Lessons Ascertained from the U.S. Shale Revolution: Abating Fugitive CH4 Releases from Unconventional Shale Gas Extraction

Krokus, Alexander1,2

1Ethical Environmental Policy Consortium, Portland, United States, 2Mark O. Hatfield School of Government, Portland State University, Portland, United States

The δ13C signal of CH4 associated with unconventional shale gas has been observed as lighter than the signal produced by conventional gas (Golding et al., 2013; Hao and Zou 2013; Turner et al. 2017; Botner et al. 2018; Howarth 2019).  Originating in 2009, the isotopic composition of CH4 in our atmosphere has become depleted and lighter, containing less 13C and more negative δ13C (Schaefer et al. 2016; Nisbet et al. 2016), a physical trait exhibited by gas trapped in unconventional tight formations possessing low permeability, that has not been exposed to oxidation.

The considerable upsurge in CH4 fluxes experienced globally since 2005 has been attributed to the commercialization of shale gas in North America (90% of it occurring in U.S. and 10% in Canada), rather than by biogenic sources (Hausmann et al. 2016; Turner et al. 2016; Rice et al. 2016; Howarth 2019).  NOAA observed an increase of 3.27ppm of CH4 globally from 2000-2006 (0.46 ppm per year), and an increase of 85.76 ppm during 2007-2018, averaging 7.15 ppm per year (NOAA 2020).  During 2006, the U.S. extracted 3 bcf of unconventional shale gas per day.  In December 2018 that amount rose to 65 bcf per day (US EIA 2019a).  Moderate estimates of increases of CH4 leakage ensuing the U.S. shale gas revolution during 2008-2014 are predicted to be 9.4 Tg per year (Alvarez et al. 2018; Howarth 2019).  CH4 possesses a GWP of 84-87 x CO2 over 20 years (US EPA 2020), and diminishing fugitive CH4 leakage from shale gas operations is an advantageous method for restricting extreme weather events (Shindell et al. 2012).

Currie et al. 2017 has demonstrated that infants born within 1km of an active HF well site will experience a 25% increase in the probability of low birth weight, and additional detrimental consequences arise when infant births occur within 3km.  Increases in childhood hematologic cancer incidences (Elliott et al. 2017; McKenzie et al. 2017), and infants born with congenital heart defects have also been observed in close proximity to HF activities (McKenzie et al. 2019).  Apergis et al. 2019 performed an empirical analysis of births occurring in all of OK’s 76 counties, beginning with the inception of the U.S. shale revolution in 2006, up until 2017.  Substantial birth complications (low birth weight and premature births) were only observed when infants were born within 5km of an UOG well site, with more severe effects transpiring within 1km.  Their regression analysis (births from 1996-2005) did not display any statistical impact on infant health prior to the inception of the U.S. shale revolution in 2006. 

Mandating the implementation of quantitative methods for CH4 leak detection when an active HF well site is within 5km of a human population, would diminish adverse effects associated with infant mortality, increase worker safety, and provide energy security by capturing CH4.  Optical gas imaging can be achieved from a far distance, ensuring the safety of the operator, and can be utilized in natural gas processing plants, power generation plants, and also offshore platforms.


Alexander served in the Oregon State Legislature as an Environmental & Economic Policy Aide for Senator Lew Frederick.  He is now a Senior Policy Advisor for the Ethical Environmental Policy Consortium, and has been successfully collaborating with federal legislators in the U.S. House of Representatives to enact bipartisan energy policy. 

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