Preindustrial 14CH4 indicates greater anthropogenic fossil CH4 emissions

  title={Preindustrial 14CH4 indicates greater anthropogenic fossil CH4 emissions},
  author={Benjamin Hmiel and Vasilii V Petrenko and Michael Dyonisius and Christo Buizert and A. M. Smith and Philip F. Place and Christina M. Harth and Ross Beaudette and Quan Hua and B. Yang and Isaac Vimont and Sylvia E. Michel and Jeffrey P. Severinghaus and David M. Etheridge and Tony Bromley and Jochen Schmitt and Xavier Fa{\"i}n and Ray F. Weiss and Edward J. Dlugokencky},
  pages={409 - 412}
Atmospheric methane (CH4) is a potent greenhouse gas, and its mole fraction has more than doubled since the preindustrial era1. Fossil fuel extraction and use are among the largest anthropogenic sources of CH4 emissions, but the precise magnitude of these contributions is a subject of debate2,3. Carbon-14 in CH4 (14CH4) can be used to distinguish between fossil (14C-free) CH4 emissions and contemporaneous biogenic sources; however, poorly constrained direct 14CH4 emissions from nuclear reactors… 
Relevant methane emission to the atmosphere from a geological gas manifestation.
Significant geological CH4 emissions from the Lusi hydrothermal system (Indonesia) are reported, measured by ground-based and satellite (TROPOMI) techniques, equivalent to the minimum value of global geo-emission derived by ice core 14CH4 estimates.
Anthropogenic emission is the main contributor to the rise of atmospheric methane during 1993–2017
Abstract Atmospheric methane (CH4) concentrations have shown a puzzling resumption in growth since 2007 following a period of stabilization from 2000 to 2006. Multiple hypotheses have been proposed
Influence of permafrost thaw on an extreme geologic methane seep
The occurrence and magnitude of natural fossil methane (CH4) emissions in the Arctic are poorly known. Emission of geologic CH4, a potent greenhouse gas, originating beneath permafrost is of
Investigating methane emissions from geologic microseepage in Western New York State, United States
Methane is a powerful greenhouse gas and a key player in atmospheric chemistry. Important uncertainties remain in the global atmospheric methane budget, with natural geologic emissions being one of
Widespread natural methane and oil leakage from sub-marine Arctic reservoirs
Parceling the anthropogenic and natural (geological) sources of fossil methane in the atmosphere remains problematic due to a lack of distinctive chemical markers for their discrimination. In this
Conflicting estimates of natural geologic methane emissions
Global bottom-up and top-down estimates of natural, geologic methane (CH4) emissions (average approximately 45 Tg yr–1) have recently been questioned by near-zero (approximately 1.6 Tg yr–1)
The Global Methane Budget 2000–2017
Abstract. Understanding and quantifying the global methane (CH4) budget is important for assessing realistic pathways to mitigate climate change. Atmospheric emissions and concentrations of CH4
Radiocarbon in Marine Methane Reveals Patchy Impact of Seeps on Surface Waters
Geological sources of methane (CH4), such as hydrocarbon seeps, are significant yet poorly constrained sources of CH4 to seawater and the overlying atmosphere. We investigate the radiocarbon content
Atmospheric methane and nitrous oxide: challenges alongthe path to Net Zero
Reductions in methane and nitrous oxide emission are arguably among the most attractive immediate options for climate action, both in cutting emissions from gas, oil and coal extraction and use, and also from agricultural and waste sources.
What do we know about the global methane budget? Results from four decades of atmospheric CH4 observations and the way forward
An overview of the state of knowledge of the dynamic atmospheric CH4 budget of sources and sinks determined from measurements of CH4 and δ13CCH4 in air samples collected predominantly at background air sampling sites is provided.


Minimal geological methane emissions during the Younger Dryas–Preboreal abrupt warming event
To the extent that the characteristics of the most recent deglaciation and the Younger Dryas–Preboreal warming are comparable to those of the current anthropogenic warming, the measurements suggest that large future atmospheric releases of methane from old carbon sources are unlikely to occur.
Centennial evolution of the atmospheric methane budget: what do the carbon isotopes tell us?
Little is known about how the methane source inventory and sinks have evolved over recent centuries. New and detailed records of methane mixing ratio and isotopic composition ( 12 CH 4 , 13 CH 4 and
Global and Regional Emissions of Radiocarbon from Nuclear Power Plants from 1972 to 2016
ABSTRACT CH4 and CO2 emissions from geologic sources, which are devoid of radiocarbon (14C), dilute the atmospheric 14C/C ratio. Observations of 14C/C can be used to estimate fossil fuel-derived CH4
14CH4 Measurements in Greenland Ice: Investigating Last Glacial Termination CH4 Sources
Measurements of 14CH4 in glacial ice, targeting this transition, performed by using ice samples obtained from an ablation site in west Greenland suggest that wetland sources were likely responsible for the majority of the Younger Dryas–Preboreal CH4 rise.
Gridded maps of geological methane emissions and their isotopic signature
Abstract. Methane (CH4) is a powerful greenhouse gas, whose natural and anthropogenic emissions contribute ∼20 % to global radiative forcing. Its atmospheric budget (sources and sinks), however, has
The atmospheric cycling of radiomethane and the "fossil fraction" of the methane source
The cycling of 14 CH4 ("radiomethane") through the atmosphere has been strongly perturbed in the industrial era by the release of 14 C-free methane from geologic reser- voirs ("fossil methane"
Preindustrial atmospheric ethane levels inferred from polar ice cores: A constraint on the geologic sources of atmospheric ethane and methane
Ethane levels were measured in air extracted from Greenland and Antarctic ice cores ranging in age from 994 to 1918 Common Era (C.E.) There is good temporal overlap between the two data sets from
The global methane budget 2000–2012
Abstract. Understanding and quantifying the global methane (CH4) budget is important for assessing realistic pathways to mitigate climate change. Atmospheric emissions and concentrations of CH4