Variations of Primary Productivity in the Northwestern Arabian Sea During the Last 23,000 Years and Their Paleoclimatological Implications

Xinquan Zhou (1, 2) , Stéphanie Duchamp-Alphonse (2) , Masa Kageyama (3, 4) , Franck Bassinot (3) , Florian Doressoundiram (2) , Catherine Kissel (3, 5)

1 SCUT - South China University of Technology [Guangzhou]
2 GEOPS - Géosciences Paris Saclay
3 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
4 CLIM - Modélisation du climat
5 CLIMAG - Climat et Magnétisme

Abstract Despite tectonic conditions and atmospheric CO 2 levels ( pCO 2 ) similar to those of present-day, geological reconstructions from the mid-Pliocene (3.3-3.0 Ma) document high lake levels in the Sahel and mesic conditions in subtropical Eurasia, suggesting drastic reorganizations of subtropical terrestrial hydroclimate during this interval. Here, using a compilation of proxy data and multi-model paleoclimate simulations, we show that the mid-Pliocene hydroclimate state is not driven by direct CO 2 radiative forcing but by a loss of northern high-latitude ice sheets and continental greening. These ice sheet and vegetation changes are long-term Earth system feedbacks to elevated pCO 2 . Further, the moist conditions in the Sahel and subtropical Eurasia during the mid-Pliocene are a product of enhanced tropospheric humidity and a stationary wave response to the surface warming pattern, which varies strongly with land cover changes. These findings highlight the potential for amplified terrestrial hydroclimate responses over long timescales to a sustained CO 2 forcing.

Domaines: Sciences de l'environnement

Xinquan Zhou, Stéphanie Duchamp-Alphonse, Masa Kageyama, Franck Bassinot, Florian Doressoundiram, et al.. Variations of Primary Productivity in the Northwestern Arabian Sea During the Last 23,000 Years and Their Paleoclimatological Implications. Paleoceanography and Paleoclimatology, 2022, 37 (10), pp.1306. ⟨10.1029/2022PA004453⟩. ⟨hal-03874269⟩