State Climate Summaries for the United States: Scientific Analyses and Processes

A set of State Climate Summaries have been produced for all 50 U.S. states. These summaries, available at stateclimatesummaries.globalchange.gov, were created in response to a growing demand for state-level information as part of the National Climate Assessment (NCA) Sustained Assessment and represent a NOAA contribution to this process. Each State Climate Summary provides stakeholders, decision makers, and informed non-scientists with up-to-date state-based information on observed and projected climate change conditions and impacts associated with future greenhouse gas emissions pathways. The summaries focus on characteristics of the physical climate and coastal issues in accordance with NOAA's mission.

Each state’s Climate Summary encompasses its climatology as well as projections of future temperature and precipitation, which are presented in order to provide a context for the assessment of future impacts. The climatological component focuses on temperature, precipitation, and noteworthy historical weather events specific to each state and relevant to the climate change discussion. Future climate scenarios are also discussed, using well-known and consistent sets of climate model simulations based on two possible futures of greenhouse gas emissions. These future scenarios present an internally consistent climate picture for every state and are intended to inform with regard to the potential impacts of climate change.

Analyses of the historical climate primarily use data from NOAA NCEI’s Climate Divisional Dataset (nClimDiv) and Global Historical Climatology Network-Daily (GHCN-D). These include statewide annual temperature time series, analyses of extremes metrics related to both temperature and precipitation, and additional metrics such as lake levels and drought indices.

Projections of future climate use analyses of data from the Coupled Model Intercomparison Project, Phase 5 (CMIP5), including statewide temperature time series under both a high and low emissions scenario, and changes in annual and seasonal precipitation under a high emissions scenario. In addition, time series of the projected number of tidal floods were created for select coastal cities.

The scientific analyses and processes utilized in each component of the Climate Summaries described above will be presented.