NASA, NOAA and the UK Met Office have released the global temperature for 2022, showing it to be a warm year, ranked sixth warmest year. It was subdued, the researchers say, because we have had the third consecutive year of La Nina conditions.
The announcement was accompanied with the usual proviso that the past nine years were the warmest recorded. But anyone thinking about the claims and numbers should also look behind the headlines.
Fig 1 shows the global temperature anomaly this century: blue is HadCRUT5, Orange is NASA and grey is NOAA.
What is quite apparent is that the global temperature record in the 21st century spends long periods relatively flat. The so-called hiatus, for instance, lasted from circa 2001 and 2013 and was ended by a very strong El Nino. Since then there has been another period of relatively unchanging temperature. Noticeable increases in temperature occur in the lead-in to an El Nino, such as the increase of approx. 0.3°C between 2011-2015.
The stepwise influence of El Nino events on the long-term trends seems very apparent. It was the strong El Nino of 1998 that marked the jump of global temperature to the hiatus, and the 2015 El Nino may have done the same. Of course no one knows how long the current stagnation will continue. Everyone is expecting the three-year La Nina to lift. Some estimate that these events have depressed the global temperature by about 0.06°C. If there is another El Nino in 2024 then a new global record will almost certainly result.
Looking at the distribution of recent warming the dominance of the arctic is obvious. It almost leads one to suggest that the phrase global warming should be replaced by arctic warming!