Preindustrial 14CH4 indicates greater anthropogenic fossil CH4 emissions
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. Car...
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ftcdlib:oai:escholarship.org:ark:/13030/qt77682176 2023-09-26T15:18:49+02:00 Preindustrial 14CH4 indicates greater anthropogenic fossil CH4 emissions Hmiel, Benjamin Petrenko, VV Dyonisius, MN Buizert, C Smith, AM Place, PF Harth, C Beaudette, R Hua, Q Yang, B Vimont, I Michel, SE Severinghaus, JP Etheridge, D Bromley, T Schmitt, J Faïn, X Weiss, RF Dlugokencky, E 409 - 412 2020-02-20 application/pdf https://escholarship.org/uc/item/77682176 unknown eScholarship, University of California qt77682176 https://escholarship.org/uc/item/77682176 public Nature, vol 578, iss 7795 Climate Action Atmosphere Biomass Carbon Radioisotopes Coal Fossil Fuels Global Warming History 18th Century 19th Century 20th Century 21st Century Human Activities Ice Cover Methane Natural Gas Petroleum General Science & Technology article 2020 ftcdlib 2023-08-28T18:03:07Z 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 have complicated this approach since the middle of the 20th century4,5. Moreover, the partitioning of total fossil CH4 emissions (presently 172 to 195 teragrams CH4 per year)2,3 between anthropogenic and natural geological sources (such as seeps and mud volcanoes) is under debate; emission inventories suggest that the latter account for about 40 to 60 teragrams CH4 per year6,7. Geological emissions were less than 15.4 teragrams CH4 per year at the end of the Pleistocene, about 11,600 years ago8, but that period is an imperfect analogue for present-day emissions owing to the large terrestrial ice sheet cover, lower sea level and extensive permafrost. Here we use preindustrial-era ice core 14CH4 measurements to show that natural geological CH4 emissions to the atmosphere were about 1.6 teragrams CH4 per year, with a maximum of 5.4 teragrams CH4 per year (95 per cent confidence limit)-an order of magnitude lower than the currently used estimates. This result indicates that anthropogenic fossil CH4 emissions are underestimated by about 38 to 58 teragrams CH4 per year, or about 25 to 40 per cent of recent estimates. Our record highlights the human impact on the atmosphere and climate, provides a firm target for inventories of the global CH4 budget, and will help to inform strategies for targeted emission reductions9,10. Article in Journal/Newspaper Ice ice core Ice Sheet permafrost University of California: eScholarship |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Climate Action Atmosphere Biomass Carbon Radioisotopes Coal Fossil Fuels Global Warming History 18th Century 19th Century 20th Century 21st Century Human Activities Ice Cover Methane Natural Gas Petroleum General Science & Technology |
spellingShingle |
Climate Action Atmosphere Biomass Carbon Radioisotopes Coal Fossil Fuels Global Warming History 18th Century 19th Century 20th Century 21st Century Human Activities Ice Cover Methane Natural Gas Petroleum General Science & Technology Hmiel, Benjamin Petrenko, VV Dyonisius, MN Buizert, C Smith, AM Place, PF Harth, C Beaudette, R Hua, Q Yang, B Vimont, I Michel, SE Severinghaus, JP Etheridge, D Bromley, T Schmitt, J Faïn, X Weiss, RF Dlugokencky, E Preindustrial 14CH4 indicates greater anthropogenic fossil CH4 emissions |
topic_facet |
Climate Action Atmosphere Biomass Carbon Radioisotopes Coal Fossil Fuels Global Warming History 18th Century 19th Century 20th Century 21st Century Human Activities Ice Cover Methane Natural Gas Petroleum General Science & Technology |
description |
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 have complicated this approach since the middle of the 20th century4,5. Moreover, the partitioning of total fossil CH4 emissions (presently 172 to 195 teragrams CH4 per year)2,3 between anthropogenic and natural geological sources (such as seeps and mud volcanoes) is under debate; emission inventories suggest that the latter account for about 40 to 60 teragrams CH4 per year6,7. Geological emissions were less than 15.4 teragrams CH4 per year at the end of the Pleistocene, about 11,600 years ago8, but that period is an imperfect analogue for present-day emissions owing to the large terrestrial ice sheet cover, lower sea level and extensive permafrost. Here we use preindustrial-era ice core 14CH4 measurements to show that natural geological CH4 emissions to the atmosphere were about 1.6 teragrams CH4 per year, with a maximum of 5.4 teragrams CH4 per year (95 per cent confidence limit)-an order of magnitude lower than the currently used estimates. This result indicates that anthropogenic fossil CH4 emissions are underestimated by about 38 to 58 teragrams CH4 per year, or about 25 to 40 per cent of recent estimates. Our record highlights the human impact on the atmosphere and climate, provides a firm target for inventories of the global CH4 budget, and will help to inform strategies for targeted emission reductions9,10. |
format |
Article in Journal/Newspaper |
author |
Hmiel, Benjamin Petrenko, VV Dyonisius, MN Buizert, C Smith, AM Place, PF Harth, C Beaudette, R Hua, Q Yang, B Vimont, I Michel, SE Severinghaus, JP Etheridge, D Bromley, T Schmitt, J Faïn, X Weiss, RF Dlugokencky, E |
author_facet |
Hmiel, Benjamin Petrenko, VV Dyonisius, MN Buizert, C Smith, AM Place, PF Harth, C Beaudette, R Hua, Q Yang, B Vimont, I Michel, SE Severinghaus, JP Etheridge, D Bromley, T Schmitt, J Faïn, X Weiss, RF Dlugokencky, E |
author_sort |
Hmiel, Benjamin |
title |
Preindustrial 14CH4 indicates greater anthropogenic fossil CH4 emissions |
title_short |
Preindustrial 14CH4 indicates greater anthropogenic fossil CH4 emissions |
title_full |
Preindustrial 14CH4 indicates greater anthropogenic fossil CH4 emissions |
title_fullStr |
Preindustrial 14CH4 indicates greater anthropogenic fossil CH4 emissions |
title_full_unstemmed |
Preindustrial 14CH4 indicates greater anthropogenic fossil CH4 emissions |
title_sort |
preindustrial 14ch4 indicates greater anthropogenic fossil ch4 emissions |
publisher |
eScholarship, University of California |
publishDate |
2020 |
url |
https://escholarship.org/uc/item/77682176 |
op_coverage |
409 - 412 |
genre |
Ice ice core Ice Sheet permafrost |
genre_facet |
Ice ice core Ice Sheet permafrost |
op_source |
Nature, vol 578, iss 7795 |
op_relation |
qt77682176 https://escholarship.org/uc/item/77682176 |
op_rights |
public |
_version_ |
1778141440824573952 |