Two charts comparing annual global average temperature anomaly series relative to 1961–1990 (top) and 1850–1900 (bottom)
Comparison of annual global average temperature anomaly series (in degrees Celsius) relative to two baselines: (a) 1961–1990 and (b) 1850–1900, taken as representative of preindustrial conditions. The black line is the ensemble mean of the new HadCRUT5 analysis. The gray shading is the 95 percent confidence interval on the HadCRUT5 analysis. Lines in other colors are data from other sources as indicated in the legend. Credit: Morice et al. [2021], Figure 8
Source: Journal of Geophysical Research: Atmospheres

HadCRUT is one of the longest running global surface temperature analyses. Morice et al. [2021] discuss the latest version of this dataset, HadCRUT5, which covers the period 1850 to 2018, longer than previous versions. (Since publication of the paper it has been further updated to 2020.) It incorporates an improved sea-surface temperature dataset and uses a more sophisticated statistical technique to better represent sparsely observed regions of the globe.

HadCRUT5 comes with two variants intended for different applications. The first is temperature anomaly data on a grid for locations where measurement data are available. The second uses statistical methods to achieve more complete global coverage for improved global and regional temperature estimates. Each variant is a 200-member ensemble with uncertainty information. The resulting estimates of global and regional mean temperature are in close agreement with all other major analyses, increasing confidence in our observational record of temperature over the globe.

Citation: Morice, C. P., Kennedy, J. J., Rayner, N. A., Winn, J. P., Hogan, E., Killick, R. E., et al. [2021]. An updated assessment of near‐surface temperature change from 1850: the HadCRUT5 data set. Journal of Geophysical Research: Atmospheres, 126, e2019JD032361.

—Minghua Zhang, Editor-in-Chief, JGR: Atmospheres

9 March 2021: This article has been updated to correct the number in the headline and details in the text.

Text © 2021. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.