Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Global ocean heat transport dominated by heat export from the tropical Pacific


Heat redistribution is one of the main mechanisms by which oceans regulate Earth’s climate. Analyses of ocean heat transport tend to emphasize global-scale seawater pathways and concepts such as the great ocean conveyor belt. However, it is the divergence or convergence of heat transport within an oceanic region, rather than the origin or destination of seawater transiting through that region, that is most immediately relevant to Earth’s heat budget. Here we use a recent gridded estimate of ocean heat transport to reveal the net effect on Earth’s heat budget, the ‘effective’ ocean heat transport, by removing internal ocean heat loops that have obscured the interpretation of measurements. The result demonstrates the overwhelming predominance of the tropical Pacific, which exports four times as much heat as is imported in the Atlantic and Arctic. It also highlights the unique ability of the Atlantic and Indian oceans to transport heat across the Equator—Northward and Southward, respectively. However, effective inter-ocean heat transports are smaller than expected, suggesting that global-scale seawater pathways play only a minor role in Earth’s heat budget.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: OHT as estimated through sections that separate ocean basins and delimit the tropics for the 1992–2011 time average.
Fig. 2: Meridional effective OHT.
Fig. 3: Scalar potential and vector potential as derived from the global vector field of OHT0 for the 1992–2011 time average.

Code availability

The code used to generate the results in the paper can be accessed from public repositories and permanent archives31,35. Maps shown in this paper and Supplementary Information were created using the M_map toolbox41, available at

Data availability

The data that support the findings of this study are available from the corresponding author upon request and via the Harvard Dataverse They are publicly available and permanently archived33,34.


  1. Stocker, T. F. in Ocean Circulation and Climate (eds Siedler, G. et al.) Ch. 1 (International Geophysics Vol. 103, Academic Press, 2013).

  2. Trenberth, K. E. & Solomon, A. The global heat balance: heat transports in the atmosphere and ocean. Clim. Dyn. 10, 107–134 (1994).

    Article  Google Scholar 

  3. Ganachaud, A. & Wunsch, C. Improved estimates of global ocean circulation, heat transport and mixing from hydrographic data. Nature 408, 453–457 (2000).

    Article  Google Scholar 

  4. Trenberth, K. E. & Caron, J. M. Estimates of meridional atmosphere and ocean heat transports. J. Clim. 14, 3433–3443 (2001).

    Article  Google Scholar 

  5. Macdonald, A. M. & Baringer, M. O. in Ocean Circulation and Climate (eds Gerold Siedler, J. G. et al.) Vol. 103 Ch. 29 (Academic Press, 2013).

  6. Fasullo, J. T. & Trenberth, K. E. The annual cycle of the energy budget. part II: meridional structures and poleward transports. J. Clim. 21, 2313–2325 (2008).

    Article  Google Scholar 

  7. Trenberth, K. E. & Fasullo, J. T. Atlantic meridional heat transports computed from balancing Earth’s energy locally. Geophys. Res. Lett. 44, 1919–1927 (2017).

    Article  Google Scholar 

  8. Tamsitt, V. et al. Spiraling pathways of global deep waters to the surface of the Southern Ocean. Nat. Commun. 8, 172 (2017).

    Article  Google Scholar 

  9. Döös, K. et al. The coupled ocean–atmosphere hydrothermohaline circulation. J. Clim. 30, 631–647 (2017).

    Article  Google Scholar 

  10. Ganachaud, A. & Wunsch, C. Large-scale ocean heat and freshwater transports during the world ocean circulation experiment. J. Clim. 16, 696–705 (2003).

    Article  Google Scholar 

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

    Article  Google Scholar 

  12. Lumpkin, R. & Speer, K. Global ocean meridional overturning. J. Phys. Oceanogr. 37, 2550–2562 (2007).

    Article  Google Scholar 

  13. Talley, L. D. Shallow, intermediate, and deep overturning components of the global heat budget. J. Phys. Oceanogr. 33, 530–560 (2003).

    Article  Google Scholar 

  14. Boccaletti, G., Ferrari, R., Adcroft, A., Ferreira, D. & Marshall, J. The vertical structure of ocean heat transport. Geophys. Res. Lett. 32, L10603 (2005).

    Article  Google Scholar 

  15. Ferrari, R. & Ferreira, D. What processes drive the ocean heat transport? Ocean Model. 38, 171–186 (2011).

    Article  Google Scholar 

  16. Speich, S. et al. Tasman leakage: a new route in the global ocean conveyor belt. Geophys. Res. Lett. 29, 55-1–55-4 (2002).

    Article  Google Scholar 

  17. Hirst, A. C. & Godfrey, J. The role of Indonesian throughflow in a global ocean GCM. J. Phys. Oceanogr. 23, 1057–1086 (1993).

    Article  Google Scholar 

  18. Sun, C. & Watts, D. R. Heat flux carried by the Antarctic Circumpolar Current mean flow. J. Geophys. Res. C 107, 2-1–2-13 (2002).

    Article  Google Scholar 

  19. Tamsitt, V., Talley, L. D., Mazloff, M. R. & Cerovečki, I. Zonal variations in the Southern Ocean heat budget. J. Clim. 29, 6563–6579 (2016).

    Article  Google Scholar 

  20. Godfrey, J. S. A sverdrup model of the depth-integrated flow for the world ocean allowing for island circulations. Geophys. Astrophys. Fluid Dyn. 45, 89–112 (1989).

    Article  Google Scholar 

  21. Song, Q., Vecchi, G. A. & Rosati, A. J. The role of the Indonesian throughflow in the Indo-Pacific climate variability in the GFDL coupled climate model. J. Clim. 20, 2434–2451 (2007).

    Article  Google Scholar 

  22. Corell, H., Nilsson, J., Döös, K. & Broström, G. Wind sensitivity of the inter-ocean heat exchange. Tellus A 61, 635–653 (2009).

    Article  Google Scholar 

  23. Speer, K. & Forget, G. in Ocean Circulation and Climate (eds Siedler, G. et al.) Vol. 103 Ch. 9 (Academic Press, 2013).

  24. Balmaseda, M. et al. The Ocean Reanalyses Intercomparison Project (ORA-IP). J. Oper. Oceanogr. 8, s80–s97 (2015).

    Google Scholar 

  25. Bryan, K. Measurements of meridional heat transport by ocean currents. J. Geophys. Res. 67, 3403–3414 (1962).

    Article  Google Scholar 

  26. Warren, B. A. Approximating the energy transport across oceanic sections. J. Geophys. Res. C 104, 7915–7919 (1999).

    Article  Google Scholar 

  27. Vranes, K., Gordon, A. L. & Ffield, A. The heat transport of the Indonesian throughflow and implications for the indian ocean heat budget. Deep Sea Res. II 49, 1391–1410 (2002).

    Article  Google Scholar 

  28. Watterson, I. G. Decomposition of global ocean currents using a simple iterative method. J. Atmos. Ocean. Technol. 18, 691–703 (2001).

    Article  Google Scholar 

  29. Chen, T.-C. Global water vapor flux and maintenance during FGGE. Mon. Weather Rev. 113, 1801–1819 (1985).

    Article  Google Scholar 

  30. Forget, G. et al. ECCO version 4: an integrated framework for non-linear inverse modeling and global ocean state estimation. Geosci. Model Dev. 8, 3071–3104 (2015).

    Article  Google Scholar 

  31. Forget, G. gcmfaces: A Matlab Toolbox Designed to Handle Gridded Earth Variables Using Compact and Generic Codes (Massachusetts Institute of Technology, 2017);

  32. Forget, G. et al. ECCO Version 4: Second Release (DSpace@MIT, 2019);

  33. Forget, G. ECCO Version 4 Release 2: Monthly 1992–2011 Time Series (Massachusetts Institute of Technology, 2016);

  34. Forget, G. ECCO Version 4 Release 2: Three Daily Tendency Terms for Temperature (Massachusetts Institute of Technology, 2016);

  35. Forget, G. ECCO Version 4: An Ocean State Estimation Framework Based on the MITgcm and its Adjoint (Massachusetts Institute of Technology, 2018);

  36. Davies, J. H. Global map of solid Earth surface heat flow. Geochem. Geophys. Geosyst. 14, 4608–4622 (2013).

    Article  Google Scholar 

  37. Forget, G. & Ponte, R. The partition of regional sea level variability. Prog. Oceanogr. 137, 173–195 (2015).

    Article  Google Scholar 

  38. Forget, G., Ferreira, D. & Liang, X. On the observability of turbulent transport rates by Argo: supporting evidence from an inversion experiment. Ocean Sci. 11, 839–853 (2015).

    Article  Google Scholar 

  39. Large, W. & Yeager, S. The global climatology of an interannually varying air–sea flux data set. Clim. Dyn. 33, 341–364 (2009).

    Article  Google Scholar 

  40. Sverdrup, H. U. in Handbuch der Physik (ed. Bartels, J.) Vol. 48 608–670 (Springer, 1957).

  41. Pawlowicz, R. M_Map: A Mapping Package for MATLAB Version 1.4j (University of British Columbia, 2018).

Download references


J. Chapin is acknowledged for helping proofread the manuscript. G.F. acknowledges support from NASA (6937342) and the Simons Foundation (549931).

Author information

Authors and Affiliations



G.F. performed the analyses and wrote the manuscript. Both authors contributed to the design of the study and interpretation of the results.

Corresponding author

Correspondence to Gaël Forget.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

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

Supplementary information

Supplementary Information

Supplementary figures and tables

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Forget, G., Ferreira, D. Global ocean heat transport dominated by heat export from the tropical Pacific. Nat. Geosci. 12, 351–354 (2019).

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI:

This article is cited by


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing