Climate bifurcation during the last deglaciation?
There were two abrupt warming events during the last deglaciation, at the start of the Bølling-Allerød and at the end of the Younger Dryas, but their underlying dynamics are unclear. Some abrupt climate changes may involve gradual forcing past a bifurcation point, in which a prevailing climate state...
Published in: | Climate of the Past |
---|---|
Main Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Copernicus Publications
2012
|
Subjects: | |
Online Access: | https://doi.org/10.5194/cp-8-1127-2012 https://doaj.org/article/088bafdfff2a47fb97d3bccdddf62637 |
id |
ftdoajarticles:oai:doaj.org/article:088bafdfff2a47fb97d3bccdddf62637 |
---|---|
record_format |
openpolar |
spelling |
ftdoajarticles:oai:doaj.org/article:088bafdfff2a47fb97d3bccdddf62637 2023-05-15T16:30:11+02:00 Climate bifurcation during the last deglaciation? T. M. Lenton V. N. Livina V. Dakos M. Scheffer 2012-07-01T00:00:00Z https://doi.org/10.5194/cp-8-1127-2012 https://doaj.org/article/088bafdfff2a47fb97d3bccdddf62637 EN eng Copernicus Publications http://www.clim-past.net/8/1127/2012/cp-8-1127-2012.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 doi:10.5194/cp-8-1127-2012 1814-9324 1814-9332 https://doaj.org/article/088bafdfff2a47fb97d3bccdddf62637 Climate of the Past, Vol 8, Iss 4, Pp 1127-1139 (2012) Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 article 2012 ftdoajarticles https://doi.org/10.5194/cp-8-1127-2012 2022-12-31T10:30:41Z There were two abrupt warming events during the last deglaciation, at the start of the Bølling-Allerød and at the end of the Younger Dryas, but their underlying dynamics are unclear. Some abrupt climate changes may involve gradual forcing past a bifurcation point, in which a prevailing climate state loses its stability and the climate tips into an alternative state, providing an early warning signal in the form of slowing responses to perturbations, which may be accompanied by increasing variability. Alternatively, short-term stochastic variability in the climate system can trigger abrupt climate changes, without early warning. Previous work has found signals consistent with slowing down during the last deglaciation as a whole, and during the Younger Dryas, but with conflicting results in the run-up to the Bølling-Allerød. Based on this, we hypothesise that a bifurcation point was approached at the end of the Younger Dryas, in which the cold climate state, with weak Atlantic overturning circulation, lost its stability, and the climate tipped irreversibly into a warm interglacial state. To test the bifurcation hypothesis, we analysed two different climate proxies in three Greenland ice cores, from the Last Glacial Maximum to the end of the Younger Dryas. Prior to the Bølling warming, there was a robust increase in climate variability but no consistent slowing down signal, suggesting this abrupt change was probably triggered by a stochastic fluctuation. The transition to the warm Bølling-Allerød state was accompanied by a slowing down in climate dynamics and an increase in climate variability. We suggest that the Bølling warming excited an internal mode of variability in Atlantic meridional overturning circulation strength, causing multi-centennial climate fluctuations. However, the return to the Younger Dryas cold state increased climate stability. We find no consistent evidence for slowing down during the Younger Dryas, or in a longer spliced record of the cold climate state before and after the Bølling-Allerød. ... Article in Journal/Newspaper Greenland Greenland ice cores Directory of Open Access Journals: DOAJ Articles Greenland Climate of the Past 8 4 1127 1139 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
spellingShingle |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 T. M. Lenton V. N. Livina V. Dakos M. Scheffer Climate bifurcation during the last deglaciation? |
topic_facet |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
description |
There were two abrupt warming events during the last deglaciation, at the start of the Bølling-Allerød and at the end of the Younger Dryas, but their underlying dynamics are unclear. Some abrupt climate changes may involve gradual forcing past a bifurcation point, in which a prevailing climate state loses its stability and the climate tips into an alternative state, providing an early warning signal in the form of slowing responses to perturbations, which may be accompanied by increasing variability. Alternatively, short-term stochastic variability in the climate system can trigger abrupt climate changes, without early warning. Previous work has found signals consistent with slowing down during the last deglaciation as a whole, and during the Younger Dryas, but with conflicting results in the run-up to the Bølling-Allerød. Based on this, we hypothesise that a bifurcation point was approached at the end of the Younger Dryas, in which the cold climate state, with weak Atlantic overturning circulation, lost its stability, and the climate tipped irreversibly into a warm interglacial state. To test the bifurcation hypothesis, we analysed two different climate proxies in three Greenland ice cores, from the Last Glacial Maximum to the end of the Younger Dryas. Prior to the Bølling warming, there was a robust increase in climate variability but no consistent slowing down signal, suggesting this abrupt change was probably triggered by a stochastic fluctuation. The transition to the warm Bølling-Allerød state was accompanied by a slowing down in climate dynamics and an increase in climate variability. We suggest that the Bølling warming excited an internal mode of variability in Atlantic meridional overturning circulation strength, causing multi-centennial climate fluctuations. However, the return to the Younger Dryas cold state increased climate stability. We find no consistent evidence for slowing down during the Younger Dryas, or in a longer spliced record of the cold climate state before and after the Bølling-Allerød. ... |
format |
Article in Journal/Newspaper |
author |
T. M. Lenton V. N. Livina V. Dakos M. Scheffer |
author_facet |
T. M. Lenton V. N. Livina V. Dakos M. Scheffer |
author_sort |
T. M. Lenton |
title |
Climate bifurcation during the last deglaciation? |
title_short |
Climate bifurcation during the last deglaciation? |
title_full |
Climate bifurcation during the last deglaciation? |
title_fullStr |
Climate bifurcation during the last deglaciation? |
title_full_unstemmed |
Climate bifurcation during the last deglaciation? |
title_sort |
climate bifurcation during the last deglaciation? |
publisher |
Copernicus Publications |
publishDate |
2012 |
url |
https://doi.org/10.5194/cp-8-1127-2012 https://doaj.org/article/088bafdfff2a47fb97d3bccdddf62637 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Greenland ice cores |
genre_facet |
Greenland Greenland ice cores |
op_source |
Climate of the Past, Vol 8, Iss 4, Pp 1127-1139 (2012) |
op_relation |
http://www.clim-past.net/8/1127/2012/cp-8-1127-2012.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 doi:10.5194/cp-8-1127-2012 1814-9324 1814-9332 https://doaj.org/article/088bafdfff2a47fb97d3bccdddf62637 |
op_doi |
https://doi.org/10.5194/cp-8-1127-2012 |
container_title |
Climate of the Past |
container_volume |
8 |
container_issue |
4 |
container_start_page |
1127 |
op_container_end_page |
1139 |
_version_ |
1766019904066027520 |