by D. Whitehouse, Dec 20, 2023 in NetZeroWatch

While 2023 will be the warmest year of the instrumental era, nobody knows why or what it means for the future of climate trends.

As can be seen from the year-to-date graph from NOAA below, 2023 started off with non-exceptional global temperature average – but from June onwards all months broke global records. Such was the cooler start to the year that it was only in September that it became apparent that 2023 could be the warmest year, surpassing the previous holder – 2016 – another El Nino year.

Clearly El Nino has a lot to do with it, coming after an unusual three years of La Nina events that tend to absorb heat in the oceans, releasing it in a subsequent El Nino, as has now happened. So as far as this represents “accelerating climate change” (as NOAA contends) it is debatable as it is mostly a delayed heat distribution, but time will tell.

It is pertinent to say that climate scientists were a little puzzled at this year’s sudden temperature surge as they cannot quite explain it: their models neither predict it nor are they able to account for the surprise. Other factors have contributed to it including the ongoing lifting of the aerosol pollution, especially by China, and the use of new formula ship fuels. The Hunga Tonga explosion that injected water vapour into the stratosphere might have had an effect, though probably a minor one. The Sun reaching the peak of the solar cycle will also have had a small influence.

All this means that 2024 could be another record year if the El Nino progresses, but 2025 will probably see global temperatures fall somewhat. Some have speculated that this will make 2024 the first year to surpass the Paris Agreement’s 1.5C threshold, although a single year is not indicative of a long term trend.

But how would we know we have passed this threshold?

Redefining Climate

Redefining Climate

Every now and then climate scientists give in to one of their greatest temptations – which is to substitute models for reality and think they are the same.

The definition of ‘climate’ adopted by the World Meteorological Organisation is the average of a particular weather parameter over 30 years. It was introduced in 1934 by the International Meteorological Organisation (WMO’s precursor) because data sets were only held to be reliable after 1900, so 1901 – 1930 was used as an initial basis for assessing climate. It has a certain arbitrariness, it could have been 25 years.

Back in 2018 we reported that in its 1.5°C report the IPCC had changed the definition of climate to what has been loosely called “the climate we are in.” It still uses 30 years for its estimate of global warming and hence climate – but now it was the 30 years centred on the present. There are some obvious problems with this. We have observational temperature data for the past 15 years but, of course, none for the next 15 years!

This IPCC trick has now resurfaced. The latest example concerns the predicted surpassing of the 1.5°C limit above pre-industrial temperature. Because of the considerable interannual variability of global temperature records, such an occurrence would inevitably only be recognised some years afterwards. For some this is not good enough and the proposed solution is to side-line empirical temperature data by mixing it with the output of speculative climate models. Welcome to model land, where the rules and reality are different.

This is where the UK Met Office comes in with a highly ingenious proposition. They are suggesting to mix ten years of past temperature data with ten years of projected temperatures to establish the climate we are currently experiencing. Bingo!

There are, of course, problems with this shrewd ploy, not least the possibility of another global temperature pause or the skewing of the trends due to the up and downs of El Ninos.

The Met Office’s cunning plan is part of a trend we have mentioned before – making the ‘climate’ period shorter and the ‘weather’ longer. What was once defined as short-term weather is now called climate, ignoring the 30 year definition of climate that puts weather events into their statistical context. And of course each annual global temperature average, even those significantly influenced by a strong El Nino or La Nina, has turned into a climatic event because ocean cycles themselves have now become near-term climate events.