Atmospheric CO₂ (Mauna Loa) vs US Secondary School Enrollment

Atmospheric CO₂ (Mauna Loa) and US Secondary School Enrollment correlate at r = +0.72 over 35 years (1971–2022), p < 0.0001. With the time trend removed, r = -0.39. Direction flips without the trend.

Verdict: Direction flips without the trend. The raw correlation is 0.72, but once each series' time trend is removed it becomes -0.39. The year-to-year movements run the opposite way to the long-run trends, so the headline number is misleading.

Pearson r: +0.72
p-value: < 0.0001
Years compared (n): 35 (1971–2022)
95% confidence interval: 0.51 to 0.85
Correlation with the time trend removed: -0.39

Sources

Atmospheric CO₂ (Mauna Loa) (ppm): NOAA GML. Annual mean atmospheric carbon dioxide measured at Mauna Loa Observatory, Hawaii (NOAA GML).
US Secondary School Enrollment (% gross): World Bank. US Secondary School Enrollment (World Bank indicator SE.SEC.ENRR).

Related pairs

Atmospheric CO₂ (Mauna Loa) vs US GDP per Capita (r = +0.99)
Atmospheric CO₂ (Mauna Loa) vs US Population (r = +0.99)
Atmospheric CO₂ (Mauna Loa) vs US GDP (current US$) (r = +0.98)
Atmospheric CO₂ (Mauna Loa) vs US Cereal Yield (r = +0.98)
Atmospheric CO₂ (Mauna Loa) vs Atmospheric Methane (global) (r = +0.98)
Atmospheric CO₂ (Mauna Loa) vs US Adult Obesity (r = +0.98)

Correlation does not imply causation. How the verdict is worked out.