The year 2020 was one of the three warmest on record, and rivalled 2016 for the top spot, according to a consolidation of five leading international datasets by the World Meteorological Organization (WMO).
A naturally occurring cooling climate phenomenon, La Niña, put a brake on the heat only at the very end of the year.
All five datasets surveyed by WMO concur that 2011-2020 was the warmest decade on record, in a persistent long-term climate change trend.
The warmest six years have all been since 2015, with 2016, 2019 and 2020 being the top three.
The differences in average global temperatures among the three warmest years – 2016, 2019 and 2020 – are indistinguishably small.
The average global temperature in 2020 was about 14.9°C, 1.2 (± 0.1) °C above the pre-industrial (1850-1900) level.
“The confirmation by the World Meteorological Organization that 2020 was one of the warmest years on record is yet another stark reminder of the relentless pace of climate change, which is destroying lives and livelihoods across our planet. Today, we are at 1.2 degrees of warming and already witnessing unprecedented weather extremes in every region and on every continent. We are headed for a catastrophic temperature rise of 3 to 5 degrees Celsius this century. Making peace with nature is the defining task of the 21st century. It must be the top priority for everyone, everywhere,” said United Nations Secretary-General António Guterres.
The WMO also gave a clearer picture.
“The exceptional heat of 2020 is despite a La Niña event, which has a temporary cooling effect. It is remarkable that temperatures in 2020 were virtually on a par with 2016, when we saw one of the strongest El Niño warming events on record. This is a clear indication that the global signal from human-induced climate change is now as powerful as the force of nature.”
The La Niña event which began in late 2020 is expected to continue into early to mid-2021.
La Niña and El Niño effects on average global temperature are typically strongest in the second year of the event, and the extent to which the continued cooling effects of La Niña in 2021 may temporarily diminish the overall long-term warming trend during this coming year remains to be seen.
Sustained heat and wildfires in Siberia and low Arctic sea ice extent, as well as the record-breaking Atlantic hurricane season were among the standout features of 2020.
Temperature is just one of the indicators of climate change.
The others are: greenhouse gas concentrations; ocean heat content; ocean pH; global mean sea level; glacial mass; sea ice extent and extreme events.