Past terrestrial hydroclimate sensitivity controlled by Earth system feedbacks

• Published in: Nature Communications
• Main Authors: Feng, Ran, Bhattacharya, Tripti, Otto-Bliesner, Bette, Brady, Esther, Haywood, Alan, Tindall, Julia, Hunter, Stephen, Abe-Ouchi, Ayako, Chan, Wing-Le, Kageyama, Masa, Contoux, Camille, Guo, Chuncheng, Li, Xiangyu, Lohmann, Gerrit, Stepanek, Christian, Tan, Ning, Zhang, Qiong, Zhang, Zhongshi, Han, Zixuan, Williams, Charles, Lunt, Daniel, Dowsett, Harry, Chandan, Deepak, Peltier, W. Richard, Peltier, &
• Other Authors: University of Connecticut (UCONN), Syracuse University, National Center for Atmospheric Research Boulder (NCAR), University of Leeds, Atmosphere and Ocean Research Institute Kashiwa-shi (AORI), The University of Tokyo (UTokyo), Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Modélisation du climat (CLIM), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Bjerknes Centre for Climate Research (BCCR), Department of Biological Sciences Bergen (BIO / UiB), University of Bergen (UiB)-University of Bergen (UiB), China University of Geosciences Wuhan (CUG), Alfred Wegener Institute for Polar and Marine Research (AWI), Universität Bremen, Hohai University, Bolin Centre for Climate Research, Stockholm University, School of Geographical Sciences Bristol, University of Bristol Bristol, United States Geological Survey Reston (USGS), University of Toronto
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; Ice Sheet
• Online Access: https://hal.archives-ouvertes.fr/hal-03620581; https://hal.archives-ouvertes.fr/hal-03620581/document; https://hal.archives-ouvertes.fr/hal-03620581/file/s41467-022-28814-7.pdf; https://doi.org/10.1038/s41467-022-28814-7

International audience Despite tectonic conditions and atmospheric CO 2 levels (pCO 2) similar to those of presentday, 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 highlatitude 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.