As of course you know, it's
#notlinear – not even close to linear. The linear-insistence paradigm is drummed into science students from high school to graduate school, and beyond. Most are so captured they flatly refuse even to recognise it in themselves.
Which is pretty silly really. The trend tells the story, and if you generate it intelligently, then it *does* smooth out the effect of oceanic modes like ENSO. The simplest possible non-linear trend fitted to the Copernicus ERA5 data crosses 1.5°C in February 2028...