Glacial/interglacial wetland, biomass burning, and geologic methane emissions constrained by dual stable isotopic CH₄ ice core records
Atmospheric methane (CH₄) records reconstructed from polar ice cores represent an integrated view on processes predominantly taking place in the terrestrial biogeosphere. Here, we present dual stable isotopic methane records [δ13CH₄ and δD(CH₄)] from four Antarctic ice cores, which provide improved...
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ftunivbern:oai:boris.unibe.ch:106529 2023-08-20T04:01:06+02:00 Glacial/interglacial wetland, biomass burning, and geologic methane emissions constrained by dual stable isotopic CH₄ ice core records Bock, Michael Schmitt, Jochen Beck, Jonas Seth, Barbara Chappellaz, Jérôme Fischer, Hubertus 2017 application/pdf https://boris.unibe.ch/106529/1/bock17pnas.pdf https://boris.unibe.ch/106529/ eng eng National Academy of Sciences NAS https://boris.unibe.ch/106529/ info:eu-repo/semantics/restrictedAccess Bock, Michael; Schmitt, Jochen; Beck, Jonas; Seth, Barbara; Chappellaz, Jérôme; Fischer, Hubertus (2017). Glacial/interglacial wetland, biomass burning, and geologic methane emissions constrained by dual stable isotopic CH₄ ice core records. Proceedings of the National Academy of Sciences of the United States of America - PNAS, 114(29), E5778-E5786. National Academy of Sciences NAS 10.1073/pnas.1613883114 <http://dx.doi.org/10.1073/pnas.1613883114> 530 Physics info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion PeerReviewed 2017 ftunivbern https://doi.org/10.1073/pnas.1613883114 2023-07-31T21:38:24Z Atmospheric methane (CH₄) records reconstructed from polar ice cores represent an integrated view on processes predominantly taking place in the terrestrial biogeosphere. Here, we present dual stable isotopic methane records [δ13CH₄ and δD(CH₄)] from four Antarctic ice cores, which provide improved constraints on past changes in natural methane sources. Our isotope data show that tropical wetlands and seasonally inundated floodplains are most likely the controlling sources of atmospheric methane variations for the current and two older interglacials and their preceding glacial maxima. The changes in these sources are steered by variations in temperature, precipitation, and the water table as modulated by insolation, (local) sea level, and monsoon intensity. Based on our δD(CH₄) constraint, it seems that geologic emissions of methane may play a steady but only minor role in atmospheric CH₄ changes and that the glacial budget is not dominated by these sources. Superimposed on the glacial/interglacial variations is a marked difference in both isotope records, with systematically higher values during the last 25,000 y compared with older time periods. This shift cannot be explained by climatic changes. Rather, our isotopic methane budget points to a marked increase in fire activity, possibly caused by biome changes and accumulation of fuel related to the late Pleistocene megafauna extinction, which took place in the course of the last glacial. Article in Journal/Newspaper Antarc* Antarctic ice core BORIS (Bern Open Repository and Information System, University of Bern) Antarctic Proceedings of the National Academy of Sciences 114 29 E5778 E5786 |
institution |
Open Polar |
collection |
BORIS (Bern Open Repository and Information System, University of Bern) |
op_collection_id |
ftunivbern |
language |
English |
topic |
530 Physics |
spellingShingle |
530 Physics Bock, Michael Schmitt, Jochen Beck, Jonas Seth, Barbara Chappellaz, Jérôme Fischer, Hubertus Glacial/interglacial wetland, biomass burning, and geologic methane emissions constrained by dual stable isotopic CH₄ ice core records |
topic_facet |
530 Physics |
description |
Atmospheric methane (CH₄) records reconstructed from polar ice cores represent an integrated view on processes predominantly taking place in the terrestrial biogeosphere. Here, we present dual stable isotopic methane records [δ13CH₄ and δD(CH₄)] from four Antarctic ice cores, which provide improved constraints on past changes in natural methane sources. Our isotope data show that tropical wetlands and seasonally inundated floodplains are most likely the controlling sources of atmospheric methane variations for the current and two older interglacials and their preceding glacial maxima. The changes in these sources are steered by variations in temperature, precipitation, and the water table as modulated by insolation, (local) sea level, and monsoon intensity. Based on our δD(CH₄) constraint, it seems that geologic emissions of methane may play a steady but only minor role in atmospheric CH₄ changes and that the glacial budget is not dominated by these sources. Superimposed on the glacial/interglacial variations is a marked difference in both isotope records, with systematically higher values during the last 25,000 y compared with older time periods. This shift cannot be explained by climatic changes. Rather, our isotopic methane budget points to a marked increase in fire activity, possibly caused by biome changes and accumulation of fuel related to the late Pleistocene megafauna extinction, which took place in the course of the last glacial. |
format |
Article in Journal/Newspaper |
author |
Bock, Michael Schmitt, Jochen Beck, Jonas Seth, Barbara Chappellaz, Jérôme Fischer, Hubertus |
author_facet |
Bock, Michael Schmitt, Jochen Beck, Jonas Seth, Barbara Chappellaz, Jérôme Fischer, Hubertus |
author_sort |
Bock, Michael |
title |
Glacial/interglacial wetland, biomass burning, and geologic methane emissions constrained by dual stable isotopic CH₄ ice core records |
title_short |
Glacial/interglacial wetland, biomass burning, and geologic methane emissions constrained by dual stable isotopic CH₄ ice core records |
title_full |
Glacial/interglacial wetland, biomass burning, and geologic methane emissions constrained by dual stable isotopic CH₄ ice core records |
title_fullStr |
Glacial/interglacial wetland, biomass burning, and geologic methane emissions constrained by dual stable isotopic CH₄ ice core records |
title_full_unstemmed |
Glacial/interglacial wetland, biomass burning, and geologic methane emissions constrained by dual stable isotopic CH₄ ice core records |
title_sort |
glacial/interglacial wetland, biomass burning, and geologic methane emissions constrained by dual stable isotopic ch₄ ice core records |
publisher |
National Academy of Sciences NAS |
publishDate |
2017 |
url |
https://boris.unibe.ch/106529/1/bock17pnas.pdf https://boris.unibe.ch/106529/ |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic ice core |
genre_facet |
Antarc* Antarctic ice core |
op_source |
Bock, Michael; Schmitt, Jochen; Beck, Jonas; Seth, Barbara; Chappellaz, Jérôme; Fischer, Hubertus (2017). Glacial/interglacial wetland, biomass burning, and geologic methane emissions constrained by dual stable isotopic CH₄ ice core records. Proceedings of the National Academy of Sciences of the United States of America - PNAS, 114(29), E5778-E5786. National Academy of Sciences NAS 10.1073/pnas.1613883114 <http://dx.doi.org/10.1073/pnas.1613883114> |
op_relation |
https://boris.unibe.ch/106529/ |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1073/pnas.1613883114 |
container_title |
Proceedings of the National Academy of Sciences |
container_volume |
114 |
container_issue |
29 |
container_start_page |
E5778 |
op_container_end_page |
E5786 |
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1774722707268567040 |