Plausible Fuzzybutt

Global temperature in 2023 was odd. Having been following this on and off for a year now, I think my initial response still holds: what we have is a multitude of possibly unsatisfying answers. They way the climate works, the limited experimental affordances of climate science, and the tools we have mean that it’s not possible to say definitively what caused something like 2023, particularly not when the question is as ill-posed as that. Sure, one can try and quantify the effects of Hunga-tonga Hunga-ha’apai, but it will inevitably come with a relatively wide uncertainty range. Ditto the effects of shipping aerosols, ditto Saharan dust, ditto ENSO, ditto Antarctic ice, ditto solar forcings, ditto the interactions of all these things and others that have been posited as contributing to that oddness. The uncertainties in the inputs to these analyses, as well as the uncertainties inherent in modelling and comparison to observations mean that what we get out is fuzzy yet plausible, which is more or less where we were at the start. The fuzziness is fuzzied further because each analysis has its own particular motivations and methods that don’t necessarily align with the particular goal of explaining the global mean temperature anomaly of 2023. That’s no criticism of the individual papers mind. The motivations behind each one are sound and interesting and move the science forward (in some sense) but not necessarily towards a satisfying explanation. It seems that the Hunga-Tonga contribution is small – so we haven’t learned nothing at all – but it is uncertain, possibly more complex than that, and might even be negative.

It’s not clear that this necessarily helps us any.