[A-CG46] Emulators: development and applications

[ACG46-P05] Anthropogenic contributions to slow warming over 1998-2012

*Xuanming Su^1,3, Hideo Shiogama¹, Katsumasa Tanaka^1,2, Kaoru Tachiiri³, Tomohiro Hajima³, Michio Watanabe³, Michio Kawamiya³, KIYOSHI TAKAHASHI¹, Tokuta Yokohata¹ (1.National Institute for Environmental Studies, Japan, 2.Laboratoire des Sciences du Climat et de l’Environnement (LSCE), IPSL, CEA/CNRS/UVSQ, Université Paris-Saclay, Gif-sur-Yvette, France, 3.Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokohama, Japan)

Keywords:Slow warming, Temperature attribution, Methane and ODS, ENSO, Solar irradiance, SCM4OPT

The observed global mean surface temperature increases from 1998 to 2012 was slower than that since 1951. The relative contributions of all relevant factors including climate forcers, however, have not been comprehensively analyzed. Using a reduced-complexity climate model and an observationally constrained statistical model, we find that La Niña cooling and a descending solar cycle contributed approximately 50% and 26% of the total warming slowdown during 1998-2012 compared to 1951-2012. Furthermore, reduced ozone-depleting substances and methane accounted for roughly a quarter of the total warming slowdown, which can be explained by changes in atmospheric concentrations. We identify that human factors played an important role in slowing global warming during 1998-2012, shedding light on the evidence for controlling global warming by reducing greenhouse gas emissions.