the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
| 30 Dec 2025
Methane intensity and emissions across major oil and gas basins and individual jurisdictions using MethaneSAT observations
Abstract. Mitigating global anthropogenic methane emissions is widely recognized as an effective strategy to reduce near-term climate warming. Here, we use satellite observations from MethaneSAT (2024–2025) to characterize methane emissions from major oil and gas basins worldwide. MethaneSAT addresses a critical gap in access to quantitative measurements of spatially distributed area emissions, providing high-resolution (~4 km × 4 km), wide-swath (220–440 km) coverage. We analyze aggregated MethaneSAT emissions across six major oil and gas producing regions: the Permian (USA), San Joaquin (USA), Eagle Ford (USA/Mexico), Amu Darya (Turkmenistan and Uzbekistan), and the Zagros Foldbelt (Iran/Iraq). Regional oil and gas emissions span more than an order of magnitude, ranging from 408 t h⁻¹ (95% CI: 303–516 t h⁻¹) for the Permian basin to 30 t h⁻¹ (95% CI: 20.3–41.1 t h⁻¹) in the San Joaquin basin. Methane intensities also vary substantially across basins and sub-basins, with more than an order of magnitude variation in both production-normalized and energy-normalized metrics. These differences reflect diverse factors, including contrasts in oil versus gas production, infrastructure age, contributions of lower-producing wells, and presence or absence of emission mitigation practices. Across jurisdictions, including counties and districts, we find consistent underestimation by gridded EPA-GHGI and EDGAR bottom-up inventories relative to MethaneSAT-derived emissions. Overall, MethaneSAT data provide basin-wide and sub-regional insights into methane emissions and intensities, offering critical scientific and policy-relevant information to support targeted and effective methane mitigation strategies.
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Status: open (until 07 Mar 2026)
- RC1: 'Comment on egusphere-2025-6126', Anonymous Referee #1, 05 Feb 2026 reply
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RC2: 'Comment on egusphere-2025-6126', Anonymous Referee #2, 27 Feb 2026
reply
General Comment
This manuscript presents regional methane emissions and intensity estimates derived from MethaneSAT observations across six major oil and gas basins. The dataset is novel and timely, and the comparison with bottom-up inventories and other top-down studies is valuable. The policy relevance of production-normalized methane intensity metrics is also well aligned with ongoing international methane mitigation efforts.
However, while the dataset is strong, the manuscript would benefit from substantial restructuring and clarification to improve scientific framing, methodological transparency, and global balance. At present, the paper reads more as a capability demonstration of MethaneSAT rather than as a clearly articulated scientific investigation. Several methodological choices—particularly those related to sectoral disaggregation and spatial aggregation of prior inventories—require stronger justification. I therefore recommend major revision before the manuscript can be considered for publication.
Major Comments
- Scientific Framing and Study Objective
The Introduction provides extensive background but does not clearly articulate the central scientific question addressed by this study. It remains unclear whether the primary aim is to demonstrate MethaneSAT capability, quantify basin-scale emissions, reconcile top-down and bottom-up discrepancies, or analyze jurisdiction-level intensity differences. A stronger problem-driven framing would significantly improve coherence.
- Methodological Transparency and Placement
Key elements of the inversion-based emission product are deferred to appendices, while the main text provides only brief descriptions. Given that the study’s conclusions rely fundamentally on MethaneSAT-derived emissions, the main text should more clearly summarize: Core inversion assumptions, Treatment of atmospheric transport and meteorology, Temporal representativeness of aggregated scenes, Structural sources of uncertainty. At present, readers must consult external references or appendices to understand critical methodological aspects.
- Sectoral Disaggregation and Prior Dependence
Sectoral attribution is based on proportional redistribution using composite prior inventories. While pragmatic, this approach implies that sectoral breakdowns are structurally dependent on prior spatial patterns rather than independently resolved from observations. Because sectoral results and methane intensities are central conclusions of the paper, the manuscript should: More explicitly acknowledge this dependence, Clarify the structural uncertainty associated with prior selection and spatial aggregation, Strengthen the justification for prior resolution choices (e.g., 0.4° aggregation outside the U.S.). This point is especially important for interpreting cross-region intensity differences.
- Temporal Representativeness of Aggregated Emissions
The study aggregates 33 MethaneSAT overpasses over approximately one year, yet there is limited discussion of seasonal representativeness or meteorological variability. It is unclear to what extent the aggregated emissions can be interpreted as annual averages. Further clarification is needed to present in this work.
- Global Framing vs. Regional Emphasis
While the manuscript is framed around “major oil and gas basins,” the selected regions represent a limited subset of global production areas and include a strong emphasis on U.S. basins. Given that MethaneSAT is a global observing system, readers may naturally interpret the results as indicative of broader global oil and gas emission patterns.
The authors are encouraged to clarify: the rationale for regional selection, the representativeness of these basins relative to global oil and gas production, whether the conclusions are intended to reflect global variability or only the specific observed regions. If MethaneSAT observations are not yet globally comprehensive, this limitation should be explicitly acknowledged to avoid overgeneralization. Alternatively, moderating the global framing in the Introduction and Conclusions may help align scope with coverage.
- Manuscript Structure and Narrative Coherence
The manuscript would benefit from improved structural balance and clarity of presentation. At present, some core analytical elements are relatively condensed in the main text, while detailed regional descriptions receive substantial space. A clearer emphasis on the primary analytical framework and synthesis of findings in the main body—while streamlining secondary descriptive material—would enhance readability and better highlight the study’s central contributions.
Minor Comments
- Line 79,84,88: the right references should be cited.
- Line 115: “significantgrowth” → missing space.
- Line 146: “upto” should be written as “up to.”
- Line 147: “it’s observing track” should be “its observing track.”
- Line 685: Insert the emission link?
- Inconsistent use of “95% c.i.” vs “95% CI.”
- Hyphenation inconsistencies (e.g., “gas-production normalized” vs “gas-production-normalized”).
- Several web-based references (e.g., IEA website) lack formal citation formatting and access dates consistent with ACP style.
- Ensure unit consistency throughout (t/h, kg CH₄/GJ formatting).
- Some URLs appear directly in text; these should follow ACP referencing guidelines.
Citation: https://doi.org/10.5194/egusphere-2025-6126-RC2
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Thank you for inviting me to review this manuscript, please see my attached PDF for specific comments.