> fertilizer for one Fertilizers don't contain carbon. Plants need nitrogen, potassium and phosphorus, which they can't easily get from their surroundings, so

> fertilizer for one Fertilizers don't contain carbon. Plants need nitrogen, potassium and phosphorus, which they can't easily get from their surroundings, so we provide these via fertilizers. They get their own carbon out of the CO2 in the air. We do need hydrogen to make fertilizers, and currently the cheapest way to make hydrogen is to start with methane, CH4. But this is just a matter of convenience.