Global and European temperatures

This indicator shows observed and projected changes in annual average near-surface temperature globally and for Europe. Europe is defined here as the land area in the range 34° to 72° northern latitude and -25° to 45° eastern longitude.

Temperature anomalies are presented relative to a 'pre-industrial' period between 1850 and 1899 (the beginning of instrumental temperature records). During this period, greenhouse gases from the industrial revolution are considered to have had a relatively small influence on the global climate compared with natural influences.

Methodology for indicator calculation

The following global meteorological datasets have been used to compute the time series of global mean temperature and European land temperature:

· : This dataset is a collaborative product of the Met Office Hadley Centre and the Climatic Research Unit (CRU) of the University of East Anglia. HadCRUT5 is a combination of sea-surface temperature (SST) measurements over the ocean from ships and buoys and near-surface air temperature measurements from weather stations over the land surface.

· : This dataset is a product of the National Centre for Environmental Information of the U.S. National Oceanic and Atmospheric Administration (NOAA).

· : This dataset is a product of the NASA Goddard Institute for Space Studies (GISS).

The temperature anomalies from the original datasets were adjusted here to the 'pre-industrial' period between 1850 and 1899.

· Berkeley Earth: temperature dataset produced by Berkeley Earth; an independent U.S. non-profit organization focused on environmental data science.

· ERA5 Dataset produced by ECMWF and available in the Climate Data Store. ERA5
is the fifth generation ECMWF reanalysis for the global climate and weather for the past 4 to 7 decades. Currently data is available from 1950. Reanalysis combines model data with observations from across the world into a globally complete and consistent dataset.

· conducted the second Japanese global atmospheric reanalysis, called the Japanese 55-year Reanalysis or JRA-55. It covers the period from 1958, when regular radiosonde observations began on a global basis.

These datasets were provided by the Copernicus Climate Change Service (C3S), following the developed methodology to relate recent (1991-2020) global temperature to 1850-1900, a period taken to represent the pre-industrial level. New and updated global temperature datasets have been recently published, which has resulted in a new estimate for the latest 30-year reference period 1991-2020, defined by the World Meteorological Organization (WMO). The new approach for monitoring global temperature change since the 1850-1900 period is being used in the WMO statements on 'The state of the global climate' from the Preliminary Statement for 2021 onwards (see details there, under 'Datasets and methods - Global temperature data'). This approach results in a best estimate of 0.68°C with an uncertainty range (0.54 to 0.78°C) to relate the standard WMO reference period 1981-2010 to 1850-1900. Extending this approach to the WMO reference period 1991-2010 gives a best estimate of 0.88°C with an uncertainty range (0.72-0.99°C), which sums the 0.68ºC of additional warming from pre-industrial to the 1981-2010 period, the 0.19ºC difference from 1981-2010 to 1991-2020, according to ERA5, and an adjustment of 0.01ºC for consistency with new estimates documented by the Sixth IPCC Assessment Report. In the datasets here provided by C3S this method has been used, by calculating the anomalies of each dataset relative to its own average for 1981-2010 and adding the offset of 0.88°C, to then relate it to 1850-1900.

IPCC estimates are not available for the all-land, European and Arctic regions for which C3S provides temperature indicators. For these cases, the changes from 1850-1900 are based on estimates of the differences between 1991-2020 and 1850-1900 averages derived from the Berkeley Earth, GISTEMPv4, HadCRUT5 and NOAAGlobalTempv5 datasets.

Spatially explicit temperature trends in Europe are derived from ERA5-Land reanalysis. ERA5-Land provides high resolution information of surface variables over global land areas. It is produced by the European Centre for Medium-Range Weather Foreacasts (ECMWF). The dataset covers the period from 1950 on. Trends are calculated using the annual mean and then applying an ordinary least squares regression using the model y=a+b*x+e, where e is assumed to be a first order autoregressive process. The significance is computed from a two-sided Student's test for the null hypothesis of no trend. The code used to extract the trend and significance results is the same as in the IPCC Atlas. The underlying temperature data is a model result coming from a replay of the land component of the ERA5 climate reanalysis. ERA5-Land comes with a series of improvements, including higher spatial resolution, making it more accurate for all types of land applications. Trend analyses should be treated with caution.

The projected changes in European near-surface air temperature (°C) are based on the multi-model ensemble average of GCM simulations from the Coupled Model Intercomparison Project Phase 6 (CMIP6) initiative. CMIP6 is a project coordinated by the Working Group on Coupled Modelling (WGCM) as part of the World Climate Research Programme (WCRP).

Further information on all these datasets is available from the cited publications.

For more past and future changes the European Climate Data Explorer (ECDE) provides interactive access to a growing selection of climate indices by theme and sector reflecting the priorities of the European Environment Agency (EEA). The underlying data is from the Climate Data store (CDS) of the Copernicus climate change service (C3S).

Near-surface air temperature gives one of the clearest signals of global and regional climate change. Anthropogenic influence, mainly through emissions of greenhouse gases, is responsible for most of the observed increase in global mean temperature (GMT) in recent decades. For these reasons, GMT has been chosen as the indicator to monitor the 'ultimate objective' of the United Nations Framework Convention on Climate Change (UNFCCC).

The Paris Agreement adopted in December 2015 defines the long-term goal to 'hold the increase in the global average temperature to well below 2°C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5°C above pre-industrial levels, since this would significantly . The need to limit the increase in GMT in accordance with the goals of the UNFCCC is also recognised in the Sendai Framework for Disaster Risk Reduction 2015-2030 and in .

Rising mean temperatures are also increasing the frequency and severity of heatwaves globally and in Europe.

No uncertainties have been specified