As many have noted, 2025 is a “square” year, since 2025 = 45². This seems like an excuse to do an almost literal heatmap, showing the concentration of atmospheric carbon from 1BCE to 2024. The data, taken from Our World in Data here, who link to the original sources, has gaps. In almost all cases we have simply copied the previous non-null value for the map, the only exception being 1BCE, where we took the value from 1CE (the year 1). Action is required.
A PDF version is available here.
