Depending on which global surface temperature data set you look at – and I looked at HadCRUT5, NOAAGlobalTemp, GISTEMP, Berkeley Earth, ERA5 and JRA-55 – it was somewhere between the 5th and 7th warmest. We can’t estimate global temperature precisely, so we have to live with a little imprecision in the rankings.

Nevertheless, we can state almost categorically that it is not 1st, 2nd, 3rd or 4th warmest. We can also say with equal conviction that it is warmer than the other 165 years in the 172-year global temperature record.

The seven years since 2015 (including 2015 to save you having to do the maths) have all been warmer than any year before 2015. Within that raft of exceptionally warm years, 2016 is most likely the warmest. 2016 started with a strong El Niño pushing things around and generally asserting itself in the Tropical Pacific. Years starting with an El Niño tend to be slightly warmer globally than those that start otherwise. Years that start with La Nina, as 2021 did, tend to be slightly cooler. The difference between the two extremes is around two to four tenths of a degree. There’s not a definitive number because no two El Niños or La Niñas* are the same and anyway, there’s no great book of global accounting from which one can read off the numbers; there’s no special part of global temperature labelled “ENSO**”.

2021 didn’t just start with La Nina, it ended with one too, which means that 2022 is also likely to be on the cooler side of the very recent past*** and, at the same time, on the warmer side of the less than recent past. That it’s very likely to be another very warm year in the context of the full record should come as no surprise. In the past week, the latest figures from NOAA an IAP showed that heat continued to accumulate in the global oceans. This year was a new record high. The continued piling up of heat, most of which is going into the ocean, indicates that greenhouse gases are still keeping the climate out of balance. One symptom of that imbalance and the long-term accumulation of heat is the equally long-term rise in global temperature.

In short, global warming continues.

This post continues a sporadic series of posts. See e.g. 2020, 2015, 2014.

* Apologies for my dreadful Spanish.

** El Niño Southern Oscillation, which is not really an oscillation, that word giving the impression that it dependably rocks back and fore from El Niño to La Nina to El Niño to La Niña. The current consecutive La Niñas show that it doesn’t quite work like that.

*** The eruption in Tonga – devastating as it was – has not, at the time of writing, pushed sufficient sulphur into the stratosphere to cause a significant reduction in the global temperature****. Further volcanic activity, however, cannot be ruled out. Predictions of annual average temperature, though typically rendered as a traditional error bar with a strong implication that the outcomes are distributed Normally, have a often-unacknowledged cold tail. There’s a small chance of a significant eruption in any given year and historical eruptions have cooled the earth to varying and, occasionally disquieting, degrees. Big eruptions can have a long-term effect on ocean temperature.

**** Of course, as we have learned from “the event that must not be named and maybe never existed (shut up stop talking about it)” small amounts of “background” volcanic aerosol – even if they don’t amount to something on the scale of the Pinatubo eruption – can still contribute to variability in short-to-mid term temperature variability*****.

***** Almost everything can, mind, which makes it rather tricky to back out an individual effect. ******

****** Not that it stops people from trying.