Higher nitrogen fertilizer use is strongly linked to greater nitrous oxide emissions from crop residues.
Comparing Emission Totals - Indirect emissions (N2O) - Crop Residues with Nutrient nitrogen N (total) — Nitrogen fertilizer content applied that leaches across 149 countries, 2023–2050.
- Rank correlation
- +0.84
- Holding size constant
- +0.57
- Countries compared
- 149
- Period
- 2023–2050
What might link these
Nitrogen fertilizers can leach into soils, where microbial activity may convert excess nitrogen into nitrous oxide (N2O), a potent greenhouse gas. However, the partial correlation drops after controlling for population and GDP, suggesting economic or agricultural intensity factors may inflate the raw link.
Why this is not proof of anything
This is a correlation across countries, not an experiment. It cannot show that either indicator causes the other, and both may simply follow a third thing. Correlation alone cannot rule out unmeasured confounders like farming practices or soil types driving both variables.
The second figure above repeats the measurement with national population and income held constant. It is the more conservative number: a relationship that largely disappears there was mostly telling you that larger, richer countries have more of most things.
How this was measured
Both indicators were ranked across every country reporting each, and the two rankings compared — ranks rather than raw values, because a handful of very large countries can otherwise manufacture a relationship on their own. The calculation is arithmetic over figures already published on this site; the commentary above is drafted from the two indicator names and the resulting coefficients.