Nitrogen pollution

“Why is the fertiliser that feeds half the world also poisoning its water and air?”

47%

of the nitrogen added to the world's farmland is taken up by crops; most of the rest escapes as pollution

Lassaletta et al., Environmental Research Letters, 2014

15%

less fertiliser used by millions of Chinese farms taught better methods, even as their yields rose

Cui et al., Nature, 2018

Root causes (expand to see solutions)

Nitrogen pollution is the hidden cost of synthetic fertiliser, the invention that lets the world grow enough food but also leaks vast amounts of reactive nitrogen into rivers, seas and the air.

What's at stake

In the sea, fertiliser runoff feeds algal blooms that rot into dead zones where fish and shellfish suffocate. In drinking water, nitrate is linked to 'blue baby syndrome' in infants and to bowel and thyroid cancers. In the air, nitrogen becomes nitrous oxide, a greenhouse gas about 270 times stronger than carbon dioxide, along with smog that harms the lungs.

The global picture

China

High severity

The world's largest fertiliser user, China long spread far more nitrogen than crops could take up, polluting rivers and groundwater across its farming regions.

Nitrogen pollution reaches farming regions worldwide, from Europe's rivers to the coastal waters of Southeast Asia and Latin America.