Quantifying Uncertainty in Climate Change Analyses

Uncertainty is a feature of any planning study, whether climate change is explicitly included or not. Accounting for and disclosing uncertainty is an established component of good planning practices. In water resources planning this has traditionally included uncertainties associated with natural climate and hydrologic variability, future population and economic conditions, and future technological advances and social trends. Climate change involves added uncertainties associated with future GHG emissions conditions and the hydroclimatic response to current and future emissions as projected by numerical models. This appendix describes the sources of climate change-related uncertainty and methods for quantifying uncertainty in planning.