2021 one of the seven warmest years on record: WMO

Although average global temperatures were temporarily cooled by the 2020–2022 La Niña events, 2021 was still one of the seven warmest years on record, according to six leading international datasets consolidated by the World Meteorological Organization (WMO). Global warming and other long-term climate change trends are meanwhile expected to continue as a result of record levels of heat-trapping greenhouse gases in the atmosphere.

The WMO uses six international datasets to ensure the most comprehensive, authoritative temperature assessment. The same data are used in its annual State of the Climate reports, which inform the international community on global climate indicators.

The average global temperature in 2021 was about 1.11°C above pre-industrial (1850–1900) levels, making it the seventh consecutive year where global temperature has been over 1°C above pre-industrial levels, according to all datasets compiled by WMO. Indeed, the warmest seven years have all been since 2015, with 2016, 2019 and 2020 constituting the top three. An exceptionally strong El Niño event occurred in 2016, which contributed to record global average warming.

The Copernicus Climate Change Service estimated that 2021 was the fifth-warmest year on record, only marginally warmer than 2015 and 2018. The US National Oceanic and Atmospheric Administration and the Berkeley Earth group found that 2021 was nominally the sixth-warmest year, while NASA’s Goddard Institute for Space Studies and the University of East Anglia’s Climatic Research Unit have 2021 effectively tied for sixth-warmest. Data from the Japanese Meteorological Agency reanalysis meanwhile ranks 2021 as nominally the seventh-warmest year. The small differences among these datasets indicate the margin of error for calculating the average global temperature.

“Back-to-back La Niña events mean that 2021 warming was relatively less pronounced compared to recent years; even so, 2021 was still warmer than previous years influenced by La Niña,” said WMO Secretary-General Professor Petteri Taalas. “The overall long-term warming as a result of greenhouse gas increases is now far larger than the year-to-year variability in global average temperatures caused by naturally occurring climate drivers.

“The year 2021 will be remembered for a record-shattering temperature of nearly 50°C in Canada, comparable to the values reported in the hot Saharan Desert of Algeria; exceptional rainfall; and deadly flooding in Asia and Europe as well as drought in parts of Africa and South America,” Prof Taalas continued. “Climate change impacts and weather-related hazards had life-changing and devastating impacts on communities on every single continent.”

The temperature figures will be incorporated into the WMO’s State of the Climate report for 2021, which will be issued in April 2022.

Image credit: ©stock.adobe.com/au/Quality Stock Arts

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