A follow-up to the annual version of this animation (ERA5, 1940-2025): same reanalysis, same 1991-2020 baseline, but this time month by month instead of year by year, and starting in 1982 instead of 1940 to keep the frame count manageable. Going monthly changes what the animation shows. The annual version told the story of the long-term trend, decades slowly shifting from blue to red. This one adds the pulse underneath it: El Niño and La Niña events flare up and fade over 12-18 months in the tropical Pacific, marine heatwaves flash on and off in specific basins, and the seasonal cycle itself becomes visible as the whole ocean breathes. None of that survives annual averaging, it's smoothed away before you ever see it.

528 months of sea surface temperature anomaly (ERA5 reanalysis), projected onto Spilhaus so the entire world ocean stays visible in every frame, nothing rotates out of view.

Data: ERA5, Copernicus Climate Change Service (C3S)