Large-scale vegetation response to the 8.2 ka BP cooling event in East Asia

Abstract

The 8.2 ka BP cooling event is the most prominent and abrupt climate event in the Holocene at mid-to-high latitudes in the Northern Hemisphere. In this paper, we conduct model simulations of vegetation responses to the 8.2 ka BP event over East Asia, and compare them with pollen-based vegetation records. Our results reveal that all major Plant Functional Types responded to the climate changes, but the magnitude, timing, and impact of their responses varied. In addition, it was found that after the 8.2 ka BP climate event the vegetation did not always recover to the state simulated before the perturbation, suggesting that different vegetation compositions may occur under similar climate conditions. Changes in temperature exerted a major influence on the vegetation dynamics in the most high latitude regions, and changes in both temperature and precipitation were responsible for the vegetation changes at mid-to-high-latitudes. Compared with pollen-based vegetation reconstructions, our model simulations generally capture the main features of vegetation responses to the 8.2 ka BP event. Notably, only a relatively small proportion of taxa were climatically sensitive during the 8.2 ka BP cooling in pollen records. Only one high-resolution pollen record indicated that the vegetation did not recover to the pre-perturbed state, showing a different vegetation composition after the 8.2 ka BP event similar to our simulations. Such different vegetation compositions could be a long-lasting effect of abrupt climate changes on vegetation through eco-physiological and ecosystem demographic processes, e.g., plant competition. Moreover, our model simulations suggest a more pronounced vegetation responses to the severe cooling in the north and weaker responses to less cooling in the south. Since significant vegetation responses during this event were only seen in few records, more high-resolution pollen records and simulations in terms of vegetation responses to different abrupt climate changes are needed in future.