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

• Published in: Journal of Geophysical Research: Atmospheres
• Main Authors: Kravitz, Ben, Caldeira, Ken, Boucher, Olivier, Robock, Alan, Rasch, Philip J., Alterskjær, Kari, Karam, Diana Bou, Cole, Jason N. S., Curry, Charles L., Haywood, James M., Irvine, Peter J., Ji, Duoying, Jones, Andy, Kristjánsson, Jón Egill, Lunt, Daniel J., Moore, John C., Niemeier, Ulrike, Schmidt, Hauke, Schulz, Michael, Singh, Balwinder, Tilmes, Simone, Watanabe, Shingo, Yang, Shuting, Yoon, Jin-Ho
• Other Authors: 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)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2013
• Subjects: geoengineering; model intercomparison; Earth Science; [SDU]Sciences of the Universe [physics]; Arctic; Sea ice
• Online Access: https://hal.science/hal-04114060; https://hal.science/hal-04114060/document; https://hal.science/hal-04114060/file/JGR%20Atmospheres%20-%202013%20-%20Kravitz%20-%20Climate%20model%20response%20from%20the%20Geoengineering%20Model%20Intercomparison%20Project%20GeoMIP.pdf; https://doi.org/10.1002/jgrd.50646

International audience 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 CO 2 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 CO 2 concentrations and prevents 97% of the Arctic sea ice loss that would otherwise occur under high CO 2 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 CO 2 fertilization, but also in part due to reduced plant heat stress compared to a high CO 2 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.