Climate model response from the Geoengineering Model Intercomparison Project (GeoMIP)

• Main Authors: Kravitz, B., Caldeira, K., Boucher, O., Robock, A., Rasch, P.J., Alterskjær, K., Bou Karam, Diana, Cole, J.N.S., Curry, C.L., Haywood, J.M., Irvine, P.J., Ji, D., Jones, A., Kristjánsson, J.E., Lunt, D.J., Moore, J.C., Niemeier, U., Schmidt, H., Schulz, M, Singh, B., Tilmes, S., Watanabe, S., Yang, S., Yoon, J.-H.
• Other Authors: Pacific Northwest National Laboratory (PNNL), Department of Global Ecology Carnegie (DGE), Carnegie Institution for Science, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Department of Environmental Sciences New Brunswick, School of Environmental and Biological Sciences New Brunswick, Rutgers, The State University of New Jersey New Brunswick (RU), Rutgers University System (Rutgers)-Rutgers University System (Rutgers)-Rutgers, The State University of New Jersey New Brunswick (RU), Rutgers University System (Rutgers)-Rutgers University System (Rutgers), Department of Geosciences Oslo, Faculty of Mathematics and Natural Sciences Oslo, University of Oslo (UiO)-University of Oslo (UiO), 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), Canadian Centre for Climate Modelling and Analysis (CCCma), Environment and Climate Change Canada, School of Earth and Ocean Sciences, University of Victoria, Victoria BC, Canada, Met Office Hadley Centre for Climate Change (MOHC), United Kingdom Met Office Exeter, College of Engineering, Mathematics and Physical Sciences Exeter (EMPS), University of Exeter, Institute for Advanced Sustainability Studies Potsdam (IASS), State Key Laboratory of Earth Surface Processes and Resource Ecology (ESPRE), Beijing Normal University (BNU), University of Bristol Bristol, Max Planck Institute for Meteorology (MPI-M), Max-Planck-Gesellschaft, Norwegian Meteorological Institute Oslo (MET), National Center for Atmospheric Research Boulder (NCAR), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Danish Meteorological Institute (DMI)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2013
• Subjects: [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Arctic; Sea ice
• Online Access: https://hal.archives-ouvertes.fr/hal-01091232; https://hal.archives-ouvertes.fr/hal-01091232/document; https://hal.archives-ouvertes.fr/hal-01091232/file/ark%20_67375_WNG-6N74K5PB-P.pdf

International audience Solar geoengineering - deliberate reduction in the amount of solar radiation retained by the Earth - has been proposed as a means of counteracting some of the climatic effects of anthropogenic greenhouse gas emissions. We present results from Experiment G1 of the Geoengineering Model Intercomparison Project, in which 12 climate models have simulated the climate response to an abrupt quadrupling of CO2 from preindustrial concentrations brought into radiative balance via a globally uniform reduction in insolation. Models show this reduction largely offsets global mean surface temperature increases due to quadrupled CO2 concentrations and prevents 97% of the Arctic sea ice loss that would otherwise occur under high CO2 levels but, compared to the preindustrial climate, leaves the tropics cooler (-0.3 K) and the poles warmer (+0.8 K). Annual mean precipitation minus evaporation anomalies for G1 are less than 0.2 mm day-1 in magnitude over 92% of the globe, but some tropical regions receive less precipitation, in part due to increased moist static stability and suppression of convection. Global average net primary productivity increases by 120% in G1 over simulated preindustrial levels, primarily from CO2 fertilization, but also in part due to reduced plant heat stress compared to a high CO2 world with no geoengineering. All models show that uniform solar geoengineering in G1 cannot simultaneously return regional and global temperature and hydrologic cycle intensity to preindustrial levels. Key Points Temperature reduction from uniform geoengineering is not uniform Geoengineering cannot offset both temperature and hydrology changes NPP increases mostly due to CO2 fertilization ©2013. American Geophysical Union. All Rights Reserved.