Iran’s methane super-emitters: assessment of discrepancies between satellite observations and inventories

Abstract

This study presents a satellite-based assessment of methane (CH₄) super-emitters (> 100 kg h⁻¹) across Iran’s oil and gas (O&G) and waste sectors from 2022 to 2025. Annualized top-down emissions from O&G super-emitters ranged from 1390 ± 70 kton year⁻¹ to 6500 ± 200 kton year⁻¹, and waste-sector emissions from 110 ± 20 kton year⁻¹ to 630 ± 70 kton year⁻¹, with inter-annual differences largely reflecting source variability and the study’s focus on super-emitters. An independent bottom-up IPCC Tier-1 recalculation for Iran's solid waste disposal sites yielded 700 [160–1900] kton year⁻¹ of CH₄ emissions, substantially exceeding both Iran’s 3^rd National Inventory Report (23 kton year⁻¹) and EDGAR v8.0 (400–500 kton year⁻¹). Seasonal CH₄ emission patterns were identified, with O&G emissions peaking in warmer months and waste emissions in cooler months. While satellite-based observations are useful, following our communications with the National Iranian Petrochemical Company (NIPC) we concluded that some of satellite-based reported CH₄ emission points were questionable, possibly due to spectral overlap of CH₄ with other hydrocarbons and/or spatial misattribution. Satellite observations require complementary ground-based and airborne measurements at source- and site-levels for robust quantification, attribution, and verification. Overall, the results reveal that Iran requires a comprehensive focus on advancing emission monitoring, reporting and verification for emission inventories, which have not been updated since 2017, and highlight considerable mitigation potential through flare-gas utilization for domestic or industrial uses, landfill gas recovery, and engagement with international initiatives such as Oil and Gas Methane Partnership 2.0 (OGMP 2.0) and International Methane Emission Observatory (IMEO).