Hacker News Reader

Urea comes from the Harber process [1] Basically most of food fertilizer depends on fossil fuels.

The usual chain is natural gas -> ammonia -> urea. Thus, one of the key factors influencing the supply is Hurricane Ida, which led to remarkably long shutdowns in natural gas production. https://www.eia.gov/naturalgas/weekly/archivenew_ngwu/2021/1...

Ammonia (made from natural gas) and carbon dioxide.