CRUTEM (Climatic Research Unit temperature) is a high-profile global land-surface temperature dataset which has formed the basis of observed global warming over land over the past century and a half. Osborn et al.  discuss a major update to the dataset (CRUTEM5), which extends the time period from the previous range of 1850-2011 to 1850-2019. It also includes measurements from more than 3000 additional stations and uses improved methods of quality control and gridding algorithms. The global, annual-mean land temperature has increased by 1.6°C from 1861-1900 to the mean of the last 5 years (for comparison, the uncertainty on individual annual means is only -0.11°C to +0.10°C in recent years). The dataset can be used to study both global and regional climate variabilities and changes.
Citation: Osborn, T. J., Jones, P. D., Lister, D. H., Morice, C. P., Simpson, I. R., Winn, J. P., et al. . Land surface air temperature variations across the globe updated to 2019: the CRUTEM5 dataset. Journal of Geophysical Research: Atmospheres, 126, e2019JD032352. https://doi.org/10.1029/2019JD032352
—Minghua Zhang, Editor-in-Chief, JGR: Atmospheres