2020 one of three warmest years on record: WMO

The analysis, fed by five global temperature datasets, also finds that the period 2011-2020 was the hottest decade on record, and that the six warmest years have all occurred since 2015.

The global average surface temperature of Earth in 2020 and 2016 remained the same statistically. If it had not happened then 2020 would have been the warmest year on record. According to NOAA, the planet's seven warmest years on record have all been since 2014, with 10 of the warmest years since 2005 happening.

"Whether one year is a record or not is not really that important, the important things are long-term trends", he said.

Additionally, "we still increased [atmospheric] carbon dioxide by two parts per million previous year", Gavin Schmidt, climate scientist and director of NASA's Goddard Institute for Space Studies in New York City, told Space.com during a media teleconference Thursday as part of the 101st American Meteorological Society Annual Meeting. The presence of heat-trapping greenhouse gases in the atmosphere is one of the major reasons for global warming. Whereas in 2016, El Niño caused a big boom in temperature. Unlike his predecessor, President Donald Trump, Biden has vowed to re-enter the Paris Agreement climate deal and do more to combat climate change and reduce greenhouse gas emissions.

Though NASA's calculations peg 2020 as effectively tied with 2016 for the hottest year on record, analyses by researchers with the U.S. National Oceanic and Atmospheric Administration suggest that 2020 was actually slightly cooler than 2016.

The data sets used by the WMO.

The WMO, a U.N. agency, relied on data from observing sites and ships and buoys from NOAA and NASA and the United Kingdom's Met Office Hadley Centre and the University of East Anglia's Climatic Research Unit. They have recorded in recent years records of heat and big fires.

The largest source of year-to-year variability in global temperatures typically comes from the El Nino-Southern Oscillation (ENSO), a naturally occurring cycle of heat exchange between the ocean and atmosphere.

The La Nina event, which began in late 2020, is expected to continue into early to mid-2021.

An annotated map of the world plotted with the year's most significant climate events. Local weather plays a role in regional temperature variations, so not every region on Earth experiences similar amounts of warming even in a record year.

The WMO said the standout weather features of 2020 were the sustained heat and wildfires in Siberia and the low Arctic sea ice extent, plus the record-breaking Atlantic hurricane season.

"The NASA data shows 2016 and 2020 very close together, though, in the NASA data, 2020 is slightly ahead", Schmidt said during Thursday's media teleconference. The loss of Arctic sea ice - whose annual minimum area is declining by about 13 percent per decade - makes the region less reflective, meaning more sunlight is absorbed by the oceans and temperatures rise further still.

NOAA and NASA monitored satellites in orbit and about 20,000 weather stations all over the planet.

Global temperature difference from 1850-1900, with colours representing the results of different datasets. This has led to atmospheric concentrations of carbon dioxide, methane, and nitrous oxide that are unprecedented in at least the last 800,000 years. However, the World Meteorological Organisation was also at the forefront in 2016.