CO₂ rose about 40 ppm between the 1960s and the 1990s

CO₂ rose about 40 ppm between the 1960s and the 1990s

Question. How fast did annual mean CO₂ climb at Mauna Loa?

• Encoding. A thin path and dots show each year's mean of its measured weeks. A band behind them spans the lowest to the highest measured week, so the seasonal swing of about 6.5 ppm stays in view.
• Ordering. Chronological years; no endpoint extension.
• Baseline. The concentration axis is not forced to zero because position, not bar length, encodes value.
• Scale. One linear concentration scale; partial endpoint years remain included and documented.

What this design gives up

The band shows how wide each year's swing was, but not when in the year the peak and trough fell. Week-level gaps disappear; the related notebooks keep them.

This is the historical flask-data revision distributed with statsmodels, not the latest NOAA series. Missing weeks stay null. Weekly observations at one station are not global spatial measurements.