Observed and projected changes in absolute temperature records across the contiguous United States

Abstract

Changes in the extent of absolute, all-time, daily temperature records across the contiguous United States were examined using observations and climate model simulations. Observations from station data and reanalysis from 1980 to 2013 show increased extent of absolute highest temperature records and decreased extent of absolute lowest temperature records. Conversely, station data from 1920 to 2013 showed decreased extent of absolute highest records with nearly half of such records occurring in the 1930s during exceptional widespread drought. Simulated changes in the extent of absolute temperature records from climate model experiments were in general agreement with observed changes for recent decades. However, fewer lowest temperature records and highest temperature records were observed since 2000 than simulated by most models. Climate models project a continued increase in the occurrence of highest temperature records and decline in lowest temperature records through the mid-21st century. Key Points Increases in absolute record highs and decreases in record lows since 1980Lack of absolute coolest records since 2000 exceeded most climate simulationsProjected increase in novel absolute warmest records for coming decades