Global Change will have considerable effects in tundra ecosystems, due to the magnitude of expected temperature increases, high levels of pollution (in some areas) and the fragility of the Arctic environment.
One of the main objectives of the TUNDRA project is to understand the effects of climatic change on the Arctic environment. A prerequisite is to have good knowledge of the present climate and its natural variability. The following activities in the project address these issues:
Regional climate model: This
model has a resolution of 20 km and adequately depicts topographic features
in the Usa Basin, such as the Ural Mountains.
Past climate variability: The analysis that covers periods of tens to thousands of years is based on several methods, such as long series of meteorological data, tree-rings, and fossil pollen, diatoms and macroscopic plant remains.
In TUNDRA we pay special attention to Global Change processes in the Arctic that influence global climate, the so-called Arctic feedbacks to Global Warming. These include:
Arctic treeline dynamics: The amount of carbon in plant material in treeless tundra is much lower than in taiga forests. A northward migration of the Arctic treeline due to warming of the climate replaces tundra vegetation with taiga forests increasing the total amount of carbon dioxide sequestered by plants.
Soil and peat carbon dynamics: Tundra (and taiga) soils often accumulate thick layers of partly decomposed plant material in the form of litter and humus, due to low temperatures which prevent rapid decay. This process is even more accentuated under wet conditions such as those prevailing in mires, where peat deposits several meters thick accumulate. All this material in soils and mires represents an important sink for atmospheric carbon dioxide.
Methane fluxes: The same mires are a major source of the greenhouse gas methane. Mires play a mixed role in greenhouse warming: peat acts as a carbon dioxide sink but it is also a methane source.
Changes in freshwater runoff: Freshwater from Arctic rivers (but also melting ice caps, glaciers and sea ice) flowing into the Arctic Ocean affects ocean circulation patterns, which play a key role in the exchange of heat between tropical and polar regions. For the European Arctic it is particularly important to determine what will happen to the Atlantic Gulf Stream which keeps climate in western Europe relatively mild. The Arctic Ocean is also an important sink for atmospheric carbon dioxide. Sediments, carbon, nutrients and pollutants carried by rivers into the Arctic Basin affect the uptake of carbon by the marine biota and environment.
Albedo changes: Snow cover (and sea ice) reflects much of the incoming radiation from the sun back into space, cooling the atmosphere. Any changes in snow cover will affect the global heat budget of the planet.
Also regional impacts of Global Change are evaluated:
Pollution in waters and on land: Pollutants are measured in lakes, rivers, snow, soils, lichens and mires. Their origin could be long-range transport from heavily industrialised regions at middle latitudes or local sources. Pollution is important for human health but can also affect ecosystem function at a regional scale.
Global Change is a global challenge. Ultimately it is collective human behaviour that determines levels of fossil fuel emissions and pollution. Social anthropologists will conduct interviews in towns and villages in the Usa Basin to assess social perception of environmental degradation. These studies aim to establish how people with different backgrounds relate to their environment. We will compare views as expressed by Indigenous Peoples with those articulated by the more recent Russian immigrants, who came to the Arctic to work in industry. Observations on social perception can be compared to levels of pollution as measured in the Usa Basin by other participants in the TUNDRA project. Special emphasis is given to understand how social awareness might affect environmental legislation and its implementation in the future, with consequences for the Arctic environment and, indirectly, global climate.
Permafrost melting: Extensive melting of frozen ground affects the stability of urbanand industrial infrastructure (including pipelines), with environmental, economic and social consequences. This aspect is studied in more detail by the INTAS project ‘Permafrost in the Usa Basin: distribution, characterisation, dynamics and effects on infrastructure’, which will be carried out in close cooperation with the TUNDRA project. This 2-year project is funded by INTAS (1999-2000).