Arctic Sea Ice Extent (September) vs US Military Expenditure

Arctic Sea Ice Extent (September) and US Military Expenditure correlate at r = +0.55 over 46 years (1979–2024), p < 0.0001. With the time trend removed, r = -0.34. Direction flips without the trend.

Verdict: Direction flips without the trend. The raw correlation is 0.55, but once each series' time trend is removed it becomes -0.34. The year-to-year movements run the opposite way to the long-run trends, so the headline number is misleading.

Pearson r: +0.55
p-value: < 0.0001
Years compared (n): 46 (1979–2024)
95% confidence interval: 0.31 to 0.73
Correlation with the time trend removed: -0.34

Sources

Arctic Sea Ice Extent (September) (million km²): NSIDC. Mean Arctic sea ice extent in September, the yearly minimum (NSIDC Sea Ice Index).
US Military Expenditure (% of GDP): World Bank. US Military Expenditure (World Bank indicator MS.MIL.XPND.GD.ZS).

Related pairs

Arctic Sea Ice Extent (September) vs US Mobile Subscriptions (r = -0.92)
US Infant Mortality vs US Military Expenditure (r = +0.91)
Arctic Sea Ice Extent (September) vs US Resident Patent Applications (r = -0.91)
Arctic Sea Ice Extent (September) vs US Adult Obesity (r = -0.91)
Arctic Sea Ice Extent (September) vs US Population (r = -0.90)
Arctic Sea Ice Extent (September) vs US Marriage Rate (r = +0.90)

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