Comprehensive View of Scientific Studies on Methane Emissions
from U.S. Oil and Gas Operations

A wave of science over the last seven years reports that methane emissions from the U.S. oil and gas system are far higher than the official U.S. government counts, all the way from wellheads to stove tops, gas-fired power plants, and LNG export terminals. In addition, the literature shows that methane emissions from the national oil and gas system are growing.

The literature reports that methane emissions from the oil and gas sector are at least twice the level stated by EPA and, in turn, twice the level reported by the U.S. government to the UNFCCC under the terms of the Paris Climate Agreement.
 

The largest, most robust (and most recent) study finds methane emissions from the U.S. oil and gas system are roughly three times the official U.S. government estimate (Sherwin et al. 2024). The data also established an average leak rate of 2.95%, above the generally accepted leak rate of 2.7% that makes gas-fired power worse than coal-fired power (Hamburg 2013)

Because methane washes out of the atmosphere fairly quickly, modern era levels of atmospheric methane (1,900 ppb, compared to the pre-industrial level of ~700 ppb) are maintained only by massive ongoing anthropogenic emissions - to which the global oil and gas system is firmly established as a major contributor.

The tracker currently highlights over 100 studies published over the last seven years as well as several older studies that provide important context or findings. Of particular note, Sherwin et al. 2024, Zhang et al 2020., Negron et al. 2023, Chen et al. 2022, Ayassee et al. 2022, Yu et al. 2022, Ren et al. 2018, and Weller et al 2020. provide extensive evidence that total emissions from the U.S. oil and gas system are not only significantly higher official U.S, estimate but are also significantly higher than estimated in older literature (e.g. as estimated by Alvarez et al. 2018 - which found emissions are about 60% higher than EPA estimates).

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The EPA has not updated the official U.S. estimate of methane emissions, failing to account for the science going back to Alvarez et al. 2018 and even further. Instead, the EPA under the Trump Administration lowered its estimates of methane emissions from the oil and gas sector. To date, the EPA under the Biden Administration has maintained these lower estimates.

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The recent surge in global atmospheric methane over the past decade (+125 ppb) extends and is built upon the modern era level of atmospheric methane - a baseline level which, per above, is maintained in good part by the global oil and gas system. Most studies report that the U.S. oil and gas system is also a contributor to this unexpected global surge in atmospheric methane. An authoritative assessment of the literature published in 2020 reports that methane emissions from the U.S. oil and gas operations are among the contributors to the recent surge (Jackson et al. 2020 and Saunois et al 2020) as does the IPCC WGI report published in August of 2021.

However, estimates of the size of this contribution, from across the literature, fall across a wide range, with some studies indicating that U.S. oil/gas production is one of the primary drivers of the global surge, while others, particularly several more recent studies, find that global oil/gas production is only a minor contributing factor (e.g. Oh et al. 2022, Feng et al. 2022a, and Basu et al. 2022). Regardless of the size of its contribution to the recent surge, the global oil and gas sector, including U.S. oil and gas operations, is established as a major ongoing contributor to the modern-era level of methane which props up the surge.

A related issue is the scale of any methane emissions driven by climate feedback loops such as increased rainfall and/or rising temperatures.  Studies on these “induced” emissions have been published indicating there may be an ongoing feedback loop.  However, the uncertainty about these findings is extremely large - as highlighted by authors. There are conflicting studies.  And the scale of the increase appears small relative to the size of industrial emissions - for now.

For more information, contact: Hunter Cutting, hcutting@climatenexus.org