scholarly journals Role of the tropical Atlantic for the interhemispheric heat transport during the last deglaciation

Author(s):  
Karl J. F. Meier ◽  
André Bahr ◽  
Cristiano M. Chiessi ◽  
Ana Luiza Albuquerque ◽  
Jacek Raddatz ◽  
...  
Nature ◽  
1999 ◽  
Vol 402 (6761) ◽  
pp. 511-514 ◽  
Author(s):  
Carsten Rühlemann ◽  
Stefan Mulitza ◽  
Peter J. Müller ◽  
Gerold Wefer ◽  
Rainer Zahn

Geology ◽  
2019 ◽  
Vol 48 (1) ◽  
pp. 82-86 ◽  
Author(s):  
Yanhong Zheng ◽  
Zhengkun Fang ◽  
Tongyu Fan ◽  
Zhao Liu ◽  
Zhangzhang Wang ◽  
...  

Abstract The role of boreal wetlands in driving variations in atmospheric methane (CH4) concentrations across the last deglaciation (20–10 ka) and the Holocene is debated. Most studies infer the sources of atmospheric methane via ice-core records of methane concentration and its light stable isotopic composition. However, direct evidence for variations in the methane cycle from the wetlands themselves is relatively limited. Here, we used a suite of biomarker proxies to reconstruct the methane cycle in the Chinese Hani peat across the past 16 k.y. We found two periods of enhanced methanogenesis, at ca. 15–11 ka and ca. 10–6 ka, whereas weak methanogenesis characterized the late Holocene. These periods of enhanced methanogenesis relate to periods of high/increasing temperatures, supporting a temperature control on the wetland methane cycle. We found no biomarker evidence for intense methanotrophy throughout the past 16 k.y., and, contrary to previous studies, we found no clear control of hydrology on the peatland methane cycle. Although the onset of methanogenesis at Hani at ca. 15 ka coincided with a negative shift in methane δ13C in the ice cores, there is no consistent correlation between changes in the reconstructed methane cycle of the boreal Hani peat and atmospheric CH4 concentrations.


Nature ◽  
1996 ◽  
Vol 380 (6569) ◽  
pp. 51-54 ◽  
Author(s):  
Konrad A. Hughen ◽  
Jonathan T. Overpeck ◽  
Larry C. Peterson ◽  
Susan Trumbore

2021 ◽  
Author(s):  
Victor van Aalderen ◽  
Sylvie Charbit ◽  
Christophe Dumas ◽  
Masa Kageyama

<p>Recent observations show an acceleration of the glacier outflow in the West Antarctic ice sheet (WAIS) since the mid-1990s and an increase in calving events. Compared to the 1979-1990 period, mass loss from WAIS has been increased by a factor six between 2009 and 2017. The reduced buttressing effect from ice-shelf breakup may favour the ice flow from outlet glaciers and in turn the sea-level rise with potential noticeable consequences on human societies. However, despite continuous model improvements, large uncertainties are still present on the representation future evolution of the WAIS. The large panel of different results in the projections of the future sea-level rise stands, in part, to our misunderstanding of the process responsible for the marine ice sheet evolution. A possible approach to better constrain these processes, is to investigate past marine ice sheets, such as the Barents-Kara ice sheet (BKIS) at the Last Glacial Maximum (LGM), which can be considered, to a certain extent, as an analogue of the WAIS. Our objective is to study the processes responsible for the collapse of the BKIS during the last deglaciation. To simulate the evolution of the BKIS, we use the GRISLI ice-sheet model (20 km x 20 km) forced by different CMIP5/PMIP3 and CMIP6/PMIP4 models. We will present the response of the ice sheet to different types of atmospheric and oceanic forcing at the LGM coming from the PMIP models. This study represents a first step before studying more in depth the respective role of each climatic field but also the role of sea level rise coming from other LGM ice sheets in triggering the retreat of the BKIS at the beginning of the last deglaciation and the impacts of the dynamical processes.</p>


2017 ◽  
Vol 177 ◽  
pp. 120-129 ◽  
Author(s):  
Guoqiang Chu ◽  
Qing Sun ◽  
Qingzeng Zhu ◽  
Yabing Shan ◽  
Wenyu Shang ◽  
...  

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