Regional Environmental Changes in Siberia and Their Global Consequences

In this introduction chapter, we describe geographical, climatic, environmental, and demographic characteristics of Siberia and outline major problems dealt with in regional studies of this vast region including those important for the Global Earth System. The science questions, which are put in this chapter, are further addressed in detail throughout the book.

This chapter provides a brief description of the information resources currently supporting environmental studies of Siberia including key references and points of contact. It describes environmental, hydrological, and meteorological datasets available for Siberia as well as the tools developed to organize and seamlessly deliver these data to the international research community for studying regional environmental and climatic dynamics of the ongoing global changes. Three-hour and daily datasets of major meteorological characteristics measured at the Siberian weather stations and relevant metadata sets are the first tangible resources available to the researchers. However, most of the Siberian territory is sparsely populated and the observational networks that provide regional in situ observations are also sparse. Therefore, other information resources described below are based upon, or include as their integral part, remote sensing and model output data. These resources are (a) land information system for Siberia that includes cartographical materials, data of different inventories and surveys, diverse databases of in situ measurements and remote sensing products, and numerous auxiliary models for assessment of relevant biophysical indicators of Siberian ecosystems; (b) remote sensing Earth observation products and tools for data search, data access, data visualization, and analysis over Siberia; and (c) a suite of online systems to monitor, process, visualize, analyze, and access Earth science remote sensing products and regional climatic and meteorological geospatial datasets, as well as a variety of geospatial data on climate, climate forecast, hydrology, hydrological forecast, environmental remote sensing, socioeconomic information, etc.

This chapter provides observational evidence of climatic variations in Siberia for three time scales: during the past 10,000 years, during the past millennium prior to instrumental observations, and for the past 130 years during the period of large-scale meteorological observations. The observational evidence is appended with the global climate model projections for the twenty-first century based on the most probable scenarios of the future dynamics of the major anthropogenic and natural factors responsible for contemporary climatic changes. Historically, climate of Siberia varied broadly. It was both warmer and colder than the present. However, during the past century, it became much warmer; the cold season precipitation north of 55°N increased, but no rainfall increase over most of Siberia has occurred. This led to drier summer conditions and to increased possibility of droughts and fire weather. Projections of the future climate indicate the further temperature increases, more in the cold season and less in the warm season, significant changes in the hydrological cycle in Central and southern Siberia (summer dryness), ecosystems’ shifts, and changes in the permafrost distribution and stability. Observed and projected frequencies of various extreme events have increased recently and are projected to further increase. While in the north of Siberia, contemporary models predict warmer winters at the end of the twenty-first century and paleoreconstructions hint to warmer summers compared to the present warming observed during the period of instrumental observations. These three groups of estimates are broadly consistent with each other.

This chapter looks at several aspects of the hydrological regime across Siberia using long-term historical data and model simulation results to provide a better understanding of ongoing changes and future directions. It begins with a survey of the major components of water balance: river flow, precipitation, and evapotranspiration. This is followed by the primary focus on the Siberian river systems with emphasis on annual variability and the anomalously high river discharge in 2007, the seasonality of river flow with increases in winter discharge, and changes in magnitude of minimum river flow and the temporal shifts in maximum river flow. Other components related to the river systems are also explored, including the thermal regime showing a lack of widespread evidence for increasing river temperature while the ice cover over the major rivers is decreasing in terms of both the duration of ice cover and ice thickness. Related hydrological conditions (e.g., groundwater hydrology) demonstrate an increase in both levels and temperatures; however, there is evidence for some local decreases in groundwater level. Additionally, increases in groundwater runoff from the taiga zone are observed. Total thermokarst lake area is changing, depending on the landscape zone. Northern zones of tundra are gaining lake area, while the southern tundra and taiga regions are losing lake area. This chapter concludes with a look at possible future changes in the region’s hydrology. River discharge in the major Siberian watersheds is expected to rise, and this result is consistent across a majority of the global climate models’ projections for the twenty-first century.

This chapter examines effects of climate change on human infrastructure in permafrost regions of Siberia. The presence and dynamic nature of ice-rich permafrost constitute a distinctive engineering environment. Many engineering problems in Siberia are associated with (1) changes in the temperature of the upper permafrost, (2) increased depth of seasonal thaw penetration, and (3) progressive thawing and disappearance of permafrost. These changes can lead to loss of soil bearing strength, increased soil permeability, and increased potential for development of such cryogenic processes as differential thaw settlement and heave, and development of thermokarst terrain. Each of these phenomena has the capacity for severe negative consequences on human infrastructure in the high latitudes. Results to date indicate that major permafrost-related impacts have already been detected in many Siberian regions, including changes in the temperature and distribution of permafrost, thickening of the seasonally thawed layer (the active layer), and changes in the distribution and quantity of ice in the ground. A quantitative geographic assessment of the ability of frozen ground to support engineering structures under rapidly changing climatic conditions in a variety of settings is provided in this chapter. Results show substantial decreases of permafrost bearing capacity over the last 40 years in some regions of Northern Siberia. Although a substantial proportion of reported deformations of structures and buildings on permafrost can be attributed to climatic warming, other technogenic factors have to be considered. The socioeconomic crisis resulted in reduced infrastructure monitoring and maintenance in many cities on permafrost during the early 1990s which have greatly contributed to the decrease in infrastructure stability.

This chapter considers the current state of Siberian terrestrial ecosystems, their spatial distribution, and major biometric characteristics. Ongoing climate change and the dramatic increase of accompanying anthropogenic pressure provide different but mostly negative impacts on Siberian ecosystems. Future climates of the region may lead to substantial drying on large territories, acceleration of disturbance regimes, deterioration of ecosystems, and positive feedback to global warming. The region requires urgent development and implementation of strategies of adaptation to, and mitigation of, negative consequences of climate change.

This chapter provides background on socioeconomic contexts followed by synthesis of remote sensing-based case studies highlighting major human influences on the Siberian landscape during three eras: Soviet (1917–1991), early post-Soviet transformation (starting after 1991), and recent/emerging. During 1975–2001, Landsat-based LCLUC data in East Siberia showed characteristic patterns including: high rates of logging during the Soviet era that declined abruptly and remained low after 1989, a decline in agriculture (and subsequent reforestation) beginning prior to 1991, and a decline in mature conifer and increase in deciduous forest. In the far north, multiple remote sensing data over time demonstrated the degradation and mortality of the larch forests surrounding the Norilsk nickel mining complex. In East Siberia, multiple remote sensing data showed that oil and gas reconnaissance directly disturb the landscape but that their indirect influence on increased fire occurrence is of greater consequence. Along the Siberia-China Amur River border, replanting and the almost complete removal of mature conifer are evident in Landsat data on the Chinese side, whereas fire predominates on the Siberian side. In the recent/emerging era, LCLUC in Siberia is being influenced by greater transnationalism and increased demand for wood from other Asian countries. Oil and gas development is shifting to East Siberia. Pipelines and infrastructure are being built across Siberian lands directly to the Pacific and to China. Remote sensing–based analyses have been integral to increased knowledge of past and emerging trends in human dimensions of environmental change across the vast geographic region of Siberia.

This chapter considers specific atmospheric pollution problems in Siberia, the current state of studies and strategic activities, and peculiarities of Siberian environmental protection problems, risk assessment, and tendencies in atmospheric pollution in Siberia, including health-affecting pollutants, greenhouse gases, aerosols, etc. The chapter does not presume to cover all the aspects of atmospheric pollution in Siberia. Its main focus is a short general overview of the existing problems of airborne pollution in Siberia and methodological aspects of air pollution impact assessments followed by several examples of such studies for Siberia. In particular, the following issues are described: (1) sources and characteristics of air pollution in Siberia, (2) air quality and atmospheric composition characterization, (3) assessment of airborne pollution in Siberia from air and space, (4) methodology and models for air pollution assessment on different scales, and (5) case studies of long-range atmospheric transport of heavy metals from industries of the Ural and Norilsk regions.

This chapter summarizes the volume content focusing on land change in Siberia. The volume is compilation of results of the most recent international studies of Earth’s system interactions including biogeochemical and water cycles, natural ecosystems changes, and human impacts on environment. Outstanding scientific challenges are outlined as they were discussed in each chapter.