DOI: 10.7282/t3tt4tbr
title: Probability-weighted ensembles of U.S. county-level climate projections for climate risk analysis: Table directory.

description: Quantitative assessment of climate change risk requires a method for constructing probabilistic time series of changes in physical climate parameters. Here, we develop two such methods, Surrogate/Model Mixed Ensemble (SMME) and Monte Carlo Pattern/Residual (MCPR), and apply them to construct joint probability density functions (PDFs) of temperature and precipitation change over the 21st century for every county in the United States. Both methods produce likely (67% probability) temperature and precipitation projections consistent with the Intergovernmental Panel on Climate Change's interpretation of an equal-weighted Coupled Model Intercomparison Project 5 (CMIP5) ensemble, but also provide full PDFs that include tail estimates. For example, both methods indicate that, under representative concentration pathway (RCP) 8.5, there is a 5% chance that the contiguous United States could warm by at least 8°C. Variance decomposition of SMME and MCPR projections indicate that background variability dominates uncertainty in the early 21st century, while forcing-driven changes emerge in the second half of the 21st century. By separating CMIP5 projections into unforced and forced components using linear regression, these methods generate estimates of unforced variability from existing CMIP5 projections without requiring the computationally expensive use of multiple realizations of a single GCM.The TABLE directory has summaries of probabilistic climate projections for temperature, precipitation, and maximum wet-bulb temperature.Tables are in CSV format including1) 20-year average temperature, precipitation change (%) where extreme temperature exceedances are provided for CONUS (Continental United States) counties, states, and pre-defined regions (see Rasmussen et al., [2016] for region definitions), all files are in degree Celsius and anomalies are relative to 1981-2010,2) Minimum daily temperature (number of days in a year with minimum daily temperature below 0C (32F) - note that these are absolute number of days and are not relative to a historical baseline),3) Number of days in a year with minimum daily temperature below 75F (i.e. "hot nights"),4) Maximum daily temperature - number of days in a year with maximum daily temperature above 35C (95F) (population weighted),5) Precipitation - all are percent change relative to 1981-2010 precipitation totals, seasonal and annual,6) Wet bulb temperature.This data set is intended to accompany these studies:(1) T. Houser, R.E. Kopp, S.M. Hsiang, M. Delgado, A.S. Jina, K. Larsen,M. Mastrandrea, S. Mohan, R. Muir-Wood, D.J. Rasmussen, J. Rising,and P. Wilson. (2015). American Climate Prospectus: Economic Risksin the United States. Columbia University Press. ISBN: 978-0231174565(2) D. J. Rasmussen, M. Meinshausen, and R. E. Kopp. (2016). Probability-weighted ensembles of U.S. county-level climate projections for climaterisk analysis. Journal of Applied Meteorology and Climatology. DOI: 10.1175/JAMC-D-15-0302.1Please cite these works when using any results generated with these projections.Copyright © 2016 by ROBERT E. KOPP AND RHODIUM GROUP LLCThis dataset is made available under a non-Commercial Creative Commons License.https://creativecommons.org/licenses/by-nc/3.0/us/You are free to: 1. Share - copy and redistribute the material in any medium or format2. Remix, transform, and build upon the materialYou must:1. Attribution - You must give appropriate credit, provide a link to the license, and indicate if changes were made. You may do so in any reasonable manner, but not in any way that suggests the licensor endorses you or your use.2. You may not use the material for commercial purposes.No warranties are given.