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Sensitivity of a high-elevation Rocky Mountain watershed to altered climate and CO2

January 1, 2000

We explored the hydrologic and ecological responses of a headwater mountain catchment, Loch Vale watershed, to climate change and doubling of atmospheric CO2 scenarios using the Regional Hydro-Ecological Simulation System (RHESSys). A slight (2°C) cooling, comparable to conditions observed over the past 40 years, led to greater snowpack and slightly less runoff, evaporation, transpiration, and plant productivity. An increase of 2°C yielded the opposite response, but model output for an increase of 4°C showed dramatic changes in timing of hydrologic responses. The snowpack was reduced by 50%, and runoff and soil water increased and occurred 4–5 weeks earlier with 4°C warming. Alpine tundra photosynthetic rates responded more to warmer and wetter conditions than subalpine forest, but subalpine forest showed a greater response to doubling of atmospheric CO2 than tundra. Even though water use efficiency increased with the double CO2 scenario, this had little effect on basin-wide runoff because the catchment is largely unvegetated. Changes in winter and spring climate conditions were more important to hydrologic and vegetation dynamics than changes that occurred during summer.

Publication Year 2000
Title Sensitivity of a high-elevation Rocky Mountain watershed to altered climate and CO2
DOI 10.1029/1999WR900263
Authors Jill Baron, Melannie D. Hartman, L.E. Band, R.B. Lammers
Publication Type Article
Publication Subtype Journal Article
Series Title Water Resources Research
Index ID 1015329
Record Source USGS Publications Warehouse
USGS Organization Fort Collins Science Center