The "scatter line plot" in TFA is all same shade of red on white with no year labels. This seems like a missed visualization opportunity. Using some kind of color scheme/gradient to represent the 1979-2026 years in a way that can show long-term "trend". (A 50 frame movie at, say, 5 fps with same axes or maybe "all years" as faded background as the current year pops around in bold is another possibility, but a scientific paper format doesn't let people do .mp4s.) I know I've seen multi-colored "scatter lines" in IPCC reports. Seemed worth asking rather than doing it myself.
Yeah, kinda like the spirals used for (air?) temperature:
https://svs.gsfc.nasa.gov/5190/