This dataset was assembled using statistically downscaled climate projections from the NASA Earth Exchange-Global Daily Downscaled Projections (NEX-GDDP) project. These climate change scenarios have been developed using global climate models (GCMs) from the Coupled Model Intercomparison Project Phase 6 (CMIP6) and four different future scenarios, known as Shared Socioeconomic Pathways (SSPs). The four SSPs involved in this project are SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5. The raw NEX-GDDP-CMIP6 data has a spatial resolution of 0.25 degrees and a daily temporal resolution. The NEX-GDDP-CMIP6 data was processed to calculate change in climatic variables for each season (fall, spring, summer, winter) and annually for 30-year periods. The five period comparisons available in the dataset are as follows: 1976-2005 to 2025-2054, 1976-2005 to 2045-2074, 1976-2005 to 2070-2099, 2025-2054 to 2045 to 2074, and 2025-2054 to 2070 to 2099. The six climatic variables included in the dataset are change in: total precipitation [in], total precipitation [%], total potential evapotranspiration [in], total potential evapotranspiration [%], maximum temperature [degF], and minimum temperature [degF]. This data was then used to produce an ensemble median of all available NEX-GDDP downscaled GCMs for each variable. Not all GCMs downscaled in NEX-GDDP had availability for every variable and scenario combination. The ensemble data was summarized by HUC-12 feature classes described above.

This dataset was produced by the US EPA to support research and online mapping activities related to EnviroAtlas. EnviroAtlas (https://www.epa.gov/enviroatlas) allows the user to interact with a web-based, easy-to-use, mapping application to view and analyze multiple ecosystem services for the contiguous United States. The dataset is available as downloadable data (https://edg.epa.gov/data/Public/ORD/EnviroAtlas) or as an EnviroAtlas map service. Additional descriptive information about each attribute in this dataset can be found in its associated EnviroAtlas Fact Sheets (https://www.epa.gov/enviroatlas/enviroatlas-fact-sheets).