A schism in climate science

2023 was the warmest year of the instrumental era

Many researchers are looking with apprehension to see what happens between now and the end of the year, as the warming El Niño fades and the cooling La Niña takes over. The stakes are high. This year could be a decisive one for the credibility of climate models.

The current El Niño commenced in June 2023 and provided a release valve for the excess heat stored over previous years in the Pacific Ocean. It propelled the planet into uncharted territory and has climate scientists rattled, in a rare show of disagreement. The fact is that they don’t have a good explanation for why it is so hot.

For some, this is just the latest blow to the credibility of the field, coming after earlier problems such as the failure to find an explanation for the lack of global surface warming between 2002 and 2014. Others maintain that that until last year, climate scientists were pretty good at explaining things. Whatever way you look at it, the recent warmth has caused a schism in climate science.

It is clear that the sharp uptick in global temperatures last year cannot yet be used as proof of an acceleration in the rate of climate change – a single year’s data is not climate.

Research is under way to identify possible reasons for the warmth: the impact of additional cooling from volcanic eruptions or the reduction of shipping aerosol pollution perhaps. But these factors only go part way in forming an explanation; they might account for about half of the observed warming.  So natural variability, including the solar cycle, must also be included at higher levels than usually considered relevant in climate models if a complete explanation is to be delivered.

If the temperature anomaly does not stabilise by August then we will truly be in uncharted territory. Perhaps nature is changing how the climate system operates much sooner than some scientists had anticipated. Whatever happens, faith in climate models will suffer.

So it is uncertain how soon a transition to a cooler La Niña will bring respite from the heat. But twin conclusions are much more clear: that the models are inadequate and that we do not understand global warming as well as many scientists have claimed.