Potential Climate-Induced Vegetation Change in Siberia in the Twenty-First Century

Abstract

Siberian climate change investigations had already registered climate warming by the end of the twentieth century, especially over the decade of 1991–2000. Our goal is to model hot spots of potential climate-induced vegetation change across central Siberia for three time periods: from 1960 to 1990, from 1990 to 2020 and from 1990 to 2080. January and July temperature and annual precipitation anomalies between climatic means before 1960 and for the 1960–1990 period are calculated from the observed data across central Siberia. Anomalies for 2020 and 2080 are derived from two climate change scenarios HADCM3 A1FI and B1 of the Hadley Centre. Our Siberian bioclimatic model operates using three climate indices (degree-days above 5°C, degree-days below 0°C, annual moisture index) and permafrost active layer depth. These are mapped for 1990, 2020 and 2080 and then coupled with our bioclimatic models to predict vegetation distributions and “hot spots” of vegetation change for indicated time slices. Our analyses demonstrate the far-reaching effects of a changing climate on vegetation cover. Hot spots of potential Siberian vegetation change are predicted for 1990. Observations of vegetation change in Siberia have already been documented in the literature. Vegetation habitats should be significantly perturbed by 2020, and markedly perturbed by 2080. Because of a dryer climate, forest-steppe and steppe ecosystems, rather than forests, are predicted to dominate central Siberian landscapes. Despite the predicted increase in warming, permafrost is not predicted to thaw deep enough to support dark taiga over the Siberian plain, where the larch taiga will continue to be the dominant zonobiome. On the contrary, in the southern mountains in the absence of permafrost, dark taiga is predicted to remain the dominant orobiome.