Periglacial and Paraglacial Processes and Environments
Periglacial and paraglacial environments, located outside ice sheet margins but responding to similar climate forcings, are key to identifying climate change effects upon the Earth system. These environments are relicts of cold Earth processes and so are most sensitive to global warming. Changes in the distribution and thickness of permafrost in continental interiors have implications for ecosystem and landscape stability. Periglacial Alpine environments are experiencing increased rockfall and mass movement, leading to rock glacier instability and sediment release to downstream rivers. In turn, these landscape effects impact on natural hazards and human activities in these sensitive and geologically transient environments.
Papers in this volume explore some of these interrelated issues in field studies from Europe, North America and Asia. The volume will be of interest to geomorphologists, modellers, environmental managers, planners and engineers working on landscape, climate and environmental change in periglacial and paraglacial areas.
Proglacial, periglacial or paraglacial?
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Published:January 01, 2009
Abstract
The terms proglacial and periglacial are well-understood descriptors of contemporary and past environments, but the paraglacial concept is more controversial and has prompted vigorous debate. Definitions are reviewed and the paraglacial concept is considered critically. It is argued that the term ‘paraglacial’ defined as ‘non-glacial processes conditioned by glaciation’ describes landscapes that are adjusted neither to Last Glacial Maximum nor to contemporary geomorphic processes. Where a landscape is paraglacial it can be characterized in terms of rate of change and trajectory of that change. It cannot be defined in relation to glaciers (as in proglacial) or by cold-climate processes (as in periglacial). Almost all paraglacial landforms and all paraglacial landscapes are transient and transitional. An interesting challenge of paraglacial landscapes is then to determine their rates of change; how far they have advanced along the trajectory from glacial to non-glacial; and how to recognize empirically the temporal and spatial relationships between proglacial, periglacial, paraglacial and fluvial landscapes. Implications of this approach to paraglacial landscapes are discussed in relation to historical and dynamic geomorphology.