Fate of the Atlantic Meridional Overturning Circulation: Strong decline under continued warming and Greenland melting

• Published in: Geophysical Research Letters
• Main Authors: Bakker, P., Schmittner, A., Lenaerts, J. T. M., Abe-Ouchi, A., Bi, D., van den Broeke, M. R., Chan, W.-L., Hu, A., Beadling, R. L., Marsland, S. J., Mernild, S. H., Saenko, O. A., Swingedouw, D., Sullivan, A., Yin, J.
• Other Authors: Univ Arizona, Dept Geosci, College or Earth, Ocean, and Atmospheric Sciences; Oregon State University; Corvallis Oregon USA, Institute for Marine and Atmospheric research; Utrecht University; Utrecht Netherlands, Atmosphere and Ocean Research Institute; University of Tokyo; Tokyo Japan, CSIRO Oceans and Atmosphere; Aspendale Victoria Australia, National Center for Atmospheric Research; Boulder Colorado USA, Department of Geosciences; University of Arizona; Tucson Arizona USA, Faculty of Engineering and Science; Sogn og Fjordane University College; Sogndal Norway, Canadian Centre for Climate Modelling and Analysis; Victoria British Columbia Canada, Institut Pierre-Simon Laplace; Paris France
• Format: Article in Journal/Newspaper
• Language: English
• Published: AMER GEOPHYSICAL UNION 2016
• Subjects: Atlantic Meridional Overturning Circulation; climate change; general circulation model; Greenland; Rus’; Ice Sheet
• Online Access: http://hdl.handle.net/10150/622754; https://doi.org/10.1002/2016GL070457

The most recent Intergovernmental Panel on Climate Change assessment report concludes that the Atlantic Meridional Overturning Circulation (AMOC) could weaken substantially but is very unlikely to collapse in the 21st century. However, the assessment largely neglected Greenland Ice Sheet (GrIS) mass loss, lacked a comprehensive uncertainty analysis, and was limited to the 21st century. Here in a community effort, improved estimates of GrIS mass loss are included in multicentennial projections using eight state-of-the-science climate models, and an AMOC emulator is used to provide a probabilistic uncertainty assessment. We find that GrIS melting affects AMOC projections, even though it is of secondary importance. By years 2090-2100, the AMOC weakens by 18% [-3%, -34%; 90% probability] in an intermediate greenhouse-gas mitigation scenario and by 37% [-15%, -65%] under continued high emissions. Afterward, it stabilizes in the former but continues to decline in the latter to -74% [+4%, -100%] by 2290-2300, with a 44% likelihood of an AMOC collapse. This result suggests that an AMOC collapse can be avoided by CO2 mitigation. National Oceanographic and Atmospheric Administration [NA15OAR4310239]; Netherlands Earth System Science Center (NESSC); Polar Program of the Netherlands Organization for Scientific Research (NWO); Regional and Global Climate Modelling Program (RGCM) of the U.S. Department of Energy's Office of Science (BER) [DE-FC02-97ER62402]; Office of Science of the U.S. Department of Energy; ArCS; ICA-RUS; Natural Environment Research Council 6 month embargo; First Published: 13 December 2016. This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [e-mail].