ERA5 Copernicus Climate Change Data

Time series of global daily mean surface air temperature (2-meter height) estimates from the ECMWF Reanalysis version 5 (ERA5) for the period January 1940 to present. Reanalysis combines model data with observations from across the world into a globally complete and consistent dataset using the laws of physics.

Data Source:
Hersbach, H., Bell, B., Berrisford, P., Biavati, G., Horányi, A., Muñoz Sabater, J., Nicolas, J., Peubey, C., Radu, R., Rozum, I., Schepers, D., Simmons, A., Soci, C., Dee, D., Thépaut, J-N. (2023): ERA5 hourly data on single levels from 1940 to present. Copernicus Climate Change Service (C3S) Climate Data Store (CDS), DOI: 10.24381/cds.adbb2d47 (Accessed daily via https://climatereanalyzer.org/clim/t2_daily/)

Pre-industrial level:
"1850-1900 is the earliest feasible reference period for the globe based on instrumental data and chosen to be representative of the pre-industrial level for the purpose of monitoring the approach of global temperature to the limits specified in the Paris Agreement. As ERA5 does not cover this period, a method is needed to relate present-day values to this early period. (...) A standard offset of 0.88°C is added to the annual anomaly with respect to 1991-2020."
see Copernicus: Climate Bulletin - About the data and analysis