title: Assessing recent warming using instrumentally homogeneous sea surface temperature records.
abstract: Sea surface temperature (SST) records are subject to potential biases due to changing instrumentation and measurement practices. Significant differences exist between commonly used composite SST reconstructions from the National Oceanic and Atmospheric Administration's Extended Reconstruction Sea Surface Temperature (ERSST), the Hadley Centre SST data set (HadSST3), and the Japanese Meteorological Agency's Centennial Observation-Based Estimates of SSTs (COBE-SST) from 2003 to the present. The update from ERSST version 3b to version 4 resulted in an increase in the operational SST trend estimate during the last 19 years from 0.07° to 0.12°C per decade, indicating a higher rate of warming in recent years. We show that ERSST version 4 trends generally agree with largely independent, near-global, and instrumentally homogeneous SST measurements from floating buoys, Argo floats, and radiometer-based satellite measurements that have been developed and deployed during the past two decades. We find a large cooling bias in ERSST version 3b and smaller but significant cooling biases in HadSST3 and COBE-SST from 2003 to the present, with respect to most series examined. These results suggest that reported rates of SST warming in recent years have been underestimated in these three data sets.
authors.affiliation: Energy and Resources Group, University of California, Berkeley, Berkeley, CA 94720, USA.; Berkeley Earth, Berkeley, CA 94705, USA.
authors.forename: Zeke
authors.initials: Z
authors.lastname: Hausfather
authors.affiliation: Department of Chemistry, University of York, York, U.K.
authors.forename: Kevin
authors.identifier: 0000-0002-0189-1437
authors.initials: K
authors.lastname: Cowtan
authors.affiliation: Independent Researcher, Montreal, Quebec, Canada.
authors.forename: David C
authors.initials: DC
authors.lastname: Clarke
authors.affiliation: Department of Environmental Science and Policy, George Mason University, Fairfax, VA 22030, USA.
authors.forename: Peter
authors.identifier: 0000-0002-6951-7126
authors.initials: P
authors.lastname: Jacobs
authors.affiliation: NASA Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA.
authors.forename: Mark
authors.identifier: 0000-0001-7063-631X
authors.initials: M
authors.lastname: Richardson
authors.affiliation: Berkeley Earth, Berkeley, CA 94705, USA.
authors.forename: Robert
authors.initials: R
authors.lastname: Rohde
keywords: Climate change; homogeneity; sea surface temperature