These downscaled climate projections are being displayed in CBI's landscape climate dashboard at: http://climateconsole.org/multi-lcc
Ten climate models were selected, either General Circulation Models (GCMs) or Earth System Models (ESMs), from the 5th Coupled Model Intercomparison Project (CMIP5; Taylor et al. 2012). The models (CanESM2, CCSM4, HadGEM2-CC, HadGEM2-ES, IPSL-CM5A-MR, NorESM1-M, BCC-CSM1-1-M, MIROC5, CSIRO-Mk3.6.0) were chosen based on the evaluation of their ability to simulate historical climate conditions globally and specifically over the southwestern United States, for the specific needs of California water resource planning (O'Daly et al. 2015).
These climate models capture a wide range of projected change for both annual average temperature and annual precipitation under the representative concentration pathway (RCP) 8.5 (Meinshausen et al. 2011; van Vuuren et al. 2011). RCP8.5 is a high energy-intensive scenario that results from high population growth and a moderate rate of technology development without establishment of climate change policies.
We used the downscaled climate projections from the NASA Earth Exchange (NEX) U.S. Downscaled Climate Projections (NEX US-DCP30) dataset (Thrasher et al. 2013) for the entire state of California. We chose two thirty-year periods, 2016-2045 and 2046-2075, to represent the projected futures. Each climate model projections were averaged over those periods and a multi-model ensemble mean of the ten model projections was also calculated for each time period.
One of the 10 models, CMCC-CMS, did not include vapor pressure/relative humidity and ultimately was dropped from our analysis because the vegetation model used to simulate the various climate impacts needed this variable to run.
References
Meinshausen, M., Smith, S.J., Calvin, K., Daniel, J.S., Kainuma, M.L.T., Lamarque, J.F. et al. (2011). The RCP greenhouse gas concentrations and their extensions from 1765 to 2300. Clim Change, 109, 213-241.
O'Daly, W., Keeley, F. & Woled, J. (2015). Perspectives and Guidance for Climate Change Analysis. California Department of Water Resources and Climate Change Technical Advisory Group, p. 142. Available at:http://www.water.ca.gov/climatechange/docs/2015/Perspectives_Guidance_Climate_Change_Analysis.pdf
Thrasher, B., Xiong, J., Wang, W., Melton, F., Michaelis, A. & Nemani, R. (2013). Downscaled Climate Projections Suitable for Resource Management. Eos, Transactions American Geophysical Union, 94, 321-323.
Van Vuuren, D.P., Edmonds, J., Kainuma, M., Riahi, K., Thomson, A., Hibbard, K., Hurtt, G.C., Kram, T., Krey, V., Lamarque, J.F. and T. Masui. (2011) The representative concentration pathways: an overview. Climatic change, 109: 5-31.