About the Data
Climate model projections for the Columbia Basin Climate Source are based on output from an ensemble of 12 statistically downscaled Global Climate Model (GCM) projections (PCIC; pacificclimate.org) from the Coupled Model Intercomparison Project Phase 5 (CMIP; Taylor et al., 2012). The model output from the GCM sources is downscaled to a finer resolution using Bias Correction/Constructed Analogues with Quantile mapping recording (BCCAQ; Werner and Cannon, 2015). The data for the simulation period (1950-2100) is at a resolution of 300 arc-seconds or roughly 10 km. Climate projections are provided for the 2020s, 2030s, 2040s, 2050s, 2060s, 2070s, and 2080s using a 30-year average for each time period. For example, the 2020s represent 2011-2040. Historical climate is provided for the 1960s (i.e. 1951-1980) to allow comparison with 20th century climate.
Model output is displayed in scenarios of low global emissions (RCP4.5) and high global emissions (RCP8.5), also referred to as 'business as usual'. The RCPs are numbered (e.g. RCP8.5 or RCP4.5) according to the radiative forcing in W/m2 that will result from additional GHG emissions by the end of the century. The low global emissions scenario (RCP4.5) is considered to be optimistic and, although insufficient to maintain global temperatures to below 2°C warming above pre-industrial temperatures, would require significant international cooperation that exceeds current commitments of signatories to the Paris climate agreement (unfccc.int, 2017). Global emissions are still moving along a trajectory that could lead to 3-5°C of warming by the end of the century, highlighting the significant gap between the emission reductions pledged by Paris Agreement signatories and the reductions required to meet the 2°C target (e.g. see Knutti et al., 2016). Consequently, it is important to also consider the high global emissions scenario (RCP8.5) in planning for climate change in the Basin.
- Knutti R., Rogelj J., Sedláček J. and E. M. Fischer. (2016). A scientific critique of the two-degree climate change target. Nature Geoscience, 9, 13–18.
- Pacific Climate Impacts Consortium (PCIC). Available at: https://www.pacificclimate.org [Accessed 9 Mar. 2018].
- Taylor, K.E., Stouffer, R.J. and G.A. Meehl. (2012). An Overview of CMIP5 and the Experiment Design. Bull. Amer. Meteor. Soc., 93, 485–498.
- The Paris Agreement. Available at: http://www.unfccc.int/paris_agreement/items/9485.php [Accessed 9 Mar. 2018].
- Werner, A.T. and A.J. Cannon. (2015). Hydrologic extremes – an intercomparison of multiple gridded statistical downscaling methods. Hydrology and Earth System Sciences Discussion, 12, 6170 – 6239.