JpGU-AGU Joint Meeting 2020

Presentation information

[E] Oral

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS08] Paleoclimatology and paleoceanography

convener:Yusuke Okazaki(Department of Earth and Planetary Sciences, Graduate School of Science, Kyushu University), Benoit Thibodeau(University of Hong Kong), Akitomo Yamamoto(Japan Agency for Marine-Earth Science and TechnologyAtmosphere and Ocean Research Institute), Hitoshi Hasegawa(Faculty of Science and Technology, Kochi University)

[MIS08-16] Change in the Atlantic Meridional Overturning Circulation over the last 1,500 years

★Invited Papers

*Benoit Thibodeau1 (1.The University of Hong Kong, Division of Earth and Planetary Sciences & SWIRE Institute of Marine Science)

Keywords:AMOC, Stable Isotope, Geochemistry, Climate Change

The Atlantic meridional overturning circulation (AMOC) is a key component of the global climate system as it transports warm waters to the high latitudes which allow the formation of intermediate and deep Atlantic water masses. Models have predicted a slowdown, or even a collapse of the AMOC under global warming and increased freshwater flux. While some field data are available for the last decade, they do not provide the perspective required to evaluate the present state of AMOC against its natural variability. Moreover, until recently the intensity of the AMOC beyond the last century was mostly unknown, which also limited our understanding of the present state of the AMOC. Over the past year research groups managed to develop paleo reconstruction of the AMOC strength and highlighted the fact that the 20th century AMOC is significantly weaker than it was over the last millennium (Rahmstorf et al., 2015; Thibodeau et al., 2018) and that this weakening is of unprecedented amplitude over this period (Caesar et al., 2018; Thibodeau et al., 2010).

Caesar, L., Rahmstorf, S., Robinson, A., Feulner, G., Saba, V., 2018. Observed fingerprint of a weakening Atlantic Ocean overturning circulation. Nature 556, 191–196.

Rahmstorf, S., Box, J.E., Feulner, G., Mann, M.E., Robinson, A., Rutherford, S., Schaffernicht, E.J., 2015. Exceptional twentieth-century slowdown in Atlantic Ocean overturning circulation. Nat. Clim. Chang. 5, 475–480.

Thibodeau, B., de Vernal, A., Hillaire-Marcel, C., Mucci, A., 2010. Twentieth century warming in deep waters of the Gulf of St. Lawrence: A unique feature of the last millennium. Geophys. Res. Lett. 37.

Thibodeau, B., Not, C., Zhu, J., Schmittner, A., Noone, D., Tabor, C., Zhang, J., Liu, Z., 2018. Last Century Warming Over the Canadian Atlantic Shelves Linked to Weak Atlantic Meridional Overturning Circulation. Geophys. Res. Lett. 45, 12,376-12,385.