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Methane emissions from fossil fuel exploitation (oil, gas, coal) are a significant target for climate policy, but current national emission inventories submitted to the United Nations Framework Convention on Climate Change (UNFCCC) have high levels of uncertainty. To address this, researchers utilized satellite observations from the TROPOMI instrument over a period of 22 months to better estimate national emissions worldwide.

The study found that global emissions from oil and gas were 62.7 ± 11.5 Tg a−1, and emissions from coal were 32.7 ± 5.2 Tg a−1. These oil and gas emissions were 30% higher than the global total reported by the UNFCCC due to under-reporting from major emitters such as the US, Russia, Venezuela, and Turkmenistan. Additionally, eight countries had methane emission intensities from the oil and gas sector exceeding 5% of their gas production, with Venezuela, Iraq, and Angola reaching 20%. Lowering these intensities to the global average level of 2.4% could reduce global oil and gas emissions by 11 Tg a−1 or 18%.

Methane is the second most important greenhouse gas after CO2 and contributes to global warming. The Paris Agreement requires countries to set goals for reducing methane emissions, and the Global Methane Pledge aims to decrease collective methane emissions by 30% by 2030. Fossil fuel exploitation accounts for a significant portion of anthropogenic methane emissions and has the potential to be cost-effective to control.

Current national inventories of methane emissions are typically uncertain, making it challenging to set and track mitigation goals. The study utilized a top-down approach, combining satellite observations with bottom-up inventories, to provide more accurate estimates of emissions. Previous top-down studies used sparse data from surface sites, aircraft, and satellites like GOSAT. However, the TROPOMI satellite launched in 2017 provides higher global data density with daily mapping of methane columns.

The researchers conducted regional inversions of TROPOMI data and used the GEOS-Chem model for atmospheric transport simulation to quantify emissions from fossil fuel exploitation. By comparing the results with field measurements and employing different bottom-up inventories, satellite data densities, and inversion parameters, the study improved inventory estimates and demonstrated the potential of TROPOMI to assist national bottom-up estimates.

In conclusion, this study highlights the discrepancy between reported methane emissions from oil and gas and the actual global emissions, as well as the potential for reducing these emissions by lowering emission intensities. The utilization of satellite observations and inversion methods can provide more accurate estimates for national inventories and aid in tracking progress towards mitigation goals.

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