The 2020-2022 La Nina events temporarily cooled temperatures, but 2021 was one of the seven warmest recorded years, and Canada logged a Sahara Desert-like temperature of 50 C, according to the World Meteorological Organization (WMO).
The WMO said in a statement on Tuesday that consolidated global warming and other long-term climate change trends are expected to continue due to record levels of heat-trapping greenhouse gases in the atmosphere.
“Back-to-back La Nina 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 Nina,” said WMO Secretary-General Petteri Taalas.
La Nina refers to the extensive cooling of the ocean surface temperatures in the central and eastern equatorial Pacific Ocean, coupled with changes in the tropical atmospheric circulation.
It usually has the opposite impacts on weather and climate as El Nino.
Taalas said the overall long-term warming because of greenhouse gas increases is far more extensive than the year-to-year variability in global average temperatures caused by naturally occurring climate drivers.
The average global temperature in 2021 was about 1.11 (plus/minus 0.13) C above the pre-industrial (1850-1900) levels.
According to the WMO, last year was the seventh consecutive year (2015-2021) when the global temperature was over 1 C above pre-industrial levels.
Canada records 50 C
“The year 2021 will be remembered for a record-shattering temperature of nearly 50 C (122 F) in Canada,” said Taalas.
That is, “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,” he said.
He noted that climate change impacts and weather-related hazards triggered life-changing and devastating effects on every continent.
The warmest seven years have all been since 2015, with 2016, 2019, and 2020 the top three.
A powerful El Nino event occurred in 2016, contributing to record global average warming.
WMO said it 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, informing the international community on global climate indicators.
Temperature is just one of the indicators of climate change, says the WMO.
Others include greenhouse gas concentrations, ocean heat content, ocean pH, global mean sea level, glacial mass, and sea ice extent.
WMO notes that the legally binding Paris Agreement signed in 2016 seeks to hold the global average temperature increase to below 2 C, above pre-industrial levels while seeking to limit the temperature increase to 1.5 C above pre-industrial levels.
At 1.11 C above the pre-industrial (1850-1900) levels, the global average temperature in 2021 is already approaching the lower limit of temperature increase the Paris Agreement seeks to avert, the organization said./aa