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A reversal of climatic trends in the North Atlantic since 2005

Abstract

In the mid-1990s the North Atlantic subpolar gyre warmed rapidly1, which had important climate impacts such as increased hurricane numbers2 and changes to rainfall over Africa, Europe and North America3,4. Evidence suggests that the warming was largely due to a strengthening of the ocean circulation, particularly the Atlantic Meridional Overturning Circulation1,5,6,7. Since the mid-1990s direct and indirect measurements have suggested a decline in the strength of the ocean circulation8,9, which is expected to lead to a reduction in northward heat transport10,11. Here we show that since 2005 a large volume of the upper North Atlantic Ocean has cooled significantly by approximately 0.45 °C or 1.5 × 1022 J, reversing the previous warming trend. By analysing observations and a state-of-the-art climate model, we show that this cooling is consistent with a reduction in the strength of the ocean circulation and heat transport, linked to record low densities in the deep Labrador Sea9. The low density in the deep Labrador Sea is primarily due to deep ocean warming since 1995, but a long-term freshening also played a role. The observed upper ocean cooling since 2005 is not consistent with the hypothesis that anthropogenic aerosols directly drive Atlantic temperatures12.

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Figure 1: Recent upper ocean trends in the North Atlantic.
Figure 2: The role of the atmosphere in recent changes in the North Atlantic.
Figure 3: Simulated ocean trends following a reduction in deep Labrador Sea density.

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References

  1. Robson, J., Sutton, R., Lohmann, K., Smith, D. & Palmer, M. Causes of the rapid warming of the North Atlantic Ocean in the mid 1990s. J. Clim. 25, 4116–4134 (2012).

    Article  Google Scholar 

  2. Smith, D. M. et al. Skilful multi-year predictions of Atlantic hurricane frequency. Nature Geosci. 3, 846–849 (2010).

    Article  Google Scholar 

  3. Zhang, R. & Delworth, T. Impact of Atlantic multidecadal oscillations on India/Sahel rainfall and Atlantic hurricanes. Geophys. Res. Lett. 33, L17712 (2006).

    Article  Google Scholar 

  4. Sutton, R. T. & Dong, B. Atlantic Ocean influence on a shift in European climate in the 1990s. Nature Geosci. 5, 788–792 (2012).

    Article  Google Scholar 

  5. Yeager, S., Karspeck, A., Danabasoglu, G., Tribbia, J. & Teng, H. A decadal prediction case study: late twentieth-century North Atlantic Ocean heat content. J. Clim. 25, 5173–5189 (2012).

    Article  Google Scholar 

  6. Robson, J. I., Sutton, R. T. & Smith, D. M. Initialized predictions of the rapid warming of the North Atlantic Ocean in the mid 1990s. Geophys. Res. Lett. 25, L19713 (2012).

    Google Scholar 

  7. Yeager, S. & Danabasoglu, G. The origins of late-twentieth-century variations in the large-scale North Atlantic circulation. J. Clim. 27, 3222–3247 (2014).

    Article  Google Scholar 

  8. Smeed, D. et al. Observed decline of the Atlantic Meridional Overturning Circulation 2004 to 2012. Ocean Sci. Discus. 10, 1619–1645 (2013).

    Article  Google Scholar 

  9. Robson, J., Hodson, D., Hawkins, E. & Sutton, R. Atlantic overturning in decline? Nature Geosci. 7, 2–3 (2014).

    Article  Google Scholar 

  10. Dong, B. & Sutton, R. T. Mechanism of interdecadal thermohaline circulation variability in a coupled ocean-atmosphere GCM. J. Clim. 18, 1117–1135 (2005).

    Article  Google Scholar 

  11. Hermanson, L. et al. Forecast cooling of the Atlantic subpolar gyre and associated impacts. Geophys. Res. Lett. 41, 5167–5174 (2014).

    Article  Google Scholar 

  12. Booth, B., Dunstone, N., Halloran, P., Andrews, T. & Bellouin, N. Aerosols implicated as a prime driver of twentieth-century North Atlantic climate variability. Nature 484, 228–232 (2012).

    Article  Google Scholar 

  13. Hodson, D. L. & Sutton, R. T. The impact of resolution on the adjustment and decadal variability of the Atlantic Meridional Overturning Circulation in a coupled climate model. Clim. Dynam. 39, 3057–3073 (2012).

    Article  Google Scholar 

  14. McCarthy, G. D., Haigh, I. D., Hirschi, J. J.-M., Grist, J. P. & Smeed, D. A. Ocean impact on decadal Atlantic climate variability revealed by sea-level observations. Nature 521, 508–510 (2015).

    Article  Google Scholar 

  15. Clement, A. et al. The Atlantic Multidecadal Oscillation without a role for ocean circulation. Science 350, 320–324 (2015).

    Article  Google Scholar 

  16. Kloewer, M., Latif, M., Ding, H., Greatbatch, R. J. & Park, W. Atlantic Meridional Overturning Circulation and the prediction of North Atlantic sea surface temperature. Earth Planet. Sci. Lett. 406, 1–6 (2014).

    Article  Google Scholar 

  17. Hurrell, J. W. Decadal trends in the North Atlantic Oscillation: regional temperatures and precipitation. Science 269, 676–679 (1995).

    Article  Google Scholar 

  18. Zhang, R. & Vallis, G. The role of bottom vortex stretching on the path of the North Atlantic western boundary current and on the northern recirculation gyre. J. Phys. Oceanogr. 37, 2053–2080 (2007).

    Article  Google Scholar 

  19. Roberts, C. D., Garry, F. K. & Jackson, L. C. A multimodel study of sea surface temperature and subsurface density fingerprints of the Atlantic Meridional Overturning Circulation. J. Clim. 26, 9155–9174 (2013).

    Article  Google Scholar 

  20. Johns, W. et al. Continuous, array-based estimates of Atlantic Ocean heat transport at 26.5° N. J. Clim. 24, 2429–2449 (2011).

    Article  Google Scholar 

  21. Visbeck, M. et al. in The North Atlantic Oscillation: Cinematic Significance and Environmental Impact (eds Hurrell, J. W. et al.) 113–146 (American Geophysical Union, 2003).

    Book  Google Scholar 

  22. Menary, M. B., Hodson, D. L., Robson, J. I., Sutton, R. T. & Wood, R. A. A mechanism of internal decadal Atlantic Ocean variability in a high-resolution coupled climate model. J. Clim. 28, 7764–7785 (2015).

    Article  Google Scholar 

  23. Lozier, M. S., Roussenov, V., Reed, M. S. & Williams, R. G. Opposing decadal changes for the North Atlantic Meridional Overturning Circulation. Nature Geosci. 3, 728–734 (2010).

    Article  Google Scholar 

  24. Hátún, H., Sandø, A. B., Drange, H., Hansen, B. & Valdimarsson, H. Influence of the Atlantic subpolar gyre on the thermohaline circulation. Science 309, 1841–1844 (2005).

    Article  Google Scholar 

  25. Barrier, N., Cassou, C., Deshayes, J. & Treguier, A.-M. Response of North Atlantic Ocean circulation to atmospheric weather regimes. J. Phys. Oceanogr. 44, 179–201 (2014).

    Article  Google Scholar 

  26. Gettelman, A., Shindell, D. & Lamarque, J. Impact of aerosol radiative effects on 2000–2010 surface temperatures. Clim. Dynam. 45, 2165–2179 (2015).

    Article  Google Scholar 

  27. Pinto, J. G. & Raible, C. C. Past and recent changes in the North Atlantic Oscillation. WIREs Clim. Change 3, 79–90 (2012).

    Article  Google Scholar 

  28. Rahmstorf, S. et al. Exceptional twentieth-century slowdown in Atlantic Ocean overturning circulation. Nature Clim. Change 5, 475–480 (2015).

    Article  Google Scholar 

  29. Curry, R. & Mauritzen, C. Dilution of the northern North Atlantic Ocean in recent decades. Science 308, 1772–1774 (2005).

    Article  Google Scholar 

  30. McGregor, S. et al. Recent Walker Circulation strengthening and Pacific cooling amplified by Atlantic warming. Nature Clim. Change 4, 888–892 (2014).

    Article  Google Scholar 

  31. Good, S. A., Martin, M. J. & Rayner, N. A. EN4: Quality controlled ocean temperature and salinity profiles and monthly objective analyses with uncertainty estimates. J. Geophys. Res. 118, 6704–6716 (2013).

    Article  Google Scholar 

  32. Rayner, N. et al. Global analyses of sea surface temperature, sea ice, and night marine air temperature since the late nineteenth century. J. Geophys. Res. 108, 4407 (2003).

    Article  Google Scholar 

  33. Kalnay, E. et al. The NCEP/NCAR 40-year reanalysis project. Bull. Am. Meteorol. Soc. 77, 437–471 (1996).

    Article  Google Scholar 

  34. Josey, S., Gulev, S. & Yu, L. in Ocean Circulation and Climate: A 21st Century Perspective (eds Sidler, G., Griffies, S., Gould, J. & Church, J.) 115–136 (Academic, 2013).

    Book  Google Scholar 

  35. Williams, K. et al. The Met Office Global Coupled model 2.0 (GC2) configuration. Geosci. Model Dev. Discus. 8, 521–565 (2015).

    Article  Google Scholar 

  36. Baehr, J., Hirschi, J., Beismann, J. & Marotzke, J. Monitoring the meridional overturning circulation in the North Atlantic: a model-based array design study. J. Mar. Res. 62, 283–312 (2004).

    Article  Google Scholar 

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Acknowledgements

We thank the UK Met Office, and particularly M. Andrews, for providing the model data used in this study. J.R. was supported by the Seasonal-to-Decadal Climate Prediction for the Improvement of European Climate Service project (SPECS, GA 308378) and J.R. and P.O. were supported by the Dynamics and Predictability of the Atlantic Meridional Overturning and Climate project (DYNAMOC, NE/M005127/1). R.S. was supported by NERC via the National Centre for Atmospheric Science (NCAS), including the ACSIS project.

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J.R. and R.S. jointly conceived the study. J.R. and P.O. analysed the observational and model data. J.R. led the writing of the manuscript with contributions and input from all authors.

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Correspondence to Jon Robson.

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The authors declare no competing financial interests.

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Robson, J., Ortega, P. & Sutton, R. A reversal of climatic trends in the North Atlantic since 2005. Nature Geosci 9, 513–517 (2016). https://doi.org/10.1038/ngeo2727

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