Intensified Southern Hemisphere Westerlies regulated atmospheric CO2 during the last deglaciation

Geology ◽  
2013 ◽  
Vol 41 (8) ◽  
pp. 831-834 ◽  
Author(s):  
C. Mayr ◽  
A. Lücke ◽  
S. Wagner ◽  
H. Wissel ◽  
C. Ohlendorf ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Atmospheric Co2 ◽  
Last Deglaciation ◽  
The Last Deglaciation ◽  
Southern Hemisphere Westerlies

scholarly journals Hydrographic shifts south of Australia over the last deglaciation and possible interhemispheric linkages

2021 ◽  
pp. 1-12
Author(s):  
Matthias Moros ◽  
Patrick De Deckker ◽  
Kerstin Perner ◽  
Ulysses S. Ninnemann ◽  
Lukas Wacker ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Southern Hemisphere ◽  
Critical Role ◽  
Temperature Response ◽  
South Australia ◽  
Last Deglaciation ◽  
Tight Coupling ◽  
Oceanic Fronts ◽  
The Last Deglaciation ◽  
Circumpolar Current

Abstract Northern and southern hemispheric influences—particularly changes in Southern Hemisphere westerly winds (SSW) and Southern Ocean ventilation—triggered the stepwise atmospheric CO2 increase that accompanied the last deglaciation. One approach for gaining potential insights into past changes in SWW/CO2 upwelling is to reconstruct the positions of the northern oceanic fronts associated with the Antarctic Circumpolar Current. Using two deep-sea cores located ~600 km apart off the southern coast of Australia, we detail oceanic changes from ~23 to 6 ka using foraminifer faunal and biomarker alkenone records. Our results indicate a tight coupling between hydrographic and related frontal displacements offshore South Australia (and by analogy, possibly the entire Southern Ocean) and Northern Hemisphere (NH) climate that may help confirm previous hypotheses that the westerlies play a critical role in modulating CO2 uptake and release from the Southern Ocean on millennial and potentially even centennial timescales. The intensity and extent of the northward displacements of the Subtropical Front following well-known NH cold events seem to decrease with progressing NH ice sheet deglaciation and parallel a weakening NH temperature response and amplitude of Intertropical Convergence Zone shifts. In addition, an exceptional poleward shift of Southern Hemisphere fronts occurs during the NH Heinrich Stadial 1. This event was likely facilitated by the NH ice maximum and acted as a coup-de-grâce for glacial ocean stratification and its high CO2 capacitance. Thus, through its influence on the global atmosphere and on ocean mixing, “excessive” NH glaciation could have triggered its own demise by facilitating the destratification of the glacial ocean CO2 state.

scholarly journals Northern and southern hemisphere controls on seasonal sea surface temperatures in the Indian Ocean during the last deglaciation

2013 ◽  
Vol 28 (4) ◽  
pp. 619-632 ◽  
Author(s):  
Yiming V. Wang ◽  
Guillaume Leduc ◽  
Marcus Regenberg ◽  
Nils Andersen ◽  
Thomas Larsen ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Southern Hemisphere ◽  
Sea Surface ◽  
Sea Surface Temperatures ◽  
Last Deglaciation ◽  
Surface Temperatures ◽  
The Indian Ocean ◽  
The Last Deglaciation

Northern Hemisphere forcing of Southern Hemisphere climate during the last deglaciation

Nature ◽  
2013 ◽  
Vol 494 (7435) ◽  
pp. 81-85 ◽  
Author(s):  
Feng He ◽  
Jeremy D. Shakun ◽  
Peter U. Clark ◽  
Anders E. Carlson ◽  
Zhengyu Liu ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Last Deglaciation ◽  
The Last Deglaciation

scholarly journals Hydrologic Change in New Zealand During the Last Deglaciation Linked to Reorganization of the Southern Hemisphere Westerly Winds

2019 ◽  
Vol 34 (12) ◽  
pp. 2158-2170 ◽  
Author(s):  
Jessica L. Hinojosa ◽  
Christopher M. Moy ◽  
Marcus Vandergoes ◽  
Sarah J. Feakins ◽  
Alex L. Sessions
Keyword(s):  
New Zealand ◽  
Southern Hemisphere ◽  
Last Deglaciation ◽  
Westerly Winds ◽  
Hydrologic Change ◽  
The Last Deglaciation ◽  
Southern Hemisphere Westerly Winds

scholarly journals Leads and lags between Antarctic temperature and carbon dioxide during the last deglaciation

2017 ◽  
Author(s):  
Léa Gest ◽  
Frédéric Parrenin ◽  
Jai Chowdhry Beeman ◽  
Dominique Raynaud ◽  
Tyler J. Fudge ◽  
...  
Keyword(s):  
Ice Core ◽  
Ice Cores ◽  
Atmospheric Co2 ◽  
Last Deglaciation ◽  
High Accumulation ◽  
Volcanic Event ◽  
Sequence Of Events ◽  
The Last Deglaciation ◽  
Paleoclimate Records ◽  
The Antarctic

Abstract. To understand causal relationships in past climate variations, it is essential to have accurate chronologies of paleoclimate records. The last deglaciation, which occurred from 18 000 to 11 000 years ago, is especially interesting, since it is the most recent large climatic variation of global extent. Ice cores in Antarctica provide important paleoclimate proxies, such as regional temperature and global atmospheric CO2. However, temperature is recorded in the ice while CO2 is recorded in the enclosed air bubbles. The ages of the former and of the latter are different since air is trapped at 50–120 m below the surface. It is therefore necessary to correct for this air-ice shift to accurately infer the sequence of events. Here we accurately determine the phasing between East Antarctic temperature and atmospheric CO2 variations during the last deglacial warming based on Antarctic ice core records. We build a stack of East Antarctic temperature variations by averaging the records from 4 ice cores (EPICA Dome C, Dome Fuji, EPICA Dronning Maud Land and Talos Dome), all accurately synchronized by volcanic event matching. We place this stack onto the WAIS Divide WD2014 age scale by synchronizing EPICA Dome C and WAIS Divide using volcanic event matching, which allows comparison with the high resolution CO2 record from WAIS Divide. Since WAIS Divide is a high accumulation site, its air age scale, which has previously been determined by firn modeling, is more robust. Finally, we assess the CO2/Antarctic temperature phasing by determining four periods when their trends change abruptly. We find that at the onset of the last deglaciation and at the onset of the Antarctic Cold Reversal (ACR) period CO2 and Antarctic temperature are synchronous within a range of 210 years. Then CO2 slightly leads by 165 ± 116 years at the end of the Antarctic Cold Reversal (ACR) period. Finally, Antarctic temperature significantly leads by 406 ± 200 years at the onset of the Holocene period. Our results further support the hypothesis of no convective zone at EPICA Dome C during the last deglaciation and the use of nitrogen-15 to infer the height of the diffusive zone. Future climate and carbon cycle modeling works should take into account this robust phasing constraint.

Influence of atmospheric CO2 on the decline of C4 plants during the last deglaciation

Nature ◽  
1994 ◽  
Vol 368 (6471) ◽  
pp. 533-536 ◽  
Author(s):  
David R. Cole ◽  
H. Curtis Monger
Keyword(s):  
C4 Plants ◽  
Atmospheric Co2 ◽  
Last Deglaciation ◽  
The Last Deglaciation
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