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Climate change, flooding in arid environments, and erosion rates

Peter Molnar
Climate change, flooding in arid environments, and erosion rates
Geology (Boulder) (December 2001) 29 (12): 1071-1074


Although regional climates throughout much of the world appear to have become more arid in late Cenozoic time, sedimentation rates, and therefore presumably erosion rates, have increased. For sustained erosion of elevated terrain, at least where glaciers are not the major erosive agent, rivers must incise. Therefore bed-load transport by rivers should be a rate-limiting process in erosion. Theories of bed-load transport call for a threshold in either stream power per unit area or shear stress before the bed load can be moved, and most transport should be accomplished during high discharge. The frequency-magnitude distribution of floods shows that the ratio of magnitudes of, for example, 100 yr floods and annual floods is greater in arid than in humid environments. Thus, a shift toward more arid conditions may have increased relative magnitudes of rare floods or, conversely, increased the frequency of large floods. Such a shift, despite a decrease in precipitation and discharge, could have doubled incision rates, particularly in regions already quite arid.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 29
Serial Issue: 12
Title: Climate change, flooding in arid environments, and erosion rates
Author(s): Molnar, Peter
Affiliation: University of Colorado at Boulder, Department of Geological Sciences, Boulder, CO, United States
Pages: 1071-1074
Published: 200112
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 32
Accession Number: 2001-075871
Categories: Geomorphology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2019, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 200124
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