Fate of the Atlantic Meridional Overturning Circulation: Strong decline under continued warming and Greenland melting: AMOC PROJECTIONS FOR WARMING AND GIS MELT
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- College or Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis Oregon USA; Now at MARUM, University of Bremen, Bremen Germany
- 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; Antarctic and Sub-Antarctic Program, Universidad de Magallanes, Punta Arenas Chile
- Canadian Centre for Climate Modelling and Analysis, Victoria British Columbia Canada
- Institut Pierre-Simon Laplace, Paris France
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.
- Research Organization:
- National Center for Atmospheric Research (NCAR), Boulder, CO (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- DOE Contract Number:
- FC02-97ER62402
- OSTI ID:
- 1436486
- Journal Information:
- Geophysical Research Letters, Vol. 43, Issue 23; ISSN 0094-8276
- Publisher:
- American Geophysical Union
- Country of Publication:
- United States
- Language:
- English
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