Ocean methane hydrates as a slow tipping point in the global carbon cycle
We present a model of the global methane inventory as hydrate and bubbles below the sea floor. The model predicts the inventory of CH4 in the ocean today to be ≈1600–2,000 Pg of C. Most of the hydrate in the model is in the Pacific, in large part because lower oxygen levels enhance the preservation...
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ftpubmed:oai:pubmedcentral.nih.gov:2584575 2023-05-15T13:35:32+02:00 Ocean methane hydrates as a slow tipping point in the global carbon cycle Archer, David Buffett, Bruce Brovkin, Victor 2009-12-08 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2584575 http://www.ncbi.nlm.nih.gov/pubmed/19017807 https://doi.org/10.1073/pnas.0800885105 en eng National Academy of Sciences http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2584575 http://www.ncbi.nlm.nih.gov/pubmed/19017807 http://dx.doi.org/10.1073/pnas.0800885105 © 2009 by The National Academy of Sciences of the USA Tipping Elements in Earth Systems Special Feature Text 2009 ftpubmed https://doi.org/10.1073/pnas.0800885105 2013-09-02T07:52:34Z We present a model of the global methane inventory as hydrate and bubbles below the sea floor. The model predicts the inventory of CH4 in the ocean today to be ≈1600–2,000 Pg of C. Most of the hydrate in the model is in the Pacific, in large part because lower oxygen levels enhance the preservation of organic carbon. Because the oxygen concentration today may be different from the long-term average, the sensitivity of the model to O2 is a source of uncertainty in predicting hydrate inventories. Cold water column temperatures in the high latitudes lead to buildup of hydrates in the Arctic and Antarctic at shallower depths than is possible in low latitudes. A critical bubble volume fraction threshold has been proposed as a critical threshold at which gas migrates all through the sediment column. Our model lacks many factors that lead to heterogeneity in the real hydrate reservoir in the ocean, such as preferential hydrate formation in sandy sediments and subsurface gas migration, and is therefore conservative in its prediction of releasable methane, finding only 35 Pg of C released after 3 °C of uniform warming by using a 10% critical bubble volume. If 2.5% bubble volume is taken as critical, then 940 Pg of C might escape in response to 3 °C warming. This hydrate model embedded into a global climate model predicts ≈0.4–0.5 °C additional warming from the hydrate response to fossil fuel CO2 release, initially because of methane, but persisting through the 10-kyr duration of the simulations because of the CO2 oxidation product of methane. Text Antarc* Antarctic Arctic PubMed Central (PMC) Antarctic Arctic Pacific Proceedings of the National Academy of Sciences 106 49 20596 20601 |
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English |
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Tipping Elements in Earth Systems Special Feature |
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Tipping Elements in Earth Systems Special Feature Archer, David Buffett, Bruce Brovkin, Victor Ocean methane hydrates as a slow tipping point in the global carbon cycle |
topic_facet |
Tipping Elements in Earth Systems Special Feature |
description |
We present a model of the global methane inventory as hydrate and bubbles below the sea floor. The model predicts the inventory of CH4 in the ocean today to be ≈1600–2,000 Pg of C. Most of the hydrate in the model is in the Pacific, in large part because lower oxygen levels enhance the preservation of organic carbon. Because the oxygen concentration today may be different from the long-term average, the sensitivity of the model to O2 is a source of uncertainty in predicting hydrate inventories. Cold water column temperatures in the high latitudes lead to buildup of hydrates in the Arctic and Antarctic at shallower depths than is possible in low latitudes. A critical bubble volume fraction threshold has been proposed as a critical threshold at which gas migrates all through the sediment column. Our model lacks many factors that lead to heterogeneity in the real hydrate reservoir in the ocean, such as preferential hydrate formation in sandy sediments and subsurface gas migration, and is therefore conservative in its prediction of releasable methane, finding only 35 Pg of C released after 3 °C of uniform warming by using a 10% critical bubble volume. If 2.5% bubble volume is taken as critical, then 940 Pg of C might escape in response to 3 °C warming. This hydrate model embedded into a global climate model predicts ≈0.4–0.5 °C additional warming from the hydrate response to fossil fuel CO2 release, initially because of methane, but persisting through the 10-kyr duration of the simulations because of the CO2 oxidation product of methane. |
format |
Text |
author |
Archer, David Buffett, Bruce Brovkin, Victor |
author_facet |
Archer, David Buffett, Bruce Brovkin, Victor |
author_sort |
Archer, David |
title |
Ocean methane hydrates as a slow tipping point in the global carbon cycle |
title_short |
Ocean methane hydrates as a slow tipping point in the global carbon cycle |
title_full |
Ocean methane hydrates as a slow tipping point in the global carbon cycle |
title_fullStr |
Ocean methane hydrates as a slow tipping point in the global carbon cycle |
title_full_unstemmed |
Ocean methane hydrates as a slow tipping point in the global carbon cycle |
title_sort |
ocean methane hydrates as a slow tipping point in the global carbon cycle |
publisher |
National Academy of Sciences |
publishDate |
2009 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2584575 http://www.ncbi.nlm.nih.gov/pubmed/19017807 https://doi.org/10.1073/pnas.0800885105 |
geographic |
Antarctic Arctic Pacific |
geographic_facet |
Antarctic Arctic Pacific |
genre |
Antarc* Antarctic Arctic |
genre_facet |
Antarc* Antarctic Arctic |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2584575 http://www.ncbi.nlm.nih.gov/pubmed/19017807 http://dx.doi.org/10.1073/pnas.0800885105 |
op_rights |
© 2009 by The National Academy of Sciences of the USA |
op_doi |
https://doi.org/10.1073/pnas.0800885105 |
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Proceedings of the National Academy of Sciences |
container_volume |
106 |
container_issue |
49 |
container_start_page |
20596 |
op_container_end_page |
20601 |
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1766066799776890880 |