Article | Published:

Latitudinal shift of the Atlantic Meridional Overturning Circulation source regions under a warming climate

Nature Climate Changevolume 8pages10131020 (2018) | Download Citation


The strength of the Atlantic Meridional Overturning Circulation, a key indicator of the climate state, is maintained by the subduction of dense water that feeds the deep southwards branch. At present, this subduction occurs almost entirely in the subpolar region, in the Labrador, Irminger and Nordic seas; however, whether this will continue under climate change is unknown. Here we use a quantitative Lagrangian diagnostic applied to climate model output to show that, in response to warming, the main source regions of this mixed-layer subduction shift northwards to the Arctic Basin and southwards to the subtropical gyre. These shifts are explained by changes in background stratification, mixed-layer depth and ocean circulation, highlighting the need to consider the full three-dimensionality of the circulation and its changes to accurately predict the future climate state.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Data availability

The data sets generated and analysed during the current study are available upon request from the corresponding author.

Additional information

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.


  1. 1.

    Jackson, L. C. et al. Global and European climate impacts of a slowdown of the AMOC in a high resolution GCM. Clim. Dynam. 45, 3299–3316 (2015).

  2. 2.

    McCarthy, G. et al. Measuring the Atlantic meridional overturning circulation at 26º N. Prog. Oceanogr. 130, 91–111 (2015).

  3. 3.

    Mercier, H. et al. Variability of the meridional overturning circulation at the Greenland–Portugal OVIDE section from 1993 to 2010. Prog. Oceanogr. 132, 250–261 (2015).

  4. 4.

    Caesar, L., Rahmstorf, G. F. S., Robinson, A. & Saba, V. Observed finger-print of a weakening Atlantic Ocean overturning circulation. Nature 556, 191–196 (2018).

  5. 5.

    Thornalley, D. J. R. et al. Anomalously weak Labrador Sea convection and Atlantic overturning during the past 150 years. Nature 556, 227–230 (2018).

  6. 6.

    IPCC Climate Change 2013: The Physical Science Basis (eds Stocker, T. F. et al.) (Cambridge Univ. Press, 2013).

  7. 7.

    Taylor, K. E., Stouffer, R. J. & Meehl, G. A. An overview of CMIP5 and the experiment design. Bull. Am. Meteorol. Soc. 93, 485–498 (2012).

  8. 8.

    Schmittner, A., Latif, M. & Schneider, B. Model projections of the North Atlantic thermohaline circulation for the 21st century assessed by observations. Geophys. Res. Lett. 32, L23710 (2005).

  9. 9.

    Cheng, W., Chiang, J. C. & Zhang, D. Atlantic meridional overturning circulation (AMOC) in CMIP5 models: RCP and historical simulations. J. Clim. 26, 7187–7197 (2013).

  10. 10.

    Jahn, A. & Holland, M. M. Implications of Arctic sea ice changes for North Atlantic deep convection and the meridional overturning circulation in CCSM4-CMIP5 simulations. Geophys. Res. Lett. 40, 1206–1211 (2013).

  11. 11.

    Buckley, M. W. & Marshall, J. Observations, inferences, and mechanisms of the Atlantic Meridional Overturning Circulation: A review. Rev. Geophys. 54, 5–63 (2016).

  12. 12.

    Pillar, H. R., Heimbach, P., Johnson, H. L. & Marshall, D. P. Dynamical attribution of recent variability in Atlantic overturning. J. Clim. 29, 3339–3352 (2016).

  13. 13.

    Polo, I., Robson, J., Sutton, R. & Balmaseda, M. A. The importance of wind and buoyancy forcing for the boundary density variations and the geostrophic component of the AMOC at 26°N. J. Phys. Oceanogr. 44, 2387–2408 (2014).

  14. 14.

    Medhaug, I., Langehaug, H. R., Eldevik, T., Furevik, T. & Bentsen, M. Mechanisms for decadal scale variability in a simulated Atlantic meridional overturning circulation. Clim. Dynam. 39, 77–93 (2012).

  15. 15.

    Deshayes, J. & Frankignoul, C. Simulated variability of the circulation in the North Atlantic from 1953 to 2003. J. Clim. 21, 4919 (2008).

  16. 16.

    Lohmann, K. et al. The role of subpolar deep water formation and Nordic Seas overflows in simulated multidecadal variability of the Atlantic meridional overturning circulation. Ocean Sci. 10, 227–241 (2014).

  17. 17.

    Moat, B. I., Josey, S. A. & Sinha, B. Impact of Barents Sea winter air–sea exchanges on Fram Strait dense water transport. J. Geophys. Res. 119, 1009–1021 (2014).

  18. 18.

    Thomas, M. D., Tréguier, A.-M., Blanke, B., Deshayes, J. & Voldoire, A. A Lagrangian method to isolate the impacts of mixed layer subduction on the meridional overturning circulation in a numerical model. J. Clim. 28, 7503–7517 (2015).

  19. 19.

    Lique, C., Johnson, H. L. & Plancherel, Y. Emergence of deep convection in the Arctic Ocean under a warming climate. Clim. Dynam. 50, 3849–3851 (2018).

  20. 20.

    Voldoire, A. et al. The CNRM-CM5. 1 global climate model: description and basic evaluation. Clim. Dynam. 40, 2091–2121 (2013).

  21. 21.

    MacGilchrist, G. A., Marshall, D. P., Johnson, H. L., Lique, C. & Thomas, M. Characterizing the chaotic nature of ocean ventilation. J. Geophys. Res. Oceans 122, 7577–7594 (2017).

  22. 22.

    Marzocchi, A. et al. The North Atlantic subpolar circulation in an eddy-resolving global ocean model. J. Mar. Syst. 142, 126–143 (2015).

  23. 23.

    Heuzé, C. North Atlantic deep water formation and AMOC in CMIP5 models. Ocean Sci. 13, 609–622 (2017).

  24. 24.

    Pickart, R. S. & Spall, M. A. Impact of Labrador Sea convection on the North Atlantic meridional overturning circulation. J. Phys. Oceanogr. 37, 2207–2227 (2007).

  25. 25.

    Sarafanov, A. et al. Mean full-depth summer circulation and transports at the northern periphery of the Atlantic Ocean in the 2000s. J. Geophys. Res. Oceans 117, C01014 (2012).

  26. 26.

    Dickson, R. R. & Brown, J. The production of North Atlantic Deep Water: sources, rates, and pathways. J. Geophys. Res. Oceans 99, 12,319–12,341 (1994).

  27. 27.

    Schott, F. A., McCreary, J. P. & Johnson, G. C. in Earth’s Climate: The Ocean–Atmosphere Interaction (eds Wang, C. et al.) 261–304 (AGU, Washington DC, 2004).

  28. 28.

    Kostov, Y., Armour, K. C. & Marshall, J. Impact of the Atlantic meridional overturning circulation on ocean heat storage and transient climate change. Geophys. Res. Lett. 41, 2108–2116 (2014).

  29. 29.

    Williams, R. G., Marshall, J. C. & Spall, M. A. Does Stommel’s mixed layer “demon” work? J. Phys. Oceanogr. 25, 3089–3102 (1995).

  30. 30.

    Capotondi, A., Alexander, M. A., Bond, N. A., Curchitser, E. N. & Scott, J. D. Enhanced upper ocean stratification with climate change in the CMIP3 models. J. Geophys. Res. Oceans 117, C04031 (2012).

  31. 31.

    Heuzé, C., Heywood, K. J., Stevens, D. P. & Ridley, J. K. Changes in global ocean bottom properties and volume transports in CMIP5 models under climate change scenarios. J. Clim. 28, 2917–2944 (2015).

  32. 32.

    Falina, A. et al. On the cascading of dense shelf waters in the Irminger Sea. J. Phys. Oceanogr. 42, 2254–2267 (2012).

  33. 33.

    Germe, A., Houssais, M.-N., Herbaut, C. & Cassou, C. Greenland Sea sea ice variability over 1979–2007 and its link to the surface atmosphere. J. Geophys. Res. Oceans 116, C10034 (2011).

  34. 34.

    Peralta-Ferriz, C. & Woodgate, R. A. Seasonal and interannual variability of pan-arctic surface mixed layer properties from 1979 to 2012 from hydrographic data, and the dominance of stratification for multiyear mixed layer depth shoaling. Prog. Oceanogr. 134, 19–53 (2015).

  35. 35.

    Kuhlbrodt, T., Titz, S., Feudel, U. & Rahmstorf, S. A simple model of seasonal open ocean convection. Ocean Dynam. 52, 36–49 (2001).

  36. 36.

    McCartney, M. S. & Talley, L. D. The subpolar mode water of the North Atlantic Ocean. J. Phys. Oceanogr. 12, 1169–1188 (1982).

  37. 37.

    Trossman, D. S., Thompson, L. A., Kelly, K. A. & Kwon, Y.-O. Estimates of North Atlantic ventilation and mode water formation for winters 2002–06. J. Phys. Oceanogr. 39, 2600–2617 (2009).

  38. 38.

    Thomas, M. D. & Fedorov, A. V. The eastern subtropical Pacific origin of the equatorial cold bias in climate models: a Lagrangian perspective. J. Clim. 30, 5885–5900 (2017).

  39. 39.

    Burkholder, K. C. & Lozier, M. S. Subtropical to subpolar pathways in the North Atlantic: deductions from Lagrangian trajectories. J. Geophys. Res. Oceans 116, C07017 (2011).

  40. 40.

    BrodeauL.. & Koenigk, T. Extinction of the northern oceanic deep convection in an ensemble of climate model simulations of the 20th and 21st centuries. Clim. Dynam. 46, 2863–2882 (2016).

  41. 41.

    Xu, L., Xie, S.-P. & Liu, Q. Mode water ventilation and subtropical countercurrent over the North Pacific in CMIP5 simulations and future projections. J. Geophys. Res. Oceans 117, C12009 (2012).

  42. 42.

    Lazier, J. The renewal of Labrador Sea water. Deep Sea Res. Oceanogr. Abstr. 20, 341–353 (1973).

  43. 43.

    Våge, K. et al. Surprising return of deep convection to the subpolar North Atlantic Ocean in winter 2007–2008. Nat. Geosci. 2, 67–72 (2009).

  44. 44.

    Piron, A., Thierry, V., Mercier, H. & Caniaux, G. Argo float observations of basin-scale deep convection in the Irminger sea during winter 2011–2012. Deep Sea Res. I 109, 76–90 (2016).

  45. 45.

    Sévellec, F., Fedorov, A. V. & Liu, W. Arctic sea-ice decline weakens the Atlantic Meridional Overturning Circulation. Nat. Clim. Change 7, 604–610 (2017).

  46. 46.

    Yang, H. et al. Intensification and poleward shift of subtropical western boundary currents in a warming climate. J. Geophys. Res. Oceans 121, 4928–4945 (2016).

  47. 47.

    Bakker, P. et al. Fate of the Atlantic Meridional Overturning Circulation: Strong decline under continued warming and Greenland melting. Geophys. Res. Lett. 43, 12 (2016).

  48. 48.

    Gillard, L. C., Hu, X., Myers, P. G. & Bamber, J. L. Meltwater pathways from marine terminating glaciers of the Greenland ice sheet. Geophys. Res. Lett. 43, 10 (2016).

  49. 49.

    Exarchou, E., Kuhlbrodt, T., Gregory, J. M. & Smith, R. S. Ocean heat uptake processes: a model intercomparison. J. Clim. 28, 887–908 (2015).

  50. 50.

    Pérez, F. F. et al. Atlantic Ocean CO2 uptake reduced by weakening of the meridional overturning circulation. Nat. Geosci. 6, 146–152 (2013).

  51. 51.

    Winton, M., Griffies, S. M., Samuels, B. L., Sarmiento, J. L. & Frölicher, T. L. Connecting changing ocean circulation with changing climate. J. Clim. 26, 2268–2278 (2013).

  52. 52.

    Hewitt, H. et al. Design and implementation of the infrastructure of HadGEM3: The next-generation Met Office climate modelling system. Geosci. Model Dev. 4, 223–253 (2011).

  53. 53.

    Madec, G. NEMO Ocean Engine, Note du Pôle Modélisation 27 (Institut Pierre-Simon Laplace, 2008).

  54. 54.

    Salas y Mélia, D. A global coupled sea ice–ocean model. Ocean Model. 4, 137–172 (2002).

  55. 55.

    Déqué, M., Dreveton, C., Braun, A. & Cariolle, D. The ARPEGE/IFS atmosphere model: a contribution to the French community climate modelling. Clim. Dyn. 10, 249–266 (1994).

  56. 56.

    Le Sommer, J., Penduff, T., Theetten, S., Madec, G. & Barnier, B. How momentum advection schemes influence current topography interactions at eddy permitting resolution. Ocean Model. 29, 1–14 (2009).

  57. 57.

    Gent, P. R. & McWilliams, J. C. Isopycnal mixing in ocean circulation models. J. Phys. Oceanogr. 20, 150–160 (1990).

  58. 58.

    Blanke, B. & Delecluse, P. Variability of the tropical Atlantic ocean simulated by a general circulation model with two different mixed-layer physics. J. Phys. Oceanogr. 23, 1363–1388 (1993).

  59. 59.

    Danabasoglu, G. et al. North Atlantic simulations in Coordinated Ocean-ice Reference Experiments phase II (CORE-II). Part I: Mean states. Ocean Model. 73, 76–107 (2014).

  60. 60.

    Danabasoglu, G. et al. North Atlantic simulations in Coordinated Ocean-ice Reference Experiments phase II (CORE-II). Part II: Inter-annual to decadal variability. Ocean Model. 97, 65–90 (2016).

  61. 61.

    Ilicak, M. et al. An assessment of the Arctic Ocean in a suite of interannual CORE-II simulations. Part III: Hydrography and fluxes. Ocean Model. 100, 141–161 (2016).

  62. 62.

    Wang, Q. et al. An assessment of the Arctic Ocean in a suite of interannual CORE-II simulations. Part I: Sea ice and solid freshwater. Ocean Model. 99, 110–132 (2016).

  63. 63.

    Wang, Q. et al. An assessment of the Arctic Ocean in a suite of interannual CORE-II simulations. Part II: Liquid freshwater. Ocean Model. 99, 86–109 (2016).

  64. 64.

    Blanke, B. & Raynaud, S. Kinematics of the Pacific Equatorial Undercurrent: an Eulerian and Lagrangian approach from GCM results. J. Phys. Oceanogr. 27, 1038–1053 (1997).

  65. 65.

    Blanke, B., Arhan, M., Speich, S. & Pailler, K. Diagnosing and picturing the North Atlantic segment of the global conveyor belt by means of an ocean general circulation model. J. Phys. Oceanogr. 32, 1430–1451 (2002).

  66. 66.

    Holdsworth, A. M. & Myers, P. G. The influence of high-frequency atmospheric forcing on the circulation and deep convection of the Labrador Sea. J. Clim. 28, 4980–4996 (2015).

  67. 67.

    Van Sebille, E. et al. Lagrangian ocean analysis: Fundamentals and practices. Ocean Model. 121, 49–75 (2018).

  68. 68.

    Valdivieso Da Costa, M. & Blanke, B. Lagrangian methods for flow climatologies and trajectory error assessment. Ocean Model. 6, 335–358 (2004).

Download references


We are deeply grateful to A. Voldoire and R. Séférian (CNRM, Toulouse, France) for making the model outputs from the different simulations available, and providing guidance on their use.

Author information


  1. IFREMER, Univ. Brest, CNRS, IRD, LOPS, Plouzané, France

    • Camille Lique
  2. Department of Geology and Geophysics, Yale University, New Haven, CT, USA

    • Matthew D. Thomas


  1. Search for Camille Lique in:

  2. Search for Matthew D. Thomas in:


C.L. and M.T. designed the study. M.T. performed the Lagrangian analysis. C.L. and M.T. analysed the results. C.L. wrote the manuscript with input from M.T.

Competing interests

The authors declare no competing interests.

Corresponding author

Correspondence to Camille Lique.

Supplementary information

  1. Supplementary Information

    Supplementary figures 1–3, Supplementary references

About this article

Publication history





Further reading