Uncertainty in climate change impacts on streamflow in Be River Catchment, Vietnam

This paper focuses on the uncertainty in climate change impacts on streamflow in Be River Catchment. Uncertainty associated with GCM structure from a subset of CMIP3 (CCCMA CGCM3.1, CSIRO Mk30, IPSL CM4, MPI ECHAM5, NCAR CCSM3.0, UKMO HadGEM1, and UKMO HadCM3), SRES emission scenarios (A1B, A2, B1, and B2), and prescribed increases in global mean temperature (0.5 degrees C to 6 degrees C) using SWAT model is investigated. For prescribed warming scenarios using HadCM3, linear decreases in mean annual streamflow range from 3.1 to 16.7%. Differences in projected annual streamflow between SRES emission scenarios using HadCM3 are small (-5.6% to -4.6%). Under the A1B scenario and 2 degrees C increase in global mean temperature using seven GCMs, there is substantial disparity, by -2.925.5% and -8.319.1%, respectively. It is generally reasonable to conclude that GCM structure-related uncertainty is greater than that associated with the emission scenarios and climate sensitivity.