Possible role of dust-induced regional warming in abrupt climate change during the last glacial period

RECORDS from loess, sediments and ice cores indicate that the concentrations of tropospheric aerosols were higher in glacial periods than they are today, and that they peaked just before glacial terminations(1-10). Energy-balance models have suggested(11-14) that these high glacial aerosol loadings were a source of glacial cooling of the order of 1-3 degrees C. Here we present a different view based on three-dimensional climate simulations, which suggest that high glacial dust loading may have caused significant, episodic regional warming of over 5 degrees C downwind of major Asian and ice-margin dust sources, Less warming was likely close to and over the oceans because of local cooling by seasalt and marine sulphate aerosols. Abrupt changes in dust loading are associated with the Dansgaard-Oeschger and Heinrich climate events and with glacial termination(3,8,15), suggesting that dust-induced warming may have played a role in triggering these large shifts in Pleistocene climate.