The averaging reduces the signal from short-term natural variability, such as associated with El Niño events and volcanic eruptions, which can leave a clear mark on annual averages. The averaging also reduces the differences among the various available temperature datasets. The indicator is nevertheless sensitive to longer-term variations in surface air temperature such as those associated with decadal and multi-decadal oceanic oscillations.
Various datasets show the latest five-year average global temperature to be the highest on record. Warming since the start of the industrial era in the 18th century is estimated to be around 1.1°C. Current values are consistent with an average increase by 0.1°C every five to six years since the mid-1970s, although the rate of warming, viewed from a five-year perspective, has not been steady. The five-year averages centred on the years from 2003 to 2012 showed hardly any change, for example. The indicator then rises sharply due to the exceptional warmth of the years 2015, 2016 and 2017.
The datasets used here to extend the time series back to the 19th century are the latest versions of three datasets compared in the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change. These versions continue to show a difference noted in AR5 in global-mean temperature for the period 1920 to 1970, whereas for recent decades the datasets agree well.
Generally, the average temperature over Europe has increased during the industrial era and it has risen sharply since the 1980s. The 60-month average values are around 9.7°C for periods ending in 2016 and 2017, about 1.8°C higher than values for the latter half of the 19th century. This temperature increase for Europe is about 0.8°C larger than the corresponding increase for the globe as a whole. The Paris Agreement aims to hold the increase in global average temperature over the industrial era to well below 2°C and to pursue efforts to limit the increase to 1.5°C.
Decadal-scale variations are much more prominent for the European than for the global domain. The contrast between the warm conditions of the 1930s and the cold conditions of the early 1940s is a particularly striking feature of the European temperature.
The “About the data” section explains more about the production and reliability of the values presented here.