Reconstruction and prediction of climate and vegetation change in the Holocene in the Altai-Sayan mountains, Central Asia

Abstract

Two quantitative methods were used to reconstruct paleoenvironments and vegetation in the Altai-Sayan mountains, Central Asia, during the Holocene. The 'biomization' method of Prentice et al (1996 Clim. Dyn.12 185-96), applied to the surface pollen record, worked fairly well in the reconstructions of current vegetation. Applying this method to fossil pollen data, we reconstructed site paleovegetation. Our montane bioclimatic model, MontBioCliM, was used inversely to convert site paleovegetation into site paleoclimates. The differences between site paleo and current climates served as past climate change scenarios. The climatic anomalies for 2020, 2050, and 2080 derived from HadCM3 A1FI and B1 of the Hadley Centre, UK, served as climate change scenarios in the 21st century. MontBioCliM was applied directly to all climate scenarios through the Holocene to map past and future mountain vegetation over the Altai-Sayan mountains. Our results suggest that the early Holocene ca 10 000BP was cold and dry; the period between 8000 and 5300BP was warm and moist; and the time slice ca 3200BP was cooler and drier than the present. Using kappa statistics, we showed that the vegetation at 8000 BP and 5300BP was similar, as was the vegetation at 10 000BP and 3200 BP, while future vegetation was predicted to be dissimilar to any of the paleovegetation reconstructions. The mid-Holocene is frequently hypothesized to be an analog of future climate warming; however, being known as warm and moist in Siberia, the mid-Holocene climate would likely impact terrestrial ecosystems differently from the projected warm and dry mid-century climate. © 2009 IOP Publishing Ltd.