The global surface temperature for 2021 was the sixth highest since record keeping began in 1880, according to a statement issued Thursday by NOAA scientists.
In a separate analysis of global temperature data, NASA has 2021 tying with 2018 as the sixth-warmest year on record.
The following summary from NOAA National Centers for Environmental Information is part of the suite of climate services NOAA provides to government, business, academia and the public to support informed decision-making.
NOAA:
Global land and ocean surface temperature: For 2021, the average temperature across global surfaces was 1.51°F (0.84°C) above the 20th-century average and the sixth highest in the 1880-2021 record.
The year 2021 marks the 45th consecutive year (since 1977) with global temperatures, at least nominally, above the 20th-century average. The nine years spanning 2013 through 2021 rank among the 10-warmest years on record.
For the 21-year span that is considered a reasonable surrogate for pre-industrial conditions (1880–1900), the 2021 global land and ocean temperature was 1.87°F (1.04°C) above the average.
The annual global surface temperature has increased at an average rate of +0.14°F (+0.08°C) per decade since 1880; however, since 1981 the average rate of increase is more than twice that rate (+0.32°F / +0.18°C).
The year began in the midst of a cold phase El Niño Southern Oscillation (ENSO) episode across the central and eastern tropical Pacific Ocean, which developed in August 2020. This phase, known as La Niña, tends to cool global temperatures slightly, while the warm phase ENSO (also known as El Niño) tends to boost global temperatures.
The 2021 Northern Hemisphere surface temperature was the sixth highest in the 142-year record at 1.96°F (1.09°C) above the 20th century average. Of note, the Northern Hemisphere land surface temperature was the third highest on record. Only the years of 2016 (second) and 2020 (warmest) were warmer.
Meanwhile, the 2021 Southern Hemisphere surface temperature was the ninth highest on record.
Record-high temperatures over land surfaces were measured across parts of northern Africa, southern Asia, and southern South America in 2021.
Record-high sea surface temperatures were observed across parts of the Atlantic and Pacific oceans.
However, no land or ocean areas were record cold for the year.
Global ocean heat content (OHC): The upper ocean heat content, which addresses the amount of heat stored in the 0-2000 meters depth of the ocean, was record high in 2021, surpassing the previous record set in 2020. The seven highest OHC have all occurred in the last seven years (2015-2021).
Arctic sea ice extent: Each month in 2021, with the exceptions of September and December, had a monthly Arctic sea ice extent that ranked among the 10-smallest extents for each respective month. However, no month had a record low sea ice extent during the year.
When averaging monthly data from theNational Snow and Ice Data Center, the average annual sea ice extent in the Arctic was approximately 4.08 million square miles – the ninth smallest annual average sea ice extent in the 1979-2021 record.
The last seven years (2015-2021) had an annual sea ice extent that ranked among the 10 smallest on record.
Antarctic sea ice extent: The annual Antarctic sea ice extent was slightly below average at 4.42 million square miles. No month had a record low or high sea ice extent during 2021. 2021
Global Tropical Cyclones: The year 2021 had an above-average global tropical cyclone activity with a total of 94 named storms. This value ties with 1994 as the 10th-highest number of named storms in the 41-year record.
Despite the above-average number of named storms, there were only 37 hurricane-strength tropical cyclones – the lowest number for global hurricane-strength tropical cyclones on record, one less than the now-second lowest of 38 set in 2009.
