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Title: Fate of the Atlantic Meridional Overturning Circulation: Strong decline under continued warming and Greenland melting: AMOC PROJECTIONS FOR WARMING AND GIS MELT

Abstract

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.

Authors:
ORCiD logo [1]; ORCiD logo [2]; ORCiD logo [3]; ORCiD logo [4];  [5]; ORCiD logo [3]; ORCiD logo [4]; ORCiD logo [6]; ORCiD logo [7]; ORCiD logo [5]; ORCiD logo [8]; ORCiD logo [9]; ORCiD logo [10]; ORCiD logo [5]; ORCiD logo [7]
  1. College or Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis Oregon USA; Now at MARUM, University of Bremen, Bremen Germany
  2. College or Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis Oregon USA
  3. Institute for Marine and Atmospheric research, Utrecht University, Utrecht Netherlands
  4. Atmosphere and Ocean Research Institute, University of Tokyo, Tokyo Japan
  5. CSIRO Oceans and Atmosphere, Aspendale Victoria Australia
  6. National Center for Atmospheric Research, Boulder Colorado USA
  7. Department of Geosciences, University of Arizona, Tucson Arizona USA
  8. Faculty of Engineering and Science, Sogn og Fjordane University College, Sogndal Norway; Antarctic and Sub-Antarctic Program, Universidad de Magallanes, Punta Arenas Chile
  9. Canadian Centre for Climate Modelling and Analysis, Victoria British Columbia Canada
  10. Institut Pierre-Simon Laplace, Paris France
Publication Date:
Research Org.:
National Center for Atmospheric Research, Boulder, CO (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1436486
DOE Contract Number:  
FC02-97ER62402
Resource Type:
Journal Article
Journal Name:
Geophysical Research Letters
Additional Journal Information:
Journal Volume: 43; Journal Issue: 23; Journal ID: ISSN 0094-8276
Publisher:
American Geophysical Union
Country of Publication:
United States
Language:
English

Citation Formats

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., and Yin, J. Fate of the Atlantic Meridional Overturning Circulation: Strong decline under continued warming and Greenland melting: AMOC PROJECTIONS FOR WARMING AND GIS MELT. United States: N. p., 2016. Web. doi:10.1002/2016GL070457.
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. Fate of the Atlantic Meridional Overturning Circulation: Strong decline under continued warming and Greenland melting: AMOC PROJECTIONS FOR WARMING AND GIS MELT. United States. doi:10.1002/2016GL070457.
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., and Yin, J. Tue . "Fate of the Atlantic Meridional Overturning Circulation: Strong decline under continued warming and Greenland melting: AMOC PROJECTIONS FOR WARMING AND GIS MELT". United States. doi:10.1002/2016GL070457.
@article{osti_1436486,
title = {Fate of the Atlantic Meridional Overturning Circulation: Strong decline under continued warming and Greenland melting: AMOC PROJECTIONS FOR WARMING AND GIS MELT},
author = {Bakker, P. and Schmittner, A. and Lenaerts, J. T. M. and Abe-Ouchi, A. and Bi, D. and van den Broeke, M. R. and Chan, W. -L. and Hu, A. and Beadling, R. L. and Marsland, S. J. and Mernild, S. H. and Saenko, O. A. and Swingedouw, D. and Sullivan, A. and Yin, J.},
abstractNote = {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.},
doi = {10.1002/2016GL070457},
journal = {Geophysical Research Letters},
issn = {0094-8276},
number = 23,
volume = 43,
place = {United States},
year = {2016},
month = {12}
}

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