Global temperature anomaly data come from NOAA's
Global Surface Temperature Analysis (NOAAGlobalTemp),
which uses comprehensive data collections of increased global coverage over land
(Global Historical Climatology
Network-Monthly)
and ocean
(Extended Reconstructed Sea Surface Temperature)
surfaces. These datasets have data from 1850 to the present. The land and ocean datasets are blended into
a single product to produce the combined global land and ocean temperature anomalies. The available timeseries of
global-scale temperature anomalies are calculated with respect to the 1901-2000 average, while the
mapping tool displays global-scale temperature anomalies with respect to the 1991-2020 base period.
For more information on these anomalies, please visit
Global Surface Temperature Anomalies.
NOAA's National Centers for Environmental Information