H2 in Antarctic firn air: Atmospheric reconstructions and implications for anthropogenic emissions
The atmospheric history of molecular hydrogen (H2) from 1852 to 2003 was reconstructed from measurements of firn air collected at Megadunes, Antarctica. The reconstruction shows that H2 levels in the southern hemisphere were roughly constant near 330 parts per billion (ppb; nmol H2 mol-1 air) during...
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ftcdlib:oai:escholarship.org:ark:/13030/qt1rc9r56f 2023-09-05T13:13:38+02:00 H2 in Antarctic firn air: Atmospheric reconstructions and implications for anthropogenic emissions Patterson, John D Aydin, Murat Crotwell, Andrew M Pétron, Gabrielle Severinghaus, Jeffrey P Krummel, Paul B Langenfelds, Ray L Saltzman, Eric S e2103335118 2021-09-07 application/pdf https://escholarship.org/uc/item/1rc9r56f unknown eScholarship, University of California qt1rc9r56f https://escholarship.org/uc/item/1rc9r56f public Proceedings of the National Academy of Sciences of the United States of America, vol 118, iss 36 Climate Action Antarctic Regions Anthropogenic Effects Atmosphere Environmental Monitoring Humans Hydrogen Models Theoretical Vehicle Emissions atmospheric hydrogen firn air Antarctica H-2 emissions H2 emissions article 2021 ftcdlib 2023-08-21T18:05:46Z The atmospheric history of molecular hydrogen (H2) from 1852 to 2003 was reconstructed from measurements of firn air collected at Megadunes, Antarctica. The reconstruction shows that H2 levels in the southern hemisphere were roughly constant near 330 parts per billion (ppb; nmol H2 mol-1 air) during the mid to late 1800s. Over the twentieth century, H2 levels rose by about 70% to 550 ppb. The reconstruction shows good agreement with the H2 atmospheric history based on firn air measurements from the South Pole. The broad trends in atmospheric H2 over the twentieth century can be explained by increased methane oxidation and anthropogenic emissions. The H2 rise shows no evidence of deceleration during the last quarter of the twentieth century despite an expected reduction in automotive emissions following more stringent regulations. During the late twentieth century, atmospheric CO levels decreased due to a reduction in automotive emissions. It is surprising that atmospheric H2 did not respond similarly as automotive exhaust is thought to be the dominant source of anthropogenic H2. The monotonic late twentieth century rise in H2 levels is consistent with late twentieth-century flask air measurements from high southern latitudes. An additional unknown source of H2 is needed to explain twentieth-century trends in atmospheric H2 and to resolve the discrepancy between bottom-up and top-down estimates of the anthropogenic source term. The firn air-based atmospheric history of H2 provides a baseline from which to assess human impact on the H2 cycle over the last 150 y and validate models that will be used to project future trends in atmospheric composition as H2 becomes a more common energy source. Article in Journal/Newspaper Antarc* Antarctic Antarctica South pole South pole University of California: eScholarship Antarctic South Pole |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Climate Action Antarctic Regions Anthropogenic Effects Atmosphere Environmental Monitoring Humans Hydrogen Models Theoretical Vehicle Emissions atmospheric hydrogen firn air Antarctica H-2 emissions H2 emissions |
spellingShingle |
Climate Action Antarctic Regions Anthropogenic Effects Atmosphere Environmental Monitoring Humans Hydrogen Models Theoretical Vehicle Emissions atmospheric hydrogen firn air Antarctica H-2 emissions H2 emissions Patterson, John D Aydin, Murat Crotwell, Andrew M Pétron, Gabrielle Severinghaus, Jeffrey P Krummel, Paul B Langenfelds, Ray L Saltzman, Eric S H2 in Antarctic firn air: Atmospheric reconstructions and implications for anthropogenic emissions |
topic_facet |
Climate Action Antarctic Regions Anthropogenic Effects Atmosphere Environmental Monitoring Humans Hydrogen Models Theoretical Vehicle Emissions atmospheric hydrogen firn air Antarctica H-2 emissions H2 emissions |
description |
The atmospheric history of molecular hydrogen (H2) from 1852 to 2003 was reconstructed from measurements of firn air collected at Megadunes, Antarctica. The reconstruction shows that H2 levels in the southern hemisphere were roughly constant near 330 parts per billion (ppb; nmol H2 mol-1 air) during the mid to late 1800s. Over the twentieth century, H2 levels rose by about 70% to 550 ppb. The reconstruction shows good agreement with the H2 atmospheric history based on firn air measurements from the South Pole. The broad trends in atmospheric H2 over the twentieth century can be explained by increased methane oxidation and anthropogenic emissions. The H2 rise shows no evidence of deceleration during the last quarter of the twentieth century despite an expected reduction in automotive emissions following more stringent regulations. During the late twentieth century, atmospheric CO levels decreased due to a reduction in automotive emissions. It is surprising that atmospheric H2 did not respond similarly as automotive exhaust is thought to be the dominant source of anthropogenic H2. The monotonic late twentieth century rise in H2 levels is consistent with late twentieth-century flask air measurements from high southern latitudes. An additional unknown source of H2 is needed to explain twentieth-century trends in atmospheric H2 and to resolve the discrepancy between bottom-up and top-down estimates of the anthropogenic source term. The firn air-based atmospheric history of H2 provides a baseline from which to assess human impact on the H2 cycle over the last 150 y and validate models that will be used to project future trends in atmospheric composition as H2 becomes a more common energy source. |
format |
Article in Journal/Newspaper |
author |
Patterson, John D Aydin, Murat Crotwell, Andrew M Pétron, Gabrielle Severinghaus, Jeffrey P Krummel, Paul B Langenfelds, Ray L Saltzman, Eric S |
author_facet |
Patterson, John D Aydin, Murat Crotwell, Andrew M Pétron, Gabrielle Severinghaus, Jeffrey P Krummel, Paul B Langenfelds, Ray L Saltzman, Eric S |
author_sort |
Patterson, John D |
title |
H2 in Antarctic firn air: Atmospheric reconstructions and implications for anthropogenic emissions |
title_short |
H2 in Antarctic firn air: Atmospheric reconstructions and implications for anthropogenic emissions |
title_full |
H2 in Antarctic firn air: Atmospheric reconstructions and implications for anthropogenic emissions |
title_fullStr |
H2 in Antarctic firn air: Atmospheric reconstructions and implications for anthropogenic emissions |
title_full_unstemmed |
H2 in Antarctic firn air: Atmospheric reconstructions and implications for anthropogenic emissions |
title_sort |
h2 in antarctic firn air: atmospheric reconstructions and implications for anthropogenic emissions |
publisher |
eScholarship, University of California |
publishDate |
2021 |
url |
https://escholarship.org/uc/item/1rc9r56f |
op_coverage |
e2103335118 |
geographic |
Antarctic South Pole |
geographic_facet |
Antarctic South Pole |
genre |
Antarc* Antarctic Antarctica South pole South pole |
genre_facet |
Antarc* Antarctic Antarctica South pole South pole |
op_source |
Proceedings of the National Academy of Sciences of the United States of America, vol 118, iss 36 |
op_relation |
qt1rc9r56f https://escholarship.org/uc/item/1rc9r56f |
op_rights |
public |
_version_ |
1776204839257112576 |