BC over the past 150 years, from the preindustrial to the modern period. Although BC concentration levels in the Nam Co Lake sediments were lower than those from other high mountain lakes, the temporal trend of BC fluxes clearly showed a recent rise, reflecting increased emissions from anthropogenic activities. The BC records were relatively constant until 1900, then began to gradually increase, with a sharp rise beginning around 1960. Recent decades show about 2.5-fold increase of BC compared to the background level. The emission inventory in conjunction with air mass trajectories further demonstrates that BC in the Nam Co Lake region was most likely transported from South Asia. Rapid economic development in South Asia is expected to continue in the next decades; therefore, the influence of BC over the TP merits further investigations.