Holocene CO₂ & Temperature — Last 12,000 Years

About this chart. This is the scientifically honest counterpart to the widely circulated meme that plots “proxy temperature” as a Z-score against EPICA Dome C CO₂ in raw ppm over the last ≈11 000 years and concludes “no correlation”. The meme’s appearance of decoupling is an artefact of three choices: (1) normalising temperature by its own standard deviation, which stretches a real ≈1 °C Holocene swing into ±2 visual units; (2) plotting CO₂ in raw ppm on a tight 250–290 axis where natural variation looks comparatively trivial; and most importantly (3) truncating the chart in the mid-19th century, just before CO₂ starts to move and well before the corresponding temperature response.

Here both series are in physical units (°C anomaly, ppm) on a shared 1800–1900 baseline, and both run through the present. Over the Holocene the CO₂ record (left of ≈1800 CE) really is nearly flat — a ≈20 ppm drift in 11 000 years — so any “correlation” calculation against the much larger temperature swing was always doomed by lack of CO₂ variance, not by any physical decoupling. The relevant test is at the right edge of the chart, where CO₂ finally does move: from ≈280 ppm in 1850 to ≈425 ppm today, with HadCRUT5 tracking from roughly 0 to +1.3 °C in the same window. Use View: 200 yr to zoom the modern era.

Two y-axes. Temperature (°C anomaly vs 1800–1900) on the left; CO₂ (ppm) on the right. The axes are independent — their relative scaling is a presentational choice, not a physical claim.