Evaluating the Agroclimatic Potential of Central Siberia

Abstract

Human beings have traditionally cultivated the fertile soils of the steppe and forest-steppe for agriculture. Forests are predicted to migrate northward in a warmer climate and are likely to be replaced by forest-steppe and steppe ecosystems. We analysed potential climate change impacts on agriculture in south/central Siberia, hypothesizing that agriculture in traditionally cold Siberia may benefit from warming. Current carbon (C) fluxes in agrosystems have also been analysed, as they are important for the development of land use strategies. Potentials for cropping were evaluated based on simple climate indices such as temperature sums above a base of 5 °C (GDD5), and an annual moisture index (AMI), which is the ratio of GDD5 to annual precipitation. Envelope models which determine crop range, and regression models which determine crop yields, were constructed and applied to climate change scenarios for several time frames: 1960–1990, using historic data; and data taken from HadCM3 B1 and A2 scenarios for 2020 and 2090. Analyses of carbon fluxes in agrosystems showed that plant phytomass and soil humus serve as a principal C sink. Mineralization flux forms from phytodetritus decomposition, and recently formed humus includes portions of “used” mobile humus. Currently, the C balance of agrosystems is slightly in deficit: the C loss is 0.25 t ha−1 year−1. From 50 to 85 % of central Siberia is predicted to be climatically suitable for agriculture by the end of the century, and only soil potential would limit crop advance and expansion to the north. Crop production could double. Future Siberian climatic resources could provide the potential for a great variety of crops to grow which previously did not exist on these lands. Traditional Siberian crops could gradually shift as far as 500 km northward (about 50–70 km per decade) if soil conditions are suitable, and new crops which are non-existent today may be introduced in the dry south, which would necessitate irrigation. Agriculture in central Siberia would likely benefit from climate warming. Adaptation measures would sustain and promote food security in a warmer Siberia.