Research Projects: Global Warming and the Human-Nature dimension in Siberia: Social Adaptation to the Changes of the Terrestrial Ecosystem, with an Emphasis on Water Environments

Global Warming and the Human-Nature Dimension in Siberia:
Social Adaptation to the Changes of the Terrestrial Ecosystem, with an Emphasis on Water Environments

hiyama Tetsuya RIHN

fujiwara Junko RIHN

yamaguchi Yasushi Nagoya University

sasai Takahiro Nagoya University

yasunari Tetsuzo Nagoya University

ohta Takeshi Nagoya University

sugimoto Atsuko Hokkaido University

yamazaki Takeshi Tohoku University

takakura Hiroki Tohoku University

okumura Makoto Tohoku University

tatsuzawa Shiro Hokkaido University

Global warming will likely transform Siberian environments. Early evidence indicates that the hydrological, carbon, and methane cycles are undergoing rapid change, with potentially grave impact on Siberian flora and fauna. Human inhabitants, who have adapted to great changes in social structure and environment in the past, will be forced to adapt again, but to a cascading series of environmental changes whose dimensions are understood only in outline. This project uses multiple satellite and surface systems to track changes in the carbon and hydrologic cycles and the cryosphere, and assesses their likely interactions and significance for human inhabitants of the region. The project is jointly conducted by Japanese and Russian universities and research institutes.

The Lena River Basin in Eastern Siberia is covered in larch forest but receives little precipitation. Permafrost provides moisture to the forest. The area is thus an ideal setting in which to study the effects of climate warming, as the forest-permafrost symbiosis is extremely susceptible to abnormal variations in temperature. Abnormally high temperatures have been recorded in the region in recent years, and changes in the ecosystem and cryosphere environment, such as forest degradation and frequent flooding, are evident.

This research project takes natural and social science perspectives on three aspects of climate-associated environmental change. The project is designed to: 1) describe current variation in water and carbon cycles and predict likely variation in the near future; 2) make field observations of the effect of carbon and hydrologic variabilty in Eastern Siberian landscapes, and identify key exchanges or driving forces; and 3) examine the capability of the multi-ethnic Siberian peoples, and their distinct social economies, to adapt to predicted change in their climate and terrestrial ecosystems.

Three research groups are organized in order to realize these goals (Fig.1). The Siberia bird's-eye group (Group 1) uses climatic and satellite remote sensing data to describe change in climate and in principal patterns of human adaptation. The Water cycle and ecosystem interaction group (Group 2) uses dendrochronology, isotope-analysis, flux monitoring, and hydrological analysis in order to examine interaction between climate and vegetation. The Human ecology group (Group 3) elucidates the impact of climate and ecological change described above on the residential life in urban and agricultural districts in Eastern Siberia and the cultural practices and social systems of local minority peoples related to their capacities for adaptation.

Analytical emphasis is on flood, as flood impacts are significant and climate change increases flood frequency and intensity. Flood frequency and extent are described through remotely sensed and field based data (Fig. 2). Data show a recent gradual increase in upstream air temperature (in the southern part of the Lena River Basin) yet little change in air temperature downstream (northern part of the basin near the Arctic Ocean). River ice-jam floods along the Lena River were detected by satellite each thaw season. In addition, a spatio-temporal survey of flood around the Alazeya River Basin was conducted (Fig. 3).

Field surveys and remote sensing determined that insect damage and forest fires were major causes of forest degradation. A dynamic vegetation model of Eastern Siberia, including forest fire and soil freezing and thawing, predicted that an annual mean air temperature rise of more than 2º C will thaw permafrost to a depth prohibiting larch forest growth.

Cellulose carbon isotope samples taken from larch forest in the Siberian tundra-taiga transition zone described inter-annual variations of precipitation and soil moisture. Changes in the seasonal larch growth pattern are clearly associated with water stress. Based on this analysis, the group made point-scale measurements of inter-annual variations in soil moisture from 1950s to 2000s.

A new monitoring site was established in the middle reaches of the Aldan River (Ust' Maya), where precipitation is high in relation to that at Yakutsk, in order to clarify the precipitation-forest reponse relationships. The new flux-tower (in addition to the one operating at Yakutsk) allowed continuous measurement of hydro-meteorological elements, sensible heat, latent heat (evapotranspiration), and carbon dioxide fluxes. Numerical simulation based on a regional (non-hydrostatic) climate model revealed that increases in surface wetness due to global warming would not significantly increase precipitation through evapotranspiration. Extensive land cover change from taiga forest- to grass-cover or water surface would have a much greater positive impact on precipitation in Eastern Siberia.

A newly established research contract between RIHN and the Melnikov Permafrost Institute, Siberian Branch of the Russian Academy of Sciences, has allowed joint study of permafrost groundwater and ground ice in central Eastern Siberia (Photo 1). As a first step, the age of groundwater found in several natural springs was established as a few tens of years. Researchers from both institutes also made improvements to the conventional water circulation model allowing better prediction of the Lena River Basin water cycle.

This group documented the folk knowledge of middle Lena River Basin peoples related to river ice-jam floods. Group researchers combined field data and newspaper reports with remotely sensed data in order to develop a graphic display of recent flooding patterns, and so the influence of global warming on the frozen water environment. The group analyzed the traffic density, vehicle type, and quantity of freight travelling over the frozen Lena River in winter. Such frozen-river “roads” are the most important public transport in the region, but access to them will be dramatically decreased with global warming (Fig.4).

Transmitters attached to wild reindeers will reveal their pattern of movement in relation to environmental variables such as vegetation status and snow depth. Direct observation of reindeer herders and investigation of hunting and traffic in furs and of salmon havests will clarify dynamics affecting these three important areas of human-animal interaction. Disaster-driven emigration is a new indicator of adaptation and maladjustment to climate change, and field research is now underway in villages experiencing significant out-migration.

It is necessary to examine local media for environment- and climate-related reports, development plans and policies in Siberia. The apparent path of industrial development, especially in relation to energy and road infrastructure, will likely have a significant effect on Eastern Siberian social life and water environments.