The fertilizer crisis is usually framed as a natural gas problem. When gas prices rise, ammonia costs rise, fertilizer plants reduce production, and farmers become exposed to a global commodity chain they cannot control. That diagnosis is correct but incomplete. Across Europe, thousands of anaerobic digesters are already producing a methane-rich gas close to the farms and food industries that consume fertilizer. Most sites burn it in a combined heat and power unit, upgrade it to biomethane, or flare a small surplus. Very few ask a more disruptive…