Current state of the carbon budget and the capacity of Russian soils for carbon sequestration

The growing population of the Earth is unlikely to stop using traditional energy sources in the foreseeable future, though energy-saving technologies are being actively developed and the use of nontraditional renewable energy sources is expanding. The analysis of the modern state of the global carbon turnover indicates that the greenhouse effect will continue to grow despite serious measures undertaken to reduce the industrial emission of carbon dioxide. The existing hopes to sequester CO2 on a large scale via conversion of various land uses into forest ecosystems are not justified, because forest stands reaching the climax stage stop further accumulation of carbon in the aboveground biomass, so that the carbon balance approaches zero; in mature and overripe forests, it may become negative. The level of the organic matter accumulation in soils also has its limits specified by the soil and climatic characteristics of a given area. The reverse process of the transformation of forest and meadow cenoses into agrocenoses subjected to regular tillage leads to the active mineralization of the soil organic matter with the release of the accumulated organic carbon into the atmosphere. Mature tree stands are highly susceptible to various external impacts, including fires and invasions of pests and diseases. Though the ecological significance of afforestation measures is beyond question, it is important to concentrate efforts on the development of adaptation measures towards changing environmental and climatic conditions, i.e., to develop efficient technologies to protect humans from extreme weather events, to control forest fires, pest invasions, and floods, etc. For Russia, it is important to be prepared for the potential permafrost thawing and, hence, for solving problems of safe construction in the extreme North and in the permafrost zone.