Centennial-scale changes in the global carbon cycle during the last deglaciation
Global climate and the concentration of atmospheric carbon dioxide (CO2) are correlated over recent glacial cycles. The combination of processes responsible for a rise in atmospheric CO2 at the last glacial termination (23,000 to 9,000years ago), however, remains uncertain. Establishing the timing a...
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ftcdlib:oai:escholarship.org:ark:/13030/qt1c62p1k7 2023-10-01T03:51:55+02:00 Centennial-scale changes in the global carbon cycle during the last deglaciation Marcott, Shaun A Bauska, Thomas K Buizert, Christo Steig, Eric J Rosen, Julia L Cuffey, Kurt M Fudge, TJ Severinghaus, Jeffery P Ahn, Jinho Kalk, Michael L McConnell, Joseph R Sowers, Todd Taylor, Kendrick C White, James WC Brook, Edward J 616 - 619 2014-10-30 application/pdf https://escholarship.org/uc/item/1c62p1k7 unknown eScholarship, University of California qt1c62p1k7 https://escholarship.org/uc/item/1c62p1k7 public Nature, vol 514, iss 7524 Climate Action Antarctic Regions Atmosphere Carbon Cycle Carbon Dioxide Greenhouse Effect Greenland History Ancient Ice Cover Isotopes Methane Oceans and Seas Water General Science & Technology article 2014 ftcdlib 2023-09-04T18:02:54Z Global climate and the concentration of atmospheric carbon dioxide (CO2) are correlated over recent glacial cycles. The combination of processes responsible for a rise in atmospheric CO2 at the last glacial termination (23,000 to 9,000years ago), however, remains uncertain. Establishing the timing and rate of CO2 changes in the past provides critical insight into the mechanisms that influence the carbon cycle and helps put present and future anthropogenic emissions in context. Here we present CO2 and methane (CH4) records of the last deglaciation from a new high-accumulation West Antarctic ice core with unprecedented temporal resolution and precise chronology. We show that although low-frequency CO2 variations parallel changes in Antarctic temperature, abrupt CO2 changes occur that have a clear relationship with abrupt climate changes in the Northern Hemisphere. A significant proportion of the direct radiative forcing associated with the rise in atmospheric CO2 occurred in three sudden steps, each of 10 to 15 parts per million. Every step took place in less than two centuries and was followed by no notable change in atmospheric CO2 for about 1,000 to 1,500years. Slow, millennial-scale ventilation of Southern Ocean CO2-rich, deep-ocean water masses is thought to have been fundamental to the rise in atmospheric CO2 associated with the glacial termination, given the strong covariance of CO2 levels and Antarctic temperatures. Our data establish a contribution from an abrupt, centennial-scale mode of CO2 variability that is not directly related to Antarctic temperature. We suggest that processes operating on centennial timescales, probably involving the Atlantic meridional overturning circulation, seem to be influencing global carbon-cycle dynamics and are at present not widely considered in Earth system models. Article in Journal/Newspaper Antarc* Antarctic Greenland ice core Southern Ocean University of California: eScholarship Antarctic Southern Ocean Greenland |
institution |
Open Polar |
collection |
University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Climate Action Antarctic Regions Atmosphere Carbon Cycle Carbon Dioxide Greenhouse Effect Greenland History Ancient Ice Cover Isotopes Methane Oceans and Seas Water General Science & Technology |
spellingShingle |
Climate Action Antarctic Regions Atmosphere Carbon Cycle Carbon Dioxide Greenhouse Effect Greenland History Ancient Ice Cover Isotopes Methane Oceans and Seas Water General Science & Technology Marcott, Shaun A Bauska, Thomas K Buizert, Christo Steig, Eric J Rosen, Julia L Cuffey, Kurt M Fudge, TJ Severinghaus, Jeffery P Ahn, Jinho Kalk, Michael L McConnell, Joseph R Sowers, Todd Taylor, Kendrick C White, James WC Brook, Edward J Centennial-scale changes in the global carbon cycle during the last deglaciation |
topic_facet |
Climate Action Antarctic Regions Atmosphere Carbon Cycle Carbon Dioxide Greenhouse Effect Greenland History Ancient Ice Cover Isotopes Methane Oceans and Seas Water General Science & Technology |
description |
Global climate and the concentration of atmospheric carbon dioxide (CO2) are correlated over recent glacial cycles. The combination of processes responsible for a rise in atmospheric CO2 at the last glacial termination (23,000 to 9,000years ago), however, remains uncertain. Establishing the timing and rate of CO2 changes in the past provides critical insight into the mechanisms that influence the carbon cycle and helps put present and future anthropogenic emissions in context. Here we present CO2 and methane (CH4) records of the last deglaciation from a new high-accumulation West Antarctic ice core with unprecedented temporal resolution and precise chronology. We show that although low-frequency CO2 variations parallel changes in Antarctic temperature, abrupt CO2 changes occur that have a clear relationship with abrupt climate changes in the Northern Hemisphere. A significant proportion of the direct radiative forcing associated with the rise in atmospheric CO2 occurred in three sudden steps, each of 10 to 15 parts per million. Every step took place in less than two centuries and was followed by no notable change in atmospheric CO2 for about 1,000 to 1,500years. Slow, millennial-scale ventilation of Southern Ocean CO2-rich, deep-ocean water masses is thought to have been fundamental to the rise in atmospheric CO2 associated with the glacial termination, given the strong covariance of CO2 levels and Antarctic temperatures. Our data establish a contribution from an abrupt, centennial-scale mode of CO2 variability that is not directly related to Antarctic temperature. We suggest that processes operating on centennial timescales, probably involving the Atlantic meridional overturning circulation, seem to be influencing global carbon-cycle dynamics and are at present not widely considered in Earth system models. |
format |
Article in Journal/Newspaper |
author |
Marcott, Shaun A Bauska, Thomas K Buizert, Christo Steig, Eric J Rosen, Julia L Cuffey, Kurt M Fudge, TJ Severinghaus, Jeffery P Ahn, Jinho Kalk, Michael L McConnell, Joseph R Sowers, Todd Taylor, Kendrick C White, James WC Brook, Edward J |
author_facet |
Marcott, Shaun A Bauska, Thomas K Buizert, Christo Steig, Eric J Rosen, Julia L Cuffey, Kurt M Fudge, TJ Severinghaus, Jeffery P Ahn, Jinho Kalk, Michael L McConnell, Joseph R Sowers, Todd Taylor, Kendrick C White, James WC Brook, Edward J |
author_sort |
Marcott, Shaun A |
title |
Centennial-scale changes in the global carbon cycle during the last deglaciation |
title_short |
Centennial-scale changes in the global carbon cycle during the last deglaciation |
title_full |
Centennial-scale changes in the global carbon cycle during the last deglaciation |
title_fullStr |
Centennial-scale changes in the global carbon cycle during the last deglaciation |
title_full_unstemmed |
Centennial-scale changes in the global carbon cycle during the last deglaciation |
title_sort |
centennial-scale changes in the global carbon cycle during the last deglaciation |
publisher |
eScholarship, University of California |
publishDate |
2014 |
url |
https://escholarship.org/uc/item/1c62p1k7 |
op_coverage |
616 - 619 |
geographic |
Antarctic Southern Ocean Greenland |
geographic_facet |
Antarctic Southern Ocean Greenland |
genre |
Antarc* Antarctic Greenland ice core Southern Ocean |
genre_facet |
Antarc* Antarctic Greenland ice core Southern Ocean |
op_source |
Nature, vol 514, iss 7524 |
op_relation |
qt1c62p1k7 https://escholarship.org/uc/item/1c62p1k7 |
op_rights |
public |
_version_ |
1778517278639259648 |